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Effective Date: December 10, 2005
Mandatory Compliance Date: June 10, 2006
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Technical Standards Document
Number 135, Revision 2
Light Vehicle Brake Systems
As defined by section
12 of the Motor Vehicle Safety Act, a Technical Standards Document
(TSD) is a document that reproduces an enactment of a foreign government
(e.g. a Federal Motor Vehicle Safety Standard issued by the U.S. National
Highway Traffic Safety Administration). According to the Act, the Motor
Vehicle Safety Regulations may alter or override some provisions
contained in a TSD or specify additional requirements; consequently, it
is advisable to read a TSD in conjunction with the Act and its counterpart
Regulation. As a guide, where modifications have been made, the corresponding
clause number is indicated in the margin of the TSD within parentheses.
TSDs are revised from time to time in order to incorporate amendments
made to the reference document, at which time a Notice of Revision is
published in the Canada Gazette Part I. All TSDs are assigned
a revision number, with "Revision 0" designating the original version
Identification of Changes
In order to facilitate the incorporation of a TSD, certain non-technical
changes may be made to the foreign enactment. These may include the deletion
of words, phrases, figures, or sections that do not apply under the Act
or Regulations, the conversion of imperial to metric units, the deletion
of superseded dates, and minor changes of an editorial nature. Additions
are underlined, and provisions that do not apply are stroked
through. Where an entire section has been deleted, it is replaced
by: "[CONTENT DELETED]". Changes are also made where there is
a reporting requirement or reference in the foreign enactment that does
not apply in Canada. For example, the name and address of the U.S. Department
of Transportation are replaced by those of the Department of Transport.
Effective Dates
The original version of a TSD comes into effect on the date that
the regulation in which it is first incorporated by reference is published
in the Canada Gazette Part II. Subsequent revisions of a TSD come
into effect on the date of publication of the Notice of Revision in the
Canada Gazette Part I. The Effective Date is that of the publication
of the final amendment or the notice of revision in the Canada Gazette.
Compliance with the requirements of a newly issued TSD is not mandatory
until six months following the effective date, during which time it is
permissible to continue to comply with the requirements of the previous
Regulation or TSD. Manufacturers and importers must comply with the requirements
of a newly issued TSD as of the Mandatory Compliance Date.
Official Version of Technical Standards Documents
Technical Standards Documents may be consulted electronically in both
HTML and Portable Document Format (PDF) on the Department of Transports
Web site at www.tc.gc.ca/RoadSafety/mvstm_tsd/index_e.htm.
The PDF version is a replica of the TSD as published by the Department
and is to be used for the purposes of legal interpretation and application.
The HTML version is provided for information purposes only.
(Original signed by)
Director, Motor Vehicle Standards and Research
for the Minister of Transport,
Ottawa, Ontario
Technical Standards Document
Number 135, Revision 2
LIGHT VEHICLE BRAKE SYSTEMS
(Ce
document est aussi disponible en français.)
The text of this document is based on the U.S. Code of Federal
Regulations (CFR), Title 49, Part 571, Federal Motor Vehicle Safety
Standard No. 135, Light Vehicle Brake Systems, revised as of October
1, 2004, and the Final Rule published in the Federal Register
on June 30, 2005 (Vol. 70, No. 125, p. 37706).
This Technical Standards Document (TSD) standard
specifies requirements for service brake and associated parking brake
systems.
The purpose of this TSD standard is to ensure
safe braking performance under normal and emergency driving conditions.
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[CONTENT DELETED] For applicability, see section
135 of Schedule IV to the Motor Vehicle Safety Regulations.
Adhesion utilization curves means curves showing, for specified
load conditions, the adhesion utilized by each axle of a vehicle plotted
against the braking ratio of the vehicle. (diagrammes d'adhérence)
* Antilock brake system or ABS
means a portion of a service brake system that automatically controls
the degree of rotational wheel slip during braking by:
(1) sensing the rate of angular rotation of the wheels;
(2) transmitting signals regarding the rate of wheel angular rotation
to one or more controlling devices which interpret those signals and generate
responsive controlling output signals; and
(3) transmitting those controlling signals to one or more modulator
devices which adjust brake actuating forces in response to those signals.
(dispositif de frein anti-blocage ou ABS)
* Backup system means
a portion of a service brake system, such as a pump, that automatically
supplies energy in the event of a primary brake power source failure.
(système de secours)
Brake factor means the slope of the linear least squares regression
equation best representing the measured torque output of a brake as a
function of the measured applied line pressure during a given brake application
for which no wheel lockup occurs. (coefficient de freinage)
Brake hold-off pressure means the maximum applied line pressure
for which no brake torque is developed, as predicted by the pressure axis
intercept of the linear least squares regression equation best representing
the measured torque output of a brake as a function of the measured applied
line pressure during a given brake application. (pression de repos
des freins)
* Brake power assist unit means
a device installed in a hydraulic brake system that reduces the amount
of muscular force that a driver must apply to actuate the system, and
that, if inoperative, does not prevent the driver from braking the vehicle
by a continued application of muscular force on the service brake control.
(unité d'assistance de frein)
* Brake power unit means
a device installed in a brake system that provides the energy required
to actuate the brakes, either directly or indirectly through an auxiliary
device, with driver action consisting only of modulating the energy application
level. (unité de servo-frein)
Braking ratio means the deceleration of the vehicle divided by
the gravitational acceleration constant. (taux de freinage)
Electric vehicle or EV means a motor vehicle that is powered
by an electric motor drawing current from rechargeable storage batteries,
fuel cells, or other portable sources of electrical current, and which
may include a non-electrical source of power designed to charge the batteries
and components thereof. (véhicule électrique ou EV)
Electrically-actuated service brakes means service brakes that
utilize electrical energy to actuate the foundation brakes. (freins
de service électriques)
Functional failure means a failure of a component (either electrical
or mechanical in nature) which renders the system totally or partially
inoperative yet the structural integrity of the system is maintained.
(défaillance de fonctionnement)
* Hydraulic brake system means
a system that uses hydraulic fluid as a medium for transmitting force
from a service brake control to the service brake and that may incorporate
a brake power assist unit or a brake power unit. (système
de freinage hydraulique)
Initial brake temperature or IBT means
the average temperature of the service brakes on the hottest axle of the
vehicle 0.32 km (0.2 mi.) before any brake application. (température
initiale des freins)
Lightly loaded vehicle mass weight or
LLVM LLVW means unloaded vehicle weight
plus the weight of a mass of 180 kg (396 lb.), including driver
and instrumentation. (masse du véhicule avec charge légère)
Maximum speed of a vehicle or Vmax means the
highest speed attainable by accelerating at a maximum rate from a standing
start for a distance of 3.2 km (2 mi.) on a level surface, with the vehicle
at its lightly loaded vehicle mass weight, and,
if an EV, with the propulsion batteries at a state of charge of not less
than 95 percent at the beginning of the run. (vitesse maximale dun
véhicule ou Vmax)
Objective brake factor means the arithmetic average of all the
brake factors measured over the twenty brake applications defined in S7.4,
for all wheel positions having a given brake configuration. (coefficient
de freinage objectif)
Peak friction coefficient or PFC means the ratio of the
maximum value of braking test wheel longitudinal force to the simultaneous
vertical force occurring prior to wheel lockup, as the braking torque
is progressively increased. (coefficient maximal de friction)
Pressure component means a brake system component that contains
the brake system fluid and controls or senses the fluid pressure. (élément
sous pression)
Regenerative braking system or RBS means an electrical
energy system that is installed in an EV for recovering or dissipating
kinetic energy, and which uses the propulsion motor(s) as a retarder for
partial braking of the EV while returning electrical energy to the propulsion
battery(s) or dissipating electrical energy. (système de freinage à
récupération ou RBS)
* Snub means the braking
deceleration of a vehicle from a higher reference speed to a lower reference
speed that is greater than zero. (ralentissement)
* Split service brake system
means a brake system consisting of two or more subsystems actuated
by a single control designed so that a leakage-type failure of a pressure
component in a single subsystem (except structural failure of a housing
that is common to two or more subsystems) does not impair the operation
of any other subsystem. (système de frein de service partagé)
* Stopping distance means
the distance traveled by a vehicle from the point of application of force
to the brake control to the point at which the vehicle reaches a full
stop. (distance d'arrêt)
* Variable brake proportioning system
means a system that has one or more proportioning devices which
automatically change the brake pressure ratio between any two or more
wheels to compensate for changes in wheel loading due to static load changes
and/or dynamic weight transfer, or due to deceleration. (compensateur
de freinage)
Wheel lockup means 100 percent wheel slip. (blocage des roues)
Each vehicle shall be equipped with a service brake system acting on
all wheels.
S5.1.1 Wear adjustment. Wear of the service brakes shall be compensated
for by means of a system of automatic adjustment.
S5.1.2 Wear status. The wear condition of all service brakes shall
be indicated by either:
(a) Acoustic or optical devices warning the driver at his or her driving
position when lining replacement is necessary, or
(b) A means of visually checking the degree of brake lining wear, from
the outside or underside of the vehicle, utilizing only the tools or
equipment normally supplied with the vehicle. The removal of wheels
is permitted for this purpose.
S5.1.3 Regenerative braking system
(a) For an EV equipped with RBS, the RBS is considered to be part
of the service brake system if it is automatically activated by an application
of the service brake control, if there is no means provided for the driver
to disconnect or otherwise deactivate it, and if it is activated in all
transmission positions, including neutral.
(b) For an EV that is equipped with both ABS and RBS that is part of
the service brake system, the ABS must control the RBS.
Each vehicle shall be equipped with a parking brake system of a friction
type with solely mechanical means to retain engagement.
S5.3.1 The service brakes shall be activated by means of a foot
control. The control of the parking brake shall be independent of the
service brake control, and may be either a hand or foot control.
S5.3.2 For vehicles equipped with ABS, a control to manually disable
the ABS, either fully or partially, is prohibited.
S5.4.1 Master cylinder reservoirs. A master cylinder shall have
a reservoir compartment for each service brake subsystem serviced by the
master cylinder. Loss of fluid from one compartment shall not result in
a complete loss of brake fluid from another compartment.
S5.4.2 Reservoir capacity. Reservoirs, whether for master cylinders
or other type systems, shall have a total minimum capacity equivalent
to the fluid displacement resulting when all the wheel cylinders or caliper
pistons serviced by the reservoirs move from a new lining, fully retracted
position (as adjusted initially to the manufacturer's recommended setting)
to a fully worn, fully applied position, as determined in accordance with
S7.17(c) of this TSD standard. Reservoirs shall
have completely separate compartments for each subsystem except that,
in reservoir systems utilizing a portion of the reservoir for a common
supply to two or more subsystems, individual partial compartments shall
each have a minimum volume of fluid equal to at least the volume displaced
by the master cylinder piston servicing the subsystem, during a full stroke
of the piston. Each brake power unit reservoir servicing only the brake
system shall have a minimum capacity equivalent to the fluid displacement
required to charge the system piston(s) or accumulator(s) to normal operating
pressure plus the displacement resulting when all the wheel cylinders
or caliper pistons serviced by the reservoir or accumulator(s) move from
a new lining, fully retracted position (as adjusted initially to the manufacturer's
recommended setting) to a fully worn, fully applied position.
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S5.4.3 Reservoir labeling. Each vehicle equipped with hydraulic brakes
shall have a brake fluid warning statement that reads as follows, in letters
at least 3.2 mm (1/8 in.) high: "WARNING: Clean filler cap before removing.
Use only ____ fluid from a sealed container." (Inserting the recommended
type of brake fluid as specified in 49 CFR 571.116, e.g., "DOT 3.")
The lettering shall be:
(a) permanently affixed, engraved or embossed;
(b) located so as to be visible by direct view, either on or within
100 mm (3.94 in.) of the brake fluid reservoir filler plug or cap; and
(c) of a color that contrasts with its background, if it is not engraved
or embossed.
S5.4.4 Fluid level indication. Brake fluid reservoirs shall be
so constructed that the level of fluid can be checked without need for
the reservoir to be opened. This requirement is deemed to have been met
if the vehicle is equipped with a transparent brake fluid reservoir or
a brake fluid level indicator meeting the requirements of S5.5.1(a)(1).
Each vehicle shall have one or more visual brake system warning indicators,
mounted in front of and in clear view of the driver, which meet the requirements
of S5.5.1 through S5.5.5. In addition, a vehicle manufactured without
a split service brake system shall be equipped with an audible warning
signal that activates under the conditions specified in S5.5.1(a).
S5.5.1 Activation. An indicator shall be activated when the ignition
("start") switch is in the "on" ("run")
position and whenever any of conditions (a) through (g) occurs:
(a) A gross loss of fluid or fluid pressure (such as caused by rupture
of a brake line but not by a structural failure of a housing that is
common to two or more subsystems) as indicated by one of the following
conditions (chosen at the option of the manufacturer):
(1) A drop in the level of the brake fluid in any master cylinder
reservoir compartment to less than the recommended safe level specified
by the manufacturer or to one-fourth of the fluid capacity of that
reservoir compartment, whichever is greater.
(2) For vehicles equipped with a split service brake system, a differential
pressure of 1.5 MPa (218 psi) between the intact and failed brake
subsystems measured at a master cylinder outlet or a slave cylinder
outlet.
(3) A drop in the supply pressure in a brake power unit to one-half
of the normal system pressure.
(b) Any electrical functional failure in an antilock or variable brake
proportioning system.
(c) Application of the parking brake.
(d) Brake lining wear-out, if the manufacturer has elected to use an
electrical device to provide an optical warning to meet the requirements
of S5.1.2(a).
(e) For a vehicle with electrically-actuated service brakes, failure
of the source of electric power to those brakes, or diminution of the
state of charge of the batteries to less than a level specified by the
manufacturer for the purpose of warning a driver of degraded brake performance.
(f) For a vehicle with electric transmission of the service brake control
signal, failure of a brake control circuit.
(g) For an EV with a regenerative braking system that is part of the
service brake system, failure of the RBS.
S5.5.2 Function check
(a) All indicators shall be activated as a check function by either:
(1) Automatic activation when the ignition ("start") switch
is turned to the "on" ("run") position when the engine
is not running, or when the ignition ("start") switch is in
a position between "on" ("run") and "start"
that is designated by the manufacturer as a check position, or
(2) A single manual action by the driver, such as momentary activation
of a test button or switch mounted on the instrument panel in front
of and in clear view of the driver, or, in the case of an indicator
for application of the parking brake, by applying the parking brake
when the ignition is in the "on" ("run") position.
(b) In the case of a vehicle that has an interlock device that prevents
the engine from being started under one or more conditions, check functions
meeting the requirements of S5.5.2(a) need not be operational under
any condition in which the engine cannot be started.
(c) The manufacturer shall explain the brake check function test procedure
in the owner's manual.
S5.5.3 Duration. Each indicator activated due to a condition specified
in S5.5.1 shall remain activated as long as the condition exists, whenever
the ignition ("start") switch is in the "on" ("run")
position, whether or not the engine is running.
S5.5.4 Function. When a visual warning indicator is activated,
it may be continuous or flashing, except that the visual warning indicator
on a vehicle not equipped with a split service brake system shall be flashing.
The audible warning required for a vehicle manufactured without a split
service brake system may be continuous or intermittent.
S5.5.5 Labeling
(a) Each visual indicator shall display a word or words in accordance
with the requirements of section 101 of the Motor Vehicle Safety
Regulations Standard No. 101 (49 CFR 571.101) and this
section, which shall be legible to the driver under all daytime and nighttime
conditions when activated. Unless otherwise specified, the words shall
have letters not less than 3.2 mm (1/8 in.) high and the letters and background
shall be of contrasting colors, one of which is red. Words or symbols,
in addition to those required by section 101 Standard No. 101
and this section, may be provided for purposes of clarity.
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(b) Vehicles manufactured with a split service brake system may use
a common brake warning indicator to indicate two or more of the functions
described in S5.5.1(a) through S5.5.1(g). If a common indicator
is used, it shall display the word "Brake".
(c) A vehicle manufactured without a split service brake system shall
use a separate indicator to indicate the failure condition in S5.5.1(a).
This indicator shall display the words "STOP - BRAKE FAILURE"
in block capital letters not less than 6.4 mm (1/4 in.) in height.
(d) If separate indicators are used for one or more than one of the
functions described in S5.5.1(a) through S5.5.1(g), the indicators shall
display the following wording:
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(1) If a separate indicator is provided for the low brake fluid condition
in S5.5.1(a)(1), the words "Brake Fluid" shall be used except
for vehicles using hydraulic system mineral oil.
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(2) If a separate indicator is provided for the gross loss of pressure
condition in S5.5.1(a)(2), the words "Brake Pressure" shall
be used.
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(3) If a separate indicator is provided for the condition specified in
S5.5.1(b), the letters and background shall be of contrasting colors,
one of which is yellow. The indicator shall be labeled with the words
"Antilock" or "Anti-lock" or "ABS"; or "Brake
Proportioning," in accordance with Table 2 of section 101
Standard No. 101.
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(4) If a separate indicator is provided for application of the parking
brake as specified for S5.5.1(c), the single word "Park"
or the words "Parking Brake" may be used.
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(5) If a separate indicator is provided to indicate brake lining
wear-out as specified in S5.5.1(d), the words "Brake Wear"
shall be used.
(6) If a separate indicator is provided for the condition specified in
S5.5.1(g), the letters and background shall be of contrasting colors,
one of which is yellow. The indicator shall be labeled with the symbol
"RBS". RBS failure in a system that is part of the service brake
system may also be indicated by a yellow lamp that also indicates "ABS"
failure and displays the symbol "ABS/RBS."
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(7) If a separate indicator is provided for any other function, the display
shall include the word "Brake" and the appropriate additional
labeling.
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Each vehicle shall meet the complete performance requirements of this
TSD standard without:
(a) Detachment or fracture of any component of the braking system,
such as brake springs and brake shoes or disc pad facings, other than
minor cracks that do not impair attachment of the friction facings.
All mechanical components of the braking system shall be intact and
functional. Friction facing tearout (complete detachment of lining)
shall not exceed 10 percent of the lining on any single frictional
element.
(b) Any visible brake fluid or lubricant on the friction surface of
the brake, or leakage at the master cylinder or brake power unit reservoir
cover, seal, and filler openings.
Each vehicle must meet the performance requirements specified in S7 under
the following test conditions and in accordance with the test procedures
and test sequence specified. Where a range of conditions is specified,
the vehicle must meet the requirements at all points within the range.
S6.1.1 Ambient temperature. The ambient temperature is any
temperature between 0°C (32°F) and 40°C (104°F).
S6.1.2 Wind speed. The wind speed is not greater than 5 m/s (11.2
mph).
S6.2.1 Pavement friction. Unless otherwise specified, the
road test surface produces a peak friction coefficient (PFC) of 0.9 when
measured using an American Society for Testing and Materials (ASTM) E1136
standard reference test tire, in accordance with ASTM Method E 1337-90,
at a speed of 64.4 km/h (40 mph), without water delivery.
S6.2.2 Gradient. Except for the parking brake gradient holding
test, the test surface has no more than a 1% gradient in the direction
of testing and no more than a 2% gradient perpendicular to the direction
of testing.
S6.2.3 Lane width. Road tests are conducted on a test lane 3.5
m (11.5 ft.) wide.
S6.3.1 Vehicle mass weight
S6.3.1.1 For the tests at GVWR, the vehicle is loaded to
its GVWR such that the weight on each axle as measured at the tire-ground
interface is in proportion to its GAWR, with the fuel tank filled to 100%
of capacity. However, if the weight on any axle of a vehicle at LLVM
LLVW exceeds the axle’s proportional share of the GVWR, the
load required to reach GVWR is placed so that the weight on that axle
remains the same as at LLVM LLVW.
S6.3.1.2 For the test at LLVM LLVW, the vehicle
is loaded to its LLVM LLVW such that the added mass
weight is distributed in the front passenger seat area.
S6.3.2 Fuel tank loading. The fuel tank is filled to 100% of capacity
at the beginning of testing and may not be less than 75% of capacity during
any part of the testing.
S6.3.3 Lining preparation. At the beginning of preparation for
the road tests, the brakes of the vehicle are in the same condition as
when the vehicle was manufactured. No burnishing or other special preparation
is allowed, unless all vehicles sold to the public are similarly prepared
as a part of the manufacturing process.
S6.3.4 Adjustments and repairs. These requirements must be met
without replacing any brake system parts or making any adjustments to
the brake system except as specified in this TSD standard.
Where brake adjustments are specified (S7.1.3), adjust the brakes, including
the parking brakes, in accordance with the manufacturer's recommendation.
No brake adjustments are allowed during or between subsequent tests in
the test sequence.
S6.3.5 Automatic brake adjusters. Automatic adjusters are operational
throughout the entire test sequence. They may be adjusted either manually
or by other means, as recommended by the manufacturer, only prior to the
beginning of the road test sequence.
S6.3.6 Antilock brake system (ABS). If a car is equipped with
an ABS, the ABS is fully operational for all tests, except where specified
in the following sections.
S6.3.7 Variable brake proportioning valve. If a car is equipped
with a variable brake proportioning system, the proportioning valve is
fully operational for all tests except the test for failed variable brake
proportioning system.
S6.3.8 Tire inflation pressure. Tires are inflated to the pressure
recommended by the vehicle manufacturer for the GVWR of the vehicle.
S6.3.9 Engine. Engine idle speed and ignition timing are set according
to the manufacturer's recommendations. If the vehicle is equipped with
an adjustable engine speed governor, it is adjusted according to the manufacturer's
recommendations.
S6.3.10 Vehicle openings. All vehicle openings (doors, windows,
hood, trunk, convertible top, cargo doors, etc.) are closed except as
required for instrumentation purposes.
S6.3.11 State of charge of batteries for EVs
S6.3.11.1 The state of charge of the propulsion batteries is determined
in accordance with SAE Recommended Practice J227a, Electric Vehicle
Test Procedure, February 1976. The applicable sections of J227a are
3.2.1 through 3.2.4, 3.3.1 through 3.3.2.2, 3.4.1 and 3.4.2, 4.2.1, 5.2,
5.2.1, and 5.3.
S6.3.11.2 At the beginning of the burnish procedure (S7.1 of this
TSD standard) in the test sequence, each propulsion battery
is at the maximum state of charge recommended by the manufacturer, as
stated in the vehicle operator's manual or on a label that is permanently
attached to the vehicle, or, if the manufacturer has made no recommendation,
not less than 95 percent. During the 200-stop burnish procedure, the propulsion
batteries are restored to the maximum state of charge determined as above,
after each increment of 40 burnish stops until the burnish procedure is
complete. The batteries may be charged at a more frequent interval during
a particular 40-stop increment only if the EV is incapable of achieving
the initial burnish test speed during that increment. During the burnish
procedure, the propulsion batteries may be charged by external means or
replaced by batteries that are at a state of charge of not less than 95
percent. For an EV having a manual control for setting the level of regenerative
braking, the manual control, at the beginning of the burnish procedure,
is set to provide maximum regenerative braking throughout the burnish.
S6.3.11.3 At the beginning of each performance test in the test
sequence (S7.2 through S7.17 of this TSD standard), unless
otherwise specified, an EV's propulsion batteries are at the state of
charge recommended by the manufacturer, as stated in the vehicle operator's
manual or on a label that is permanently attached to the vehicle, or,
if the manufacturer has made no recommendation, at a state of charge of
not less than 95 percent. No further charging of any propulsion battery
occurs during any of the performance tests in the test sequence of this
TSD standard. If the propulsion batteries are depleted during
a test sequence such that the vehicle reaches automatic shut-down, will
not accelerate, or the low state of charge brake warning lamp is illuminated,
the vehicle is to be accelerated to brake test speed by auxiliary means.
If a battery is replaced rather than recharged, the replacement battery
shall be charged and measured for state of charge in accordance with these
procedures.
S6.3.12 State of charge of batteries for electrically-actuated
service brakes. A vehicle equipped with electrically-actuated
service brakes also performs the following test series. Conduct 10 stopping
tests from a speed of 100 km/h (62.1 mph) or the maximum vehicle speed,
whichever is less. At least two of the 10 stopping distances must be less
than or equal to 70 meters (230 ft.). The vehicle is loaded to GVWR and
the transmission is in the neutral position when the service brake control
is actuated and throughout the remainder of the test. Each battery providing
power to the electrically-actuated service brakes shall be in a depleted
state of charge for conditions (a), (b), or (c) of this paragraph as appropriate.
An auxiliary means may be used to accelerate an EV to test speed.
(a) For an EV equipped with electrically-actuated service brakes deriving
power from the propulsion batteries and with automatic shut-down capability
of the propulsion motor(s), the propulsion batteries are at not more than
five percent above the EV actual automatic shut-down critical value. The
critical value is determined by measuring the state of charge of each
propulsion battery at the instant that automatic shut-down occurs.
(b) For an EV equipped with electrically-actuated service brakes deriving
power from the propulsion batteries and with no automatic shut-down capability
of the propulsion motor(s), the propulsion batteries are at an average
of not more than five percent above the actual state of charge at which
the brake failure warning signal, required by S5.5.1(e) of this TSD
standard, is illuminated.
(c) For a vehicle which has one or more auxiliary batteries that provides
electrical energy to operate the electrically-actuated service brakes,
each auxiliary battery is at not more than five percent above the actual
state of charge at which the brake failure warning signal, required by
S5.5.1(e) of this TSD standard, is illuminated.
S6.3.13 Electric vehicles
S6.3.13.1
(a) For an EV equipped with an RBS that is part of the service brake
system, the RBS is operational during the burnish and all tests, except
for the test of a failed RBS.
(b) For an EV equipped with an RBS that is not part of the service
brake system, the RBS is operational and set to produce the maximum
regenerative braking effect during the burnish, and is disabled during
the test procedures. If the vehicle is equipped with a neutral gear
that automatically disables the RBS, the test procedures which are designated
to be conducted in gear may be conducted in neutral.
S6.3.13.2 For tests conducted "in neutral", the operator
of an EV with no "neutral" position (or other means such as
a clutch for disconnecting the drive train from the propulsion motor[s])
does not apply any electromotive force to the propulsion motor(s). Any
electromotive force that is applied to the propulsion motor(s) automatically
remains in effect unless otherwise specified by the test procedure.
S6.4.1 Brake temperature measurement. The brake temperature is
measured by plug-type thermocouples installed in the approximate center
of the facing length and width of the most heavily loaded shoe or disc
pad, one per brake, as shown in Figure 1. A second thermocouple may be
installed at the beginning of the test sequence if the lining wear is
expected to reach a point causing the first thermocouple to contact the
metal rubbing surface of a drum or rotor. For center-grooved shoes or
pads, thermocouples are installed within 3 mm (0.12 in.) to 6 mm
(0.24 in.) of the groove and as close to the center as possible.
S6.4.2 Brake line pressure measurement for the torque wheel test.
The vehicle shall be fitted with pressure transducers in each hydraulic
circuit. On hydraulically proportioned circuits, the pressure transducer
shall be downstream of the operative proportioning valve.
S6.4.3 Brake torque measurement for the torque wheel test. The
vehicle shall be fitted with torque wheels at each wheel position, including
slip ring assemblies and wheel speed indicators to permit wheel lock to
be detected.
|
Note: The second thermocouple shall be installed at 2.03 mm (0.080 in.)
depth within 25.4 mm (1 in.) circumferentially of the thermocouple
installed
at 1.02 mm (0.040 in.) depth.
Figure 1 — Typical Plug-Type Thermocouple Installations
|
S6.5.1 Brake control. All service brake system performance requirements,
including the partial system requirements of S7.7, S7.10 and S7.11, must
be met solely by use of the service brake control.
S6.5.2 Test speeds. If a vehicle is incapable of attaining the
specified normal test speed, it is tested at a speed that is a multiple
of 5 km/h (3.1 mph) that is 4 to 8 km/h (2.5 to 5.0 mph) less than its
maximum speed, and its performance must be within a stopping distance
given by the formula provided for the specific requirement.
S6.5.3 Stopping distance
S6.5.3.1 The braking performance of a vehicle is determined by
measuring the stopping distance from a given initial speed.
S6.5.3.2 Unless otherwise specified, the vehicle is stopped in
the shortest distance achievable (best effort) on all stops. Where more
than one stop is required for a given set of test conditions, a vehicle
is deemed to comply with the corresponding stopping distance requirements
if at least one of the stops is made within the prescribed distance.
S6.5.3.3 In the stopping distance formulas given for each applicable
test (such as S £ 0.10V + 0.0060V2),
S is the maximum stopping distance in meters, and V is the test speed
in km/h.
S6.5.4 Vehicle position and attitude
S6.5.4.1 The vehicle is aligned in the center of the lane at the
start of each brake application. Steering corrections are permitted during
each stop.
S6.5.4.2 Stops are made without any part of the vehicle leaving
the lane and without rotation of the vehicle about its vertical axis of
more than ± 15° from the center line of the test lane at any
time during any stop.
S6.5.5 Transmission selector control
S6.5.5.1 For tests in neutral, a stop or snub is made in accordance
with the following procedures:
(a) Exceed the test speed by 6 to 12 km/h (3.7 to 7.5 mph);
(b) Close the throttle and coast in gear to approximately 3 km/h (1.9
mph) above the test speed;
(c) Shift to neutral; and
(d) When the test speed is reached, apply the brakes.
S6.5.5.2 For tests in gear, a stop or snub is made in accordance
with the following procedures:
(a) With the transmission selector in the control position recommended
by the manufacturer for driving on a level surface at the applicable test
speed, exceed the test speed by 6 to 12 km/h (3.7 to 7.5 mph);
(b) Close the throttle and coast in gear; and
(c) When the test speed is reached apply the brakes.
(d) To avoid engine stall, a manual transmission may be shifted to
neutral (or the clutch disengaged) when the vehicle speed is below 30
km/h (18.6 mph).
S6.5.6 Initial brake temperature (IBT). If the lower limit of
the specified IBT for the first stop in a test sequence (other than a
parking brake grade holding test) has not been reached, the brakes are
heated to the IBT by making one or more brake applications from a speed
of 50 km/h (31.1 mph), at a deceleration rate not greater than 3 m/s2
(9.8 fps2).
Each vehicle shall meet all the applicable requirements of this section,
when tested according to the conditions and procedures set forth below
and in S6., in the sequence specified in Table 1:
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Table 1 — Road Test Schedule
Testing order
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Section No.
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Vehicle loaded to GVWR:
1 Burnish ..................................
2 Wheel lock sequence .............
Vehicle loaded to LLVM LLVW:
3 Wheel lock sequence .............
4 ABS performance ..................
5 Torque wheel .........................
Vehicle loaded to GVWR:
6 Torque wheel .........................
7 Cold effectiveness ..................
8 High speed effectiveness .........
9 Stops with engine off ...............
Vehicle loaded to LLVM LLVW:
10 Cold effectiveness ................
11 High speed effectiveness ......
12 Failed antilock .....................
13 Failed proportioning valve ....
14 Hydraulic circuit failure .........
Vehicle loaded to GVWR:
15 Hydraulic circuit failure .........
16 Failed antilock .....................
17 Failed proportioning valve ....
18 Power brake unit failure .......
19 Parking brake ......................
20 Heating snubs ......................
21 Hot performance ..................
22 Brake cooling .......................
23 Recovery performance .........
24 Final inspection .....................
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S7.1
S7.2
S7.2
S7.3
S7.4
S7.4
S7.5
S7.6
S7.7
S7.5
S7.6
S7.8
S7.9
S7.10
S7.10
S7.8
S7.9
S7.11
S7.12
S7.13
S7.14
S7.15
S7.16
S7.17
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S7.1.1 General information. Any pretest instrumentation checks
are conducted as part of the burnish procedure, including any necessary
rechecks after instrumentation repair, replacement or adjustment. Instrumentation
check test conditions must be in accordance with the burnish test procedure
specified in S7.1.2 and S7.1.3.
S7.1.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In gear.
S7.1.3 Test conditions and procedures. The road test surface conditions
specified in S6.2 do not apply to the burnish procedure.
(a) IBT: £ 100°C (212°F).
(b) Test speed: 80 km/h (49.7 mph).
(c) Pedal force: Adjust as necessary to maintain specified constant deceleration
rate.
(d) Deceleration rate: Maintain a constant deceleration rate of 3.0 m/s2
(9.8 fps2).
(e) Wheel lockup: No lockup of any wheel allowed for longer than 0.1
second at speeds greater than 15 km/h (9.3 mph).
(f) Number of runs: 200 stops.
(g) Interval between runs: The interval from the start of one service
brake application to the start of the next is either the time necessary
to reduce the IBT to 100°C (212°F) or less, or the distance of 2 km (1.24
mi.), whichever occurs first.
(h) Accelerate to 80 km/h (49.7 mph) after each stop and maintain that
speed until making the next stop.
(i) After burnishing, adjust the brakes as specified in S6.3.4.
S7.2.1 General information
(a) The purpose of this test is to ensure that lockup of both front
wheels occurs either simultaneously with, or at a lower deceleration
rate than, the lockup of both rear wheels, when tested on road surfaces
affording adhesion such that wheel lockup of the first axle occurs at
a braking ratio of between 0.15 and 0.80, inclusive.
(b) This test is for vehicles without antilock brake systems.
(c) This wheel lock sequence test is to be used as a screening test
to evaluate a vehicle's axle lockup sequence and to determine whether
the torque wheel test in S7.4 must be conducted.
(d) For this test, a simultaneous lockup of the front and rear wheels
refers to the conditions when the time interval between the first occurrence
of lockup of the last (second) wheel on the rear axle and the first
occurrence of lockup of the last (second) wheel on the front axle is
£ 0.1 second for vehicle speeds > 15 km/h
(9.3 mph).
(e) A front or rear axle lockup is defined as the point in time when
the last (second) wheel on an axle locks up.
(f) Vehicles that lock their front axle simultaneously or at lower
deceleration rates than their rear axle need not be tested to the torque
wheel procedure.
(g) Vehicles which lock their rear axle at deceleration rates lower
than the front axle shall also be tested in accordance with the torque
wheel procedure in S7.4.
(h) Any determination of noncompliance for failing adhesion utilization
requirements shall be based on torque wheel test results.
S7.2.2 Vehicle conditions
(a) Vehicle load: GVWR and LLVM LLVW.
(b) Transmission position: In neutral.
S7.2.3 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C
(212°F).
(b) Test speed: 65 km/h (40.4 mph) for a braking ratio £
0.50; 100 km/h (62.1 mph) for a braking ratio > 0.50.
(c) Pedal force:
(1) Pedal force is applied and controlled by the vehicle driver or by
a mechanical brake pedal actuator.
(2) Pedal force is increased at a linear rate such that the first axle
lockup occurs no less than one-half (0.5) second and no more than one
and one-half (1.5) seconds after the initial application of the pedal.
(3) The pedal is released when the second axle locks, or when the pedal
force reaches 1 kN (225 lb.), or 0.1 second after first axle lockup,
whichever occurs first.
(d) Wheel lockup: Only wheel lockups above a vehicle speed of 15 km/h
(9.3 mph) are considered in determining the results of this test.
(e) Test surfaces: This test is conducted, for each loading condition,
on two different test surfaces that will result in a braking ratio of
between 0.15 and 0.80, inclusive. NHTSA reserves the right to
choose the test surfaces to be used based on adhesion utilization curves
or any other method of determining "worst case" conditions.
(f) The data recording equipment shall have a minimum sampling rate of
40 Hz.
(g) Data to be recorded: The following information must be automatically
recorded in phase continuously throughout each test run such that values
of the variables can be cross-referenced in real time.
(1) Vehicle speed.
(2) Brake pedal force.
(3) Angular velocity at each wheel.
(4) Actual instantaneous vehicle deceleration or the deceleration calculated
by differentiation of the vehicle speed.
(h) Speed channel filtration: For analog instrumentation, the speed channel
shall be filtered by using a low-pass filter having a cut-off frequency
of less than one-fourth the sampling rate.
(i) Test procedure: For each test surface, three runs meeting the pedal
force application and time for wheel lockup requirements shall be made.
Up to a total of six runs will be allowed to obtain three valid runs.
Only the first three valid runs obtained shall be used for data analysis
purposes.
S7.2.4 Performance requirements
(a) In order to pass this test a vehicle shall be capable of meeting
the test requirements on all test surfaces that will result in a braking
ratio of between 0.15 and 0.80, inclusive.
(b) If all three valid runs on each surface result in the front axle
locking before or simultaneously with the rear axle, or the front axle
locks up with only one or no wheels locking on the rear axle, the torque
wheel procedure need not be run, and the vehicle is considered to meet
the adhesion utilization requirements of this TSD standard.
This performance requirement shall be met for all vehicle braking ratios
between 0.15 and 0.80.
(c) If any one of the three valid runs on any surface results in the
rear axle locking before the front axle or the rear axle locks up with
only one or no wheels locking on the front axle, the torque wheel procedure
shall be performed. This performance requirement shall be met for all
vehicle braking ratios between 0.15 and 0.80.
(d) If any one of the three valid runs on any surface results in neither
axle locking (i.e., only one or no wheels locked on each axle) before
a pedal force of 1 kN (225 lb.) is reached, the vehicle shall be
tested to the torque wheel procedure.
(e) If the conditions listed in paragraph (c) or (d) of this section
occur, vehicle compliance shall be determined from the results of a
torque wheel test performed in accordance with S7.4.
(f) An EV with RBS that is part of the service brake system shall meet
the performance requirements over the entire normal operating range
of the RBS.
S7.4.1 General information. This test is for vehicles without
any ABS. The purpose of the test is to determine the adhesion utilization
of a vehicle.
S7.4.2 Vehicle conditions
(a) Vehicle load: GVWR and LLVM LLVW.
(b) Transmission position: In neutral.
(c) Tires: For this test, a separate set of tires, identical to those
used for all other tests under section 7.0, may be used.
S7.4.3 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speeds: 100 km/h (62.1 mph) and 50 km/h (31.1 mph).
(c) Pedal force: Pedal force is increased at a linear rate between
100 and 150 N/sec. (22.5 and 33.7 lb./sec.) for the 100 km/h (62.1 mph)
test speed, or between 100 and 200 N/sec. (22.5 and 45.0 lb./sec.) for
the 50 km/h (31.1 mph) test speed, until the first axle locks or until
a pedal force of 1 kN (225 lb.) is reached, whichever occurs first.
(d) Cooling: Between brake applications, the vehicle is driven at speeds
up to 100 km/h (62.1 mph) until the IBT specified in S7.4.3(a) is
reached.
(e) Number of runs: With the vehicle at LLVM LLVW, run
five stops from a speed of 100 km/h (62.1 mph) and five stops
from a speed of 50 km/h (31.1 mph), while alternating between the two
test speeds after each stop. With the vehicle at GVWR, repeat the five
stops at each test speed while alternating between the two test speeds.
(f) Test surface: PFC of at least 0.9.
(g) Data to be recorded: The following information must be automatically
recorded in phase continuously throughout each test run such that values
of the variables can be cross-referenced in real time:
(1) Vehicle speed.
(2) Brake pedal force.
(3) Angular velocity at each wheel.
(4) Brake torque at each wheel.
(5) Hydraulic brake line pressure in each brake circuit. Hydraulically
proportioned circuits shall be fitted with transducers on at least one
front wheel and one rear wheel downstream of the operative proportioning
or pressure limiting valve(s).
(6) Vehicle deceleration.
(h) Sample rate: All data acquisition and recording equipment shall support
a minimum sample rate of 40 Hz on all channels.
(i) Determination of front versus rear brake pressure: Determine the
front versus rear brake pressure relationship over the entire range of
line pressures. Unless the vehicle has a variable brake proportioning
system, this determination is made by static test. If the vehicle has
a variable brake proportioning system, dynamic tests are run with the
vehicle both empty and loaded. 15 snubs from 50 km/h (31.1 mph) are made
for each of the two load conditions, using the same initial conditions
specified in this section.
S7.4.4 Data reduction
(a) The data from each brake application under S7.4.3 is filtered using
a five-point, on-center moving average for each data channel.
(b) For each brake application under S7.4.3, determine the slope (brake
factor) and pressure axis intercept (brake hold-off pressure) of the
linear least squares equation best describing the measured torque output
at each braked wheel as a function of measured line pressure applied
at the same wheel. Only torque output values obtained from data collected
when the vehicle deceleration is within the range of 0.15 g to
0.80 g are used in the regression analysis.
(c) Average the results of paragraph (b) of this section to calculate
the average brake factor and brake hold-off pressure for all brake applications
for the front axle.
(d) Average the results of paragraph (b) of this section to calculate
the average brake factor and brake hold-off pressure for all brake applications
for the rear axle.
(e) Using the relationship between front and rear brake line pressure
determined in S7.4.3(i) and the tire rolling radius, calculate the braking
force at each axle as a function of front brake line pressure.
(f) Calculate the braking ratio of the vehicle as a function of the
front brake line pressure using the following equation:
(g) Calculate the adhesion utilized at each axle as a function of braking
ratio using the following equations:
(h) Plot f1 and f2 obtained in
(g) as a function of z, for both GVWR and LLVM LLVW
load conditions. These are the adhesion utilization curves for the vehicle,
which are compared to the performance requirements in S7.4.5, shown graphically
in Figure 2: |
Figure 2 — Adhesion Utilization Requirements
|
S7.4.5 Performance requirements. For all braking ratios between
0.15 and 0.80, each adhesion utilization curve for a rear axle shall be
situated below a line defined by z = 0.9k where z
is the braking ratio and k is the PFC.
S7.4.5.1 An EV with RBS that is part of the service brake system
shall meet the performance requirement over the entire normal operating
range of the RBS.
S7.5.1 Vehicle conditions
(a) Vehicle load: GVWR and LLVM LLVW.
(b) Transmission position: In neutral.
S7.5.2 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
(g) For each stop, bring the vehicle to test speed and then stop the
vehicle in the shortest possible distance under the specified conditions.
S7.5.3 Performance requirements
(a) Stopping distance for 100 km/h (62.1 mph) test speed: £
70 m (230 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0060V2.
This test is not run if vehicle maximum speed is less than or equal to
125 km/h (77.7 mph).
S7.6.1 Vehicle conditions
(a) Vehicle load: GVWR and LLVM LLVW.
(b) Transmission position: In gear.
S7.6.2 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 80% of vehicle maximum speed if 125 km/h (77.7 mph) <
vehicle maximum speed < 200 km/h (124.3 mph), or 160 km/h (99.4 mph)
if vehicle maximum speed ³ 200 km/h (124.3 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
S7.6.3 Performance requirements
Stopping distance: S £ 0.10V
+ 0.0067V2.
S7.7.1 General information. This test is for vehicles equipped
with one or more brake power units or brake power assist units. This test
is also for EVs.
S7.7.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In neutral.
(c) Vehicle engine: Off (not running).
(d) Ignition key position: May be returned to "on" position
after turning engine off, or a device may be used to "kill"
the engine while leaving the ignition key in the "on" position.
S7.7.3 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel allowed for longer than 0.1
second at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
(g) All system reservoirs (brake power and/or assist units) are fully
charged and the vehicle's engine is off (not running) at the beginning
of each stop.
(h) For an EV, this test is conducted with no electrical power supplied
to the vehicle's propulsion motor(s), but with the RBS and brake power
or power assist still operating, unless cutting off the supply of electrical
power to the propulsion motor(s) also disables those systems.
S7.7.4 Performance requirements
(a) Stopping distance for 100 km/h (62.1 mph) test speed: £
70 m (230 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0060V2.
S7.8.1 Vehicle conditions
(a) Vehicle loading: LLVM LLVW and GVWR.
(b) Transmission position: In neutral.
S7.8.2 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for more than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
(g) Functional failure simulation:
(1) Disconnect the functional power source or any other electrical connector
that creates a functional failure.
(2) Determine whether the brake system indicator is activated when any
electrical functional failure of the antilock system is created.
(3) Restore the system to normal at the completion of this test.
(h) If more than one antilock brake subsystem is provided, repeat test
for each subsystem.
S7.8.3 Performance requirements. For service brakes on a vehicle
equipped with one or more antilock systems, in the event of any single
functional failure in any such system, the service brake system shall
continue to operate and shall stop the vehicle as specified in S7.8.3(a)
or S7.8.3(b).
(a) Stopping distance for 100 km/h (62.1 mph) test speed: £
85 m (279 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0075V2.
S7.9.1 Vehicle conditions
(a) Vehicle load: LLVM LLVW and GVWR.
(b) Transmission position: In neutral.
S7.9.2 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
(g) Functional failure simulation:
(1) Disconnect the functional power source or mechanical linkage to render
the variable brake proportioning system inoperative.
(2) If the system utilizes electrical components, determine whether the
brake system indicator is activated when any electrical functional failure
of the variable proportioning system is created.
(3) Restore the system to normal at the completion of this test.
(h) If more than one variable brake proportioning subsystem is provided,
repeat the test for each subsystem.
S7.9.3 Performance requirements. The service brakes on a vehicle
equipped with one or more variable brake proportioning systems, in the
event of any single function failure in any such system, shall continue
to operate and shall stop the vehicle as specified in S7.9.3(a) or S7.9.3(b).
(a) Stopping distance for 100 km/h (62.1 mph) test speed: £
110 m (361 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0100V2.
S7.10.1 General information. This test is for vehicles manufactured
with or without a split service brake system.
S7.10.2 Vehicle conditions
(a) Vehicle load: LLVM LLVW and GVWR.
(b) Transmission position: In neutral.
S7.10.3 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Test surface: PFC of 0.9.
(f) Alter the service brake system to produce any single failure. For
a hydraulic circuit, this may be any single rupture or leakage type
failure, other than a structural failure of a housing that is common
to two or more subsystems. For a vehicle in which the brake signal is
transmitted electrically between the brake pedal and some or all of
the foundation brakes, regardless of the means of actuation of the foundation
brakes, this may be any single failure in any circuit that electrically
transmits the brake signal. For an EV with RBS that is part of the service
brake system, this may be any single failure in the RBS.
(g) Determine the control force pressure level or fluid level (as appropriate
for the indicator being tested) necessary to activate the brake warning
indicator.
(h) Number of runs: After the brake warning indicator has been activated,
make the following stops depending on the type of brake system:
(1) 4 stops for a split service brake system.
(2) 10 consecutive stops for a non-split service brake system.
(i) Each stop is made by a continuous application of the service brake
control.
(j) Restore the service brake system to normal at the completion of
this test.
(k) Repeat the entire sequence for each of the other subsystems.
S7.10.4 Performance requirements. For vehicles manufactured with
a split service brake system, in the event of any failure in a single
subsystem, as specified in S7.10.3(f) of this TSD standard,
and after activation of the brake system indicator as specified in S5.5.1,
the remaining portions of the service brake system shall continue to operate
and shall stop the vehicle as specified in S7.10.4(a) or S7.10.4(b). For
vehicles not manufactured with a split service brake system, in the event
of any failure in any component of the service brake system, as specified
in S7.10.3(f), and after activation of the brake system indicator as specified
in S5.5.1 of this TSD standard, the vehicle shall, by operation
of the service brake control, stop 10 times consecutively as specified
in S7.10.4(a) or S7.10.4(b).
(a) Stopping distance from 100 km/h (62.1 mph) test speed: £
168 m (551 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0158V2.
S7.11.1 General information. This test is for vehicles equipped
with one or more brake power units or brake power assist units.
S7.11.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In neutral.
S7.11.3 Test conditions and procedures
(a) IBT: ³ 65°C (149°F), £ 100°C (212°F).
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: ³ 65 N (14.6 lb.), £
500 N (112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 6 stops.
(f) Test surface: PFC of 0.9.
(g) Disconnect the primary source of power for one brake power assist
unit or brake power unit, or one of the brake power unit or brake power
assist unit subsystems if two or more subsystems are provided.
(h) If the brake power unit or power assist unit operates in conjunction
with a backup system and the backup system is automatically activated
in the event of a primary power service failure, the backup system is
operative during this test.
(i) Exhaust any residual brake power reserve capability of the disconnected
system.
(j) Make each of the 6 stops by a continuous application of the service
brake control.
(k) Restore the system to normal at completion of this test.
(l) For vehicles equipped with more than one brake power unit or brake
power assist unit, conduct tests for each in turn.
(m) For vehicles with electrically-actuated service brakes (brake power
unit), this test is conducted with any single electrical failure in
the electrically-actuated service brakes instead of a failure of any
other brake power or brake power assist unit, and all other systems
intact.
S7.11.4 Performance requirements. The service brakes on a vehicle
equipped with one or more brake power assist units or brake power units,
with one such unit inoperative and depleted of all reserve capability,
shall stop the vehicle as specified in S7.11.4(a) or S7.11.4(b).
(a) Stopping distance from 100 km/h (62.1 mph) test speed: £
168 m (551 ft.).
(b) Stopping distance for reduced test speed: S £
0.10V + 0.0158V2.
S7.12.1 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In neutral.
(c) Parking brake burnish:
(1) For vehicles with parking brake systems not utilizing the service
friction elements, the friction elements of such a system are burnished
prior to the parking brake test according to the published recommendations
furnished to the purchaser by the manufacturer.
(2) If no recommendations are furnished, the vehicle's parking brake
system is tested in an unburnished condition.
S7.12.2 Test conditions and procedures
(a) IBT:
(1) Parking brake systems utilizing service brake friction materials
shall be tested with the IBT £ 100°C (212°F)
and shall have no additional burnishing or artificial heating prior to
the start of the parking brake test.
(2) Parking brake systems utilizing non-service brake friction materials
shall be tested with the friction materials at ambient temperature at
the start of the test. The friction materials shall have no additional
burnishing or artificial heating prior to or during the parking brake
test.
(b) Parking brake control force: Hand control £
400 N (89.9 lb.); foot control £ 500 N (112.4 lb.).
(c) Hand force measurement locations: The force required for actuation
of a hand-operated brake system is measured at the center of the hand
grip area or at a distance of 40 mm (1.57 in.) from the end of the actuation
lever as illustrated in Figure 3.
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Figure 3 — Location for Measuring Brake Application Force (Hand Brake)
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(d) Parking brake applications: 1 application and up to 2 reapplications,
if necessary.
(e) Test surface gradient: 20% grade.
(f) Drive the vehicle onto the grade with the longitudinal axis of
the vehicle in the direction of the slope of the grade.
(g) Stop the vehicle and hold it stationary by applying the service
brake control and place the transmission in neutral.
(h) With the service brake applied sufficiently to just keep the vehicle
from rolling, apply the parking brake as specified in S7.12.2(i) or
S7.12.2(j).
(i) For a vehicle equipped with mechanically-applied parking brakes,
make a single application of the parking brake control with a force
not exceeding the limits specified in S7.12.2(b). For a vehicle using
an electrically-activated parking brake, apply the parking brake by
activating the parking brake control.
(j) In the case of a parking brake system that does not allow application
of the specified force in a single application, a series of applications
may be made to achieve the specified force.
(k) Following the application of the parking brakes, release all force
on the service brake control and, if the vehicle remains stationary,
start the measurement of time.
(l) If the vehicle does not remain stationary, reapplication of a force
to the parking brake control at the level specified in S7.12.2(b) as
appropriate for the vehicle being tested (without release of the ratcheting
or other holding mechanism of the parking brake) is used up to two times
to attain a stationary position.
(m) Verify the operation of the parking brake application indicator.
(n) Following observation of the vehicle in a stationary condition
for the specified time in one direction, repeat the same test procedure
with the vehicle orientation in the opposite direction on the same grade.
S7.12.3 Performance requirement. The parking brake system shall
hold the vehicle stationary for 5 minutes in both a forward and reverse
direction on the grade.
S7.13.1 General information. The purpose of the snubs is to heat
up the brakes in preparation for the hot performance test which follows
immediately.
S7.13.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In gear.
S7.13.3 Test conditions and procedures
(a) IBT:
(1) Establish an IBT before the first brake application (snub) of ³
55°C (131°F), £ 65°C (149°F).
(2) IBT before subsequent snubs are those occurring at the distance intervals.
(b) Number of snubs: 15.
(c) Test speeds: The initial speed for each snub is 120 km/h (74.6 mph)
or 80% of Vmax, whichever is slower. Each snub is terminated
at one-half the initial speed.
(d) Deceleration rate:
(1) Maintain a constant deceleration rate of 3.0 m/s2
(9.8 fps2).
(2) Attain the specified deceleration within one second and maintain
it for the remainder of the snub.
(e) Pedal force: Adjust as necessary to maintain the specified constant
deceleration rate.
(f) Time interval: Maintain an interval of 45 seconds between the start
of brake applications (snubs).
(g) Accelerate as rapidly as possible to the initial test speed immediately
after each snub.
(h) Immediately after the 15th snub, accelerate to 100 km/h (62.1 mph)
and commence the hot performance test.
S7.14.1 General information. The hot performance test is conducted
immediately after completion of the 15th heating snub.
S7.14.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In neutral.
S7.14.3 Test conditions and procedures
(a) IBT: Temperature achieved at completion of heating snubs.
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force:
(1) The first stop is done with an average pedal force not greater than
the average pedal force recorded during the shortest GVWR cold effectiveness
stop.
(2) The second stop is done with a pedal force not greater than 500 N
(112.4 lb.).
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 2 stops.
(f) Immediately after the 15th heating snub, accelerate to 100 km/h (62.1
mph) and commence the first stop of the hot performance test.
(g) If the vehicle is incapable of attaining 100 km/h (62.1 mph), it
is tested at the same speed used for the GVWR cold effectiveness test.
(h) Immediately after completion of the first hot performance stop, accelerate
as rapidly as possible to the specified test speed and conduct the second
hot performance stop.
(i) Immediately after completion of the second hot performance stop,
drive 1.5 km (0.93 mi.) at 50 km/h (31.1 mph) before the first
cooling stop.
S7.14.4 Performance requirements
(a) For the first hot stop, the stopping distance must be less
than or equal to a calculated distance which is based on 60 percent
of the deceleration actually achieved on the shortest GVWR cold effectiveness
stop. The following equations shall be used in calculating the performance
requirement:
(b) In addition to the requirement in S7.14.4(a), the
stopping distance for at least one of the two hot stops must be S
£ 89 m (292 ft.) from a test speed of 100 km/h
(62.1 mph) or, for reduced test speed, S £
0.10V + 0.0079V2. The results of the second
stop may not be used to meet the requirements of S7.14.4(a).
S7.15.1 General information. The cooling stops are conducted immediately
after completion of the hot performance test.
S7.15.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In gear.
S7.15.3 Test conditions and procedures
(a) IBT: Temperature achieved at completion of hot performance.
(b) Test speed: 50 km/h (31.1 mph).
(c) Pedal force: Adjust as necessary to maintain specified constant
deceleration rate.
(d) Deceleration rate: Maintain a constant deceleration rate of 3.0
m/s2 (9.8 fps2).
(e) Wheel lockup: No lockup of any wheel for longer than 0.1 second
allowed at speeds greater than 15 km/h (9.3 mph).
(f) Number of runs: 4 stops.
(g) Immediately after the hot performance stops, drive 1.5 km (0.93
mi.) at 50 km/h (31.1 mph) before the first cooling stop.
(h) For the first through the third cooling stops:
(1) After each stop, immediately accelerate at the maximum rate to
50 km/h (31.1 mph).
(2) Maintain that speed until beginning the next stop at a distance
of 1.5 km (0.93 mi.) from the beginning of the previous stop.
(i) For the fourth cooling stop:
(1) Immediately after the fourth stop, accelerate at the maximum
rate to 100 km/h
(62.1 mph).
(2) Maintain that speed until beginning the recovery performance
stops at a distance of
1.5 km (0.93 mi.) after the beginning of the fourth cooling stop.
S7.16.1 General information. The recovery performance test is
conducted immediately after completion of the brake cooling stops.
S7.16.2 Vehicle conditions
(a) Vehicle load: GVWR only.
(b) Transmission position: In neutral.
S7.16.3 Test conditions and procedures
(a) IBT: Temperature achieved at completion of cooling stops.
(b) Test speed: 100 km/h (62.1 mph).
(c) Pedal force: The average pedal force shall not be greater than the
average pedal force recorded during the shortest GVWR cold effectiveness
stop.
(d) Wheel lockup: No lockup of any wheel for longer than 0.1 second allowed
at speeds greater than 15 km/h (9.3 mph).
(e) Number of runs: 2 stops.
(f) Immediately after the fourth cooling stop, accelerate at the maximum
rate to 100 km/h (62.1 mph).
(g) Maintain that speed until beginning the first recovery performance
stop at a distance of 1.5 km (0.93 mi.) after the beginning of the
fourth cooling stop.
(h) If the vehicle is incapable of attaining 100 km/h (62.1 mph), it
is tested at the same speed used for the GVWR cold effectiveness test.
(i) Immediately after completion of the first recovery performance stop,
accelerate as rapidly as possible to the specified test speed and conduct
the second recovery performance stop.
S7.16.4 Performance requirements. The stopping distance, S,
for at least one of the two stops must be within the following limits:
Inspect:
(a) The service brake system for detachment or fracture of any components,
such as brake springs and brake shoes or disc pad facings.
(b) The friction surface of the brake, the master cylinder or brake
power unit reservoir cover, and seal and filler openings for leakage
of brake fluid or lubricant.
(c) The master cylinder or brake power unit reservoir for compliance
with the volume and labeling requirements of S5.4.2 and S5.4.3. In determining
the fully applied worn condition, assume that the lining is worn to
(1) rivet or bolt heads on riveted or bolted linings or
(2) within 0.8 mm (1/32 in.) of shoe or pad mounting surface on bonded
linings or
(3) the limit recommended by the manufacturer, whichever is larger
relative to the total possible shoe or pad movement. Drums or rotors
are assumed to be at nominal design drum diameter or rotor thickness.
Linings are assumed adjusted for normal operating clearance in the
released position.
(d) The brake system indicators for compliance with operation in various
key positions, lens color, labeling, and location, in accordance with
S5.5.
ENDNOTES:
* Please see subsection
2(1) of the Motor Vehicle Safety Regulations for the applicable
definition.
The numbers in parentheses in the margin
refer to subsections of section
135 of the Regulations that supersede the requirements of the
TSD provision.
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