SAE J1911 pdf download

SAE J1911 pdf download.Test Procedure for Air Reservoir Capacity—Highway Type Vehicles.
1. This SAE Recommended Practice provides instructions and test procedures for air braked vehicles including but not limited to trucks, truck-tractors, trailers, dollies, and buses used on highways but does not include off-highway vehicles.
1.1 Purpose—This document provides a method of determining the air reservoir capacity of highway type vehicles using compressed air to actuate or transmit actuation power to the foundation brakes. Air reservoir capacity is the ability to provide adequate brake pressure after a number of brake applications.
2. References
2.1 ApplIcable Pubilcalions—The following p4ithcations form a part of this specficatlon to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply.
2.1.1 SAE PueucAnol+—Avallable from SAE, 400 Commonwealth Drive, Warrendale, 15096-001.
SAE J 1609—Air Reservoir Capacity Performance Guide—Commercial Vehicles
2.1.2 FEDERAL PueuCATIoei—Available from the Superintendent of Documents, U. S. Government Printing Office. Mail Stop: SSOP Washington. DC 20402-9320.
Federal Molar Vehicle Safety Standard 121—Air Brake Systems
3. Instrumentation and Equipment
3.1 InstrumentatIon
3.1.1 Timing device accurate to within 1% of elapsed time.
3.1.2 Pressure gauges or electronic pressure measuring syslems accurate to within 2% of pressure.
4. Vehicle Condition
4.1 All air connections shall be secured so that the leakage rate for the entire air system. with all service brakes applied and parking brakes released, with pressure of 586 kPa ± 34.5 kPa (85 psi i 5 psi), shall not exceed 6.89 kPa (1 psi) per minute. For leakage rate evaluation of towing vehicles, the “0.820 L (50 in3) reservoir” coupler shall be connected to the rear control line coupler and the dummy coupler to the rear supply line coupler. Parking brake and trailer air supply valves shall be positioned so that the parking brakes are released and the supply line to any towed vehicle coupler is pressurized. The control line to any couplers for towed vehicles shall also be pressurized to 586 kPa ± 34.5 kPa (85 psi ± 5 psi).
4.2 Brakes on new vehicles shall be burnished in accordance with paragraph S6.1 .8 of FMVSS 121. Brakes on used vehicles need not be burnished if the friction material contact surface is over 80% for drum brakes and over 99% for disc brakes.
4.3 Brakes are to be adjusted to the vehicle manufacturers published instructions. Where Instructions differ between new and burnished linings/pads, adjustments specified for burnished linings/pads shall be followed.
4.4 If the vehicle is equipped with any type of load proportioning valve(s), the vehicle axles, which are affected by these valves, shall be loaded to their GAWRs or the valve(s) bypassed.
4.5 If the vehicle Is equipped with any air reservoir(s) to operate systems other than the brake system, such reservoirs shall be isolated. All air operated equipment outside of the brake system shall be in the “off’ position.
5. Test Procedure
5.1 Trucks, Truck-Tractors, and Buses
I5.1.1 Park the vehicle on a level surface and chock the wheels. Drain all air tanks of moisture to obtain maximum air tank capacity.
5.1.2 On towing vehicles, attach the “0.820 L (50 in3) reservoir” coupler to the vehicles trailer control line coupler and the dummy coupler to the trailer supply line coupler.
5.1.3 Install a pressure gage (transducer) in the “0.820 L (50 in3) reservoir7 the reservoir that controls the compressor “cut-in” and “cut-out,” and in one service brake actuator of each set of actuators having a common input pressure.
5.1.4 lIthe optional regulator valves are used to regulate brake application pressures, install one in each line supplying air to the foot valve at its respective reservoir.
5.1.5 Position the parking brake air control valve(s) in the cab so that the parking brakes are released and, if the test vehicle is a towing vehicle, the trailer air supply line is pressurized.
5.1.6 Charge the air system to the vehicle rnanutacturer’s specified minimum “cut-out pressure.
5.1.7 Make at least 5 full brake applications, by fully depressing the foot valve, to exercise the brake system.
5.1.8 If the regulator valves specified in 3.2.1.1 are used, adjust the valves so that the ouput is 586 kPa (85 psi) when the foot valve is fully depressed.
5.1.9 Charge the air system to the vehicle manufacturer’s specified minimum “cut-out” pressure. Isolate the air system from the air supply so that the reservoirs are not supplied with air during the test.