真空助力器标准-GM

Brake Actuation System Performance

GM Confidential

© Copyright 2005 General Motors Corporation All Rights Reserved

October 2005 Originating Department: North American Engineering Standards

Page 1 of 10

1 Scope

Note: Nothing in the specification supersedes applicable laws and regulations unless specific exemption has been obtained.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

1.1 Purpose. The purpose of this test is to objectively quantify brake actuation system performance.

1.2 Foreword. This procedure outlines a brake actuation subsystem bench test. The brake booster and master cylinder are evaluated as an assembly without measurement fixtures between the components. Test conditions are established to approximate the conditions the components experience in a vehicle. This test procedure shall be used for development and/or validation testing. The performance metrics validated with this procedure are: • Apply and Release Response Time • Average Pressure Hysteresis • Cut-in

• Effective Area • Initial Rise

• Initial Travel Loss and Efficiency •

No Power Force Loss and Efficiency

• Power Slope

• Primary, Secondary, and Total Travel and

Displacement • Return Cut-out •

Total Boost Force

• Total Output Efficiency

1.3 Applicability. This test applies to light or medium duty vehicles equipped with a hydraulic brake system and a brake power assist unit.

2 References

Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None 2.2 GM Standards/Specifications.

None

3 Resources

3.1 Facilities. Milford Proving Ground (Chassis Component Development) or equivalent test facility.

3.2 Equipment.

3.2.1 Test Bench and Capability. An actuation system test bench capable of measuring these required performance parameters: 3.2.1.1 Input Force (N). 3.2.1.2 Input Travel (mm).

3.2.1.3 Output Line Pressure (kPa). 3.2.1.4 Output Fluid Displacement (cc). 3.2.1.5 Booster And Source Vacuum (kPa).

3.2.2 Test Bench Features. The test bench shall incorporate the following features/functions:

3.2.2.1 Vacuum pump and vacuum reservoir tank with automatic vacuum level control.

3.2.2.2 Displacement simulation devices and/or plumbing for calipers/drums.

3.3 Test Vehicle/Test Piece. Test parts and brake corner compliance information shall be attained from the requesting engineer. A minimum of three parts shall be tested to attain confidence in the results.

3.4 Test Time. Calendar time: 1 to 2 days Test hours: 2 to 8 hours Coordination hours

1 to

2 hours

3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. One (1) technician trained in the operation of the actuation system test machine.