GB/T 36986-2018Dynamic testing methods of brake performance for automobiles (English PDF)

1 Scope

This Standard specifies the technical conditions and methods for the automobile inspection agency to perform dynamic detection of the brake performance of the automobiles in use.

This Standard is applicable to the dynamic testing and verification of brake performance for automobiles.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB 7258, Safety specifications for power-driven vehicles operating on roads

GB/T 18314, Specifications for global positioning system (GPS) surveys

GB 21861-2014, Items and methods of motor vehicles safety technology inspection

GB/T 28529, Platform brake tester

GB/T 28945, Portable braking performance tester for vehicles

JJF 1168, Calibration Specification for Portable Braking Performance Tester for Motor Vehicle

JJF 1193, Calibration Specification for Non-contact Automotive Speedometer

JJG 1020, Platform Brake Testers

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

4 Technical conditions for dynamic testing methods of brake performance for automobiles

e) Brake pedal force for hydraulic braking. passenger vehicle with a seat number of not more than 9 seats shall be no more than 400N; other vehicles shall be no more than 450N.

4.2 Technical conditions for testing on the road are as follows.

a) The test pavement shall be hard, clean, dry, flat cement or asphalt pavement; the pavement adhesion coefficient shall not be less than 0.7; the longitudinal slope of the pavement shall be no more than 1%; and the pavement shall not have obvious damage, protrusions and depressions;

b) The test pavement length shall be no less than 100m and the width shall be no less than 6m;

c) Test lane edge shall be drawn;

d) The wind speed shall not exceed 5m/s when testing;

e) Portable braking performance tester for dynamic testing of brake performance for automobiles shall comply with the provisions of GB/T 28945; its main metrological performance indicators shall meet the requirements of JJF 1168;

f) The main metrological performance of the non-contact speedometer for dynamic testing of brake performance for automobiles shall meet the requirements of JJF 1193;

g) The main technical performance of the GPS detection system for dynamic testing of brake performance for automobiles shall meet the requirements of GB/T 18314;

h) The test results in both directions of the test road shall meet the requirements.

4.3 Technical conditions for testing by platform are as follows.

a) The flat brake test bench shall be selected according to the axle load of the vehicle to be tested;

b) The surface of the flat brake inspection table shall be clean and free of foreign matter and oil. The adhesion coefficient of the surface of the platform shall not be less than 0.75;

c) The flat brake inspection station shall comply with the provisions of GB/T 28529, and its main measurement performance indicators shall meet the requirements of JJG 1020;

5 Dynamic testing methods of brake performance for automobiles

a) Install the speed sensor in the proper position of the vehicle under test to meet the working requirements and connect with the host.

b) Install the non-contact speedometer speed indicator in a position that is easy for the driver to observe.

c) Install the pedal force gauge on the brake pedal and connect to the main unit.

d) Operate the instrument, select the brake test mode and enter the test state.

e) The vehicle under test starts, accelerates along the midline of the test lane to a slightly higher than the initial brake speed, and then sets the transmission to neutral. Step on the brake pedal when taxiing to the specified initial speed to stop the vehicle. Read the fully deduced average deceleration, braking initial speed, braking distance, speed, pedal force measured by the non-contact speedometer. And check if the vehicle has exited the test lane edge.

f) If the difference between the detected initial braking speed and the specified initial braking speed exceeds ±2km/h, the test result is invalid. Or correct the measured braking distance according to formula (1).

Where, S0 - Braking distance at the specified initial braking speed, in meters (m); v0 - Specified initial braking speed, in kilometers per hour (km/h); ve - Measured initial braking speed, in kilometers per hour (km/h); Se - Measured braking distance, in meters (m).

5.1.2.3 The method of testing by using GPS technology is.

a) Install the pedal force gauge on the brake pedal and connect to the main unit.

b) Select a base station GPS receiving subsystem for an open, undisturbed location.

c) Set up a mobile station GPS receiving subsystem on the car under test.

d) Turn on the base station GPS receiving subsystem and the mobile station GPS receiving subsystem to enter the test state.

Annex B (informative) Record sheet of testing by platform

Table B.1 gives the data sheet for testing methods by platform. […]