Modern motor vehicle drive systems are characterised by a multitude of complex control and regulating systems optimally adapting the drive characteristics to the respective driving condition. Known systems are electronic devices for regulating the brake system to obtain increased safety by means of automatic slip regulation when braking (ABS, ESP etc.) or accelerating. Anti Lock Braking Systems (ABS) became a standard device in all actual vehicles. At present a high rate of vehicles equipped with ABS with ages up to ten or twelve years are on the road. The existing information about the availability and reliability of these systems is insufficient. Furthermore, it is not defined, how these systems can be effectively checked on their correct function. At present, the efficiency of these systems is only tested after the production of the car and no further tests or periodic checking occur during it's whole lifetime. Only self-checks are done by the systems self diagnosis routine and the results are documented in the fault memory. It is unknown, whether these self checks are sufficient to cover most of the failures which appear in the system, or if additional efficiency tests are necessary. Nevertheless, this information is necessary for the estimation about the influences of these systems on traffic safety. Therefore, in this study the functional behaviour of older ABS systems is examined with a four wheel ABS Test Bench from TUEV Rheinland. A large number of vehicles (>250) is tested to ensure the correctness of the statistics. The vehicles for the tests are acquired during the periodical inspection tests at the TUEV Kraftfahrt testing facilities. A test sequence for the four wheel test bench is defined to make the detection of failures and discrepancies of the ABS possible. After data collection, a detailed evaluation of the data is carried out. The result of the evaluation determines the rate of defective ABS. The functional behaviour during the efficiency test is analysed and the appeared failures are compared with the fault memory content before and after the efficiency test on the test bench. Herewith, important information of the failure detection rates of the two test types is generated. Furthermore, it is investigated, if the implementation of the tests in the given procedure of the periodic testing is practicable. (Author/publisher)
Abstract