Method for synthesizing the laboratory exhaust emission test from car engines based on road tests

The work concerns the development of emission control methods in car exhausts, in a manner consistent with operating conditions, by improving driving tests. Based on the literature study, it was demonstrated that the improvement in the representativeness (accuracy) of driving tests should be based on the appropriate introduction of a random factor in the programming of the speed of the tested vehicle. The paper presents the original method of synthesis of exhaust emission tests on a chassis dynamometer. The developed method consists in transferring to the laboratory program the driving test linearized vehicle speeds approximating the actual driving sections, the condition of continuity of the speed function is fulfilled. Thanks to meeting the conditions of continuity of synthesized sections, an important feature of the method is the possibility of random selection of the order of their implementation in the test. This corresponds to the random nature of the conditions existing in real traffic while maintaining similarity of pollutant emissions. The effectiveness of the proposed method was verified experimentally. A series of rides on a designated route in real road traffic was carried out, with registration of the operating parameters of the test vehicle and exhaust emissions using a mobile analyzer. Then the car was placed in a laboratory stand and the exhaust emissions were analyzed using stationary analyzers. The driving tests were programmed according to the actual course of the car's operating speed (so-called "direct" tests) and "synthetic tests" programmed according to the author's method. A significant convergence was found between road and laboratory tests.