PROPOSITION OF NEW SINGLE TEST CYCLE OF INTERNAL COMBUSTION ENGINE DURING STAND RELIABILITY TESTS

Abstract

A test-stand reliability evaluation of automotive internal combustion engines is carried out so as to determine the selected reliability parameters, such as an average occurrence of defects, an average frequency of part exchange, an average frequency of engine regulation or the wear of selected engine components. The values of these indicators make it possible to estimate the durability of components used as well as of the whole structure of the engine. During reliability test-stand research, the engine is run according to multiple repeated cycles of operation. The conditions of engine operation during reliability tests can be characterized by time invariability and extreme values of rotational speed and torque. In this article the authors prove that the conditions of real automotive engine operation are much more diversified (city driving) with a high share of partial loads (intercity driving). Another significant difference in test-stand reliability evaluation and real operation is the frequency of engine start-ups. In real conditions engine start-ups are far more frequent. The authors propose a new test cycle, which will enable reproducing the real engine operation conditions in stand tests. Characteristic features of this test include more frequent starts and distinguishing between the two kinds of variability in conditions of operation: city and intercity driving, with “lighter” values of rotational speed and torque.