Modelling of the inlet system and examination of the effect of inlet pipe length on engine operation parameters

In the paper are presented assumptions for developing a computational model of engine inlet system. The aim of developing an inlet system model will be determination of the effect of different factors on the value of engine filling coefficient and, what is connected with that, on the parameters of its operation. Intention of the author is that a model developed will be of developmental character and would be capable of being expanded by further components enlarging the range of its applications. In the paper are also presented the results of test bed examinations for the SW-680 engine with the inlet system enabling modiflcation of the length of inlet pipes. Findings are presented in the form of external characteristics where the effect of inlet pipe length on such parameters like power or torque, as well as on the rotational speed at which a maximum torque, is visible. The effect of inlet pipe length on torque rotational speed can be of significant importance in case of a possibility ofshaping the engine characteristic and matching the area of engine operation with vehicle operating conditions, which is presented on universal characteristics in the form of resistance-to-motion lines. Test bed examinations have also served a purpose of verifying the model developed. The author is aware of the fact that the model presented requires further development. After considering certain corrections, it will be possible to develop a working computer programme being of use in simulation tests for the inlet systems of different engines.