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The authors of this paper investigated the influences of fuel supply timing delay on fuel consumption maxmum combustion pressure, NOx emission and smoke of two diesel engines with shallow type combustion system Based on measured, indicator diagram, combustion rate and NOx emission were predicted by using phenomenological combustion model. Furthermore, theoritical of the test result were made.

In this paper authors propose a new method for estimation of cylinder compression. Under motoring condition, when the transient rotational speed fluctuation of flywheel within a working cycle has been measured, the Max. compressive pressure of each cylinder were calculated based on the principle of inertia acceleration. The testing results of 4 and 6 cylinder engines show that, the measured errors were within ±3%, so it is a proper tool for fast estimation the compression of engine mounted on vehicles especially.

The heat release rate patterns of fuel combustion determines the changing of pressure and temperature of gases within cylinder, and furthermore made an important effect of the fuel economy, power - output, noise level and exhaust emission. In this paper, the authors discuss the fuel economy, power - output and combustion noise of R4102Q D.I. diesel engine. In optimum simulation concerning fuel economy and power-output, the indicative heat efficiency and mean indicative pressure were almost always taken as objective function. In consideration of the effect of gas pressure upon the friction losses of diesel engine, the effetive heat efficiency and mean effective pressure were taken as objective function in this paper. By comparison with testing data, when the instantaneous friction was taken into consideration, the prediction accuracy of simulations was improved.

In this paper, computational non-steady gas flow process simulating of intake system of Model SD2100 diesel engine have been made by using the characteristic method. In the meantime, intake air pressure waves in the engine intake pipe under different engine rotative speeds have been measured on the engine test rig with an inverted drive, and exploratory investigation conducted into the influence of intake pipe length, design of pipe branch, air fitter and other factors on the charging efficiency and intake air pressure wave. The computed results agree mainly with the measured data. Because of having used the design of two-branch short pipes equal-length in intake system of SD2100 diesel engine, the interaction phenomenon of intake air pressure waves of two cylinders each other is found out both in test and computation, thereby, the intake air chargings into two cylinders are unequal.

It is simple and advisable as well as efficacious to improve the dynamic and economic properties of two-stroke motorcycle petrol engine by means of exhaust dynamic effect. In this paper, the exhaust pipe design method and the effect of some exhaust system factors on the exhaust dynamic effect are researched into by test for the exhaust systems of the two models of motorcycle engines. Under several operating conditions, exhaust pressure waves are measured respectively at the different points on the exhaust pipes of variously designed sizes. Having analysed the measured exhaust pressure waves and the results simulatively calculated, the relative problems to reasonablely utilize the exhaust dynamic effect of two-stroke motorcycle petrol engines are discussed in some detail.