A silencer to attenuate engine exhaust noise using active control methods is developed. The device consists of an electrically driven valve, combined with a buffer volume, which is connected to the exhaust outlet. Using the mean flow through the valve and the pressure fluctuations in the volume, the valve regulates the flow in such a way that only the mean flow passes through the exhaust outlet...

Emissions from modern SI-engines are reduced by a three way catalyst. However if there are leaks in the exhaust system before the catalyst emissions increase for two reasons. First the untreated emissions leak out. Second which is worse, due to waves in the exhaust system, oxygen leaks into the manifold and causes an oxygen sensor offset. The result is increased emissions as the air/fuel contro...

In this paper we analyze the nonlinear dynamic behavior of an internal exhaust gas recirculation system based on a mean-value model of an experimental automotive engine equipped with a camshaft phaser. We develop a control scheme that adjusts camshaft timing to reduce feedgas emissions while maintaining transient engine torque response similar to that of a conventional engine with zero exhaust ...

Multiobjective design optimization system of exhaust manifold shapes for a car engine has been developed using Divided Range Multiobjective Genetic Algorithm (DRMOGA) to obtain more engine power as well as to achieve less environmental impact. The three-dimensional manifold shapes are evaluated by the unstructured, unsteady Euler code coupled with the empirical engine cycle simulation code. Thi...

Nacrtak This paper presents the test results of exhaust emissions from the engine of a wheeled harvester. On the basis of the present analysis, the ranges of most frequently used engine loads and speeds were determined. The obtained time density characteristics (distribution of engine speeds and loads in time) of the engines were referred to the measuring points of the exhaust emission homologa...

The effects of spark timing and exhaust valve timing change on exhaust gas temperature during cold start of an SI engine are studied through engine bench tests. It is observed that the exhaust gas temperature increases when the spark timing and valve timing are retarded individually or simultaneously, due to late combustion or slow flame speed. However, using COVimep it is also investigated tha...

NOx –SCR over Ag/ Al2O3 catalyst using ethanol (C2H5OH) as a reductant has proven its ability to significantly reduce NOx emission in a simulated engine exhaust gas environment. However the real engine exhaust gas environment is too complicated to be simulated. Therefore,the performance evaluation of the Ag/ Al2O3 catalyst in real exhaust gas environment is necessary. Moreover, the ethanol dosi...

This paper develops an exhaust manifold pressure estimation method for a Diesel engine equipped with a variable geometry turbine (VGT) turbocharger. Extrapolated VGT data-maps are used directly for the estimation of the exhaust pressure using a noniterative Newton-Raphson based method suitable for real-time applications. This approach can give more accurate estimations than traditional methods ...