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In automotive applications, the filling and emptying of internal combustion engine are sometimes analyzed from the frequency spectrum of manifolds. However, this is always established with the assumption of small disturbances which is not realistic in engine ducting, where large pressure fluctuations may arise. For this reason, this paper presents a comparison between the frequency spectrum obtained with the assumption of small disturbances and spectra obtained with a shock test bench. Results of this study show that differences exist. These conclusions are validated by the use of a one-dimensional code which gives the possibility to determine the different parameters which have an influence on the results.

This paper presents an experimental study of a water injection (WI) application where water fog is added in the intake of a common rail High-Speed Direct Injection (HSDI) automobile Diesel engine in order to reduce pollutant emissions Nitrogen Oxides and Particulate Matter (NOx and PM) for future emissions standards. Also studied are the physical parameters of the engine (in-cylinder pressure, air inlet temperature, air mass flow, specific fuel consumption etc). The results are compared with those obtained with low-pressure dry Exhaust Gas Recirculation (LP EGR) on the same engine. Tests performed with the water injection system show that a much better NOx / PM trade-off (reduced NOx emission levels at constant PM emission levels) is obtained than with EGR especially at points of high engine loads. In addition, tests are performed with EGR in parallel with water injection to investigate the reduction of NOx emissions while potentially reducing water consumption.

One of the main advantage of a hybrid thermal-electric vehicle is that the internal combustion engine (ICE) can be shut down when not needed anymore (Stop&Start system, propulsion with full-electric mode), thus reducing fuel consumption. But this use of the ICE impacts its thermal behavior because of a lack of heat source and thermal losses. Furthermore, the ICE is sometimes used with higher load in order to charge the batteries that increases the total heating power produced by the combustion. Therefore, the simulation of hybrid vehicles becomes really interesting to evaluate the effect of different control strategies (energy repartition between the engine and the electric motor) on the fuel consumption. However, in most of actual hybrid vehicles simulation tools, for calculation speed reasons, the thermal phenomena are either not taken into account, or their calculation is not based on physical equations (empirical formulas). Their predictive capability is then limited.

Unsteady flow in the inlet and exhaust systems of Internal Combustion Engines can be simulated with multi-dimensional simulation codes. Due to their computational time, other methods are widely used and give the opportunity of coupling it with a model of the complete engine. This paper reports on an investigation undertaken to compare the accuracy of the method of inertia, the acoustic method and the one-dimensional method for modeling the gas flow in pipe systems. Results of this study give the advantage and disadvantage of each approach. The comparison shows good agreement between one-dimensional and experimental results while the calculation time is kept acceptable.