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The article deals with the design of the internal combustion engines. Disadvantages of piston engine are pointed out and advantages of rotary engines are stressed. The simply calculations are added in order to convince the opponents. The very early development procedures of the two rotary engines design are described. The important parts of first rotary engine are machined out and the difficulties that occur already during the assembly phase are pointed out. On the basis of the analysis of the troubles that we have with this first rotary engine the second rotary engine is proposed. The working concept for this second rotary engine is described.

The paper discusses some aspects of injecting or adding water either into the intake air or to the fuel of a truck diesel engine in order to reduce harmful emissions. The effects of some interesting approaches of water addition are briefly discussed. On the basis of our experiments on a diesel truck engine with an in-line injection system, the following cases are considered: fuel/water emulsion injection into the combustion chamber; multi-point water injection into the air in the intake manifold; mono-point water injection before turbocharger as well as mono-point water injection after the turbocharger. For the fuel/water emulsion injection approach, the injection characteristics as well as the fuel spray characteristics are analyzed using the numerical simulation. On the basis of this analysis, the effects of injection and spray characteristics on emissions and other engine characteristics at several operating regimes are discussed for different fuel/water ratios.

The paper describes a procedure for optimizing the conventional diesel fuel injection system by employing an approximation method of mathematical programming. The shape of the cam profile is represented by a Bézier curve and some of the coordinates of the control points are adopted as design variables. Other design variables concern the pump plunger prelift, the geometrical end of delivery and the length of high pressure tube. The objective function is build upon a target shape of the injection rate while the imposed constraints are related to the pump plunger acceleration, the local radius of the cam profile, the residual pressure, the vapour volume, the pressure squareness and to the design variables. The theory is illustrated with several numerical examples.

The paper describes a procedure for optimizing the cam profile of a pump in a diesel fuel injection system by employing an approximation method of mathematical programming. The shape of the profile is represented by a Bézier curve and some of the coordinates of the control points are adopted as design variables. The objective function is build upon a target shape of the pump plunger velocity while the imposed constraints are related to the local radius of the cam profile, pump plunger acceleration and to the design variables. The procedure is appropriate to be included into the optimal design procedure of the whole fuel injection system. The theory is illustrated with numerical examples.

The paper describes an improved mathematical model to simulate the injection processes in conventional fuel injection equipment for diesel engines. The improvements refer to the presence of the snubber valve employed to reduce the reflected pressure wave amplitudes, to the cavitation phenomenon and the manner in which it is taken into account as well as to the variable fluid properties of one-phase (neat fuel) and two-phase (fuel-vapour) fluid. With the proposed modelling technique, it is possible to predict numerically the performance of conventional fuel injection equipment on the whole range of engine operating conditions with satisfactory accuracy and acceptable computational effort.