It is well known that work to create an internal combustion engine (ICE) whose distinctive feature would be the absence of reciprocating motion in its main unit was started practically from the moment an ICE was developed with crank conversion of reciprocating motion into rotary motion of the output shaft (engines with crank conversion of piston motion are later called piston engines). The development of such work is primarily an attempt to eliminate the shortcomings originally inherent in piston ICES.

Despite a tremendous number of technical proposals for developing an ICE without the crank and connecting-rod assembly, until now the only "competitor" of the piston ICE has been the so-called Wankel's rotor-piston engine (RPE).

The main advantage of Wankel's engine with respect to the piston one is its much greater power with similar size and weight parameters; new shortcomings, however, appeared which are peculiar to Wankel's RPE, and which cannot even theoretically be eliminated.

• · poor combustion of fuel mixture (resulting in low efficiency and extremely unsatisfactory environ mental performance);

• · short engine life;

• · substantial restriction of the upper limit of the rotor-piston revolution number;

• · low compression ratio in the operating volume (which excludes the possibility of developing a rotor diesel engine);

• · significant heat loads.

A radically new RPE with the major quality of rotor-type engines, namely, a small volume of the mechanism converting fuel energy into output shaft rotating motion is free from many shortcomings of Wankel's engine.

• · absence of side pressure forces of the piston on cylinder walls (i.e. lateral walls of the cylinder are not at all subject to wear);

• · the shape of the operating volume where the fuel mixture is burned is close to an optimal tent-like shape, allowing it to attain complete combustion at a level no worse than that of piston engines;

• · the cyclical nature of distribution of forces acting from the piston side on the output shaft is favorable, ensuring substantially less vibration level in comparison with piston engines where a full balance of rotating parts is unattainable even in theory;

• · the compression ratio may be much greater than in Wankel's engine (this thus shows major potential for developing a rotor diesel engine);

• · qualitative piston packing in respect to lateral walls of the polyhedral cylinder.

The design of the new engine is much lower in weight and volume than piston engines (2 or 3 times) and Wankel's engines (up to 1.5 times), though their output is equal. The new engine can successfully compete with piston engines and Wankel's engines in such vehicles as cars, light aircraft (designed specifically for record achieve ments), light helicopters, light surface ships, hanggliders, and unmanned flying vehicles used for sports and other purposes.

The implementation of such designs will take a long time and therefore only large industrial associations are likely to be able to undertake them.

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