The efficiency of the present combustion engines decreases remarkable when they are used at part loads, even this is their primary range of use in the car engines. This thing increases the fuel consumption and the emissions.

It is generally know that the efficiency of the combustion engines is the better, the higher its maximum pressure and temperature are. The construction of the engine, for example the bearings, limits the maximum pressure and for example the allowed level of NOx limits the maximum temperature.

It is generally known that for example in the turbo charged engines the pressure, produced by the charger, decreases at the part loads and at the low engine rotation speed, when the maximum pressure of the engine decreases as well as its efficiency.

It is generally known that at the part loads the maximum temperature of the engine decreases, for example in the diesel engines, because of the fact that there is no adjustment of the amount of the air going into the engine, but the amount of the fuel injected into the cylinder shall be decreased.

It is generally known that the mass flow of the air, going into the engine, shall be decreased, if its temperature is increased, when its pressure stays constant.

It is generally known that the end temperature of the compression in the combustion engine <BR> <BR> increases, if the temperature of the air (gas etc. ), going into the cylinder, shall be increased and by doing like this, the pressure at the end of the compression is not changing. <BR> <BR> <P>It is generally known that when the fuel is burning, the rise of the temperature of the gas (air etc. ) in<BR> the cylinder of the engine is the higher, the smaller the mass of the gas (air etc. ) is per the same amount of the fuel.

It is generally known that the efficiency of the combustion engine is the higher, the higher is the temperature of the start point of the heat input (= burning) and the bigger is the rise of the temperature in the cylinder of the engine (for example Canot), caused by the heat input (= burning).

It is generally known that in the diesel engines having, a low compression ratio, there are problems in the ignition of the fuel at the part loads and when starting.

The Patent US. Pat. 4112679 tries to solve the problem of the ignition of the fuel and the cold start in the turbo charged diesel engines having a low compression ratio, by heating with different methods the air going into the cylinder. The before mentioned patent takes in no way stand on the other problems in the diesel engine or on its process, for example on its maximum temperature, or pressure, or efficiency. It also don't take stand on the pressure of the air going into the engine at different load situations, for example at part load. The concerning patent in question don't deal with the by passing partially, or wholly, the intercooler of the air going into the cylinder, as a method of heating it. The concerning patent refers only to a turbo charged engine, even thou there exist other chargers, for example pressure wave or Comprex charger, mechanical chargers, electrical charges etc.

It is generally known that it is possible to keep at the part loads the pressure of the engine, produced by the turbo charge (exhaust turbo charge), constant, or almost constant, by means of so called electrically supported turbo charger (exhaust gas turbo charger), electrical additional blower etc. <BR> <BR> <P>It is generally know that the pressure of the gas (air etc. ), produced by the mechanical chargers, is almost independent of the load and of the speed of the engine (for example vane compressor, piston <BR> <BR> compressors, so called G-charger etc. ) and that it is possible to keep the pressure constant in these chargers, for example by means of the control of the speed of their rotation, by means of the waste gate, the adjustment of the harmful space, by throttling the suction side etc.

The enclosed method of increasing the efficiency of the engine at the part load is based on the fact that, when using the combustion engine at the part load, the temperature of the gas (mixture of <BR> <BR> gases, dispersion etc. ), going into the cylinder, shall be increased so that its pressure stays constant.

The enclosed method of increasing the efficiency at the part loads is easy to apply to the normal combustion engines, specially to the diesel engines, is characterized in that, when using it at the part loads of the engine, the gas (mixture of gases, dispersion etc. ), going into the cylinder is controlled so that its pressure stays almost constant, but its temperature shall be increased for example by means of by passing partially or wholly the possible intercooler of the charged air <BR> <BR> (charged engine) and, or by heating the before mentioned gas (mixture of gases, dispersion etc. ), for example by means of the heat exchanger from the exhaust gases, besides of the before mentioned by passing, so that the maximum pressure in the cylinder stays at as high level as possible, close to the maximum allowable pressure of the engine, clearly higher than without the before mentioned action and this will be also the case with the maximum temperature. By doing like this and by controlling the firing and, or the ignition or the injection of the fuel, it is possible to achieve in the cylinder at the beginning of the work cycle almost or wholly the allowable maximum pressure and temperature of the engine. By doing so, the engine shall have the best efficiency at the part load and its emissions shall be at a low level.