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Claims

Advantages for a four-stroke engine with compression ignition means.

- higher volumetric efficiency ;
- higher specific output ;
- lower losses due to mechanical friction ;
- engine accommodation to the cetane number ;
- accurate definition of an ideal temperature at the end of the compression phase, so to provide suitable self-ignition of the fuel in all circumstances ( from cold starting to high supercharging pressures ) ;
- better engine performance at high altitudes ;
- lower emissions of hydrocarbons and nitrogen oxide in the exhaust gases.

Advantages for a four-stroke engine with spark ignition means.

- higher volumetric efficiency ;
- higher specific output ;
- lower losses due to mechanical friction and pumping ;
- higher partial-load effeciency of the engine, due to a higher compression ratio proportionally to the depression in the intake pipe (closing of the throttle valve) ;
- engine accomodation to the octane number ;
- better engine performance at high altitudes ;
- better air-fuel mixture homogeneity ;
- lower emmissions of carbon monoxide, nitrogen oxides and hydrocarbons in the exhaust gases.

Advantages and conditions of use of the four-stroke engine with compression ignition means and high supercharging pressure levels, mounted in road haulage tractors.

The reduction of the displacement of each cylinder of the engine, based on the mean piston speed, permits an increase in the speed of the engine and a consistent decrease in low frequencies. A higher gear reduction on the gearbox - output shaft assembly should howewer be provided up to the second engine-drive reduction. Since the mechanical friction is proportional to the displacement and less load-sensitive, the efficiency is higher. The engine brake may be kept whilst increasing the power of the engine, supported by a speed limiter on the vehicle.

Claims