Precombustion Engine

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Precombustion Engine


an internal combustion engine in which carburetion is improved by means of a precombustion chamber. The fuel, or working mixture, is first fed into the precombustion chamber, where it is partially burned. When the fuel vapors are ignited, the pressure in the chamber increases, as a result of which the mixture of heated fuel and combustion products enters the combustion chamber above the piston. The steady rate of combustion of the fuel as it is expelled from the precombustion chamber into the combustion chamber provides for a uniform increase in the pressure in the cylinder, which results in the smoother operation of the precombustion engine.

A diesel’s precombustion engine operates steadily, without smoking, over a wide range of rotational speeds, and its injection pressure is lower than that of other diesel types. An important advantage of such engines is that they can use any grade of fuel. A disadvantage is the difficulty in starting because self-ignition requires thorough preheating of the precombustion chamber. To facilitate starting, electric glow plugs are used to preheat the air in the precombustion chamber.

For gasoline precombustion engines, the fuel consumption is 6 to 8 percent lower by weight, and there are fewer toxic exhausts. However, stability and reliability of performance are diminished under some modes of operation.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The 40D is powered by a water-cooled 450 hp Cat 3408 PCTA turbocharged and aftercooled precombustion engine (335 kW at 2,100 rev/min).