1. Field of the Invention
This invention relates to an internal combustion engine provided with a precombustion chamber, and more particularly to the engine having a precombustion chamber and of a gasoline injection type for use in a motor vehicle, which engine is designed to improve fuel consumption and purification of exhaust gases.
2. Description of the Prior Art
According to the prior art, in the engine having the precombustion chamber provided separately from the main combustion chamber, there is produced a rich mixture gas condition in the precombustion chamber by injecting fuel into the precombustion chamber and there is produced a lean mixture gas condition in the main combustion chamber by blowing apart of the mixture gas supplied to the precombustion chamber into the main combustion chamber, whereby a stratification of the mixture gas and two stage combustion are performed. In this case, the production of NOx of detrimental components contained in exhaust gases may be suppressed. However, because of combustion of the rich mixture in the precombustion chamber, an unfavorable amount of hydrocarbons and carbon monoxide is produced.
In usual internal combustion engines, to which the present invention is applied, the combustion chamber is divided into a main combustion chamber and a precombustion chamber, while the intake and exhaust of gases are controlled by means of intake and exhaust valves provided in the main combustion chamber. The main combustion chamber is communicated through a communicating passage with the precombustion chamber. The precombustion chamber is provided with an ignition plug and a fuel injection nozzle, whereby the rich mixture is charged and ignited in the precombustion chamber and then the flame thus produced is introduced into the main combustion chamber for the ensuing combustion of the lean mixture gas therein. In this respect, it is important that air should be supplied through the communicating passage into the precombustion chamber from the main combustion chamber without being adversely affected by the throttling action due to the communicating passage and that the flame should be uniformly diffused throughout the main combustion chamber to effect the secondary or ensuing combustion therein. In addition, the velocity of swirl flow of the mixture charge within the precombustion chamber should be damped to thereby lower the pressure increasing rate for the removal of the detrimental components contained in exhaust gases as well as the reduction in the level of noise incident to the combustion.