What are the types of combustion chambers of diesel generator sets?

    Diesel generator set combustion chamber refers to the space formed above the top surface of the piston and below the bottom surface of the cylinder head when the piston is at the top dead center. The combustion chamber of the diesel generator set affects the quality of the combustible mixture. According to different ways to improve the quality of fuel and air mixture, the combustion chamber of a diesel generator set can be roughly divided into the following two types:

1. Direct injection combustion chamber.
    It mainly relies on the injection of fuel to cooperate with the shape of the combustion chamber, so that the fuel and air are evenly mixed.
The direct injection combustion chamber is divided into unified type, spherical oil film type, and compound type combustion chamber. The combustion chamber shape is related to the geometry of the piston tip face.

• The oil-film combustion chamber is spherical and is located at the top of the piston. The fuel is sprayed onto the wall of the combustion chamber. The chamber space is ignited first, followed by the fuel evaporated from the walls. This kind of combustion chamber can make the working process soft, the fuel burns completely, the sound is quiet and smokeless, and the light fuel can be used. The disadvantage is that it is more difficult to start at a low temperature.
• The composite combustion chamber is in the shape of a deep basin on the top of the piston, the mouth is slightly contracted, the intake vortex is formed by the special shape of the intake port, and the single-hole axial needle injector is used. The compound combustion chamber reasonably combines the oil film evaporation mixing combustion and the space mixing combustion and has the advantages of both, so it is also called a compound combustion system. Low requirements and easy start-up. The downside is the higher content of unburned hydrocarbons in the low-load exhaust.

2.the separate combustion chamber.

    The divided combustion chamber is divided into two parts, which are connected by one or several passages, and the mixing of fuel and air is realized by the gas flow between the two parts. The divided combustion chamber is further divided into two forms: swirl and pre-combustion. The well-designed piston top surface is conducive to airflow, flame propagation, rapid formation of expansion pressure, exhaust gas discharge, etc. Low-speed diesel generators and some medium and high-speed diesel generators mainly use two types of combustion chambers, swirl and pre-combustion.

    The pre-combustion chamber consists of the pre-combustion chamber and the main combustion chamber. The pre-combustion chamber is in the cylinder head, and there are one or several through holes in communication with the main combustion chamber. The fuel is injected into the pre-combustion chamber, part of the fuel is burned after ignition, and the unburned mixture is injected into the main combustion chamber at a high speed, where it is further mixed with air and burned. This combustion chamber is suitable for medium and small-power diesel generators.

    The swirl combustion chamber consists of a swirl chamber and the main combustion chamber. The swirl chamber is located on the cylinder head and is spherical or inverted bell-shaped, accounting for 50 to 80% of the total compression volume, and has a tangential passage that communicates with the main combustion chamber. During the compression stroke, the air pressed into the swirl chamber produces a strong swirl motion, which causes the fuel injected into it to mix with the air. After ignition, the mixture flows into the main combustion chamber, forming a secondary flow, which is further mixed with the air in the main combustion chamber for combustion.