| 摘要 |
1433147 I C engines systems of working DAIMLER-BENZ AG 5 June 1973 [6 June 1972] 26801/73 Heading F1B Multi-stage combustion process for an I.C. engine having an air-cell and a pre-combustion chamber opening into a variable volume principal combustion chamber, the fuel being first burnt with a deficiency of air in the pre-combustion chamber, combustion then being completed only in the principal combustion chamber, combustion of part of the fuel being delayed by keeping the volume of the air-cell free from fuel. A reciprocating piston engine 1 has an exhaust valve 4 and inlet valve, (not shown) and may include an exhaust gas driven turbo-charger 17, 18. A pre-combustion chamber 8 has a fuel injector 14 and an ignition plug 15. Air-cell 9 is connected by duct 11 to principal combustion chamber 7. The relative positions of chamber 8 and cell 9 are such that gases leaving chamber 8 are directed away from the mouth of duct 11. During the compression stroke, fresh gas is forced into both chamber 8 and cell 9 and towards the end of this stroke the fuel/ air mixture in chamber 8 is ignited and partially burnt fuel is ejected to the principal combustion chamber. As the pressure in the cylinder falls, during the expansion stroke, air from cell 9 enters the principal combustion chamber 7 to prolong combustion. The maximum temperature in chamber 7 is low so that formation of nitrogen oxides is minimized. In a first modification chamber 8 is inside chamber 9 and piston-controlled ports in the cylinder wall regulate flow to and from the cylinder. In a second modification, air-flow is through piston-controlled ports and chamber 9 is spherical and has a tangential outlet. In a third modification the cell 9 is formed in the piston crown. When the air-cell is mounted outside the cylinder a valve may be provided in the duct 11. Fig 8 shows a valve having an opening 430 leading to chamber 7 and an opening 431 leading to the air-cell. A ball 427 of magnetizable material is spring-loaded away from a seat 433 in a magnet 434. The ball closes against the spring after an initial increase in pressure due to combustion in chamber 7 and is held closed by the magnet until the pressure in chamber 7 is appreciably below that in cell 9, so that the completion of combustion is delayed. |
