| 摘要 |
Fuel is added by an injector 28 to the intake air and, to promote lean burn and auto-ignition at low engine load, fuel is also added by an injector 50 or by carburation (fig.1) to exhaust gas which is recirculated to the engine combustion chamber 10 via an external EGR pipe 30 in which the fuel is vaporised. It is ensured, eg by overall lean burn operation, that air is present in the EGR pipe 30 to mix with the vaporised fuel and the length of the EGR pipe 30 after the injector 50 (or carburettor) is extended to produce a substantial quantity of partial oxidation products and so that the duration of combustion at optimum spark timing is reduced by at least 10%. The exhaust gas may be stratified on entry to the combustion chamber 10. A controlled air supply 58 may be added to the recirculated exhaust gas and a high voltage wire 60 may ionise the exhaust gas/fuel mixture to increase the production of fuel radicals. Ignition in the combustion chamber 10 may be effected by compression at low load and by a spark plug at high load. |
