| 摘要 |
PURPOSE:To enable to prevent occurrence of engine roughness with high accuracy, to lower the specific fuel consumption of an engine and to keep the engine output high, by detecting variation of the indicated mean effective pressure for each cylinder during one cycle of engine operation and deviation of the indicated mean effective pressures of a plurality of cylinders, and controlling the rate of exhaust-gas recirculation for each cylinder on the basis of the variation and deviation of the indicated mean effective pressures. CONSTITUTION:The rate of exhaust-gas recirculation required for the actual operational conditions of an engine is determined from the engine speed N detected from a crank signal by means of a control circuit 10, the indicated mean effective pressure calculated by a Pi-meter 9 and the throttle opening detected by a throttle opening sensor 7. On the basis of the rate of exhaust-gas recirculation thus determined, a required amount of exhaust gas is recirculated from an exhaust pipe 6a to cylinders via exhaust-gas recirculation control valves 6 in synchronism with the crank signals. In controlling the rate of exhaust-gas recirculation, it is judged that engine roughness caused by variation of the indicated mean effective pressure Pi during one cycle of engine operation or its deviation between the cylinders is within a tolerable range in case that they are lower than a prescribed tolerable value. |
