Patent ID: 8457866
Filing Date: 2013-06-04
Classification: F02D,F02M,F02P,Y02T

Abstract:
1. An ignition timing control system for an internal combustion engine that directly injects fuel into cylinders, and is operated by switching a fuel injection mode between a suction stroke injection mode in which fuel injection is performed during a suction stroke, and a compression stroke injection mode in which the fuel injection is performed during a compression stroke, the engine having an internal EGR device for executing internal EGR in which combustion gases generated by combustion of the air-fuel mixture remain in the cylinders, the ignition timing control system controlling ignition timing in the compression stroke injection mode, comprising: rotational speed-detecting means for detecting rotational speed of the engine; fuel injection amount-setting means for setting a fuel injection amount of fuel to be injected into the cylinders; fuel injection timing-setting means for setting fuel injection timing in the compression stroke injection mode according to the rotational speed of the engine and the set fuel injection amount; basic value-setting means for setting a basic value of ignition timing according to the rotational speed of the engine and the set fuel injection timing; air-fuel ratio-detecting means for detecting an air-fuel ratio of an air-fuel mixture burned in the engine; target air-fuel ratio-setting means for setting a target air-fuel ratio that serves as a target to the air-fuel ratio; internal EGR amount parameter-acquiring means for acquiring an internal EGR amount parameter indicative of an amount of the internal EGR executed by the internal EGR device; target internal EGR amount parameter-setting means for setting a target internal EGR amount parameter that serves as a target to the internal EGR amount parameter; and ignition timing-setting means for setting ignition timing in the compression stroke injection mode by correcting the basic value according to an air-fuel ratio difference between the detected air-fuel ratio and the set target air-fuel ratio, and an EGR amount difference the acquired internal EGR amount parameter and the set target internal EGR amount parameter; wherein the ignition timing-setting means corrects the basic value such that as the air-fuel ratio difference is larger, the ignition timing is set to a more advanced side, and as a degree of deviation of the internal EGR amount to a larger side with respect to the target internal EGR amount indicated by the EGR amount difference is higher, the ignition timing is set to a more advanced side.