Patent ID: 9745910
Date: 2017-08-29
CPC Classifications: F02D

Claim:
1. An engine control system, comprising: an oxygen sensor provided on a downstream side of a catalyst disposed in an exhaust pipe of an engine and configured to detect an air fuel ratio; a fuel injection valve; and an electronic control unit, wherein the electronic control unit is configured to determine a fuel injection amount for the engine based on parameters of an engine speed, a throttle opening, and an intake air pressure, predict an air fuel ratio on the downstream side of the catalyst, determine a first correction coefficient with respect to the fuel injection amount based on the predicted air fuel ratio, calculate the predicted air fuel ratio at least based on an actual air fuel ratio from the oxygen sensor and a history of the first correction coefficient, determine a deviation between the actual air fuel ratio and a time-delayed predicted air fuel ratio corresponding to the actual air fuel ratio as a prediction error, calculate a second correction coefficient based on the engine speed, the throttle opening, the intake air pressure, and the prediction error. superpose the second correction coefficient on the first correction coefficient and reduce the prediction error to zero, determine prediction accuracy based on the prediction error, temporarily stop processing at a stage at which deterioration of the prediction accuracy is decided, shorten a starting period of the electronic control unit during the stopping, determine a correction air fuel ratio by superposing the second correction coefficient with a target air fuel ratio, determine a difference between an air fuel ratio reference value and the correction air fuel ratio, determine the target air fuel ratio by adding the first correction coefficient with the air fuel ratio reference value, determine an environmental correction coefficient at least from parameters of an engine water temperature, an intake air temperature, and an atmospheric pressure, correct the fuel injection amount with the target air fuel ratio and the environmental correction coefficient, output the corrected fuel injection amount as a fuel injection time period, and control an injection of fuel of the fuel injection valve according to the fuel injection time period, wherein the predicted air fuel ratio is determined with the difference of the air fuel ratio reference value and the correction air fuel ratio, and the actual air fuel ratio.