Air fuel ratio controlling apparatus

Patent metadata

Field	Value
Publication number	US-9745910-B2
Application number	US-201213429796-A
Country	US
Kind code	B2
Filing date	Mar 26, 2012
Priority date	Mar 31, 2011
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An air feed ratio controlling apparatus can include a predictor for predicting an air fuel ratio on the downstream side of a catalyst calculates a predicted air fuel ratio at least based on an actual air fuel ratio from an oxygen sensor and a history of a first correction coefficient. The air fuel ratio controlling apparatus can also include an adaptive model corrector which determines the deviation between the actual air fuel ratio and the predicted air fuel ratio as a prediction error ERPRE, and superposes a second correction coefficient on the first correction coefficient so that the prediction error may be reduced to zero.

First claim

The invention claimed is:

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.

2. The engine control system according to claim 1 , wherein, at a stage at which deterioration of the prediction accuracy is decided by said electronic control unit, feedback is carried out so that an error between the actual air fuel ratio and a target value set in advance may be reduced to zero.

3. The engine control system according to claim 1 , wherein, at a stage at which it is decided by the electronic control unit that the prediction accuracy is assured, said electronic control unit returns the starting period of said electronic control unit to the original period, and cancels the temporary stopping of said electronic control unit.

4. The engine control system according to claim 2 ,
wherein the electronic control unit is further configured to exclusively carry out feedback so that an error between the actual air fuel ratio and a target value set in advance may be reduced to zero.

5. The engine control system according to claim 3 ,
wherein said electronic control unit is configured to carry out feedback of the first correction coefficient so that an error of the predicted air fuel ratio (DVPRE) may be reduced to zero, and
wherein said electronic control unit is configured to return the starting period to the original period, cancel the temporary stopping of said electronic control unit, and to reset a parameter of an identifier for identifying a parameter of said electronic control unit to an initial value.

6. The engine control system according to claim 1 ,
wherein the electronic control unit is further configured to decide prediction accuracy based on the prediction error, and
wherein at a stage at which the prediction accuracy is deteriorated, said electronic control unit is configured to carry out feedback so that an error between the actual air fuel ratio and a target value set in advance may be reduced to zero.

7. The engine control system according to claim 1 ,
wherein the electronic control unit is configured to temporarily stop processing for a time set in advance based on an input of a signal indicating that an air fuel ratio feedback condition is satisfied, and
to shorten a starting period of said electronic control unit during the stopping.

8. The engine control system according to claim 7 , wherein, based on the input of the signal indicating that the air fuel ratio feedback condition is satisfied, feedback is carried out so that an error between the actual air fuel ratio and a target value set in advance may be reduced to zero.

9. The engine control system according to claim 7 , wherein, at a stage at which time set in advance elapses, said electronic control unit returns the starting period of said electronic control unit to the original period, and cancels the temporary stopping of said electronic control unit.

10. The engine control system according to claim 1 ,
wherein said electronic control unit is also configured to carry out feedback for time set in advance based on an input of a signal indicating that an air fuel ratio feedback condition is satisfied so that an error between the actual air fuel ratio and a target value set in advance may be reduced to zero.

11. The engine control system according to claim 1 ,
wherein said electronic control unit is configured to carry out feedback of the first correction coefficient so that an error of the predicted air fuel ratio may be reduced to zero, and
wherein said electronic control unit is configured to temporarily stop the controlling operation, and to temporarily stop an identifier for identifying a parameter of said electronic control unit.

12. The engine control system according to claim 1 ,
wherein said electronic control unit includes a first basic fuel injection map based on the engine speed and the throttle opening, and a second basic fuel injection map based on the engine speed and the intake air pressure,
wherein said electronic control unit is further configured to select a basic fuel injection map to be used based on the engine speed and the throttle opening from between said first basic fuel injection map and said second basic fuel injection map, and
wherein where said first basic fuel injection map is selected by said electronic control unit, said electronic control unit is configured to carry out feedback of a prediction error correction amount so that the prediction error on which a weight component based on the engine speed and the throttle opening is reflected may be reduced to zero in a fixed time period, and to calculate the second correction coefficient based on the prediction error correction amount at a predetermined timing.

13. The engine control system according to claim 1 ,
wherein said electronic control unit includes a first basic fuel injection map based on the engine speed and the throttle opening, and a second basic fuel injection map based on the engine speed and the intake air pressure,
wherein said electronic control unit is further configured to select a basic fuel injection map to be used based on the engine speed and the throttle opening from between said first basic fuel injection map and said second basic fuel injection map, and
wherein where said second basic fuel injection map is selected by said electro

Assignees

• Nakamura Masanori
• Asada Yukihiro
• Kokubu Shiro
• Shida Emi
• Honda Motor Co Ltd

Inventors

• Nakamura Masanori
• Asada Yukihiro
• Kokubu Shiro
• Shida Emi

Classifications

• F02D2041/1412

  using a predictive controller · CPC title

• F02D2041/142

  using different types of control law in combination, e.g. adaptive combined with PID and sliding mode · CPC title

• F02D41/1402 Primary

  Adaptive control · CPC title

• F02D41/1403

  Sliding mode control · CPC title

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title