EGR control system for engine
First Claim
1. An engine control system comprising:
- an internal combustion engine comprising a combustion control system for controlling a combustion condition in the engine by changing over a combustion control mode between a stratified combustion mode and a homogeneous combustion mode, and an EGR system for recirculating exhaust gas of the engine to an intake air flow to the engine; and
a controller for controlling an EGR quantity by controlling the EGR system, for changing over an EGR control mode between a stratifying EGR mode for the stratified combustion mode and a homogenizing EGR mode for the homogeneous combustion mode to adapt the EGR quantity to the combustion condition of the engine, and for changing an EGR control changeover timing of changeover of the EGR control mode between the stratifying mode and the homogenizing mode in accordance with a changeover direction which is one of a first direction from the homogeneous combustion mode to the stratified combustion mode and a second direction from the stratified combustion mode to the homogeneous combustion mode;
the controller advancing the EGR control changeover timing to effect a start of a changeover of the EGR control mode in advance of a changeover of the combustion control mode when the changeover direction is the second direction from the stratified combustion mode to the homogeneous combustion mode.
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Accused Products
Abstract
An engine control system for an internal combustion engine of a type having a stratified combustion mode and a homogeneous combustion mode comprises a controller for controlling an EGR flow in the engine with an EGR control valve. The controller effects a changeover of an EGR control mode of the EGR control valve from a first EGR mode to a second EGR mode immediately in response to a changeover request signal before an actual changeover of a combustion control mode from the stratified combustion mode to the homogeneous combustion mode. In the case of a changeover from the homogeneous mode to the stratified mode, the controller effects a changeover of the EGR control mode from the second EGR mode to the first EGR mode in response to an actual changeover of the combustion control mode, with a delay after the changeover request signal.
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Citations
21 Claims
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1. An engine control system comprising:
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an internal combustion engine comprising a combustion control system for controlling a combustion condition in the engine by changing over a combustion control mode between a stratified combustion mode and a homogeneous combustion mode, and an EGR system for recirculating exhaust gas of the engine to an intake air flow to the engine; and a controller for controlling an EGR quantity by controlling the EGR system, for changing over an EGR control mode between a stratifying EGR mode for the stratified combustion mode and a homogenizing EGR mode for the homogeneous combustion mode to adapt the EGR quantity to the combustion condition of the engine, and for changing an EGR control changeover timing of changeover of the EGR control mode between the stratifying mode and the homogenizing mode in accordance with a changeover direction which is one of a first direction from the homogeneous combustion mode to the stratified combustion mode and a second direction from the stratified combustion mode to the homogeneous combustion mode;
the controller advancing the EGR control changeover timing to effect a start of a changeover of the EGR control mode in advance of a changeover of the combustion control mode when the changeover direction is the second direction from the stratified combustion mode to the homogeneous combustion mode. - View Dependent Claims (2, 3, 4, 5)
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6. An engine control system comprising:
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an internal combustion engine having a combustion control system and an EGR system, the combustion control system controlling a combustion condition in the engine by changing over a combustion control mode between a stratified combustion mode and a homogeneous combustion mode, and the EGR system recirculating exhaust gas of the engine to an intake air flow to the engine; and a controller for controlling an EGR quantity by controlling the EGR system, for changing over an EGR control mode between a stratifying EGR mode for the stratified combustion mode and a homogenizing EGR mode for the homogeneous combustion mode to adapt the EGR quantity to the combustion condition of the engine, and for changing an EGR control changeover timing of changeover of the EGR control mode between the stratifying mode and the homogenizing mode in accordance with a changeover direction which is one of a first direction from the homogeneous combustion mode to the stratified combustion mode and a second direction from the stratified combustion mode to the homogeneous combustion mode; and an engine operating condition sensor, the sensor sensing an engine operating condition of the engine, wherein the EGR system of the engine includes an EGR passage extending from an exhaust system of the engine to an intake system of the engine, and an EGR valve disposed in the EGR passage, wherein the controller produces an EGR control signal to control an opening degree of the EGR valve to control the EGR quantity in one of the stratifying EGR mode and the homogenizing EGR mode, and wherein the controller determines the changeover direction by selecting, as a desired target combustion mode, one of the stratified combustion mode and the homogeneous combustion mode in accordance with the engine operating condition sensed by the sensor, advances the EGR control changeover timing to effect a start of a changeover of the EGR mode and the homogenizing EGR mode in advance of a changeover of the combustion mode and the homogeneous combustion mode when the target combustion mode is the homogeneous combustion mode and the changeover direction is from the stratified combustion mode to the homogeneous combustion mode, and retards the EGR control changeover timing to delay a start of the changeover of the EGR control mode until the changeover of the combustion control mode when the target combustion mode is the stratified combustion mode and the changeover direction is from the homogeneous combustion mode to the stratified combustion mode. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. An engine control process for an internal combustion engine comprising a combustion control system for controlling a combustion condition in the engine by changing over a combustion control mode between a stratified combustion mode and a homogeneous combustion mode, and an EGR system for recirculating exhaust gas of the engine to an intake air flow into the engine;
- the engine control process comprising;
controlling an EGR quantity of the engine to adapt the EGR quantity to the combustion condition of the engine by changing over an EGR control mode between a stratifying EGR mode for the stratified combustion mode and a homogenizing EGR mode for the homogeneous combustion mode; and changing an EGR control changeover timing of changeover of the EGR control mode between the stratifying EGR mode and the homogenizing EGR mode in accordance with a changeover direction which is one of a first direction from the homogeneous combustion mode to the stratified combustion mode and a second direction from the stratified combustion mode to the homogeneous combustion mode, the EGR control changeover timing being advanced to effect a start of a changeover of the EGR control mode in advance of a changeover of the combustion control mode when the changeover direction is the second direction from the stratified combustion mode to the homogeneous combustion mode. - View Dependent Claims (15)
- the engine control process comprising;
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16. An engine control process for an internal combustion engine having a combustion control system and an EGR system, the combustion control system controlling a combustion condition in the engine by changing over a combustion control mode between a stratified combustion mode and a homogeneous combustion mode, and the EGR system recirculating exhaust gas of the engine to an intake air flow into the engine, the engine control process comprising:
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controlling an EGR quantity of the engine to adapt the EGR quantity to the combustion condition of the engine by changing over an EGR control mode between a stratifying EGR mode for the stratified combustion mode and a homogenizing EGR mode for the homogeneous combustion mode; and changing an EGR control changeover timing of changeover of the EGR control mode between the stratifying EGR mode and the homogenizing EGR mode in accordance with a changeover direction which is one of a first direction from the homogeneous combustion mode to the stratified combustion mode and a second direction from the stratified combustion mode to the homogeneous combustion mode, wherein the controlling step includes producing an EGR control signal, in one of the stratifying EGR mode and the homogenizing EGR mode, to control an opening degree of an EGR valve disposed in an EGR passage extending from an exhaust system of the engine to an intake system of the engine, to control the EGR quantity of the engine, wherein the changing step includes collecting input information on a sensed engine operating condition; determining the changeover direction by selecting, as a desired target combustion mode, one of the stratified combustion mode and the homogeneous combustion mode in accordance with the engine operating condition; and advancing the EGR control changeover timing to effect a start of a changeover of the EGR control mode between the stratifying EGR mode and the homogenizing EGR mode in advance of a changeover of the combustion control mode between the stratified combustion mode and the homogeneous combustion mode when the target combustion mode is the homogeneous combustion mode and the changeover direction is from the stratified combustion mode to the homogeneous combustion mode, and retarding the EGR control changeover timing to delay a start of the changeover of the EGR control mode until the changeover of the combustion control mode when the target combustion mode is the stratified combustion mode and the changeover direction is from the homogeneous combustion mode to the stratified combustion mode. - View Dependent Claims (17, 18, 19)
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20. An engine control system comprising:
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an internal combustion engine comprising at least one engine cylinder; a fuel injection system for controlling a combustion condition in the engine by injecting fuel into the engine in response to a combustion control signal which is in one of a first combustion control state for controlling the combustion condition in a stratified combustion mode and a second combustion control state for controlling the combustion condition in a homogeneous combustion mode; an EGR system comprising an EGR passage for recirculating exhaust gas of the engine into an intake air flow, and an EGR valve disposed in the EGR passage, for controlling an EGR quantity of the EGR system in response to an EGR control signal which is in one of a first EGR control state for controlling the EGR quantity in a first EGR mode adapted to the stratified combustion mode, and a second EGR control state for controlling the EGR quantity in a second EGR mode adapted to the homogeneous combustion mode; a sensor for collecting input information to determine an engine operating parameter indicative of an engine load by sensing a first engine operating condition; and a controller for controlling the combustion condition and the EGR quantity by producing the combustion control signal and the EGR control signal in accordance with the engine operating parameter, the controller being connected with the sensor and configured to produce a condition signal which is in a first condition state when the engine operating parameter is in a predetermined lower engine load region and in a second condition state when the engine operating parameter is in a predetermined higher load region, the controller being further connected with the fuel injection system and configured to change over the combustion control signal between the first and second combustion control states so that the combustion control signal is in the first combustion control state when the condition signal is in the first condition state, and in the second combustion control state when the condition signal is in the second condition state, and the controller being further connected with the EGR system and configured to effect a changeover of the EGR control signal from the first EGR control state to the second EGR control state in response to a changeover of the condition signal from the first condition state to the second condition state before a changeover of the combustion control signal from the first combustion control state to the second combustion control state, and to effect a changeover of the EGR control signal from the second EGR control state to the first EGR control state in response to a changeover of the combustion control signal from the second combustion control state to the first combustion control state with a delay after a changeover of the condition signal from the second condition state to the first condition state. - View Dependent Claims (21)
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Specification