Method and apparatus for controlling mode transition in a spark-ignition direct-injection internal combustion engine
First Claim
1. Method for operating a spark-ignition, direct-fuel injection internal combustion engine, comprising:
- commanding the engine to transition from operating in a stratified charge combustion mode to operating in a homogeneous charge combustion mode;
substantially completely discontinuing external EGR flow;
estimating an in-cylinder trapped air mass and in-cylinder EGR mass;
determining trajectories for an air/fuel ratio and the in-cylinder EGR mass, and controlling throttle position and engine fueling to achieve said trajectories;
monitoring the air/fuel ratio;
initiating double-injection fueling for each combustion cycle when the air/fuel ratio is less than a first predetermined threshold; and
initiating single-injection fueling for each combustion cycle and executing spark retard management to control the engine output torque when the air/fuel ratio is less than a second predetermined threshold.
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Accused Products
Abstract
The disclosure sets forth operating a spark-ignition, direct-fuel injection internal combustion engine, including transitioning the engine from operating in a stratified charge combustion mode to operating in a homogeneous charge combustion mode. External EGR flow is discontinued, and an in-cylinder trapped air mass and an in-cylinder EGR mass in an air intake system of the engine are estimated. Engine throttle position is controlled to achieve trajectories for air/fuel ratio and the in-cylinder EGR mass determined based upon the estimated in-cylinder trapped air mass and the in-cylinder EGR mass in the air intake system. A double-injection fueling strategy and a single-injection fueling are used during the transition.
34 Citations
20 Claims
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1. Method for operating a spark-ignition, direct-fuel injection internal combustion engine, comprising:
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commanding the engine to transition from operating in a stratified charge combustion mode to operating in a homogeneous charge combustion mode; substantially completely discontinuing external EGR flow; estimating an in-cylinder trapped air mass and in-cylinder EGR mass; determining trajectories for an air/fuel ratio and the in-cylinder EGR mass, and controlling throttle position and engine fueling to achieve said trajectories; monitoring the air/fuel ratio; initiating double-injection fueling for each combustion cycle when the air/fuel ratio is less than a first predetermined threshold; and initiating single-injection fueling for each combustion cycle and executing spark retard management to control the engine output torque when the air/fuel ratio is less than a second predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Method transitioning operation of a spark-ignition, direct-fuel injection internal combustion engine from a stratified charge combustion mode to a homogeneous charge combustion mode, comprising
estimating an in-cylinder trapped air mass and an in-cylinder EGR mass; -
controlling a throttle position, an EGR valve position, and engine fueling to achieve trajectories for an air/fuel ratio and the in-cylinder EGR mass, said trajectories based upon the estimated in-cylinder trapped air mass and the in-cylinder EGR mass; monitoring the air/fuel ratio; initiating double-injection fueling when the air/fuel ratio is less than a first predetermined threshold; and initiating single-injection fueling during each intake stroke when the air/fuel ratio is less than a second predetermined threshold. - View Dependent Claims (12, 13)
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14. Method for operating a spark-ignition, direct-fuel injection internal combustion engine selectively operative in one of a plurality of combustion modes, comprising:
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commanding a transition from a stratified charge combustion mode to a homogeneous charge combustion mode; controlling an EGR valve to a preferred position for operating the engine in the homogeneous charge combustion mode; estimating an in-cylinder trapped air mass and an in-cylinder EGR mass; controlling throttle position and engine fueling to meet an engine output torque based upon engine operation in the homogeneous charge combustion mode and based upon predetermined trajectories for the exhaust air/fuel ratio and the in-cylinder EGR mass determined based upon the estimated mass of trapped air and the in-cylinder EGR mass; monitoring air/fuel ratio; initiating double-injection fueling when the air/fuel ratio is less than a first predetermined threshold; and initiating single-injection fueling during the intake stroke and executing spark retard management to control the engine output torque when the air/fuel ratio is less than a second predetermined threshold. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification