Method and system for shutting down an engine in a hybrid vehicle
First Claim
1. A method for shutting down an internal combustion engine in a hybrid vehicle that includes at least one of a motor and a generator operatively connected to an engine crankshaft, the method comprising the steps of:
- initiating a shutdown of the engine;
reducing compression in at least one engine cylinder; and
selectively operating only the at least one of the motor and the generator to primarily influence motion of the engine crankshaft during engine shutdown to attenuate oscillations in and expedite reduction of engine crankshaft speed, wherein the selectively operating step includes selectively operating the motor or the generator to apply a predetermined torque to the engine crankshaft or a target torque profile that varies with respect to time, wherein the duration of the engine shutdown is greater than 2 seconds; and
wherein the reducing step includes continuously opening at least one engine valve during the entire duration of the engine shutdown.
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Accused Products
Abstract
A method is provided for shutting down an internal combustion engine in a hybrid vehicle that includes a motor and a generator operatively connected to an engine crankshaft. The method includes the steps of reducing compression in at least one engine cylinder and operating the motor or generator to influence motion of the engine crankshaft during engine shutdown to attenuate oscillations in and expedite reduction of engine crankshaft speed. A system for shutting down a hybrid vehicle internal combustion engine is also provided.
29 Citations
21 Claims
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1. A method for shutting down an internal combustion engine in a hybrid vehicle that includes at least one of a motor and a generator operatively connected to an engine crankshaft, the method comprising the steps of:
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initiating a shutdown of the engine; reducing compression in at least one engine cylinder; and selectively operating only the at least one of the motor and the generator to primarily influence motion of the engine crankshaft during engine shutdown to attenuate oscillations in and expedite reduction of engine crankshaft speed, wherein the selectively operating step includes selectively operating the motor or the generator to apply a predetermined torque to the engine crankshaft or a target torque profile that varies with respect to time, wherein the duration of the engine shutdown is greater than 2 seconds; and
wherein the reducing step includes continuously opening at least one engine valve during the entire duration of the engine shutdown. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 19)
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11. A system for shutting down a hybrid vehicle internal combustion engine that includes at least one engine cylinder and a crankshaft, the system comprising:
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an engine cylinder compression-reducing device; at least one of a motor and a generator operatively connected to the engine crankshaft and adapted to primarily influence motion of the engine crankshaft during engine shutdown; and a controller configured to selectively operate the compression-reducing device to reduce compression in at least one engine cylinder and to selectively operate the motor or the generator to influence motion of the engine crankshaft during engine shutdown, wherein the controller is configured to operate the motor or the generator to apply a predetermined torque to the engine crankshaft or a target torque profile that varies with respect to time, wherein the duration of the engine shutdown is greater than 2 seconds, and wherein the controller is configured to continuously open at least one engine valve during the entire duration of the engine shutdown. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 20, 21)
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Specification