Early exhaust valve opening control system and method
First Claim
1. An exhaust valve system for an internal combustion engine having a crankshaft mounted for rotation, at least one engine piston operatively connected to the crankshaft for reciprocal movement within a cylinder through cyclical successive compression and expansion strokes, an exhaust system and a turbocharger positioned in the exhaust system, comprising:
- at least one exhaust valve reciprocally mounted in the engine for movement between open and closed positions;
an exhaust valve actuating means for moving said at least one exhaust valve between said open position and said closed position, said exhaust valve actuating means including an exhaust valve opening control means for varying the timing of the opening of said at least one exhaust valve during engine operation, said exhaust valve opening control means operable in a normal timing mode for permitting normal opening of said at least one exhaust valve at a normal opening crank angle prior to an end of the expansion stroke and subsequently permitting normal closing of said at least one exhaust valve at a normal closing crank angle, and in an advanced timing mode during at least one of idle engine conditions and low load engine conditions for advancing the timing of the opening of said at least one exhaust valve to an advanced opening crank angle substantially prior to said normal opening crank angle while maintaining the timing of normal closing of said at least one exhaust valve at said normal closing crank angle so as to increase the speed of the turbocharger during operation in said advanced timing mode.
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Accused Products
Abstract
An exhaust valve system for an internal combustion engine including a turbocharger is provided for effectively increasing the turbocharged boost pressure at low load engine conditions thereby effectively improving engine transient response. The exhaust valve system includes an exhaust valve control device operable in a normal timing mode for permitting normal opening of one or more exhaust valves at a normal opening crank angle, and in an advanced timing mode for advancing the timing of the opening of the exhaust valve to an advanced opening crank angle prior to the normal opening crank angle while maintaining the timing of normal closing of the exhaust valves at a normal closing crank angle. In one embodiment, the exhaust valve control device includes a tappet and an actuating fluid supply which operate to move the tappet between expanded and collapsed states to advance the opening of the exhaust valve while permitting normal exhaust valve lift to be introduced prior to peak exhaust valve lift thereby maintaining the normal peak lift and the normal timing of exhaust valve closure. In a second embodiment, the exhaust valve control device includes a dedicated advanced timing mode rocker lever capable of selectively actuating one of a pair of exhaust valves to create an early opening exhaust event prior to a normal exhaust event.
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Citations
27 Claims
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1. An exhaust valve system for an internal combustion engine having a crankshaft mounted for rotation, at least one engine piston operatively connected to the crankshaft for reciprocal movement within a cylinder through cyclical successive compression and expansion strokes, an exhaust system and a turbocharger positioned in the exhaust system, comprising:
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at least one exhaust valve reciprocally mounted in the engine for movement between open and closed positions; an exhaust valve actuating means for moving said at least one exhaust valve between said open position and said closed position, said exhaust valve actuating means including an exhaust valve opening control means for varying the timing of the opening of said at least one exhaust valve during engine operation, said exhaust valve opening control means operable in a normal timing mode for permitting normal opening of said at least one exhaust valve at a normal opening crank angle prior to an end of the expansion stroke and subsequently permitting normal closing of said at least one exhaust valve at a normal closing crank angle, and in an advanced timing mode during at least one of idle engine conditions and low load engine conditions for advancing the timing of the opening of said at least one exhaust valve to an advanced opening crank angle substantially prior to said normal opening crank angle while maintaining the timing of normal closing of said at least one exhaust valve at said normal closing crank angle so as to increase the speed of the turbocharger during operation in said advanced timing mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An exhaust valve system for an internal combustion engine having a crankshaft mounted for rotation, at least one engine piston operatively connected to the crankshaft for reciprocal movement within a cylinder through cyclical successive compression and expansion strokes, an exhaust system and a turbocharger positioned in the exhaust system, comprising:
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at least one exhaust valve reciprocally mounted in the engine for movement between open and closed positions; an exhaust valve actuating means for moving said at least one exhaust valve between said open position and said closed position, said exhaust valve actuating means including an exhaust valve opening control means for varying the timing of opening of said at least one exhaust valve during engine operation, said exhaust valve opening control means operable in a normal timing mode for permitting normal opening of said at least one exhaust valve at a normal opening crank angle and subsequently permitting normal closing of said at least one exhaust valve at a normal closing crank angle, and in an advanced timing mode during at least one of idle engine conditions and low load engine conditions for advancing the timing of the opening of said at least one exhaust valve to an advanced opening crank angle at least 90 crank angle degrees prior to an end of the expansion stroke so as to increase the speed of the turbocharger during operation in said advanced timing mode. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for controlling the timing of opening of an exhaust valve in an internal combustion engine having a crankshaft mounted for rotation, at least one engine piston operatively connected to the crankshaft for reciprocal movement within a cylinder through cyclical successive compression and expansion strokes, an exhaust system and a turbocharger positioned in the exhaust system, comprising:
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providing at least one exhaust valve mounted in the engine for movement between open and closed positions; operating the engine in a normal timing mode causing normal opening of said at least one exhaust valve at a normal opening crank angle prior to an end of the expansion stroke and subsequently permitting normal closing of said at least one exhaust valve at a normal closing crank angle; changing the operation of the engine from said normal timing mode to an advanced timing mode during at least one of idle engine conditions and low load engine conditions for advancing the timing of the opening of said at least one exhaust valve to an advanced opening crank angle earlier than said normal opening crank angle while maintaining the timing of normal closing of said at least one exhaust valve at said normal closing crank angle so as to increase the speed of the turbocharger during operation in said advanced timing mode.
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Specification