Torque control method and system in an engine with a fully variable intake valve
First Claim
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1. A method for controlling torque during a mode transition in an engine, the engine having a fully variable intake valve communicating with an engine cylinder, the method, comprising the steps of:
- computing an intake valve closing time of the fully variable intake valve for a next scheduled cylinder having an intake stroke to provide a desired amount of air in the next scheduled cylinder; and
closing the fully variable intake valve of said scheduled next cylinder at said computed closing time to obtain a desired torque trajectory.
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Abstract
A system and a method to control torque during a mode transition in an internal combustion engine with a fully variable intake valve is disclosed. The mode transition may be a change in the number of active cylinders in a variable displacement engine, a change in compression ratio in a variable compression ratio engine, a gear change in a transmission coupled to the engine, a traction control event, and a rapid change in driver demand.
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Citations
38 Claims
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1. A method for controlling torque during a mode transition in an engine, the engine having a fully variable intake valve communicating with an engine cylinder, the method, comprising the steps of:
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computing an intake valve closing time of the fully variable intake valve for a next scheduled cylinder having an intake stroke to provide a desired amount of air in the next scheduled cylinder; and
closing the fully variable intake valve of said scheduled next cylinder at said computed closing time to obtain a desired torque trajectory. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling torque in an engine, the engine having a fully variable intake valve communicating with an engine cylinder, the method comprising:
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maintaining an engine torque during an engine mode transition by adjusting a closing time of the fully variable intake valve;
determining a desired engine torque;
determining an expected engine torque which would result in the event that said closing time of the fully variable intake valve were not adjusted; and
determining said closing time of the fully variable intake valve based on a difference between said desired engine torque and said expected engine torque. - View Dependent Claims (11)
indicating when an engine mode transition occurs; and
enabling the fully variable intake valve when said engine mode transition occurs.
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12. A method for operating an engine, the engine having a fully variable intake valve communicating with an engine cylinder, the method comprising:
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computing a new intake valve closing time of the fully variable intake valve as a function of a desired increase in an amount of inducted air for a next intake stroke of the cylinder next scheduled for an intake stroke wherein said increased inducted air into said cylinder is based on a desired torque increase and causes said torque increase within one engine revolution; and
closing the fully variable intake valve of said cylinder at said new closing time. - View Dependent Claims (13)
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14. A method for making a mode transition in an internal combustion engine with a plurality of cylinders, coupled to each of the cylinders is a fully variable intake valve, wherein the mode transition affects engine torque, the method comprising the steps of:
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determining a desired torque trajectory;
determining a next scheduled cylinder due to undergo an intake stroke;
computing an intake valve closing time of the fully variable intake valve for said next scheduled cylinder to provide a desired amount of air in said next scheduled cylinder based on said desired torque trajectory;
providing an amount of fuel to said next scheduled cylinder in proportion to said desired air;
commanding said intake valve closing time to the fully variable intake valve of said scheduled next cylinder; and
combusting said fuel and said desired air in said next scheduled cylinder to provide said desired engine torque trajectory. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A valve system in an internal combustion engine with a plurality of cylinders for making a mode transition which affects engine torque, wherein the valve system comprises:
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a fully variable intake valve coupled to the cylinder; and
an engine control unit operably connected to said engine and said fully variable intake valve, wherein said engine control unit determines a desired torque trajectory, determines a next cylinder scheduled to undergo an intake stroke, computes an intake valve closing time of the fully variable intake valve for said next scheduled cylinder to provide a desired amount of air in said next scheduled cylinder based on said desired torque trajectory, computes an amount of fuel to provide to said next schedule cylinder, and commands said intake valve closing time to the fully variable intake valve of said scheduled next cylinder. - View Dependent Claims (25, 26, 27, 28, 29)
an exhaust camshaft coupled to the engine;
an exhaust valve actuated by said camshaft; and
an exhaust valve deactivator coupled to said exhaust valve so that selected cylinders are capable of being disabled by deactivating said exhaust valve and said fully variable intake valve.
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27. The valve system as recited in claim 24, further comprising:
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an exhaust camshaft coupled to the engine;
an exhaust valve actuated by said camshaft; and
a variable valve timing mechanism coupled to said exhaust camshaft to adjust an exhaust valve timing to minimize pumping work and maximize expansion work of the engine.
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28. The valve system as recited in claim 24, further comprising a selectable intake valve coupled to the cylinder to increase airflow into the cylinder.
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29. The valve system as recited in claim 28, further comprising:
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an intake camshaft coupled to the engine to actuate said selectable intake valve; and
a variable valve timing mechanism coupled to said intake camshaft to provide improved airflow to the cylinder at high engine speeds.
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30. A method for controlling torque in an internal combustion engine in response to a mode transition of the engine, the engine having a plurality of cylinders in which are disposed a fully variable intake valve and at least one exhaust valve actuated by a camshaft, the method comprising the steps of:
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determining a desired torque trajectory;
determining a next scheduled cylinder due to undergo an intake stroke;
computing an intake valve closing time of the fully variable intake valve for said next scheduled cylinder to provide a desired amount of air in said next scheduled cylinder based on said desired torque trajectory;
providing an amount of fuel to said next scheduled cylinder in proportion to said desired air;
commanding said intake valve closing time to the fully variable intake valve of said scheduled next cylinder; and
combusting said fuel and said desired air in said next scheduled cylinder to provide said desired engine torque trajectory during said mode transition of said engine. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38)
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Specification