Strategy and control system for deactivation and reactivation of cylinders of a variable displacement engine
First Claim
1. A method for controlling a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected internal combustion engine, the engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve, a camshaft driven actuator for the intake valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the non-variable displacement cylinder, and a throttle-controlled air induction system for the cylinders, the method comprising the steps of:
- effecting a transition between a first operating mode in which both the variable displacement cylinder and the non-variable displacement cylinder are active and a second operating mode in which only the non-variable displacement cylinder is active;
retarding timing of the intake valve closing event for the variable displacement cylinder and the intake valve opening event for the variable displacement cylinder so that the events are approximately equidistant from a top-dead-center position of the piston during the transition, whereby net friction and air pumping losses are minimized;
increasing throttle opening to increase torque of the non-variable displacement cylinder;
advancing camshaft timing to increase torque for the non-variable displacement cylinder during the transition while simultaneously retarding camshaft timing and spark timing to reduce torque for the variable displacement cylinder; and
deactivating the exhaust valve, fuel injector and spark for the variable displacement cylinder during a deactivation region of the transition, the deactivation occurring during one full cycle of the engine, the torque increase and the torque decrease during the transition occurring during a torque control region of the transition in advance of the deactivation.
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Accused Products
Abstract
A strategy and control system for a variable displacement engine in which cylinder deactivation is obtained by intake cam phasing and exhaust valve deactivation. Fuel control for the engine and spark deactivation are sequenced with valve deactivation to avoid transferring engine exhaust gases to the intake manifold of the engine during a transition between full cylinder operation and partial cylinder operation. Excess air flow through the exhaust system for the engine is avoided during a transition from partial cylinder operation to full cylinder operation. These features achieve stable engine performance during the transition.
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Citations
23 Claims
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1. A method for controlling a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected internal combustion engine, the engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve, a camshaft driven actuator for the intake valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the non-variable displacement cylinder, and a throttle-controlled air induction system for the cylinders, the method comprising the steps of:
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effecting a transition between a first operating mode in which both the variable displacement cylinder and the non-variable displacement cylinder are active and a second operating mode in which only the non-variable displacement cylinder is active;
retarding timing of the intake valve closing event for the variable displacement cylinder and the intake valve opening event for the variable displacement cylinder so that the events are approximately equidistant from a top-dead-center position of the piston during the transition, whereby net friction and air pumping losses are minimized;
increasing throttle opening to increase torque of the non-variable displacement cylinder;
advancing camshaft timing to increase torque for the non-variable displacement cylinder during the transition while simultaneously retarding camshaft timing and spark timing to reduce torque for the variable displacement cylinder; and
deactivating the exhaust valve, fuel injector and spark for the variable displacement cylinder during a deactivation region of the transition, the deactivation occurring during one full cycle of the engine, the torque increase and the torque decrease during the transition occurring during a torque control region of the transition in advance of the deactivation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9)
the advancement of camshaft timing to increase torque and the retarding of camshaft and spark timing to decrease torque occurring for all cylinders in the first bank;
the increase in throttle opening to increase torque occurring for all cylinders in the second bank during the transition.
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3. The method set forth in claim 2 wherein the deactivation of camshaft, fuel injectors and spark retarding to reduce torque occurs for all cylinders in the first bank.
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4. The method set forth in claim 3 wherein the deactivation of the cylinders occurs in a sequence corresponding to a pre-selected firing order for the cylinders in the first bank.
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5. The method set forth in claim 2 wherein the engine has a common intake air induction system with a common throttle valve in communication with the intake valves for the variable displacement cylinders and the non-variable displacement cylinders.
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6. The method set forth in claim 2 wherein the cylinders of each bank have separate induction systems, each induction system having a separate throttle valve, each throttle valve being connected to a common throttle valve actuator.
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7. The method set forth in claim 2 wherein the intake valves for the first bank of cylinders remain active during the transition between the first and second operating modes while the exhaust valves are deactivated.
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9. The method set forth in claim 2 wherein the exhaust valve for each cylinder in the bank of variable displacement cylinders is deactivated during the transition to the second operating mode in the engine cycle following spark retarding and fuel injector deactivation in the immediately preceding engine cycle.
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8. A method for controlling a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected internal combustion engine, the engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve, a camshaft driven actuator for the intake valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the non-variable displacement cylinder, and a throttle-controlled air induction system for the cylinders, the method comprising the steps of:
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effecting a transition from a first operating mode in which only the non-variable displacement cylinder is active to a second operating mode in which both cylinders are active;
decreasing the throttle opening to decrease torque of the non-variable displacement cylinder;
retarding camshaft timing to decrease torque for the non-variable displacement cylinder during the transition while simultaneously advancing camshaft timing and spark timing to increase torque for the variable displacement cylinder;
activating the exhaust valve, fuel injector and spark for the variable displacement cylinder during the transition from the first operating mode to the second operating mode; and
retarding the timing of the intake valve closing event and the intake valve opening event so that the events are approximately equidistant from a top dead center position of the piston during the transition as the deactivated cylinders are reactivated, whereby friction and air pumping losses are minimized;
the torque increase of the variable displacement cylinder and the torque decrease of the non-variable displacement cylinder during the transition occurring during a torque control region of the transition, preceded by a reactivation region of the transition in which the exhaust valve, fuel injector and spark advance for the variable displacement cylinder are reactivated. - View Dependent Claims (10)
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11. A method for controlling a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected internal combustion engine, the engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve, a camshaft driven actuator for the intake valve of the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the non-variable displacement cylinder, a throttle-controlled air induction system for the cylinders, the method comprising the steps of:
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effecting a transition between a first operating mode in which both the variable displacement cylinder and the non-variable displacement cylinder are active and a second operating mode in which only the non-variable displacement cylinder is active;
increasing throttle opening to increase torque of the non-variable displacement cylinder;
advancing camshaft timing to increase torque for the non-variable displacement cylinder during the transition while simultaneously retarding camshaft timing and spark timing to reduce torque for the variable displacement cylinder; and
deactivating the exhaust valve, fuel injector and spark for the variable displacement cylinder during a deactivation region of the transition, the deactivation occurring during one full cycle of the engine, the torque increase and the torque decrease during the transition occurring during a torque control region of the transition in advance of the deactivation. - View Dependent Claims (12, 13, 14, 15, 16, 17, 19)
the advancement of camshaft timing to increase torque and the retarding of camshaft and spark timing to decrease torque occurring for all cylinders in the first bank;
the increase in throttle opening to increase torque occurring for all cylinders in the second bank during the transition.
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13. The method set forth in claim 12 wherein the deactivation of camshaft, fuel injectors and spark retarding to reduce torque occurs for all cylinders in the first bank.
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14. The method set forth in claim 13 wherein the deactivation of the cylinders occurs in a sequence corresponding to a pre-selected firing order for the cylinders in the first bank.
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15. The method set forth in claim 12 wherein the engine has a common intake air induction system with a common throttle valve in communication with the intake valves for the variable displacement cylinders and the non-variable displacement cylinders.
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16. The method set forth in claim 12 wherein the cylinders of each bank have separate induction systems, each induction system having a separate throttle valve, each throttle valve being connected to a common throttle valve actuator.
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17. The method set forth in claim 12 wherein the intake valves for the first bank of cylinders remain active during the transition between the first and second operating modes while the exhaust valves are deactivated.
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19. The method set forth in claim 12 wherein the exhaust valve for each cylinder in the bank of variable displacement cylinders is deactivated during the transition to the second operating mode in the engine cycle following spark retarding and fuel injector deactivation in the immediately preceding engine cycle.
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18. A method for controlling a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected internal combustion engine, the engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve, a camshaft driven actuator for the intake valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft driven actuator for the exhaust valve for the non-variable displacement cylinder, a throttle-controlled air induction system for the cylinders, the method comprising the steps of:
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effecting a transition from a first operating mode in which only the non-variable displacement cylinder is active to a second operating mode in which both cylinders are active;
decreasing the throttle opening to decrease torque of the non-variable displacement cylinder;
retarding camshaft timing to decrease torque for the non-variable displacement cylinder during the transition while simultaneously advancing camshaft timing and spark timing to increase torque for the variable displacement cylinder; and
activating the exhaust valve, fuel injector and spark for the variable displacement cylinder during the transition from the first operating mode to the second operating mode;
the torque increase of the variable displacement cylinder and the torque decrease of the non-variable displacement cylinder during the transition occurring during a torque control region of the transition, preceded by a reactivation region of the transition in which the exhaust valve, fuel injector and spark advance for the variable displacement cylinder are reactivated. - View Dependent Claims (20)
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21. An engine control system for a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel-injected, internal combustion engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve;
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a camshaft-driven actuator for the intake valve of the variable displacement cylinder;
a camshaft-driven actuator for the exhaust valve for the variable displacement cylinder, a camshaft-driven exhaust valve for the non-variable displacement cylinder;
a throttle controlled air induction system for the cylinders;
an engine controller for controlling fuel injection, spark retard, throttle and camshaft timing, the controller including a digital processor and a memory with a stored control algorithm;
the controller being programmed in accordance with the algorithm to effect a transition between a first operating mode in which both the variable displacement cylinder and the non-variable displacement cylinder are active and a second operating mode in which only the non-variable displacement cylinder is active;
the controller increasing throttle opening to increase torque of the non-variable displacement cylinder;
the camshaft timing being advanced by the controller to increase torque of the non-variable displacement cylinder during the transition while simultaneously retarding camshaft timing to reduce torque for the variable displacement cylinder;
the exhaust valve, the fuel injector and spark for the variable displacement cylinder being deactivated during a deactivation region of the transition, the torque decrease and the torque increase and during the transition occurring during a torque control region of the transition in advance of the deactivation. - View Dependent Claims (22)
the advancement of camshaft timing to increase torque and the retarding of camshaft and spark timing to decrease torque occurring for all cylinders in the first bank;
the increase in throttle opening to increase torque occurring in the first bank and the second bank during the transition.
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23. An engine control system for a variable displacement, multiple-cylinder, four-stroke cycle, spark-controlled, fuel injected, internal combustion engine having at least one variable displacement cylinder and one non-variable displacement cylinder, each cylinder having a piston, an exhaust valve and at least one air intake valve;
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a camshaft-driven actuator for the intake valve of the variable displacement cylinder;
a camshaft-driven actuator for the exhaust valve for the variable displacement cylinder;
a camshaft-driven actuator for the exhaust valve for the non-variable displacement cylinder;
a throttle-controlled air induction system for the cylinders;
an engine controller for controlling fuel injection, spark retard, throttle and camshaft timing, the controller including a digital processor and a memory with a stored control algorithm;
the controller being programmed in accordance with the algorithm to effect a transition between a first operating mode in which only the non-variable displacement cylinder is active and a second operating mode in which both the variable displacement cylinder and the non-variable displacement cylinder are active;
the controller decreasing throttle opening to decrease torque of the nonvariable displacement cylinder;
the camshaft timing being retarded by the controller to decrease torque of the non-variable displacement cylinder during the transition while simultaneously advancing camshaft timing to increase torque for the variable displacement cylinder;
the controller activating the exhaust valve, fuel injector and spark for the variable displacement cylinder during the transition from the first operating mode to the second operating mode;
the torque increase of the variable displacement cylinder and the torque decrease of the non-variable displacement cylinder during the transition occurring during a torque control region of the transition, preceded by a reactivation region of the transition in which the exhaust valve, fuel injector and spark advance for the variable displacement cylinder are reactivated.
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Specification