System and method for safe valve activation in a dynamic skip firing engine
First Claim
1. A method of controlling the operation of an internal combustion engine having at least one cylinder, each cylinder having an associated intake valve and an associated exhaust valve, the method comprising:
- directing skip fire operation of the engine;
determining whether an exhaust valve actuation failure has occurred in which the exhaust valve associated with a selected cylinder fails to open properly during a selected working cycle during the skip fire operation of the engine; and
when it is determined that an exhaust valve actuation failure has occurred, deactivating the intake valve associated with the selected cylinder during a subsequent working cycle in which the intake valve would otherwise have been actuated in response to the detection of the exhaust valve actuation failure.
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Accused Products
Abstract
A variety of methods and devices for controlling the operation of the intake and exhaust valves in an internal combustion engine during skip fire operation are described. In various embodiments, an exhaust valve monitor or other suitable mechanism is used to detect exhaust valve actuation faults. When an exhaust valve actuation fault is detected for a particular cylinder, the corresponding intake valve is deactivated (or not activated) in circumstances when it would otherwise be activated in order to prevent the intake valve from opening into a cylinder that contains high pressure combustion gases. The described approach is particularly beneficial when skip fire operation is combined with cylinder deactivation so that air is not pumped through the cylinders during the skipped working cycles.
95 Citations
17 Claims
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1. A method of controlling the operation of an internal combustion engine having at least one cylinder, each cylinder having an associated intake valve and an associated exhaust valve, the method comprising:
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directing skip fire operation of the engine; determining whether an exhaust valve actuation failure has occurred in which the exhaust valve associated with a selected cylinder fails to open properly during a selected working cycle during the skip fire operation of the engine; and when it is determined that an exhaust valve actuation failure has occurred, deactivating the intake valve associated with the selected cylinder during a subsequent working cycle in which the intake valve would otherwise have been actuated in response to the detection of the exhaust valve actuation failure. - View Dependent Claims (3, 4, 5, 6, 7, 8, 12)
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2. A method of controlling the intake valve of an internal combustion engine operating in skip fire mode having at least one cylinder, each cylinder having at least one intake valve and one exhaust valve, the method comprising:
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operating the engine in a skip fire mode having active working cycles and skipped working cycles, wherein during at least some of the skipped working cycle the associated cylinder is deactivated such that air is not pumped through the associated cylinder during the skipped working cycle; and during skip fire operation, opening the intake valve associated with each cylinder only after ensuring or verifying that the exhaust valve associated with such cylinder has been opened in a previous working cycle to ensure that the intake valve does not open when the cylinder contains high pressure combustion gases. - View Dependent Claims (9, 10, 11)
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13. A valve control system for use in an internal combustion engine operating in skip fire mode, the engine including a plurality of deactivatable cylinders and a camshaft, each cylinder having an associated intake valve and an associated exhaust valve, the camshaft being arranged to actuate the intake and exhaust valves, wherein for each deactivatable cylinder, the valve control system includes:
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a collapsible lifter arranged to activate and deactivate the cylinder by activating and deactivating the intake and exhaust valves associated with the cylinder, the collapsible lifter being hydraulically actuatable; a solenoid valve arranged to control the application of a high pressure hydraulic fluid to the collapsible lifter; wherein the solenoid valve and collapsible lifter are arranged to allow opening of the intake valve only after opening of the exhaust valve. - View Dependent Claims (14, 15, 16, 17)
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Specification