Engine control in fuel and/or cylinder cut off modes based on intake manifold pressure
First Claim
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1. A controller configured to control operation of an engine in a vehicle, the controller configured to:
- deactivate all working chambers of the engine in a cylinder cut off mode such that none of the working chambers are fired and no air is pumped through the working chambers from an air intake manifold to an exhaust system of the vehicle;
determining when the operation of the engine is to transition from the cylinder cut off mode to a second operational mode in response to an input to the controller;
measure intake manifold absolute pressure (MAP) in the air intake manifold; and
if the measured MAP is larger than a threshold MAP;
determine, based on the measured MAP, a number of working cycle(s) needed to pump down the measured MAP to below the threshold MAP;
operate the engine so as to pump air from the air intake manifold to the exhaust system through one or more of the working chambers of the engine for the determined number of working cycle(s); and
operate the engine in the second operational mode after the pumping of the air for the determined number of working cycle(s).
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Abstract
Methods and arrangements for transitioning an engine between a deceleration cylinder cutoff (DCCO) state and an operational state are described. In one aspect, transitions from DCCO may begin with reactivating cylinders to pump air to reduce the pressure in the intake manifold prior to firing any cylinders. The number of pumping cycles, if any, is based on intake manifold absolute pressure (MAP).
135 Citations
23 Claims
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1. A controller configured to control operation of an engine in a vehicle, the controller configured to:
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deactivate all working chambers of the engine in a cylinder cut off mode such that none of the working chambers are fired and no air is pumped through the working chambers from an air intake manifold to an exhaust system of the vehicle; determining when the operation of the engine is to transition from the cylinder cut off mode to a second operational mode in response to an input to the controller; measure intake manifold absolute pressure (MAP) in the air intake manifold; and if the measured MAP is larger than a threshold MAP; determine, based on the measured MAP, a number of working cycle(s) needed to pump down the measured MAP to below the threshold MAP; operate the engine so as to pump air from the air intake manifold to the exhaust system through one or more of the working chambers of the engine for the determined number of working cycle(s); and operate the engine in the second operational mode after the pumping of the air for the determined number of working cycle(s). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 22)
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16. A method of operating a vehicle having a crankshaft, an intake air manifold, and a plurality of working chambers of an engine, the method comprising, during operation of the engine:
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deactivating all of the working chambers in response to a no engine torque request such that none of the working chambers are fired and no air is pumped through the working chambers as the crankshaft rotates; measuring the crankshaft rotational speed; measuring intake manifold absolute pressure (MAP) when the measured crankshaft rotational speed falls below a crankshaft rotational speed threshold; ascertaining a number of air pumping working cycles needed to reduce the measured MAP to below a threshold MAP; and pumping air through the engine for the ascertained number of working cycles prior to firing any working chambers. - View Dependent Claims (17, 18, 19, 20, 21)
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23. A controller configured to control operation of an engine in a vehicle, the controller configured to:
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deactivate all working chambers of the engine in a cylinder cut off mode such that none of the working chambers are fired and no air is pumped through the working chambers from an air intake manifold to an exhaust system of the vehicle; determining when the operation of the engine is to transition from the cylinder cut off mode to a second operational mode in response to an input to the controller; measure intake manifold absolute pressure (MAP) in an air intake manifold associated with the engine; measure engine speed; determine, based on the measured MAP and engine speed, a time needed to pump air down the MAP to below a threshold MAP; operate the engine so as to pump air from the air intake manifold to the exhaust system through one or more of the working chambers of the engine for the determined time; and operate the engine in the second operational mode after the pumping of the air for the determined time.
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Specification