Engine control with cylinder deactivation and variable valve timing
View Patent ↗A valve control method for an internal combustion engine of a vehicle that uses cylinder deactivation. The method can adjust actuation phases of the engine's valves in an all-cylinder activation mode and a cylinder deactivation mode. The engine's valves may be controlled from an idle operating domain, to a fuel-economy operating domain, and in a cylinder deactivation operating domain.
1. A method of controlling valves in an internal combustion engine for a vehicle in an all-cylinder activation mode of operation and a cylinder deactivation mode of operation, comprising:
utilizing a variable valve timing system to continuously adjust engine valves during all-cylinder activation mode operation and during cylinder deactivation mode operation for increasing cylinder volumetric efficiency and reducing engine-pumping loss, thus improving fuel economy and performance;
when in at least a portion of the all-cylinder activation mode of operation, selectively advancing each intake valve actuation phase at least about 8 crank angle degrees from a nominal operating domain comprised of a respective intake and exhaust valve centerline position setpoint for the internal combustion engine if it were lacking the variable valve timing system toward a fuel-economy operating domain comprised of a respective optimum intake and exhaust valve centerline position setpoint where there is improved fuel economy relative to any other of the intake and exhaust valve centerline positions for the internal combustion engine while the internal combustion engine is using variable valve timing during the all-cylinder activation mode of operation;
concurrently, when in at least a portion of the all-cylinder activation mode of operation, selectively retarding each exhaust valve actuation phase at least about 6 crank angle degrees from the nominal operating domain toward the fuel-economy operating domain;
transitioning from the all-cylinder activation mode of operation into the cylinder deactivation mode of operation when an intake valve centerline and an exhaust valve centerline are positioned within a range of centerlines centered on the nominal operating domain;
when in the cylinder deactivation mode of operation, selectively advancing each active intake valve actuation phase within a range of about 0-10 crank angle degrees, inclusive, from the nominal operating domain toward the fuel-economy operating domain, and selectively retarding each active intake valve actuation phase within a range of about 0-10 crank angle degrees, inclusive, from the nominal operating domain toward an idle operating domain comprised of a respective valve centerline position setpoint when the engine is idling; and
concurrently, when in the cylinder deactivation mode of operation, selectively retarding each active exhaust valve actuation phase within a range of about 0-12 crank angle degrees, inclusive, from the nominal operating domain toward the fuel-economy domain, and selectively advancing each active exhaust valve actuation phase within a range of about 0-12 crank angle degrees, inclusive, from the nominal operating domain toward the idle operating domain.
2. The method of claim 1 wherein advancing each intake valve actuation phase in at least a portion of the all-cylinder activation mode of operation further comprises selectively advancing each intake valve actuation phase at least about 8 crank angle degrees from the nominal operating domain toward the fuel-economy operating domain.
3. The method of claim 2 wherein retarding each exhaust valve actuation phase in at least a portion of the all-cylinder activation mode of operation further comprises selectively retarding each exhaust valve actuation phase at least about 8 crank angle degrees from the nominal operating domain toward the fuel-economy operating domain.
4. The method of claim 3 wherein, when in the cylinder deactivation mode of operation, further comprising selectively advancing each active intake valve actuation phase within a range of about 0-6 crank angle degrees, inclusive, from the nominal operating domain toward the fuel-economy operating domain, and selectively retarding each active intake valve actuation phase within a range of about 0-6 crank angle degrees, inclusive, from the nominal operating domain toward the idle operating domain.
5. The method of claim 4 wherein, when in the cylinder deactivation mode of operation, further comprising selectively retarding each active exhaust valve actuation phase within a range of about 0-6 crank angle degrees, inclusive, from the nominal operating domain toward the fuel-economy operating domain, and selectively advancing each active exhaust valve actuation phase within a range of about 0-6 crank angle degrees, inclusive, from the nominal operating domain toward the idle operating domain.
6. A method of controlling valves in an internal combustion engine for a vehicle in an all-cylinder activation mode and a cylinder deactivation mode, comprising:
utilizing a variable valve timing system to continuously adjust engine valves though the all-cylinder activation mode and the cylinder deactivation mode for increasing cylinder volumetric efficiency and reducing engine-pumping loss, thus improving fuel economy and performance;
when in the all-cylinder activation mode, selectively advancing each intake valve actuation phase at least about 20 crank angle degrees from an idle operating domain toward a fuel-economy operating domain;
concurrently, when in the all-cylinder activation mode, selectively retarding each exhaust valve actuation phase at least about 20 crank angle degrees from the idle operating domain toward the fuel-economy operating domain;
transitioning from the all-cylinder activation mode into the cylinder deactivation mode when an intake valve centerline and an exhaust valve centerline of each intake valve and each exhaust valve are positioned within a range centered on a nominal operating domain, wherein the cylinder deactivation mode deactivates half of the cylinders of the engine when the vehicle encounters a predetermined operating condition during light-to-moderate load conditions when the vehicle is cruising;
controlling the flow of oil entering and exiting a hydraulic roller follower using an electro-hydraulic manifold assembly comprising at least one solenoid valve and an oil pressure assembly for controlling the valves in the cylinder deactivation mode;
when in the cylinder deactivation mode, selectively adjusting each active intake valve actuation phase within a range of about 0-20 crank angle degrees, inclusive, from the fuel-economy operating domain toward a cylinder deactivation operating domain;
concurrently, when in the cylinder deactivation mode, selectively adjusting each active exhaust valve actuation phase within a range of about 0-20 crank angle degrees, inclusive, from the fuel-economy operating domain toward the cylinder deactivation operating domain; and
positioning an intake valve actuation centerline and an exhaust valve actuation centerline adjacent the cylinder deactivation operating domain which is adjacent to the fuel economy operating domain for allowing the intake valve actuation centerline and exhaust valve actuation centerline positions to switch between the all-cylinder activation mode and the cylinder deactivation mode.
7. The method of claim 6 wherein advancing each intake valve actuation phase further comprises selectively advancing each intake valve actuation phase about 30 crank angle degrees from the idle operating domain toward the fuel-economy operating domain.
8. The method of claim 7 wherein retarding each exhaust valve further comprises selectively retarding each exhaust valve actuation phase about 50 crank angle degrees from the idle operating domain toward the fuel-economy operating domain.
9. The method of claim 8 wherein adjusting each intake valve further comprises selectively adjusting each active intake valve actuation phase within a range of about 5-20 crank angle degrees, inclusive, from the fuel-economy operating domain toward the cylinder deactivation operating domain.
10. The method of claim 9 wherein adjusting each exhaust valve further comprises selectively adjusting each active exhaust valve actuation phase within a range of about 5-20 crank angle degrees, inclusive, from the fuel-economy operating domain toward the cylinder deactivation operating domain.
11. The method of claim 6 wherein, when in the all-cylinder activation mode, for every 1 unit of measurement that each intake valve actuation phase is advanced, each exhaust valve actuation phase is retarded by 1 unit of measurement such that an overlap angle of the valves remains substantially the same.
12. A method of using variable valve timing system to augment a cylinder deactivation mode in an internal combustion engine for a vehicle, comprising:
transitioning from the all-cylinder activation mode into the cylinder deactivation mode when an intake valve centerline and an exhaust valve centerline are positioned within a range centered on a nominal operation domain;
initiating the cylinder deactivation mode by deactivating half of the cylinders of the engine when the vehicle encounters a predetermined operating condition during light-to-moderate load conditions when the vehicle is cruising;
when going from an all-cylinder mode and into the cylinder deactivation mode, retarding each intake valve actuation phase within a range of about 0-20 crank angle degrees, inclusive;
concurrently, advancing each exhaust valve actuation phase within a range of about 0-20 crank angle degrees, inclusive; and
controlling the flow of oil entering and exiting a hydraulic roller follower using an electro-hydraulic manifold assembly comprising at least one solenoid valve and an oil pressure assembly for controlling the valves in the cylinder deactivation mode.
13. The method of claim 12 wherein retarding each intake valve actuation phase further comprises retarding each intake valve actuation phase within a range of about 0-12 crank angle degrees, inclusive.
14. The method of claim 13 wherein advancing each exhaust valve actuation phase further comprises advancing each exhaust valve actuation phase within a range of about 0-12 crank angle degrees, inclusive.
15. The method of claim 1 , further comprising a vane-type variable valve timing mechanism that is partly controlled by a solenoid type electromagnetic actuator, a hydraulic circuit with a pump for pumping oil in and out of the vane-type variable valve timing mechanism, and an ECU for controlling the solenoid type electromagnetic actuator.
16. The method of claim 1 , further comprising, a hydraulic roller follower housing a valve deactivator assembly having a first end and a second end, wherein the first end is operatively connected to a cam located on a camshaft with a roller follower, and the second end is operatively connected to a rocker arm assembly that is operatively connected to a valve assembly comprising a valve and a spring.
17. The method of claim 5 , further comprising a vane-type variable valve timing mechanism that is partly controlled by a solenoid type electromagnetic actuator, a hydraulic circuit with a pump for pumping oil in and out of the vane-type variable valve timing mechanism, and an ECU for controlling the solenoid type electromagnetic actuator.
18. The method of claim 6 , further comprising, the hydraulic roller follower housing a valve deactivator assembly having a first end and a second end, wherein the first end is operatively connected to a cam located on a camshaft with a roller follower, and the second end is operatively connected to a rocker arm assembly that is operatively connected to a valve assembly comprising a valve and a spring.
19. The method of claim 6 , further comprising positioning at least one cam for improved torque relatively close to a cam position for improved fuel economy for producing improved torque in the cylinder deactivation mode, resulting in improved fuel economy from the cylinder deactivation and increased torque.
20. The method of claim 12 , further comprising positioning at least one cam for improved torque relatively close to a cam position for improved fuel economy and producing improved torque in the cylinder deactivation mode, resulting in improved fuel economy from the cylinder deactivation and increased torque.