Partial deactivation of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10087859-B2
Application number	US-201514964257-A
Country	US
Kind code	B2
Filing date	Dec 9, 2015
Priority date	Jan 6, 2015
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

Methods and systems are provided for an internal combustion engine having at least two cylinders configured in such a way that they form two groups, at least one cylinder of a first group being a cylinder which is operational in the event of a partial deactivation of the engine, and at least one cylinder of a second group being formed as a load-dependently switchable cylinder. An inlet-side throttle element is provided with at least one intake line of the switchable cylinder, by means of which the size of the flow cross section of the intake line can be varied, whereby the charge-air flow rate supplied to the deactivated cylinder in the event of a partial deactivation of the engine can be adjusted. Each outlet opening of a load-dependently switchable cylinder is equipped with a partially variable valve drive, with an outlet valve which opens or shuts off the outlet opening.

First claim

The invention claimed is:

1. An internal combustion engine system comprising:
at least a first and a second cylinder group, each of the first and second cylinder groups comprising at least one cylinder, wherein each cylinder includes an outlet coupled to an exhaust line for discharging exhaust gases to an exhaust system and an inlet coupled to an intake line for receiving charge air from an intake system, wherein the at least one cylinder of the first cylinder group remains active when an engine is partially shut down as a function of engine load, and wherein the at least one cylinder of the second cylinder group is deactivated when the engine is partially shutdown;
at least one throttle element coupled to the intake line of the at least one cylinder of the second cylinder group downstream of a location where the intake line branches from an overall intake line in an engine inlet manifold to vary a size of a flow cross section of the intake line;
a variable valve drive coupled to an exhaust valve of the at least one cylinder of the second cylinder group, wherein actuation of the variable valve drive deactivates the exhaust valve when the engine is partially shutdown while an intake valve of the at least one cylinder of the second cylinder group remains active; and
a controller with computer-readable instructions stored in non-transitory memory for:
in response to cylinder deactivation conditions being met,
deactivating fueling of the second cylinder group while maintaining fueling of the first cylinder group, closing the at least one throttle element, and maintaining the intake valve active while actuating the variable valve drive to deactivate the exhaust valve before an exhaust stroke following the at least one throttle element closing.

2. The system of claim 1 , wherein actuation of the variable valve drive oscillates the exhaust valve to realize a valve lift Δh between an open position and a closed position of the exhaust valve, and to open up the outlet of the at least one cylinder of the second cylinder group for an opening duration Δt, and wherein the intake valve of the at least one cylinder of the second cylinder group is coupled to a fixed valve drive.

3. The system of claim 1 , wherein the at least one throttle element is one of a valve and a pivotable flap, and wherein a position of the at least one throttle element is continuously adjustable between a fully open and a fully closed position.

4. The system of claim 1 , further comprising at least one exhaust-gas turbocharger including a turbine arranged in the exhaust line and a compressor arranged in the intake line.

5. The system of claim 1 , wherein the engine includes four cylinders in an in-line arrangement, and wherein the first group of cylinders includes two outer cylinders and wherein the second group of cylinders includes two inner cylinders in the in-line arrangement.

6. The system of claim 1 , wherein the at least one throttle element includes a plurality of throttle elements, each of the plurality of throttle elements coupled to an intake line of a corresponding cylinder of the second cylinder group.

7. The system of claim 1 , further comprising at least another throttle element coupled to the intake line of the at least one cylinder of the first cylinder group to vary a size of a flow cross section of the intake line.

8. The system of claim 2 , wherein the variable valve drive varies a lift of the exhaust valve in one of a continuously adjustable and a stepped fashion.

9. A method, comprising:
in response to a decrease in engine load below a threshold,
selectively deactivating fueling of a second group of cylinders while maintaining a first group of cylinders active;
then, deactivating exhaust valves of the second group of cylinders after completing an exhaust stroke while maintaining intake valves of the second group of cylinders active;
after deactivating the exhaust valves, closing a throttle element in an intake line of the second group of cylinders; and
during cylinder reactivation,
fully opening the throttle element before reactivating the exhaust valves and resuming fueling of the second group of cylinders.

10. The method of claim 9 , wherein selectively deactivating the exhaust valves while maintaining the intake valves active includes selectively deactivating a variable valve mechanism coupled to the exhaust valves of the second group of cylinders, the variable valve mechanism not coupled to the intake valves of the second group of cylinders.

11. The method of claim 9 , further comprising, in response to a drop in engine temperature, actuating a variable valve mechanism to admit warm exhaust gas from an exhaust line into the second group of cylinders.

12. The method of claim 9 , wherein an engine is a boosted engine including an intake compressor, the method further comprising, in response to a pressure ratio exceeding a surge level, fully opening the throttle element while actuating a variable valve mechanism to decrease the pressure ratio below the surge level.

13. The method of claim 9 , wherein closing the throttle element includes adjusting a degree of closure of the throttle element based on engine operating conditions, the degree of closure increased as engine load increases while the second cylinder group is deactivated.

14. The method of claim 9 , wherein the second group of cylinders includes a plurality of cylinders, each of the plurality of cylinders coupled to an intake line, and wherein the throttle element is coupled to the intake line of each of the plurality of cylinders in the second group of cylinders.

15. A method for an engine, comprising:
in response to cylinder deactivation conditions being met,
deactivating fuel to a second group of cylinders while maintaining fueling of a first group of cylinders;
closing a throttle element coupled to an intake line of the second group of cylinders; and
actuating a variable valve mechanism to deactivate exhaust valves of the second group of cylinders while maintaining intake valves active, wherein the throttle element is closed after deactivating the fuel, and the exhaust valves are deactivated before an exhaust stroke following the throttle element closing.

16. A method for an engine, comprising:
in response to cylinder deactivation conditions being met,
deactivating fuel to a second group of cylinders while maintaining fueling of a first group of cylinders;
closing a throttle element coupled to an intake line of the second group of cylinders; and
actuating a variable valve mechanism to deactivate exhaust valves of the second group of cylinders while maintaining intake valves active, wherein the exhaust valves are deactivated after an exhaust stroke following the fuel deactivation, and the throttle element is closed after the exhaust valves are deactivated.

17. The method of claim 15 , wherein in response to cylinder reactivation conditions being met,
selectively reactivating fuel to the second group of cylinders while actuating the variable valve mechanism to reactivate the exhaust valves of the second group of cylinders; and
then opening the throttle element.

Assignees

• Ford Global Tech Llc

Inventors

• Willems Werner
• Turner Paul Nigel
• Stief Juergen Karl
• Chen Guohui

Classifications

• F02D41/0087 Primary

  Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123) · CPC title

• F02D13/0246

  changing valve lift or valve lift and timing · CPC title

• F02D13/0242

  Variable control of the exhaust valves only · CPC title

• Y02T10/18

  Cross-Sectional Technologies · mapped topic

• Y02T10/42

  Cross-Sectional Technologies · mapped topic