Method for controlling an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11207964-B2
Application number	US-201816767788-A
Country	US
Kind code	B2
Filing date	Nov 30, 2018
Priority date	Dec 4, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The disclosure relates to a method for controlling an internal combustion engine. The internal combustion engine includes a cylinder and a piston, which runs in the cylinder, together delimiting a working chamber. The working chamber is supplied with fresh air from an intake section via an inlet valve and is connected to an exhaust manifold via exhaust valves. The internal combustion engine includes a variable valve actuation system for the actuation of the inlet valves, controlling the opening time and/or the closing time and/or the lift. A strategy for shutting down the internal combustion engine includes controlling the inlet valves of individual or all working chambers in such a way that the transfer of fresh air from the intake section to the exhaust manifold is reduced or avoided and that the drag torque of the intake combustion engine is reduced.

First claim

The invention claimed is:

1. A method for controlling an internal combustion engine having a plurality of working chambers defined by a plurality of cylinders and a plurality of pistons, the method comprising:
providing:
a first cylinder:
a first piston configured to move within the first cylinder, the first piston and the first cylinder defining a first working chamber, and the first working chamber configured to be fluidly connected to both an intake manifold via a first inlet valve, and an exhaust manifold via a first exhaust valve;
a variable valve actuation system configured to control at least one of an opening time, a closing time, or a valve lift of an inlet valve lift curve;

providing a shutdown signal to the internal combustion engine; and
changing the inlet valve lift curve to a first inlet valve lift curve as engine speed decreases below an idle speed, the first inlet valve lift curve defining a first inlet valve opening event having a first valve lift and a second valve lift greater than the first valve lift.

2. The method of claim 1 , wherein the first valve lift occurs during an exhaust stroke and the second valve lift occurs during an intake stroke, the exhaust stroke and intake stroke defining two strokes of a four-stroke engine cycle of the internal combustion engine.

3. The method of claim 1 , wherein the first valve lift is smaller than the second valve lift.

4. The method of claim 3 , wherein the first valve lift is smaller than a valve lift of the first exhaust valve.

5. The method of claim 1 , wherein the first inlet valve lift curve defines a closing of the first inlet valve before a bottom dead center position of the first piston within an intake stroke of a four-stroke engine cycle of the internal combustion engine.

6. The method of claim 1 , wherein the first inlet valve lift curve defines a closing of the first inlet valve at a first piston location of less than 90 crank angle degrees from a top dead center position of the first piston in a compression stroke of a four-stroke engine cycle of the internal combustion engine.

7. The method of claim 1 , wherein the first inlet valve lift curve defines an opening of the first inlet valve at a first piston location of less than 90 crank angle degrees from a bottom dead center position of the first piston in an exhaust stroke of a four-stroke engine cycle of the internal combustion engine.

8. The method of claim 1 , wherein the first inlet valve lift curve controls a shutdown position of the internal combustion engine.

9. The method of claim 8 , further comprising calculating a kinetic energy of the internal combustion engine before changing to the first inlet valve lift curve.

10. The method of claim 1 , wherein the first inlet valve lift curve controls a position of a second piston so that the second piston stops proximate to a bottom dead center position between an intake stroke and a compression stroke of a four-stroke engine cycle of the internal combustion engine.

11. The method of claim 10 , wherein a second working chamber between the second piston and a second cylinder is filled with fresh air.

12. The method of claim 11 , wherein the fresh air in the second working chamber is ignited during a subsequent compression stroke of the second piston following an engine start-up signal.

13. The method of claim 1 , further comprising deactivating a second inlet valve of a second working chamber as engine speed is decreasing below idle speed.

14. The method of claim 1 , further comprising recognizing a criterion for interruption of shutting down of the internal combustion engine and selecting a second inlet valve lift curve for inlet valves of any of the plurality of working chambers in an exhaust stroke so that a subsequent intake stroke brings in fresh air, the fresh air configured to be converted into a fuel/fresh air mixture and ignited in a subsequent compression stroke, the exhaust stroke and compression stroke defining two strokes of a four-stroke engine cycle of the internal combustion engine.

15. The method of claim 1 , wherein the first inlet valve lift curve defines an inlet valve opening at a first crankshaft angle and a maximum lift of the first exhaust valve occurs at a second crankshaft angle, the first crankshaft angle occurring before the second crankshaft angle within an exhaust stroke of a four-stroke cycle of the internal combustion engine.

16. A method of shutting down an internal combustion engine, the internal combustion engine having a plurality of working chambers, and each working chamber defined by one of a plurality of cylinders configured to receive one of a plurality of pistons, the method comprising:
providing:
a first cylinder;
a first piston configured to move within the first cylinder, the first piston and the first cylinder defining a first working chamber, and the first working chamber configured to cooperate with the first piston, an inlet valve, and an exhaust valve to fulfill a gas exchange process for the internal combustion engine;
a variable valve actuation system configured to control at least one of an opening time, a closing time, or a valve lift of an inlet valve lift curve;

providing a shutdown signal to the internal combustion engine; and
changing the inlet valve lift curve to a first inlet valve lift.

17. The method of claim 16 , wherein the changing the inlet valve lift curve to the first inlet valve curve changes a drag toque of the internal combustion engine such that one of the plurality of pistons is stopped n a pre-determined position relative to a four-stroke cycle of the internal combustion engine, and the pre-determined position is proximate to a bottom dead center position between an intake stroke and a compression stroke of the four-stroke cycle.

18. A method of shutting down an internal combustion engine, the internal combustion engine having a plurality of working chambers, and each of the plurality of working chambers defined by one of a plurality of cylinders configured to receive one of a plurality of pistons, the method comprising:
providing:
a first cylinder;
a first piston configured to move within the first cylinder, the first piston and the first cylinder defining a first working chamber, and the first working chamber configured to cooperate with the first piston, an inlet valve, and an exhaust valve to fulfill a gas exchange process for the internal combustion engine;
a variable valve actuation system configured to control at least one of an opening time, a closing time, or a valve lift of an inlet valve lift curve;

providing a shutdown signal to the internal combustion engine; and
changing the inlet valve lift curve to a first inlet valve lift curve, the first inlet valve lift curve defining a first inlet valve opening event having:
a first valve lift;
a second valve lift different than the first valve lift; and
a plateau arranged between the first and second valve lifts.

19. The method of claim 18 , wherein the first inlet valve lift curve: i) increases an amount of exhaust gas recirculation delivered to at least one of the plurality of working chambers during an intake stroke; and, ii) reduces a drag torque of the internal combustion engine to stop one of the plurality of pistons in a pre-determined position relative to a four-stroke cycle of the internal combustion engine.

Assignees

• Schaeffler Technologies Ag

Inventors

• Wolf Daniel
• Traversa Piergiacomo

Classifications

• B60W2030/18081

  With torque flow from driveshaft to engine, i.e. engine being driven by vehicle · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• Y02T10/62

  Hybrid vehicles · CPC title

• B60W30/18018

  Start-stop drive, e.g. in a traffic jam · CPC title

• B60W2710/06

  Combustion engines, Gas turbines · CPC title