Method for operating an internal combustion engine, and internal combustion engine

Patent metadata

Field	Value
Publication number	US-11118521-B2
Application number	US-201716305360-A
Country	US
Kind code	B2
Filing date	May 22, 2017
Priority date	Jun 7, 2016
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

The invention relates to a method for operating an internal combustion engine, which has an internal combustion motor, which forms at least two combustion chambers, which are bounded by cylinders formed in a cylinder housing and by pistons guided up and down cyclically in said cylinders and in which thermodynamic cycles can be performed during operation of the internal combustion engine, wherein then a gas exchange in the combustion chambers is controlled by means of at least one intake valve (28) and one exhaust valve in the case of each combustion chamber, which valves are actuated by means of cams, and wherein a first operating state is provided, in which the thermodynamic cycles are performed both in a first combustion chamber and in a second combustion chamber and a second operating state is provided, in which the thermodynamic cycles are performed in the first combustion chamber and the thermodynamic cycles are not performed in the second combustion chamber, is characterized in that, in order to switch from the first operating state to the second operating state, a switch is made from the use of a first intake cam to the use of a second intake cam for the actuation of the intake valve associated with the first combustion chamber. Such a method makes it possible to realize a switchover from full operation to partial operation in manner that is as torque-neutral as possible in that the torque component that ceases because of the deactivation of the cylinder or cylinders provided therefor is compensated by the one or more cylinders that continue to actively operate, at least also in that, in the event of the switchover, the delivery ratio, i.e. the ratio of the mass of fresh gas actually contained in the cylinder after the conclusion of a charge cycle to the theoretical maximum possible mass, is increased for said cylinders and, in particular, is set as high as possible.

First claim

The invention claimed is:

1. A method for operating a combustion machine comprising an internal combustion engine that has at least two combustion chambers which are delimited by cylinders formed in a cylinder housing and by pistons that move cyclically up and down therein and in which thermodynamic cycles can be carried out during operation of the combustion machine, comprising:
regulating a gas exchange in the combustion chambers by means of at least an inlet valve and an outlet valve that are actuated by means of cams, whereby:
in a first operating state, in which the thermodynamic cycles are carried out in a first combustion chamber as well as in a second combustion chamber:
actuating the at least one inlet valve of the first combustion chamber by a first inlet cam, and
actuating the at least one inlet valve of the second combustion chamber by a third inlet cam, and

in a second operating state, in which the thermodynamic cycles are carried out in the first combustion chamber and the thermodynamic cycles are not carried out in the second combustion chamber, switching from actuating the at least one inlet valve of the first combustion chamber by the first inlet cam to actuating the at least one inlet valve of the first combustion chamber by a second inlet cam.

2. The method according to claim 1 ,
wherein at least the inlet valve associated with the first combustion chamber is closed when it is actuated by means of the first inlet cam before a BDC of 60° crank angle or after a BDC of +100° crank angle, and
wherein at least the inlet valve associated with the first combustion chamber is closed by means of the second inlet cam in the range between a BDC of 50° crank angle and a BDC of +50° crank angle.

3. The method according to claim 1 , wherein a valve overlapping of the inlet and outlet valves associated with the first combustion chamber is adapted for a switchover from the first operating state to the second operating state.

4. The method according to claim 3 , wherein a change is made from using a first outlet cam to using a second outlet cam in order to actuate the outlet valve associated with the first combustion chamber.

5. The method according to claim 4 , wherein the second outlet cam effectuates a relatively early closing of the outlet in comparison to the first outlet cam.

6. The method according to claim 1 , further comprising, after switching from the first operating state to the second operating state, raising the pressure in an intake pipe of the combustion machine.

7. The method according to claim 1 , further comprising, after switching from the first operating state to the second operating state, shifting the ignition angle for the first combustion chamber in the late direction.

8. The method according to claim 1 , wherein the timing of the actuation by the second inlet cam of the at least one inlet valve associated with the first combustion chamber:
is shifted in the early direction if the timing of the first inlet cam causes the at least one inlet valve associated with the first combustion chamber to close before the BDC for the first operating state, or
is shifted in the late direction if the timing of the first inlet cam causes the at least one inlet valve associated with the first combustion chamber to close after the BDC for the first operating state.

9. A combustion machine comprising:
an internal combustion engine that has at least two combustion chambers which are delimited by cylinders formed in a cylinder housing and by pistons that move cyclically back and forth therein and in which thermodynamic cycles can be carried out during operation of the combustion machine,
wherein a first combustion chamber has at least one inlet valve actuated by a first inlet cam during a first operating state, and actuated by a second inlet cam during a second operating state;
wherein a second combustion chamber has at least one inlet valve which is actuated by a third inlet cam during the first operating state, and controlled by a fourth inlet cam during the second operating state, wherein the fourth inlet cam is configured as a zero cam which does not actuate the at least one inlet valve of the second combustion chamber,
a switchover device configured to:
switch between the first inlet cam and the second inlet cam, and
switch between the third inlet cam and the fourth inlet cam, and

a control device configured to, when switching over from the first operating state to the second operating state, control the switchover device to switch from valve control by the first inlet cam and the third inlet cam to valve control by the second inlet cam and the fourth inlet cam,
wherein, in the first operating state, thermodynamic cycles are carried out in the first combustion chamber and the second combustion chamber, and, in the second operating state, thermodynamic cycles are carried out in the first combustion chamber but not in the second combustion chamber.

10. The combustion machine according to claim 9 , wherein the first combustion chamber or the second combustion chamber has at least one outlet valve, and the at least one outlet valve of the first combustion chamber or the second combustion chamber has at least two associated outlet cams, and the switchover device is configured to switch between the at least two associated outlet cams to shift timing of the at least one outlet valve,
wherein the combustion machine further comprises a phaser to change the timing of the at least one outlet valve.

11. The method according to claim 2 , wherein at least the inlet valve associated with the first combustion chamber is closed by means of the second inlet cam in the range between a BDC of −20° crank angle (CA) and a BDC of +30° crank angle (CA).

12. The method according to claim 1 , wherein, irrespective of a raising of intake pipe pressure, timing of the second inlet cam increases volumetric efficiency of the first combustion chamber in comparison to timing of the first inlet cam.

13. The combustion machine according to claim 9 , wherein, irrespective of a raising of intake pipe pressure, timing of the second inlet cam increases volumetric efficiency of the first combustion chamber in comparison to timing of the first inlet cam.

14. The combustion machine according to claim 9 , further comprising a compressor, wherein the control device is further configured to, after switching over from the first operating state to the second operating state, causing the compressor to raise the pressure in an intake pipe of the combustion machine.

15. The combustion machine according to claim 9 , wherein:
the second inlet cam is configured to shift timing of the actuation of the at least one inlet valve associated with the first combustion chamber in the early direction if the first inlet cam is configured to close the at least one inlet valve of the first combustion chamber before BDC; and
the second inlet cam is configured to shift timing of the actuation of the at least one inlet valve associated with the first combustion chamber in late direction if the first inlet cam is configured to close the at least one inlet valve of the first combustion chamber after BDC.

Assignees

• Volkswagen Ag

Inventors

• Gessenhardt Christopher
• Hoffmeyer Henrik
• Schreeck Nico

Classifications

• F02D41/0087 Primary

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

• F01L13/0036

  the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction · CPC title

• F02D13/06

  Cutting-out cylinders · CPC title

• F02D13/0203

  Variable control of intake and exhaust valves · CPC title

• F01L2013/0052

  with cams provided on an axially slidable sleeve · CPC title