METHOD FOR PROVIDING VARIABLE COMPRESSION RATIO IN AN INTERNAL COMBUSTION ENGINE AND ACTUATOR FOR SAID METHOD

• US 20190301362A1
• Filed: 12/14/2017
• Published: 10/03/2019
• Est. Priority Date: 12/14/2016
• Status: Active Grant

• Current Assignee: Hedman Ericsson Patent AB (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Hedman Ericsson Patent AB (Telefonaktiebolaget LM Ericsson)
• Inventors: Hedman, Mats
• Granted Patent: US 10,641,167 B2
• Time in Patent Office: Days
• CPC Class Codes: F01B 31/14 Changing of compression ratio
• CPC Class Codes: F02B 75/042 the cylinderhead comprising a counter-piston
• CPC Class Codes: F02D 15/04 by alteration of volume of compression space without changing piston stroke

Abstract

In a combustion chamber of a piston combustion engine there is a displaceable piston that can be moved progressively up or down between an upper and a lower turning position. The displacement takes place via an electrically controlled step motor which is connected to the piston via a hydraulic link, including a hydraulic lock. The lock is deactivated during the displacement a certain number of steps up or down ordered by a motor control system, and when the displacement is ended, the lock is activated by said engine control system and the moving piston is locked in a certain position ordered by the motor control system.

Claims

1. A method to control the size of a combustion chamber by an actuator in the cylinder head of a piston combustion engine comprising:

A vertically displaceable piston;

A first chamber with a piston;

associated shaft having a flange and a spring in the chamber acting between the flange and a chamber floor to reposition the piston in an upward direction;

Wherein the actuator further comprises a second chamber and a third chamber filled with hydraulic fluid and separated by a valve with an opening, wherein the valve is horizontally repositionable via an electromagnet;

Wherein the actuator further comprises a step motor and a shaft vertically displaceable by said step motor in the second chamber, the method comprising;

Changing the size of the combustion chamber by displacing the valve with the electromagnet so that the opening connects the second and third chambers.

2. The method of claim 1, comprising downwardly displacing the shaft by the step motor, thereby forcing hydraulic fluid from the second chamber to the third chamber and downwardly displacing the piston-associated shaft to compress the spring while reducing the size of the combustion chamber until a repositioning of the shaft is ended.

3. The method of claim 1, comprising ending a repositioning of the shaft by displacing the valve so that the opening no longer connects the second chamber and the third chamber, whereby the piston is no longer displaceable.

4. The method of claim 1, comprising moving the shaft upwards by the step motor, thereby forcing the hydraulic fluid from the third chamber to the second chamber by action of the spring on the flange of the shaft,

wherein the piston is moved upward at a same time as the spring expands such that a size of the combustion chamber increases until displacement of the shaft has come to an end.

5. The method of claim 1, comprising ending displacement of the shaft by displacing the valve so that the opening no longer connects the second chamber and the third chamber, whereby the piston is no longer displaceable.

7. The method of claim 2, comprising ending a repositioning of the shaft by displacing the valve so that the opening no longer connects the second chamber and the third chamber, whereby the piston is no longer displaceable.

8. The method of claim 4, comprising ending the displacement of the shaft by displacing the valve so that the opening no longer connects the second chamber and the third chamber, whereby the piston is no longer displaceable.

6. An actuator comprising:

a combustion chamber;

a vertically displaceable piston;

a chamber with a piston associated shaft with a flange;

a spring between the flange and a chamber floor;

two hydraulic fluid chambers;

a valve with an opening;

an electromagnet;

a step motor; and

a shaft displaceable in one of the hydraulic fluid chambers;

wherein a size of the combustion chamber is changeable when the valve is displaced so that the opening connects the two hydraulic fluid chambers.