Method and apparatus for tensioning a chain of an internal combustion engine

• US 6,746,352 B1
• Filed: 03/26/2001
• Issued: 06/08/2004
• Est. Priority Date: 06/30/1998
• Status: Expired due to Fees

• Current Assignee: Schaeffler KG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Renold PLC
• Inventors: Trotter, Ian Ronald, Pochet, Jean-Luc, Poiret, Christian
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): Johnson, Vicky A.
• Application Number:
  US09/720,063
• Time in Patent Office: 1,170 Days
• Field of Search: 474/69, 474/70, 474/101, 474/109, 474/110
• US Class Current: 474/110
• CPC Class Codes: F01L 1/02 Valve drive transmitting-gear between valve drive and valve F01L1/12
• CPC Class Codes: F01L 1/022 Chain drive
• CPC Class Codes: F01L 1/024 Belt drive
• CPC Class Codes: F16H 2007/0806 Compression coil springs
• CPC Class Codes: F16H 2007/0812 Fluid pressure
• CPC Class Codes: F16H 2007/0861 comprising means for sensing tensioner position
• CPC Class Codes: F16H 2007/0885 the tension being a function of engine running condition
• CPC Class Codes: F16H 2007/0891 Linear path
• CPC Class Codes: F16H 7/08 Means for varying tension of belts, ropes, or chains pulleys of adjustable construction F16H55/52 ; gearings with endless belts F16H7/02; tensioning for chains or belts specially adapted for cycles B62M9/16; belt or chain tensioning arrangements for endless conveyors B65G23/44

Abstract

A chain drive assembly for an internal combustion engine comprises a chain tensioner (6) that acts upon a chain (2) that is used to drive the cam shafts (4) of the engine. The tensioner has a hydraulically actuated plunger (30) which is moveable within a housing and biasing means in the form of a solenoid (34), compression spring or motor that urges the plunger outwards of the housing at least when there is no hydraulic pressure. The tensioner is controlled by means of a control unit (8) that receives signals from various transducers that transmit signals providing information in relation to the performance of the engine. The control unit receives the measured information, calculates the desired tension to be applied to the chain and transmits the control signal to the chain tensioner so as to operate the biasing means or control the hydraulic pressure so that the desired chain tension is applied.

Claims

1. A chain drive assembly for reducing noise, vibration or wear of a chain in an internal combustion engine, the assembly comprising.

a) a chain tensioner mounted on said engine, the tensioner comprising:

i) a housing;

ii) a hydraulically actuated plunger for engaging the chain, the plunger being moveable within said housing,

iii) a fluid chamber defined between the plunger and the housing for containing hydraulic fluid, the fluid serving to activate and damp movement of the plunger;

iv) biasing means to bias the plunger outwards of the housing;

v) a passage in said housing to provide communication between the chamber and a fluid supply from the engine;

b) conduit means connecting a supply of hydraulic fluid in the engine to said passage;

c) control valve means in said conduit means for increasing and decreasing the pressure of the hydraulic fluid supplied to the chamber;

d) means for measuring a location of the plunger within the housing;

e) means for measuring an operational parameter of the engine or drive assembly;

f) means for calculating the desired chain tension in response to the measured operational parameter; and

g) means for transmitting a control signal to the chain tensioner so as to operate the control valve means to control the hydraulic pressure supplied to the chamber and therefore to control the projection of the plunger to apply the desired chain tension.

2. A chain drive assembly according to claim 1, wherein the desired chain tension is applied during operation of the chain drive assembly.

3. A chain drive assembly according to claim 1, wherein the biasing means of the plunger is a solenoid, a motor or a compression spring.

4. A chain drive assembly according to claim 3, wherein the plunger is biased against a sliding member by actuation of the solenoid or motor.

5. A chain drive assembly according to claim 4, wherein hydraulic fluid is supplied to the housing so as to act separately on the sliding member.

7. A chain drive assembly according to claim 1, wherein the operational parameter is the speed of revolution of a crankshaft of the engine.

8. A chain drive assembly according to claim 1, wherein the biasing means is an electrically operated solenoid that is supplied with a variable current to modulate the tensioner load.

9. A chain drive assembly according to claim 1, wherein the operational parameter is the speed of revolution of at least one camshaft of the engine.

10. A chain drive assembly according to claim 1, wherein the operational parameter is the torque of the crankshaft.

11. A chain drive assembly according to claim 1, wherein the operational parameter is the torque of at least one of the camshafts.

12. A chain drive assembly according to claim 1, wherein the operational parameter is the relative phase of rotation of the crankshaft and at least one camshaft.

13. A chain drive assembly according to claim 1, wherein the operational parameter is the pressure of the hydraulic fluid in the chain tensioner.

14. A chain drive assembly according to claim 1, wherein the operational parameter is the strain of the chain.

6. A chain drive assembly according to claim 6, wherein the housing has a plurality of chambers each receiving a different sized plunger member.

15. A method for tensioning the chain of a chain drive assembly so as to reduce noise, vibration or wear of the chain in an internal combustion engine, the drive assembly including a chain tensioner comprising a hydraulically operated plunger that is moveable within a housing, a fluid chamber defined between the plunger and housing for containing hydraulic fluid, the fluid serving to activate and damp movement of the plunger, biasing means to bias the plunger outwards of its housing, a passage in said housing to provide communication between the chamber and the fluid supply from the engine, and control valve means in said passage for controlling the pressure of the hydraulic fluid supplied to the housing, the method comprising the steps of:

measuring an operational parameter of the engine or drive assembly,

measuring a location of the plunger within the housing,

calculating the desired chain tension in response to the measured operational parameter, and

transmitting a control signal to the chain tensioner so as to operate the control valve means to increase and decrease the hydraulic pressure supplied to the housing and therefore to control the projection of the plunger to apply the desired chain tension.

16. A chain drive assembly for reducing noise, vibration or wear of a chain in the assembly an internal combustion engine, the assembly comprising:

a) a chain tensioner mounted on said engine, the tensioner comprising;

i) a housing;

ii) a hydraulically actuated plunger for engaging the chain, the plunger being movable within said housing the plunger comprising a plurality of plunger members;

iii) a plurality of discrete fluid chambers defined in the housing for containing hydraulic fluid, each plunger member being received in a respective chamber and each plunger member having a different working surface area presented to the hydraulic fluid, the hydraulic fluid serving to activate and damp movement of the plunger member received in the respective chamber;

iv) biasing means to bias the plunger out of the housing;

v) a passage in said housing to a provide communication between the chambers and a fluid supply from the engine;

vi) conduit means connecting a supply of hydraulic fluid in the engine to said passage;

b) control means for directing the hydraulic fluid to one or more of the chambers in the housing for increasing and decreasing the pressure of the hydraulic fluid;

c) means for measuring a location of the plunger within the housing,

d) means for measuring an operational parameter of the engine or drive assembly;

e) means for calculating the desired chain tension in response to the measured operational parameter; and

f) means for transmitting a control signal to the chain tensioner so as to operate the control means to direct the hydraulic fluid supplied to the appropriate chamber or chambers so as to control the projection of the plunger and to apply the desired chain tension.

17. A chain drive assembly according to claim 16, wherein each plunger member is of a different size.

18. A method for tensioning the chain of a chain drive assembly so as to reduce noise, vibration or wear of the chain in an internal combustion engine, the drive assembly including a chain tensioner comprising a hydraulically operated plunger that is moveable within a housing, a plurality of discrete fluid chambers defamed in the housing for containing hydraulic fluid, biasing means to bias the plunger outwards of its housing, a passage in said housing to provide communication between the chambers and the fluid supply from the engine, the plunger having a plurality of plunger members, each plunger member being received in a respective chamber and each having a different working surface area presented to the fluid, the fluid serving to activate and damp movement of the plunger member in the respective fluid chamber, and control valve means for directing the hydraulic fluid to one or more of the chambers for increasing and decreasing the pressure of the hydraulic fluid, the method comprising the steps of:

measuring an operational parameter of the engine or drive assembly;

measuring a location of the plunger within the housing;

calculating the desired chain tension in response to the measured operational parameter; and

transmitting a control signal to the chain tensioner so as to operate the control valve means to direct the hydraulic fluid to the appropriate chamber or chambers so as to control the projection of the plunger and therefore to apply the desired chain tension.

19. A chain drive assembly for reducing noise, vibration or wear of a chain in the assembly an internal combustion engine comprising a chain tensioner comprising;

a) a chain tensioner mounted on said engine, the tensioner comprising;

i) a housing;

ii) a hydraulically actuated plunger for engaging the chain, the plunger being movable within said housing;

iii) a fluid chamber defined between the plunger and the housing for containing hydraulic fluid, the fluid serving to activate and damp movement of the plunger;

iv) electrically actuated biasing means to bias the plunger out of the housing;

v) a passage in said housing to provide communication between the chamber and a fluid supply from the engine;

b) conduit means connecting a supply of hydraulic fluid in the engine to said passage;

c) control means for controlling the biasing force applied by the biasing

d) means for measuring a location of the plunger within the housing;

e) means for measuring an operational parameter of the engine or drive assembly;

f) means for calculating the desired chain tension in response to the measured operational parameter;

g) means for determining the hydraulic pressure of the fluid in the chamber;

h) means for transmitting a control signal to the chain tensioner so as to operate the control means to control the biasing force applied to the biasing means and therefore to control the projection of the plunger to apply the desired chain tension, and to switch off the biasing means when the determined hydraulic pressure reaches a predetermined threshold.

20. A method for tensioning the chain of a chain drive assembly so as to reduce noise, vibration or wear of the chain in an internal combustion engine, the drive assembly including a chain tensioner comprising a hydraulically operated plunger that is moveable within a housings a fluid chamber defined between the plunger and housing for containing hydraulic fluid, the fluid serving to activate and damp movement of the plunger, electrically actuated biasing means for biasing the plunger outwards of its housing, a passage in said housing to provide communication between the chamber and the fluid supply from the engine, and control means for controlling the biasing force applied by the biasing means, the method comprising the steps of:

measuring an operational parameter of the engine or drive assembly;

measuring a location of the plunger within the housing;

calculating the desired chain tension in response to the measured operational parameter; and

transmitting a control signal to the chain tensioner so as to operate the control means to control the biasing force applied by the biasing means thereby controlling the projection of the plunger to apply the desired chain tension,

determining the hydraulic pressure in the chamber,

switching off the biasing means when the determined hydraulic pressure reaches a predetermined threshold value.