METHOD AND SYSTEM FOR OPERATING A COMBUSTION ENGINE BRAKE

• US 20090187331A1
• Filed: 07/13/2006
• Published: 07/23/2009
• Est. Priority Date: 07/13/2006
• Status: Active Grant

• Current Assignee: Volvo Lastvagnar AB (Volvo AB)
• Original Assignee: Volvo Lastvagnar AB (Volvo AB)
• Inventors: Olsson, Goran
• Granted Patent: US 8,352,165 B2
• Time in Patent Office: Days
• US Class Current: 701/112
• CPC Class Codes: F02B 37/24 by using pumps or turbines with adjustable guide vanes
• CPC Class Codes: F02D 13/04 using engine as brake
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/12 for deceleration F02D41/0005, F02D41/107 take precedence
• CPC Class Codes: F02D 9/06 Exhaust brakes
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method and system for operating a combustion engine brake especially for a heavy vehicle like a truck or a bus is disclosed. By detecting a brake torque value which is delivered by the combustion engine brake for braking the vehicle, and, if the amount of the difference between a demanded brake torque value and the delivered brake torque value exceeds a predetermined first limit value, by operating the combustion engine brake by means of at least one additional or alternative second operating parameter which is selected in order to create a corrected brake torque value, a considerably improved accuracy, efficiency and/or reliability of the combustion engine brake can be obtained.

Claims

1. Method for operating a combustion engine brake by means of at least one first operating parameter value which is selected in order to create a demanded brake torque value, comprising

detecting a brake torque value which is delivered by the combustion engine brake for braking the vehicle, and

if the amount of the difference between the demanded brake torque value and the delivered brake torque value exceeds a predetermined first limit value, operating the combustion engine brake by means of at least one second operating parameter value which is selected or adapted or controlled in order to create a corrected brake torque value.

2. Method according to claim 1, wherein the brake torque value which is delivered by the combustion engine brake is detected by means of a real or virtual brake torque sensor.

3. Method according to claim 1, wherein a plurality of first operating parameter values is stored in the form of a table assigning to each parameter value an expected brake torque value which is obtained when the combustion engine brake is operated with the related parameter value.

4. Method according to claim 1, wherein the second operating parameter value is determined from the first operating parameter value by increasing or decreasing its value by at least one predetermined step.

5. Method according to claim 4, wherein the second operating parameter value is stored instead of the first operating parameter value in the table.

6. Method according to claim 1, wherein the at least one first and/or the at least one second operating parameter and its value is selected from the following group of parameters and parameter values, respectively:

the back pressure and its value within the exhaust system of the combustion engine, the boost pressure and its value, the pre- and/or after turbine pressure and its value, the turbine speed and its value, the variable turbine geometry (VTG) and its position.

7. Method according to claim 1, wherein a fault condition is signaled if the amount of the difference between the demanded brake torque value and the delivered brake torque value exceeds a predetermined second limit value which is larger than the first limit value.

8. System for operating a combustion engine brake comprising an engine control unit for conducting a method according to claim 1.

9. System according to claim 8, wherein the brake torque value is detected by means of at least one real or virtual torque sensor which is positioned on a power transmitting shaft of the combustion engine.

10. Engine control unit for controlling a combustion engine, wherein the engine control unit is provided for operating a combustion engine brake by a method according to claim 1.

11. Engine control unit according to claim 10, which is provided as a part of a vehicle control unit.

12. Computer program comprising a computer program code for use in or conducting a method according to claim 1 when said program is run on a microcomputer.

13. Computer program according to claim 12 adapted to be downloaded to a system or an engine control unit when run on a computer which is connected to the internet.

14. Computer program product stored on a computer readable medium, comprising a program code for use in a method according to claim 1.