Controlling a compression release brake

Patent metadata

Field	Value
Publication number	US-9546592-B2
Application number	US-201314405960-A
Country	US
Kind code	B2
Filing date	Jun 6, 2013
Priority date	Jun 7, 2012
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A method and a system are described for a compression release brake in an engine comprising an exhaust manifold connected to a turbine provided with a variable turbine geometry wherein said turbine is further connected to a back pressure valve for controlling the pressure drop over said turbine wherein the method comprises the steps of: controlling said back pressure valve on the basis of a measured engine speed and a desired braking power; calculating a desired exhaust manifold gas pressure on the basis of said measured engine speed and said desired braking power; and, controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said calculated desired exhaust manifold gas pressure is minimized.

First claim

The invention claimed is:

1. Method for controlling a compression release brake in an engine comprising an exhaust manifold connected to a turbocharger provided with a variable turbine geometry turbine wherein said turbine is further connected to a back pressure valve for controlling a pressure drop over said turbine, the method comprising:
controlling said back pressure valve on the basis of a measured engine speed and a desired braking power;
determining a desired exhaust manifold gas pressure on the basis of at least said measured engine speed and said desired braking power; and,
controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said determined desired exhaust manifold gas pressure is minimized.

2. Method according to claim 1 wherein said desired exhaust manifold gas pressure is determined on the basis of an exhaust manifold gas pressure function p exh =f(n,P s ).

3. Method according to claim 2 wherein said desired exhaust manifold gas pressure function is further dependent on, in addition to said measured engine speed and said desired braking power, an ambient air pressure p exh =f(n,p a ,P s ) or an inlet manifold air pressure p exh =f(n,p i ,P s ).

4. The method of claim 2 , wherein said exhaust manifold gas pressure function is implemented as a look-up table in a memory comprising exhaust manifold gas pressure values stored as a function of at least said measured engine speed and said desired braking power.

5. Method according to claim 1 wherein said back pressure valve is controlled using a predetermined back pressure valve function for determining position information of said back pressure valve as a function of at least said measured engine speed and said desired braking power Y BPV =f(n,P s ).

6. Method according to claim 5 wherein said back pressure valve function is further dependent on, in addition to said measured engine speed and said desired braking power, an ambient air pressure Y BPV =f(n,p a ,P s ) or an inlet manifold air pressure Y BPV =f(n,p i ,P s ).

7. The method of claim 5 , wherein said predetermined back pressure valve function is implemented as a look-up table in a memory comprising back pressure valve position values stored as a function of at least said measured engine speed and said desired braking power.

8. Method according to claim 1 wherein controlling said variable turbine geometry comprises:
receiving a desired exhaust manifold gas pressure;
determining a desired variable turbine geometry using said desired exhaust manifold gas pressure and said measured manifold gas pressure;
sending a control signal associated with said desired variable turbine geometry to one or more actuators for configuring said turbine into said desired variable turbine geometry.

9. Method according to claim 1 wherein controlling said back pressure valve comprises:
determining a back pressure valve position;
sending a control signal associated with said back pressure valve position to at least one actuator for configuring said back pressure value into said back pressure valve position.

10. Method according to claim 1 wherein said variable turbine geometry and said back pressure valve are controlled such that maximum exhaust manifold gas pressure is achieved while keeping the turbine speed below a predetermined maximum value.

11. Method according to claim 1 , wherein above a predetermined engine speed threshold value n T , the back pressure valve is closed as a function of the engine speed in order to keep a turbine speed below a maximum allowable speed, while at the same time allowing maximum brake power.

12. Method according to claim 1 , wherein above a predetermined engine speed threshold value n T , a BPV position of said back pressure valve is controlled between a 100% open position and a 40% open position, while a VTG position of said variable turbine geometry is controlled between a 10% open position and a 30% open position.

13. Method according to claim 1 wherein controlling said variable turbine geometry comprises:
actuating one or more rotatable vanes of said variable turbine geometry turbine, a sliding wall within the turbine, or both.

14. Method according to claim 1 further comprising:
receiving a request for a desired braking power.

15. A computer program product, implemented on computer-readable non-transitory storage medium, the computer program product configured for, when run on a computer, executing the method steps according to claim 1 .

16. A compression release brake controller in an engine comprising an exhaust manifold connected to a turbine provided with a variable turbine geometry wherein said turbine is further connected to a back pressure valve for controlling a pressure drop over said turbine, said controller being configured for:
controlling said back pressure valve on the basis of a measured engine speed and a desired braking power;
determining a desired exhaust manifold gas pressure on the basis of at least said measured engine speed and desired braking power; and,
controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said determined desired exhaust manifold gas pressure is minimized.

17. A system for controlling a compression release brake in an engine comprising an exhaust manifold connected to a turbine provided with a variable turbine geometry, said system comprising:
an engine speed sensor;
an exhaust manifold gas pressure sensor for measuring exhaust manifold pressure;
a back pressure valve connected to the output of said turbine for controlling a pressure drop over said turbine; and,
a compression release brake controller configured for receiving a request for a desired braking power; for controlling said back pressure valve on the basis of an engine speed measured by said engine speed sensor and said desired braking power; for calculating a desired exhaust manifold gas pressure on the basis of said measured engine speed and desired braking power; and, for controlling said variable turbine geometry such that the difference between a measured exhaust manifold gas pressure and said calculated desired exhaust manifold gas pressure is minimized.

Assignees

• Daf Trucks Nv

Inventors

• Lingens Andreas
• Peters Roel

Classifications

• F02D2200/703

  Atmospheric pressure · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F01L13/065

  Compression release engine retarders of the "Jacobs Manufacturing" type · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02D2200/0406

  Intake manifold pressure · CPC title