Controlling a compression release brake

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 the 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 calculated desired exhaust manifold gas pressure is minimized.

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;
• a back pressure valve connected to the output of said turbine for controlling the 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.