Volvo Lastvagnar Ab

Göran Olsson

Per I Persson

Per-Åke Bligård

Vinka Miketa

Henrik Ask

A diagnostic method for an exhaust pressure regulator provided in an exhaust system connected to a turbocharged internal combustion engine includes demanding engine brake, measuring a back pressure in the exhaust system by a back pressure sensor provided between the exhaust pressure regulator and a turbo unit when demanding engine brake, measuring the boost pressure by a boost pressure sensor provided in the inlet manifold when demanding engine brake, comparing the measured back pressure and the measured boost pressure with stored back pressure and boost pressure values in order to determine whether there is a defective pressure regulator or a defective backpressure sensor. A diagnostic apparatus for an exhaust pressure regulator provided in an exhaust system connected to a turbocharged internal combustion engine is also provided.

Diagnostic method and apparatus for an exhaust pressure regulator

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.

Method and system for operating a combustion engine brake

In an exhaust valve mechanism for an internal combustion engine the main rocker arm is mounted on a rocker arm shaft for normal valve operation via a cam element. A secondary rocker arm is mounted on the shaft for activation of an exhaust brake mode. The activation is achieved through supply of hydraulic pressure to a piston cylinder arrangement acting between the main and secondary rocker arms. A master piston and a slave piston are connected by a hydraulic-link allowing activation by increased hydraulic pressure. When activating the exhaust gas temperature increasing mode, the master piston is moved to an active position for part of its stroke against the force of a first resilient member. When activating the exhaust brake mode, the master piston is moved the full movement of its stroke against the combined forces of the first resilient member and a second resilient member as active position. The end of the first stroke length defines a position for the master piston allowing activation of an extra valve event.

Exhaust valve mechanism for an internal combustion engine

Method and arrangement for a turbocompound type internal combustion engine including an exhaust system for ducting the engine's exhaust gases. A supercharger turbine drives a compressor for the engine's combustion air, and an exhaust turbine is placed in the exhaust system downstream of the supercharger turbine for extracting residual energy from the exhaust flow via transmission to the combustion engine's crankshaft. The exhaust system also has an exhaust braking throttle placed downstream of the exhaust turbine. The exhaust braking throttle includes a pressure-controlled exhaust pressure regulator that makes possible variable regulation of an exhaust braking pressure in at least two steps.

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Göteborg, Sweden

Göran Olsson