Bbc Brown, Boveri & Company, Limited

Erwin Meier

Hansulrich Horler

In a diesel engine (1) supercharged by an exhaust gas turbocharger, both the compressor (4) and the turbine (3) of the supercharger are designed for full engine power and speed. A by-pass duct (8) provided with a non-return valve (9) and a control device (10) is connected between the exhaust gas duct (9) and the boost air duct (5). The turbine (3) is equipped with means (11, 12, 13) for varying the turbine equivalent cross-section. At part load, the equivalent cross-section and, simultaneously, the by-pass duct cross-section are varied in order to operate as near as possible to the surge limit of the compressor (4).

Internal combustion engine supercharged by means of an exhaust gas

An internal combustion engine has a turbo-supercharger connected to an engine charge air intake manifold and an exhaust gas turbine connected to an engine exhaust manifold. An automatic bypass includes a bypass line interconnecting the exhaust manifold upstream of the exhaust gas turbine and the air intake manifold downstream of the compressor. A bypass valve in the bypass line comprising an adjustable throttle member for adapting the quantity of bypassed gas to the respective operating state of the engine. An actuating piston closes the throttle member in response to pressures from the compressor side above a pre-selected value. The actuating piston is disposed on a side of the throttle member facing away from the air intake manifold. The resistance of the valve to flow from the compressor side to the turbine side is less than the resistance in the opposite direction. The resistance to flow, and the fully unseated valve position define an operating curve of the engine which is adjustable. The throttle member can close before the maximum engine output point is reached.

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Remetschwil, Switzerland

Erwin Meier