| 摘要 |
A hybrid supercharged engine which comprises a turbo-charger TC having a maximum capacity at a higher speed than a maximum torque rotational speed of the engine, and a positive displacement supercharger SC installed in series with the turbo-charger TC, the SC being controlled to have a constant air charging amount irrespective of an engine speed for two-stage supercharging. The hybrid supercharged engine can provide a BMEP two or more times that of a TC supercharged engine as well as a low BSFC. Further, supercharging is effected mainly by the SC at low speeds to increase an air charging amount supplied to the engine for acceleration of the TC, so that generation of turbo lag can be suppressed to thereby display a performance at a steady running even at the time of rapid accelerating from low speeds. Also, the SC effectively functions at start-up to increase a compression pressure and temperature of the engine to facilitate start-up of a high-ratio output engine which inevitably has a low compression ratio. Accordingly, it is possible to make an engine small-sized, lightweight and inexpensive and to reduce NOx emissions without sacrifice in reliability of the engine.
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