| 摘要 |
<p>PURPOSE:To achieve an alleviation of the supercharging efficiency of an internal combustion engine and heat load to an oxygen sensor installed in its exhaust system by providing a by-pass pipe on an exhaust pipe which communicates to the turbine of a turbo-charger so as to control the amount of exhaust gas by utilizing of the engine temperature and negative pressure. CONSTITUTION:A turbo-charger 13, which comprises a compressor C and turbine T, is provided with an intake system 9 and exhaust system 12 of an engine 1. In the exhaust system 9, are provided a pipe 26 by-passing over the turbine T and a control valve 29 adapted to open or close the pipe 26, and an oxygen sensor 38 and ternary catalytic converter 24 are also installed in the exhaust system 9 at a position downstream the by-pass pipe 26. The valve 29 is actuated by an actuator 32 driven by a negative pressure, in addition to that, the second chamber 36 of the actuator 32 is capable of introducing a negative pressure from an intake pipe via a change- over control valve 40 and a check valve 53. The valve 40 is opened when the temperature of cooling water 42 exceeds a predetermined value so as to introduce the negative pressure into the second chamber 36, resulting in an opening of the valve 29. A certain degree of negative pressure is also led into the first chamber 35 of the actuator 32 in accordance with the volume of air intaken. The opening degree of the valve 29 is adjusted by the pressure difference between the first and second chambers.</p> |
