| 摘要 |
<P>PROBLEM TO BE SOLVED: To protect a turbo supercharger by suddenly reducing exhaust energy on an exhaust turbine when detecting abnormal rise of supercharging pressure to prevent an excessive turbo rotating speed. <P>SOLUTION: An ECU executes second protecting control for protecting the turbo supercharger when actual supercharging pressure exceeds preset second allowable upper limit supercharging pressure. Namely, at the time when the actual supercharging pressure exceeds the second allowable upper limit supercharging pressure, an injection amount is cut and the opening of an EGR valve is controlled to be fully opened. Thus, the amount of EGR gas to return through an EGR passage to an intake passage is suddenly increased and exhaust energy on the exhaust turbine of the turbo supercharger is greatly reduced, accordingly. As a result, the excessive condition of the supercharging pressure is quickly avoided to prevent the excessive turbo rotating speed (an upper limit rotating speed for maintaining the reliability of the turbo supercharger < a turbo rotating speed), and so the tubo supercharger is protected. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
