Control device for internal combustion engine with turbo supercharger

Abstract

An object of the present invention is to control a supercharge pressure in such a manner as not to interfere with warming-up of an exhaust gas purifying catalyst, in an internal combustion engine with a turbo supercharger. To this end, a control device for an internal combustion engine with a turbo supercharger provided by the present invention makes a determined value of a target supercharge pressure with respect to a same target intake pressure smaller when a request to warm up the exhaust gas purifying catalyst is present, as compared with when the request is absent. Note that the target intake pressure is determined based on a target air amount determined from a requested torque for the internal combustion engine. The present control device operates a throttle based on the target intake pressure and an actual supercharge pressure, and operates a wastegate valve based on the target supercharge pressure.

Description

TECHNICAL FIELD[0001]The present invention relates to a control device for an internal combustion engine with a turbo supercharger, and particularly relates to a control device for an internal combustion engine with a turbo supercharger capable of actively controlling a rotational frequency of a turbine by operation of an actuator.BACKGROUND ART[0002]As one of the methods for controlling internal combustion engines for automobiles, there is known torque demand control that determines a manipulated variable of an actuator with a torque as a controlled variable. Torque demand control also can be applied to internal combustion engines with turbo superchargers. In the torque demand control of an internal combustion engine with a turbo supercharger, a manipulated variable of a throttle is determined based on a requested torque, and a manipulated variable of an actuator for supercharge pressure control is determined based on the requested torque. A supercharge pressure controlling actuato...

AI Technical Summary

Benefits of technology

[0010]According to the control device configured as above, when the request to warm up the exhaust gas purifying catalyst is present, the supercharge pressure controlling actuator is operated so that a supercharge pressure becomes lower as compared with the case in which such a request is absent. As a result that turbine work is reduced by the operation, heat loss that occurs in the turbine is reduced, and decline of the exhaust gas temperature can be suppressed.

Problems solved by technology

However, the performance required of an internal combustion engine is not only the operation performance like this.

However, in the case of an internal combustion engine with a turbo supercharger, an exhaust gas temperature is sometimes reduced due to heat loss that occurs in the turbine.

In order to increase a supercharge pressure, large turbine work is necessary, but as the turbine work is larger, the heat loss occurring in the turbine becomes larger.

Therefore, depending on the method for controlling the supercharge pressure, there arises the fear of interfering warming-up of the exhaust gas purifying catalyst due to reduction in the exhaust gas temperature in the turbine.