Hitachi, Ltd.

Hitachi Automotive Systems, Ltd.

Eiichiro Ohata

Hiroaki Hoshika

Shiro Yamaoka

Noboru Tokuyasu

Yoshihiro Sukegawa

Jun Kubo

Kaori Kashio

Toshiki Otsuki

A method for correcting an output characteristic of an in-cylinder pressure sensor has a problem of insufficient correction precision because the measurement range required for the detection of a peak in-cylinder pressure and an ignition timing resides in a high-pressure region of an in-cylinder combustion cycle, whereas a reference pressure used for correction is measured while leaving an intake valve and an exhaust valve open, so that the reference pressure is out of the required measurement range. An apparatus for measuring an in-cylinder pressure includes: exhaust pressure detection means disposed in an exhaust port of an internal combustion engine to measure an exhaust pressure in the exhaust port; exhaust pressure recording means that records time history of the measured exhaust pressure; and peak exhaust pressure detection means that detects a peak value for each pulsation cycle of the exhaust pressure on the basis of the recorded time history of the exhaust pressure. A peak value of the in-cylinder pressure for each combustion cycle is calculated using the detected peak value of the exhaust pressure, and the calculated peak value of the in-cylinder pressure is used as a reference pressure.

Apparatus for measuring in-cylinder pressure

A control apparatus of an EGR control valve has an EGR control valve has an exhaust gas recirculation passage to circulate exhaust gas of an combustion engine from an exhaust gas passage to an intake air passage. A measurement unit measures a flow rate of EGR gas flowing in the exhaust gas recirculation passage, and a controller receives an input from the measurement unit and closes the EGR control valve if the EGR-gas flow rate is smaller than a predetermined threshold value when the EGR gas is flowing from the exhaust side to the intake side of the internal combustion engine.

Control apparatus of EGR control valve

The present invention prevents an EGR sensor installed in an engine's EGR path from being soiled by soiling substances in exhaust. A catalyst is positioned upstream of the EGR sensor to purify the soiling substances in EGR gas. The status of the EGR sensor is properly controlled in accordance with the conditions of the catalyst. This ensures the EGR sensor is less likely to be affected by the soiling substances in the exhaust under any circumstances of the EGR path and allows the EGR sensor to avoid a decrease in the accuracy of EGR gas detection. An alternative configuration may be employed such that the EGR gas recirculates from the downstream side of a catalyst installed in a main exhaust path.

Exhaust gas recirculation system

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Kasama, Japan

Eiichiro Ohata