Denso Corporation

Sumiko Kohira

Hiroshi Haraguchi

Toshio Kondo

Kazuo Kobayashi

An ECU converts a cylinder pressure P and a cylinder volume V corresponding to a crank angle &#x3b8; at least from a compression stroke to a combustion and expansion stroke to a logarithmic value log P and a logarithmic value log V, respectively, to find a logarithmic conversion waveform and estimates a motoring waveform which is obtained by subtracting a pressure rise developed by combustion in a cylinder from the logarithmic conversion waveform, that is, corresponds to a non-combustion state. Further, the ECU computes a determination line Y of an ignition timing Tburn on the basis of the base line X of the estimated motoring waveform and determines the ignition timing Tburn on the basis of this determination line Y and the logarithmic conversion waveform.

Controller for internal combustion engine

An O amount in the intake air is determined based on a fresh air and an EGR gas. A consumed O amount is determined with a command injection amount Qr. Then, the consumed O amount is subtracted from the O amount in the intake air to obtain an exhaust O amount. An exhaust O concentration is estimated based on the exhaust O amount. According to the invention, the system is not affected by a delay for the exhaust gas to reach an O sensor and a delay of the chemical reaction in the O sensor. Therefore, the exhaust O concentration can be highly precisely estimated compare to the case in which the exhaust O concentration is detected by the O sensor.

Growing community of inventors

Kariya, Japan

Sumiko Kohira