Mazda Motor Corporation

Hiroshi Haehara

Daishi Ikeda

Takahiro Kono

Abnormality diagnosis device for a variable valve mechanism configured to open an exhaust valve even during an intake stroke and capable of selecting a first mode wherein the exhaust valve only opens during an exhaust stroke, or a second mode wherein the exhaust valve opens during both an exhaust stroke and an intake stroke. The abnormality diagnosis by the device determines the mechanism is abnormal when a difference between an exhaust gas returning amount calculated to recirculate from an exhaust passage into a cylinder in the second mode based on intake air amounts in the first and second modes, and an exhaust gas returning amount estimated to recirculate from an exhaust passage in the second mode based on an exhaust gas pressure, exceeds a diagnosis threshold value. The higher an exhaust gas pressure is, the larger an exhaust gas returning amount is estimated to be.

Growing community of inventors

Hatsukaichi, Japan

Hiroshi Haehara