Misfire detection apparatus and misfire detection method for multi-cylinder engine

Patent metadata

Field	Value
Publication number	US-2024384691-A1
Application number	US-202118291911-A
Country	US
Kind code	A1
Filing date	Jul 28, 2021
Priority date	Jul 28, 2021
Publication date	Nov 21, 2024
Grant date	—

Abstract

A misfire detection apparatus for multi-cylinder engine is configured to detect a misfiring state in which any of a plurality of cylinders in an engine is misfiring, the engine including: the plurality of cylinders, and a catalyst device configured to purify exhaust gas from the plurality of cylinders. The apparatus includes: a rotation sensor configured to detect a rotational speed of the engine, and an electronic control unit including a processor and a memory coupled to the processor and configured to control operation of the engine. The processor detects the misfiring state of the engine based on the rotational speed of the engine detected by the rotation sensor.

First claim

1 . A misfire detection apparatus for multi-cylinder engine, configured to detect a misfiring state in which any of a plurality of cylinders in an engine is misfiring, the engine including: the plurality of cylinders; and a catalyst device configured to purify exhaust gas from the plurality of cylinders, comprising:
a rotation sensor configured to detect a rotational speed of the engine; and an electronic control unit including a processor and a memory coupled to the processor and configured to control operation of the engine, wherein the engine is a four-stroke V-type two-cylinder engine that makes two rotations per cycle, wherein the processor determines whether the rotational speed of the engine instantaneously increases twice for every two rotations of the engine based on change characteristics of the rotational speed detected by the rotation sensor and detects the misfiring state of the engine based on a determination result in a startup period in which the rotational speed increases after cranking of the engine ends.

2 . The misfire detection apparatus for multi-cylinder engine according to claim 1 , further comprising:
an exhaust gas temperature sensor configured to detect an exhaust gas temperature of the engine, wherein the processor detects the misfiring state of the engine based on the rotational speed detected by the rotation sensor or the exhaust gas temperature detected by the exhaust gas temperature sensor.

3 . The misfire detection apparatus for multi-cylinder engine according to claim 2 , wherein
the exhaust gas temperature sensor detects the exhaust gas temperature after passing through the catalyst device.

4 . The misfire detection apparatus for multi-cylinder engine according to claim 2 , wherein
the engine includes a throttle valve configured to adjust an amount of fresh air to be supplied to the plurality of cylinders, wherein the processor:
detects the misfiring state of the engine based on the exhaust gas temperature detected by the exhaust gas temperature sensor after cranking of the engine ends and after a startup period in which the rotational speed increases elapses; and
controls operation of the throttle valve to stop the engine when the misfiring state of the engine is detected based on the exhaust gas temperature detected by the exhaust gas temperature sensor.

5 . The misfire detection apparatus for multi-cylinder engine according to claim 4 , wherein
the processor detects the misfiring state of the engine when a state in which the exhaust gas temperature detected by the exhaust gas temperature sensor exceeds a threshold continues for a predetermined time period after the startup period elapses.

6 . The misfire detection apparatus for multi-cylinder engine according to claim 4 , wherein
the processor detects the misfiring state of the engine when a rising speed of the exhaust gas temperature detected by the exhaust gas temperature sensor exceeds a threshold after the startup period elapses.

7 - 8 . (canceled)

9 . The misfire detection apparatus for multi-cylinder engine according to claim 1 , wherein
the engine includes injectors respectively configured to supply fuel to each of the plurality of cylinders, wherein the processor controls operations of the injectors to stop the engine when the misfiring state of the engine is detected based on the rotational speed detected by the rotation sensor.

10 . The misfire detection apparatus for multi-cylinder engine according to claim 9 , wherein
the processor:
estimates one of the plurality of cylinders in which the rotational speed instantaneously increases as a normal cylinder in which the normal combustion is performed, while estimates the other of the plurality of cylinders as a misfiring cylinder, when the misfiring state of the engine is detected based on the rotational speed detected by the rotation sensor;
controls operations of the injectors to stop fuel supply to the normal cylinder; and
controls operations of the injectors to restart fuel supply to the normal cylinder and to stop fuel supply to the misfiring cylinder, when operation of the engine continues after stopping fuel supply to the normal cylinder.

11 . A misfire detection method for multi-cylinder engine, configured to detect a misfiring state in which any of a plurality of cylinders in an engine is misfiring, the engine including: the plurality of cylinders; and a catalyst device configured to purify exhaust gas from the plurality of cylinders, wherein
the engine is a four-stroke V-type two-cylinder engine that makes two rotations per cycle, wherein the method comprises the steps of:
determining whether a rotational speed of the engine instantaneously increases twice for every two rotations of the engine based on change characteristics of the rotational speed and detecting the misfiring state of the engine based on a determination result in a startup period in which the rotational speed increases after cranking of the engine ends.

Assignees

• Honda Motor Co Ltd

Inventors

• Miyauchi Tomohiro

Classifications

• F02D41/06

  for engine starting or warming up {(F02D41/0255 takes precedence)} · CPC title

• F02D41/0097

  using means for generating speed signals · CPC title

• F02D2200/0802

  Temperature of the exhaust gas treatment apparatus · CPC title

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• F02D2200/101

  Engine speed · CPC title