Misfire detecting device and method for internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorHitoki Sugimoto
Life of this patent
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Abstract
A CPU determines that there is a misfire when a relative magnitude of a rotation fluctuation amount ΔT30[0] related to a cylinder subject to the determination in relation to a rotation fluctuation amounts ΔT30[4] of the previous combustion cycle is greater than or equal to the determination value Δth. However, during the execution of a catalyst warm-up process, the CPU uses, in the comparison, the relative magnitude of the rotation fluctuation amount ΔT30[0] in relation to the average ΔT30ave[0] of the smallest five of the rotation fluctuation amounts ΔT30[4] to ΔT30[40] from the past ten combustion cycles.
Claims13
A misfire detecting device for an internal combustion engine, the misfire detecting device comprising:
- circuitry configured to:
- calculate a torque index value using an output signal of a crank angle sensor as an input;
- execute a determination process that determines whether there is a misfire based on a magnitude of the torque index value related to a cylinder subject to the determination as to whether there is the misfire, including:
- determining whether there is the misfire based on a comparison between a determination value and a relative magnitude of a current torque index value of the cylinder subject to the determination in relation to an average of past torque index values;
- and
- increment a misfire counter when there is the misfire, wherein
- the past torque index values are values related to cylinders in each of which a compression top dead center occurs at a point separated from a compression top dead center of the cylinder subject to the determination by an integral multiple of an angle corresponding to one turn of a crankshaft, and
- the torque index value is a variable that characterizes a torque of the crankshaft having a cycle of a length corresponding to an interval between occurrences of the compression top dead center.
A misfire detecting method for an internal combustion engine, the method comprising:
- calculating a torque index value using an output signal of a crank angle sensor as an input;
- determining whether there is a misfire based on a magnitude of the torque index value related to a cylinder subject to the determination as to whether there is the misfire, including:
- determining whether there is the misfire based on a comparison between a determination value and a relative magnitude of a current torque index value of the cylinder subject to the determination in relation to an average of past torque index values;
- and
- incrementing a misfire counter when there is the misfire, wherein
- the past torque index values are values related to cylinders in each of which a compression top dead center occurs at a point separated from a compression top dead center of the cylinder subject to the determination by an integral multiple of an angle corresponding to one turn of a crankshaft, and
- the torque index value is a variable that characterizes a torque of the crankshaft having a cycle of a length corresponding to an interval between occurrences of the compression top dead center.
A misfire detecting device for an internal combustion engine, the misfire detecting device comprising:
- circuitry configured to:
- calculate a torque index value using an output signal of a crank angle sensor as an input;
- execute a determination process that determines whether there is a misfire based on a magnitude of the torque index value related to a cylinder subject to the determination as to whether there is the misfire, including:
- determining whether there is the misfire based on a comparison between a determination value and a relative magnitude of a current torque index value of the cylinder subject to the determination in relation to an average of past torque index values;
- execute at least one of a retardation process that retards ignition timing when a temperature of a catalyst in an exhaust passage of the internal combustion engine is relatively low and a fixed-value control process that uses an electric motor mechanically coupled to a crankshaft to control a rotation speed of the crankshaft to a fixed value;
- and
- execute the determination process during the at least one of the retardation process and the fixed-value control process, wherein
- the past torque index values are values related to cylinders in each of which a compression top dead center occurs at a point separated from a compression top dead center of the cylinder subject to the determination by an integral multiple of an angle corresponding to one turn of the crankshaft, and
- the torque index value is a variable that characterizes a torque of the crankshaft having a cycle of a length corresponding to an interval between occurrences of the compression top dead center.
Dependencies are inferred from the claim text.