Determination criterion for engine torque control device and method

An engine control method for a vehicle including an engine mounted on the vehicle and an electronic control unit including a memory which stores at least one threshold value map, the engine control method comprising:

• obtaining, by the electronic control unit, a required torque for the engine;
• obtaining an engine torque by the electronic control unit;
• determining, by the electronic control unit, whether the engine is in an excessive torque state,
• the excessive torque state being a state in which the engine torque is greater than the required torque by at least a predetermined degree;
• and
• performing, by the electronic control unit, a fail-safe process when the engine is determined to be in the excessive torque state;
• wherein
• the engine control method is performed repeatedly during a predetermined time interval;
• each of the at least one threshold value maps includes a plurality of determination modes including mutually different determination criterion for determining the excessive torque state, based on a predetermined vehicle speed related parameter, the predetermined vehicle speed related parameter being a single parameter or a combination of parameters related to a speed of the vehicle or a change in the speed of the vehicle;
• the determining whether the engine is in an excessive torque state includes selecting one of the at least one threshold value maps based on the vehicle speed related parameter, the plurality of determination modes being set such that when a value of the vehicle speed related parameter is a value corresponding to a relatively high vehicle speed, the engine is less prone to be determined to be in the excessive torque state compared to when the value of the vehicle speed related parameter is a value corresponding to a relatively low vehicle speed;
• each of the determination criterion for the excessive torque state includes a first threshold value indicating a continuing time of a state in which the engine torque is excessive relative to the required torque;
• each of the mutually different determination criterion includes a second threshold value indicating an excess of the engine torque relative to the required torque;
• and
• the engine control method further comprises setting the first threshold value by referring to the selected threshold value map, the first threshold value being greater when the vehicle speed related parameter is the value corresponding to the relatively high vehicle speed compared to when the vehicle speed related parameter is the value corresponding to the relatively low vehicle speed, the first threshold value being set based on an expected inter-vehicle distance to a preceding vehicles;
• wherein:
• the at least one threshold value map stored in the memory includes a first threshold value map and a second threshold value map,
• the second threshold value for each of the plurality of determination modes of the first threshold value map are set to be equal to each other, and
• the first threshold value for each of the plurality of determination modes of the second threshold value map are set to be equal to each other.