Patent ID: 11875616
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Control (Instruments)
Classification: CPC G | IPC G

Claim 5:
6. A vehicle state monitoring device comprising:
a memory configured to store information relating to a vehicle traveling under power from an engine; and
a processor configured to
store, in the memory, a first time series of values representing revolutions of the engine and a second time series of values representing a fuel-related parameter that is a load factor or a fuel injection rate of the engine while the vehicle travels a predetermined distance;
store a frequency relation as the information in the memory each time the vehicle travels the predetermined distance, the frequency relation being a relation between the revolutions of the engine, the fuel-related parameter, and a running frequency of the engine at the revolutions of the engine and the fuel-related parameter while the vehicle travels the predetermined distance;
store a vehicle speed relation in the memory each time the vehicle travels the predetermined distance, the vehicle speed relation being a relation between the revolutions of the engine, the fuel-related parameter, and an average value of a vehicle speed of the vehicle when the engine is running at the revolutions of the engine and the fuel-related parameter;
clear the first time series of values and the second time series of values from the memory in response to storing the frequency relation;
determine a state of the vehicle using
a first portion of the frequency relation including running frequencies of the engine at revolutions of the engine equal to or greater than a first predetermined revolutions value and fuel-related parameters equal to or less than a first predetermined parameter value,
a second portion of the frequency relation including running frequencies of the engine at revolutions of the engine equal to or less than a second predetermined revolutions value and fuel-related parameters equal to or greater than a second predetermined parameter value,
a first portion of the vehicle speed relation including average values of the vehicle speed when the engine is running at revolutions of the engine equal to or greater than the first predetermined revolutions value and fuel-related parameters equal to or less than the first predetermined parameter value, and
a second portion of the vehicle speed relation including average values of the vehicle speed when the engine is running at revolutions of the engine equal to or less than the second predetermined revolutions value and fuel-related parameters equal to or greater than the second predetermined parameter value; and

determine, when overheating of the engine occurs, a cause of the overheating, using the frequency relation and the vehicle speed relation.