System for estimating temperature of vehicle hydraulically-operated transmission

A system for estimating temperature of a plurality of frictional engaging elements installed in a vehicle hydraulically-operated transmission including a hydraulic coupling means having an input connected to an internal combustion engine mounted on the vehicle and an output connected to a gear system of the transmission, comprising:

• a hydraulic pressure supplying circuit for discharging hydraulic fluid from one of said plurality of frictional engaging elements and for supplying hydraulic fluid to another one of said plurality of frictional engaging elements to bring said one and another one of said plurality of frictional engaging elements into operation such that gear-shift is effected in the transmission;
• coolant temperature detecting means for detecting a coolant temperature of the engine;
• first heat quantity calculating means for calculating a heat quantity generated by the hydraulic coupling means;
• second heat quantity calculating means for calculating a heat quantity generated by the respective frictional engaging elements including the frictional engaging element at gearshift;
• third heat quantity calculating means for calculating a heat quantity generated by stirring of the hydraulic fluid;
• fourth heat quantity calculating means for calculating a heat quantity generated or absorbed at a heat exchanger which exchanges heat from the fluid;
• and
• frictional engaging element temperature estimating means for estimating temperatures of the respective frictional engaging elements based on the detected engine coolant temperature and the calculated heat quantities calculated by the first, second, third and fourth heat quantity calculating means.

A method for estimating temperature of a plurality of frictional engaging elements installed in a vehicle hydraulically-operated transmission including a hydraulic coupling means having an input connected to an internal combustion engine mounted on the vehicle and an output connected to a gear system of the transmission, comprising:

• a hydraulic pressure supplying circuit for discharging hydraulic pressure from one of said plurality of frictional engaging elements and for supplying hydraulic pressure to another one of said plurality of frictional engaging elements to bring said one and another one of said plurality of frictional engaging elements into operation such that gear-shift is effected in the transmission;
• comprising the steps of:
• (a) detecting a coolant temperature of the engine;
• (b) calculating a heat quantity generated by the hydraulic coupling means;
• (c) calculating a heat quantity generated by the respective frictional engaging elements;
• and
• (d) estimating temperatures of the respective frictional engaging elements based on the detected engine coolant temperature and the calculated heat quantities.

A method for estimating temperature of a plurality of frictional engaging elements installed in a vehicle hydraulically-operated transmission including a hydraulic coupling means having an input connected to an internal combustion engine mounted on the vehicle and an output connected to a gear system of the transmission, including:

• a hydraulic pressure supplying circuit of discharging hydraulic fluid from one of said plurality of frictional engaging elements and for supplying hydraulic fluid to another one of said plurality of frictional engaging elements to bring said one and another one of said plurality of frictional engaging elements into operation such that gear-shift is effected in the transmission;
• comprising the steps of:
• (a) detecting a coolant temperature of the engine;
• (b) calculating a heat quantity generated by the hydraulic coupling means;
• (c) calculating a heat quantity generated by the respective frictional engaging elements including the frictional engaging element at gear-shift;
• (d) calculating a heat quantity generated by stirring of the hydraulic fluid;
• (e) calculating a heat quantity generated or absorbed at a heat exchanger which exchanges heat from the fluid;
• and
• (f) estimating temperatures of the respective frictional engaging elements based on the detected engine coolant temperature and the calculated heat quantities.