Torque Transfer Response Enhancement on the DCT with Estimated Hydraulic Pressure in the Clutch Piston Chamber

The torque transfer response to rider throttle operation contributes to vehicle control in motorcycles equipped with a DCT (Dual Clutch Transmission). The clutch response is a key parameter to enhance torque transfer response. We have developed three new ECU control methods to enhance the clutch response on the DCT. The DCT clutch transfers torque by controlling the contact force between the clutch discs and the clutch plates. It is desirable to measure the hydraulic pressure value directly from the clutch piston chamber to control the contact force. However, since the clutch piston is a rotating body, it is impractical to place a hydraulic pressure sensor on it. Therefore, the hydraulic pressure sensor is placed along the clutch control oil line at the existing DCT system. Consequently, when oil flows in the oil line, pressure loss in the oil line causes a discrepancy between the hydraulic pressure sensor value and the clutch piston chamber pressure value, which limits the enhancement of clutch response. To enhance clutch response, we have studied the estimation of the hydraulic pressure value in the clutch piston chamber using the existing hydraulic pressure sensor value at the oil line. This estimation is based on the reaction force characteristics of the clutch piston and Bernoulli’s principle. By using the estimated hydraulic pressure, half-clutch control can be identified, which allows the application of higher feedback gain to enhance clutch response. We also implement correction of clutch control oil viscosity fluctuations based on the hydraulic pressure variations of the clutch control oil at engine startup. With these technologies applied, the clutch response time is reduced by 45% compared to the existing DCT clutch control. This also reduces torque transfer response time, ultimately allowing for smoother vehicle control.