Drive Mode

In the ECVT modes, the control system operates by deriving a target engine speed based on current vehicle speed and driver demand. In manual mode, the system derives a target engine speed based on the vehicle speed and the current gear ratio. Having obtained an engine speed target, the system calculates the appropriate ratio control motor position and instructs the GIU to deliver this position.

The engine load calculation will depend on two factors:

1. The vehicles road speed.
2. The driver's demand (throttle position).

The EMS 2000 also needs to control the speed of the ratio control motor in order to protect the transmission from damage due to drive belt slippage. This is more likely to occur at low transmission oil temperatures, and when the transmission is delivering a large change in ratio (for example, after a manual gear change, or sudden throttle movement in Drive mode).

Four speeds are used by the Ratio Control Motor. The motor is accelerated as appropriate to ensure the motor does not lose its reference, thereby compromising system control.

The EMS 2000 also knows the maximum torque that the belt can transfer across all possible ratio ranges. It is extremely important that the belt is not allowed to slip on the pulleys, as this would cause excessive wear.