Page - 118 - in Hybrid Electric Vehicles

booster regime was set at 2 min in order to avoid the complete discharging of the battery (but no less than 20%). The parameters of the ICE considered are presented in Table 3. The control of the electrical machines in the starter operating mode involves a maximum torque value (150 N m) until the ICE reaches 350 rpm. Torque command is provided by a bi-positional regulator with hysteresis. It is active when the command of ICE is active and its speed is less than 200 rpm, and it is off when the speed exceeds 400 rpm. When the ICE speed exceeds 300 rpm, the process of fuel injection into the cylinders starts and the ICE accelerates to idle speed. By applying the necessary torque to start the ICE, this is accelerated rapidly at the speed of 400 rpm in about 0.35 s. When ICE exceeds the speed of 400 rpm, the bi-positional controller becomes inactive and the combustion engine continues to spin out due to its inertia. If the pistons do not reach the maximum compression point, they will not be able to inject fuel to start the combustion pro- cess; consequently, the speed drops below 200 rpm and now the controller output is active. Therefore, the starter is controlled again and the combustion engine is brought to a speed of 400 Figure 10. Vehicle model [35]. Type Turbo diesel Compression ratio 2:1 Number of cylinders 4 Maximum torque 365 N m at 2000 rpm Cubic capacity 1994 cm3 Maximum power 120 kW at 3750 rpm Table 3. ICE parameters. Hybrid Electric Vehicles118