Torque Split Strategy for Parallel Hybrid Electric Vehicles with an Integrated Starter Generator

Table 1

The fuzzy rules of the FLC.

Rule number	Input torque	SOC	Speed	Output torque	Explanation
1	Low	Low	Low	Opt	Idle speed to mid-speed condition: but battery needs charge, so the output torque should be opt
2	Low	Low	Mid	Opt
3	Low	Low	High	High	SOC is low, high-speed condition: output torque should be up to opt
4	Low	Target	Low	Low	Battery does not need charging: output torque holds on low
5	Low	Target	Mid	Opt	Speed is mid: output torque should be opt to obtain most efficiency
6	Low	Target	High	High	High-speed condition: output torque should be up to opt
7	Low	High	Low	Low	SOC is high: battery needs discharging, and output torque should be low
8	Low	High	Mid	Low
9	Low	High	High	Opt	High-speed condition: output torque should be up to low
10	Opt	Low	Low	Opt	Battery does not need discharging, low-speed or mid-speed condition: the output torque is determined by input torque
11	Opt	Low	Mid	Opt
12	Opt	Low	High	High	Battery need charging, and high-speed condition: output torque should be high
13	Opt	Target	Low	Opt	Battery can be charged or discharged, so the electrical system can provide positive or negative torque for ICE. To obtain most efficiency, output torque should be opt
14	Opt	Target	Mid	Opt
15	Opt	Target	High	Opt
16	Opt	High	Low	Low	Battery need discharging, and low-speed condition: output torque should be low
17	Opt	High	Mid	Opt	Battery need discharging, and mid-speed condition: the electrical system can provide positive torque for ICE, so output torque should be opt
18	Opt	High	High	Opt
19	High	Low	Low	High	The electrical system can not provide positive torque for ICE, so the output torque is determined by input torque
20	High	Low	Mid	High
21	High	Low	High	High
22	High	Target	Low	Opt	The electrical system can provide positive torque for ICE. To obtain most efficiency, output torque should be opt
23	High	Target	Mid	Opt
24	High	Target	High	High	High-speed and high-torque condition
25	High	High	Low	Low	Battery need discharging, and low-speed condition: output torque should be low
26	High	High	Mid	Opt	The electrical system can provide positive torque for ICE. To obtain most efficiency, output torque should be opt
27	High	High	High	Opt