Dual Battery system - ECO Engine Stop/Start State
| ITEM | DESCRIPTION |
|---|---|
| 1 | Tandem Solenoid Starter (TSS) motor |
| 2 | Primary battery |
| 3 | Power and engine management system loads |
| 4 | Field Effect Transistor (FET) |
| 5 | Contactor 1 - open |
| 6 | Contactor 2 - closed |
| 7 | Secondary battery |
| 8 | Sensitive loads |
| 9 | Generator |
When an ECO engine start is required, the DBJB must change the battery supply via the two contactors before the TSS motor is operated to crank the engine. The GWM is connected to the ABS (Anti-Lock Brake System) control module via the high speed CAN bus. With the vehicle stationary and the engine off after an ECO engine stop, when the driver releases the brake pedal the ABS control module senses the reduction in brake pressure. This change of brake pressure state is sent as a high speed CAN message which is received by the GWM and the ECM. The GWM reacts within 105ms to instruct the DBM via the LIN bus to operate the two contactors in the DBJB to supply the sensitive loads from the secondary battery and supply the TSS motor direct from the primary battery.
When the engine is running and the generator is supplying power to the vehicle systems, the GWM again instructs the DBM to operate the two contactors in the DBJB to supply all vehicle systems from the primary battery and the generator and to isolate the secondary battery.