Description And Operation - Low Temperature Cooling System
| 1 - Integrated Dual Charging Module (IDCM) | 5 - Motor/Generator Unit (MGU) |
| 2 - Low Temperature Pressurized Coolant Bottle | 6 - Charge Air Cooler |
| 3 - Low Temperature Radiator | 7 - Low Temperature Auxiliary Coolant Pump 1 |
| 4 - Low Temperature Auxiliary Coolant Pump 2 | 8 - Power Inverter Module (PIM) |
The low temperature cooling system is a separate low pressure (5 PSI) system. The main function of the system is for cooling of the power electronics modules (MGU, IDCM and PIM) as well as the turbocharger bearings and charge air cooler. The system has two temperature sensors and two LIN controlled electronic auxiliary low temperature coolant pumps used to achieve this.
| 1 - Low Temperature Radiator | 7 - P1f Motor/Generator Unit (MGU) |
| 2 - Low Temperature Radiator Outlet Temp Sensor | 8 - Charge Air Cooler |
| 3 - Low Temperature Auxiliary Coolant Pump 2 | 9 - Throttle Body |
| 4 - Low Temperature Auxiliary Coolant Pump 1 | 10 - Turbocharger |
| 5 - Integrated Dual Charging Module (IDCM) | 11 - Low Temperature Radiator Inlet Temp Sensor |
| 6 - Power Inverter Module (PIM) |
OPERATION:
To maintain the proper temperature of the system components the PIM monitors hard wired inputs from the coolant temperature sensors in the system, as well as bus inputs from the MGU, BPCM and IDCM. Other inputs such as ambient temperature and PIM internal temperature factor into system operation. As the power electronics modules operate they will build heat. To maintain proper cooling of the system components the PIM commands the auxiliary low temperature coolant pumps to operate circulating coolant through the system. The coolant temperature flowing into and out of the low temperature radiator is monitored through two hard-wired temperature sensors. Heat induced in the cooling system is dissipated as the coolant passes through the low temperature radiator. The cooling fan can be operated to aid in dissipating heat. When the engine is running heat will build in the turbocharger. The low temperature cooling system will operate to reduce turbocharger bearing temperature and cool the charge air cooler which reduces the temperature of the air entering the engine. The PCM can send a command to the PIM to operate an after-run mode to cool the turbocharger bearings after the engine is turned off. This reduces heat soak that can cause turbocharger bearing damage on short engine off cycles.