The Purdue EcoMakers have designed a custom cooling system for their Chevy Malibu, which contains several different loops that work together to cool and heat the vehicle. Get the details on each loop below!

Main Bypass Coolant Loop

The Main Bypass Coolant Loop (highlighted in red)

The main bypass coolant loop circulates coolant throughout the engine block to prevent the engine from overheating. As hot coolant is expelled out of the engine, a portion of the coolant goes through the main bypass coolant loop. A notable part of this loop is known as the “heater core.” As hot coolant is run through the heater core, the heater core becomes hot. When warm air is desired within the cabin of the vehicle, a fan blows air across the heater core to provide hot air to the passengers of the vehicle. After the coolant passes through the heater core, the coolant returns to what is known as the “water pump” for re-circulation. The water pump is a pump that is built into the engine block and is powered directly by the engine itself, which ensures that coolant is always circulating as the engine operates.

EGR Cooler Loop

The EGR Loop (highlighted in red)

Many modern engines use a technique known as “exhaust gas recirculation,” or “EGR.” EGR is used to reduce the emissions of the engine by recirculating exhaust gas back into the intake air of the engine. However, it is more desirable if the exhaust gas is cooled before it joins the intake air – to accomplish this, a part known as an “EGR cooler” is used. In the case of this engine, hot coolant that exits the engine is what cools the exhaust gas within the EGR cooler. Although the coolant is hot as it enters the EGR cooler, it is still cooler than the high temperature exhaust gas and can effectively cool it. After cooling the exhaust gas, the coolant enters the water pump to be recirculated throughout the engine.

Radiator Coolant Bypass

The Radiator Coolant Bypass (highlighted in red)

The majority of the hot coolant that an engine ejects must cool down before it returns to the water pump for re-circulation. A radiator is used to lower the temperature of the coolant. As the hot coolant runs through the radiator air passes over its fins, which saps heat from the hot coolant inside. However, when an engine first starts the engine block is still relatively cold, which may hinder the performance of the engine. For this reason, it is not desired to cool the coolant as the engine is warming up.  The thermostat is used to solve this problem by preventing coolant from entering the radiator bypass loop until the engine block is sufficiently warm.