Hello Guys today I will explain the car cooling system which includes:
- Water Pump
- Heater Core
- Coolant temperature sensor
Water Pump is the pump that pumps the coolant to the engine. The serpentine belt in the engine drives the impeller in the water pump. The centrifugal force is used to send the coolant outside as it spins, causing the coolant to be drawn from the center. The coolant leaving the pump flows through the engine block then into water jackets, then into the radiator and finally back to the pump, and this cycle continues.
The radiator is situated right at the nose of the car, which helps the car’s engine to cool down when it is heated up. It is a heat exchanger which transfer heat generated from the engine to the atmosphere. The radiator consists of the inlet port, an outlet port, drain plug and a radiator pressure cap and a fan behind the radiator.
The thermostat is a regulating valve which controls the flow of the coolant into the radiator and maintains the optimum engine temperature. It is always covered with coolant to sense the temperature. It has a primary disc valve, secondary disc valve, wax chamber and a rod which is pressed against it.
It is a radiator-like device which also is a heat exchanger, which transfer the heat from the coolant to the air which flows inside the cabin. If the heater of your car’s cabin is on the hot coolant fro the engine is passed through a winding tube to the heater core.
Coolant Temperature sensor
The coolant temperature sensor is used to monitor the engine temperature. It consists of a sensing probe and an electrical connector. In some engine, there might be multiple sensors. The data from this is used to control the radiator fan and also update the temperature gauge in the driver console. ECU also uses this data to manage fuel injection and ignition timing.
Most Coolant temperature sensor is negative temperature coefficient type, which means as the temperature increases the resistance will decrease.
Coolant is a liquid mixture of glycol and water. As the coolant absorbs the heat from the cylinder and reaches a high temperature then it is passed through the thermostat which is an inlet for the radiator.
The coolant then reaches the radiator and the cool air from the outside lowers the temperature of the coolant and it is then sent to the engine using the lower hose and the cycle is repeated.
Working of the Cooling system
The cooling mechanism is the most essential part of the car engine. The combustion and friction of parts generate a lot of heat. The temperature has to manage inside to keep the engine sustainable.
The engine generates power by converting the chemical energy of the fuel to heat energy by combustion, this process creates a lot of heat which pushes the piston down and the power is generated. Some of the heat is carried away by the exhaust gases via exhaust valve, but some of the remaining heat is absorbed by the engine itself which raises the temperature.
Now the water pump pumps the coolant to the system. The coolant which runs through the water jacket(a safe passage for the coolant to flow without entering into the cylinder) absorbs the heat from the engine, to cool down the temperature to an operating range.
Now the coolant has absorbed the heat from the engine but the thermostat will not allow the coolant to flow into the radiator until the temperature is raised above the engine operating temperature i.e around 180 to 200° celsius. In the meantime, if the heater inside the cabin is turned on the coolant is made to flow through the heater core via bypass hose into the cabin.
When the coolant passing through the thermostat is around 180° F the wax starts to melt. The melting causes expansion of wax which in turn pushes the rod and thus opening the valve and then allowing coolant to pass through. As soon as the coolant passes outside the thermostat, the switch in the thermostat actuates the fan behind the radiator.
The coolant enters the upper tank of the radiator via an upper hose. Due to high temperature, there is a high chance of high pressure building up, which will stop the coolant from entering the upper tank. When the pressure is beyond the recommended value, the pressure regulation valve opens and allows the high pressurized coolant to flow into the coolant overflow tank
The coolant inside the radiator will cool down due to the air flowing through the space between the flat tubes. The fan in the radiator increases the cool air thus increasing the heat transfer rate. The fins on the flat tube also increase heat rate transfer, thus cooling the air more quickly.
When coolant is in the lower tank of the radiator it is completely cooled off and sent back into the engine and the cycle continues.
So that is the process of engine cooling system.
Also published on Medium.