Car Heating System

In addition to air conditioning which is used to cool the cabin air in a vehicle, most modern day vehicles are also equipped with a heating system to warm up the cabin during winters. The heating system uses the heat of the engine to warm up the cabin air. There is a heater core which acts as a heat exchanger and is built inside the vehicle HVAC (heating, ventilation, air conditioning). 

The heater core in itself is a small radiator which is connected to the engine cooling system. A liquid coolant is used in the engine cooling system which is circulated through the engine and main radiator through a pump. The purpose of coolant is to absorb excess heat from the engine. The heated coolant travels through the radiator where ambient air flow absorbs the heat from the coolant. This cycle repeats. 

When a car's heating system is activated, the super hot coolant is made to run through the heater core. A blower motor/fan blows air on the heater core which absorbs the heat from the coolant. As a result, the air gets warm and this air is circulated inside the cabin through vents. 

Depending on the amount of heat required in the cabin, occupants can choose how much warm air is required. A heater control valve is used in the heater core to vary the flow of hot coolant. But most of the HVAC system use a temperature blend door to control the amount of hot air that has to flow through the vents. The working of temperature blend door is simple. The more the door is open, the more amount of air passes through the heater core and hence the air is warmer.

If the cabin air is not warming enough according to the requirement, then the amount of coolant needs to be checked in overflow bottle and if it is low then it should be topped up. If the heating system does not work efficiently, then it means there is some problem in the engine cooling system and it can damage the engine. 

How does Car AC work?

Air conditioning (AC) in cars used to be a luxury during the 1960s, but it has become a necessity in modern day cars. A vehicle's air conditioner doesn't actually cool the air. It just removes the heat and moisture out of the air present within the vehicle. The car AC works on two cycles: refrigeration and evaporative cooling.

Car AC works on the same principle as the home/office ACs. It has five main components:

1. Compressor
2. Condenser
3. Receiver dryer
4. Expansion valve
5. Evaporator coil

The freon/refrigerant is used in AC system. The refrigerant is circulated through the entire system in closed circuit.

Compressor:

As the name suggests, compressor is used to compress the refrigerant to high pressure and temperature. In home ACs, compressor is run through electric motor. In cars, the compressor is driven by a belt connected to the engine crankshaft. A magnetic clutch is used to engage/disengage the compressor to the belt. Once compressed, the gaseous refrigerant is pushed out through discharge valve to the condenser.  

  

Condenser:

Condenser acts as a radiator to remove the heat from the refrigerant. Condenser sits in front of the car, just behind the front grille and in front of the car radiator. Ambient air passes through the condenser and removes the heat from the refrigerant. The high pressure gaseous refrigerant is converted into high pressure liquefied refrigerant.

Receiver Dryer:

The purpose of dryer is to remove the impurities and moisture from the liquefied refrigerant. It can also be used as a temporary storage tank for liquefied refrigerant.

Expansion Valve:

Expansion valve is used to control the amount of refrigerant entering the evaporator. It has a small hole which lets the valve to spray the refrigerant. As the high pressure refrigerant passes into the expansion valve, both pressure and temperature drop and it is sprayed into the evaporator in a misty form.

Evaporator:

Evaporator acts like a radiator. The low pressure, low temperature refrigerant in gaseous form passes through the coils inside the evaporator. A blower fan pulls the heat out from inside the vehicle cabin and blows the warm air over the evaporator. Since the temperature inside the evaporator is lower, it absorbs the heat from the blower and leaves behind cooler air. This cooled air is circulated into the car cabin. The refrigerant which is hot now and in gaseous form is circulated back to the compressor and the cycle keeps repeating.

Blower

Refrigerant:

Freon-R12 was used commonly but due to its damaging effects on the ozone layer, manufacturers have replaced it with R-134a. 

Car Sales Plunge to Zero in April 2020

As India announced nationwide lockdown from 24th March 2020 and with the restrictions covering the entire month of April, grim reports for automobile manufactures came out as zero sales were recorded in the month of April due to the closure of showrooms and manufacturing facilities. Big companies such as Maruti Suzuki, Hyundai and Mahindra registered zero domestic sales.

Thanks to the resumption of port operations, Maruti Suzuki was able to export 632 units abroad. The export numbers for Hyundai and Mahindra stood at 1341 and 733 units respectively for the month of April.

However, Mahindra and Mahindra did witness some tractor sales because dealers were open partially in the last month. It recorded 4716 tractor sales in India, down by 83% as against 27,495 units sold in April 2019. Mahindra's farm equipment sector exported 56 tractors last month, down by 95% compared to 1057 units exported in the same month last year.

S.No.	Manufactures	April 2020	April 2019
1	Maruti Suzuki	0	1,31,385
2	Hyundai	0	42,005
3	Mahindra and Mahindra	0	18,901
4	Toyota	0	10,112
5	Ford	0	6,515
6	Volkswagen	0	1,995
7	Honda	0	11,272
8	Tata	0	12,695
9	Renault	0	6,256
10	Nissan	0	2,027
11	Skoda	0	1,126

With lockdown extended till May 17, there is little to no hope of reviving the automobile sector in the coming months. Due to low earnings, demand especially among the middle income customers might fall sharply. Government can intervene by reducing GST for some months.