Abstract: The heat source of the heater is to use the waste heat of the engine cooling water and send it to the radiator of the heater through the water pipe. As long as the engine does not stall, the cooling water will maintain "small circulation" with the radiator. It is connected in parallel with the engine radiator. Since the heater's radiator does not have a thermostat, it maintains an uninterrupted heat source. The driving device of the heater is powered by a DC motor, which sends hot air into the car through a blower. It also allows the hot air to remove frost from the cab windshield. Let’s learn about car heaters together. 1. Car Heater
Car Heating Technology As a "mobile room", people are striving to improve their comfort while increasing their safety. To create a comfortable car environment, parameters such as the air temperature in the car must be adjusted. In winter, the temperature inside the car must be increased, so corresponding heating equipment must be installed. There are several forms of heating equipment, which can be divided according to the heat source used: non-independent (engine-based) heating systems and independent (non-engine-based) heating systems. Non-independent heating system Non-independent heating system can also be called waste heat heating system. It uses the waste heat of automobile exhaust or the waste heat of engine cooling circulating water as a heat source and introduces it into a heat exchanger. The fan blows the air inside or outside the car. Blow through the heat exchanger to warm it up.
2. How to choose a car heater
When choosing a car heater, I often worry about accidentally buying fake and inferior parts and unsuitable parts. Then when choosing, you should pay attention to the clearly visible fonts on the packaging box and the overprinting colors.
The packaging box and bag should be marked with the product name, product model, quantity, registered trademark, factory name, address and phone number, etc. Some parts are inconvenient to make, transport and store. Secondly, they are easy to Deformation.
During inspection, you can roll the shaft part along the glass plate to see if there is light leakage at the joint between the original part and the glass plate to determine whether it is bent;
Purchase a clutch follower When removing a steel plate or friction plate, you can hold the steel plate and friction plate in front of your eyes to see if they are warped;
When purchasing an oil seal, the end face of the oil seal with a skeleton should be in a perfect circle and can stick to the flat glass. There should be no deflection when closing; the outer edge of the skeleton-free oil seal should be straight. Hold it with your hand to deform it, and it should be able to return to its original shape after letting go.
3. Working principle of car heater
Waste heat heating system is a system that uses the waste heat of automobile exhaust for heating. It is called waste heat heating system. There are mainly two types: Form:
*Heat exchanger type The working principle of this device is to install a heat exchanger on the exhaust pipe of the engine to heat the air. When working, the valve leading to the muffler is closed, and the exhaust gas enters the heat exchanger to heat the air on the other side. After the cold air absorbs the heat, the temperature rises and is blown into the car by the fan. The heating effect of this device is affected by vehicle speed and engine operating conditions, and the heating temperature is unstable. In addition, SO2, H2O, etc. in the exhaust will corrode the heat exchanger tube wall; the exhaust pipe and heat exchanger increase the exhaust resistance of the engine, which has an impact on the working condition of the engine.
*The heat pipe type uses a heat pipe heat exchanger to recover the waste heat in the engine exhaust, mainly used for winter heating of large cars. The heat pipe heater has good heating effect, is safe and reliable, and the engine exhaust gas will not leak into the cabin.
The waste water heating system uses the cooling water of the engine as a heat source to heat the system, which is called a waste water heating system. This device is commonly used in cars, trucks and small charter buses.
It uses the cooling water of the engine as the heat source, and exchanges heat between the air sent by the blower and the engine cooling water through the heat exchanger in the device (generally called the heater core). Bring it indoors. In trucks, vans or pickup trucks that are not equipped with air conditioners, an assembly consisting of a heater core, a fan and a casing is generally used. The casing has air outlets that blow to the feet, the front and the windows. Air outlet for defrost function. In cars and more luxurious trucks, the heater core and evaporator (refrigerant circuit) are assembled in a box, and a fan and housing are used.
The waste heat water heating system is simple in installation and reliable in heating. It does not require additional fuel and can produce hot water as long as the engine is running.
The disadvantage is that heating can only be done when the engine cooling water temperature rises to a large circulation. In cold seasons, the heating amount is insufficient, which may even cause the engine to be overcooled and affect the normal operation of the engine. When the engine is stopped for heating, the operation of the engine increases the load of the engine. Wear and tear; it is difficult for large buses to meet heating requirements only by relying on this device, and the new diesel engines are highly efficient and have relatively little waste heat that can be used for heating.
In response to the above shortcomings of non-independent heating systems, engineers developed and applied independent heating systems.
Independent heating systems are commonly used in large luxury cars, buses and cars used in cold areas. The so-called independent means that it runs independently of the engine. According to the different media being heated, they are divided into air-heating heaters and water-heating heaters. Both types of heaters burn gasoline or diesel in a burner, and the heat generated heats the air or water. The burned gas is discharged out of the car after heat exchange, and does not pollute the air in the car room.
Independent air heating system is generally composed of a combustion chamber, a heat exchanger, a fuel supply system, an air supply system, and a control system.
The working process is: the fan motor is connected to the power supply to drive the combustion air fan and the warm air fan. At the same time, the oil pump supplies oil to the combustion chamber. The oil is atomized at the entrance of the combustion chamber and comes in from the self-combustion air inlet. The air is mixed and ignited by a spark plug. The heat generated by combustion is exchanged with the cold air coming in from the cold air inlet through the heat exchanger. The cold air turns into warm air and is supplied into the car through the warm air outlet. The operation of the entire heater is controlled by the control block.
This kind of heater is especially suitable for commercial vehicles that do not have high requirements for air distribution quality, such as minibuses, trucks, vans, engineering vehicles, especially long-distance freight vehicles. Because it runs an independent engine, it can be heated when parked and rested, which greatly reduces engine wear and emissions. It can also be used as a supplement to the car heater when the car is running.
The working principle of the independent water heating system is basically the same as that of the air heating system. The difference is that the heating medium is water instead of air, and the fan is replaced by a water pump.
The water-heated heater is connected to the cooling water pipeline of the engine and the water path of the heater core in the air conditioner. Therefore, its biggest advantage is that it can not only be used to warm the cabin, but also preheat the engine and lubricate the engine. oil to facilitate engine starting in winter and improve engine startability and durability.
Most water heaters are used in cars and buses, but they are also used in trucks and engineering vehicles in cold areas. The warm air mainly uses the internal circulation type, which has less dust and the heating is softer but not drying. When selecting a water heating heater, in addition to considering the size of the compartment, pipe resistance, etc. should also be considered.
Development Trends In summary, the installation of an independent heating system has the following functions: parking heating, reducing engine wear and emissions; auxiliary heating, the independent heating system can be turned on when the car is running; preheating engine to avoid cold starts; defrost car glass.
In cars, especially luxury cars, car air conditioners have developed into integrated cooling and heating devices. They are not just cooling or heating, but also year-round air conditioning (cooling in summer, ventilation in transition seasons, and heating in winter). heat and defrost). In recent years, with the development of China's tourism industry, passengers have put forward higher requirements for ride comfort. Liquid heaters used for winter heating of buses in European and American countries have gradually been promoted in China, especially in mid-to-high-end luxury buses and cold-heated buses. Passenger cars in the region have begun to use this independent water heating heater as a necessary accessory product. Trucks and engineering vehicles do not have high requirements for comfort. Of course, with the development of the national economy, this situation will change.
4. Mechanism of damage to the heater resistor
When the car heater is in an air volume adjustment state from small to large, the heater resistor is not involved in every gear, and the maximum gear is also That is, the heater resistor does not work when the air volume is maximum. When we usually turn off the engine when driving to the destination, the heater is often in the smallest or second-lowest gear. At this time, the heater resistor generates a lot of heat when working normally. However, because the flowing wind takes away the excess heat when the fan is working, when the fan is working normally, High temperatures will not accumulate, but at this time, the residual heat from the heater resistor cannot be taken away smoothly after the fan is turned off, which may easily cause high-temperature damage to this part. The phenomenon after damage is that there is no wind in the small air volume setting of the heater, the heater does not rotate, and there is wind only in the high air volume setting.
5. Correct operation method of car heater
The correct operation method is: before turning off the engine, adjust the air volume of the heater from the small air volume to the maximum air volume for dozens of seconds. Then turn it to the off position and turn off the flame. At this time, the heater resistor does not generate new heat in the last few dozen seconds, and there is maximum air volume to blow it to cool it, reducing the accumulation of high temperature after parking.