Over the years, Nissens has invested significant resources in research on and development of engine cooling and climate system components for the automotive segment. More than 95 years of thermal know-how and manufacturing experience mean that we are able to meet the needs for comprehensive range of high-quality spare parts, while at the same time, being a market educator for technical insight into the systems field.
As a market leading manufacturer of most essential thermal system components, Nissens offers a comprehensive product portfolio with up to 97% car park coverage. Covering everything from the fast moving to the more exotic parts of the European, Asian and American vehicle brands, Nissens is the ideal choice for quality, range and expertise.
Heat exchanger - crucial for the refrigerant state change in the system
The condenser is placed at the front of the car and is typically attached to other heat exchangers in the engine compartment like engine cooling radiator or intercooler.
The role of the condenser is to ensure that the state of the refrigerant changes from gaseous to liquid form. The change of state is called the condensation process where the refrigerant heat is extracted and exchanged with the ambient air.
The heart of the air conditioning system
The refrigerant is compressed by the compressor and transported through the system to create high and low pressure.
The compressor is crucial for the efficiency of the AC system. During an AC cycle, the compressor enables the refrigerant to change its state from gas to liquid and to flow through the different components of the system as well as through high and low pressure sides.
Ensures a proper air intake, flow and distribution which are required for the climate system to operate
The interior blower ensures a proper amount of ambient air intake. Flowing through the heat exchangers, the air can be either warm or cold and thanks to the blower, the air is distributed in the car cabin.
Typically, the blower is situated in the HVAC (Heat-Ventilation-Air-Conditioning) module located between the cabin and the engine compartment.
The interior blower is an electrical device considered fragile, due to plastic elements, and electrically sensitive to vehicle system failures.
Receiver Dryer / Accumulator
AC loop protection
The receiver dryer is a filtering unit located on the high-pressure side of the AC loop between the condenser and the expansion valve. The role of the receiver is to filter particles and debris flowing in the circuit as well as to absorb any moisture. Furthermore, it also stores oil and refrigerant.
The accumulator is a similar filtering device but applied only in vehicles with orifice tube as an expansion device. The accumulator is located on the system low-pressure side and besides the filtering and the lubricant/refrigerant storing function as in the receiver dryer, it also ensures that no liquid form of the refrigerant gets into the compressor.
Cabin heat exchanger producing cold air
A heat exchanger in the low-pressure side of the AC system, installed between the expansion valve and the compressor. Typically, located in a HVAC (Heat-Ventilation-Air-Conditioning) module behind the vehicle dashboard.
The evaporator ensures the refrigerant to evaporate, thus change its state from a liquid to a gaseous form. Ambient air blown on the evaporator’s surface enables the evaporation process inside, and during the transition process of the refrigerant’s state , the blown air flowing through the evaporator’s surface turns cold and can be directed into the vehicle cabin.
Furthermore, the evaporator dehumidifies the intake air, which is of high importance for the system’s ability to demist the vehicle panes.
Warm air production and safety by demisting the panes
The heater is an integral part of the engine cooling system. However, it contributes significantly to the climate system ensuring the production of warm air. The heater is often located behind the dashboard or in the HVAC module.
Hot coolant from the engine block passes through the heater, warming up the intake air blown on its surface by the interior blower. The air gets warmer and can be forwarded into the car cabin.
As heater produces warm air during cold days in autumn and winter, it significantly improves safety by shortening the demisting of the vehicle’s panes.
An important player of the air conditioning system
The fan plays an important, supportive role for the effective operation of the engine cooling and climate systems of the vehicle. In the climate system, the AC fan forces air through the condenser.
High operation pressures inside the condenser and the temperature produced by the condensation process require an additional air flow supporting the heat exchange between the ambient air and the refrigerant inside. Cooling produced by the fan is crucial for proper condenser operation.
Heat exchanger - essential for engine thermal control
The radiator is placed in the front of the vehicle, often attached to other heat exchangers, such as the intercooler or condenser.
The radiator is essential for the cooling of combustion engines. In such engines, there may be as many as 4,000 petrol explosions per minute, each generating temperatures of up to 1,500°C. The cooling liquid, which is circulating through a cooling jacket, cools the engine block, as well as pistons, valves, gaskets, rings, engine head, and other elements of the engine.
The circulating coolant receives the combustion heat. Flowing through the radiator, it exchanges the heat with atmospheric air.
Engine and transmission oil cooling
Oil applied for lubrication plays a significant cooling role. The oil cooler receives the lubricant’s heat and exchanges it with the ambient air or the radiator coolant. It is typically the automatic gearbox oil that needs a dedicated oil cooler. Vehicles, driving with engine oil that is cooled by a separate exchanger, is a common sight. Especially in high-performing or downsized engine vehicles, a dedicated oil cooler is an important part of the system.
In some vehicle models, the oil cooler is built into the radiator water tank. Here, the coolant plays a supportive role to the heat exchange process. In modern vehicles, an automatic gearbox oil cooler is often designed as a stand-alone unit, mounted separately in the engine compartment or on the engine block.
EC fan engagement
The fan clutch is a device controlling the engagement of the EC fan. A valve inside the clutch regulates the flow of a special silicon oil. The oil transmits the engine’s torque thus, rotating the fan.
The fan clutch can be driven by a belt and pulley or directly by the engine when mounted on the engine’s crankshaft. Depending on the cooling needs, the fan can be engaged partially or fully - saving the engine power used for the power transmission.
There are two design types of the sensor causing the clutch to engage. One with a bi-metallic, thermostatic sensor controlling the engagement and another controlled electronically by ECU signals, influenced by engine/transmission oil temperature, coolant temperature, AC system pressures or ambient air temperature.