5. Cooling system and heating

All models of the cars considered in the present manual are equipped with the engine cooling system working with an excessive pressure with thermostatic management of circulation of working liquid.


Scheme of functioning of the cooling system

The water pump of rotor type is fixed on the block of the engine and provides pumping of cooling liquid through a cooling path of the last. The stream of liquid washes regions of an arrangement of each of cylinders in the block and goes to a back part of the engine. The cooling channels laid in casting of the block and a head of cylinders provide intensive cooling of inlet and final ports, areas of installation of spark plugs and the directing plugs of final valves.

The Voskozapolnenny thermostat controls the working temperature of the engine in the course of its warming up. The first minutes after start of the cold engine the thermostat remains closed, preventing thereby circulation of cooling liquid through a radiator. When temperature of the engine reaches normal working value, the valve of the thermostat opens, connecting the radiator providing the maximum intensity of the heat sink from a working body (cooling liquid) to a cooling contour.

The cooling system has a tight design and is densely closed by the cover of a radiator capable to maintain a certain excessive pressure that provides increase in a boiling point of cooling liquid and, respectively, efficiency of the heat sink through a radiator. At excess by internal pressure in system of some certain value, the sprung plate of the radiator of the safety valve which is built in in a cover rises over the saddle, providing an overflowing of excess of cooling liquid on a connecting (overflow) tube in a broad tank. In process of cooling of system liquid automatically comes back from a tank to a radiator.

Dolivaniye of cooling liquid in system is made through a mouth of a broad tank which at the same time acts also as the receiver accumulating in itself the excess of liquid which is forced out from a radiator.

In view of the listed features of a design, such cooling system received the name closed as in it any functional losses of cooling liquid are excluded.


System of automatic air conditioning

The system of automatic air conditioning (climate control) is included in a basic equipment of the Infiniti QX4 models. Information sensors, the block of management / the automatic amplifier and a set of actuation mechanisms enter a contour of management of system.

When obtaining commands from the control panel of system of climate control the automatic amplifier analyzes the data developed by information sensors and by means of delivery of the corresponding signals on actuation mechanisms provides formation of the requested climatic conditions in interior of the car.

The automatic amplifier performs also function of the block of self-diagnostics of system failures К/В.

Performance of any recovery repair of air conditioning system has to be entrusted to specialists of car service.

Air supply in salon is made through air ducts of front and foot levels. The choice of the direction of distribution and physical parameters of an air stream is carried out by means of the system control panel switch (see the Head the Maintenance instruction). The consumption of air is regulated by the choice of the high-speed mode of functioning of the fan of a heater. At the request of the operator the air given to salon can be warmed up or cooled, depending on the choice of temperature condition of heater / system of climate control (see below). There is a possibility of activation of the mode of the closed air circulation. The detailed description of the principles of management of functioning of systems of ventilation / heating / conditioning is provided in the Head the Maintenance instruction.


Principle of the organization of heating of air

The main components of system of heating of salon are the electric fan and the heat exchanger located in a box-shaped casing of a heater. The heat exchanger by means of rubber hoses is connected to the engine cooling system. The control unit of functioning of the heater / conditioner of air is built in in the car dashboard. The cooling liquid warmed in the engine circulates via the heater heat exchanger, giving the to the air which is warmly filling a casing. At inclusion of heating of salon there is an opening of the lamellar gate therefore the internal volume of a casing of a heater connects to the volume of salon. At turning on of the fan the krylchatka of the last begins to banish the air given to salon via the heat exchanger, providing its intensive warming up.


Principle of the organization of functioning of the air conditioning system

The condenser installed ahead of a radiator, the evaporator, close to the heater heat exchanger, fixed on the engine block the compressor and a receiver dehumidifier equipped with the reducing valve of high pressure are a part of system. All components are connected among themselves by refrigerator lines.

The fan banishes the air coming to salon through the evaporator heat exchanger working in the mode, the return to the mode of functioning of a radiator. The coolant which is pumped over via the heat exchanger, evaporating, selects excess of heat at air. Temperature in salon at the same time decreases to the required comfortable value (at the choice of the operator).

The electronic control system exercises control of functioning of systems of heating and conditioning, providing a possibility of maintenance in salon of the set temperature (climate control).


Precautionary measures at service of components of the K/V system

Service of air conditioning system has to be made by exclusively prepared technicians trained in methods of safe performing procedures having skills of work with the special equipment, with observance of rules of a discharge of system, acquainted with methods of collecting and order of storage of automobile coolant.