Car Automotive

Posts Tagged ‘cylinder’

The compressor is the pump that circulates refrigerant through the system.The suction side of the compressor pulls in refrigerant in a low pressure,low temperature form. The refrigerant is then pumped through the compressor to the discharge or outlet side where it’s compressed, raising its temperature.It’s now ready once more to condense and release heat. The pressurized,heated refrigerant vapor is forced out of the compressor, through the high pressure line, to the condenser.

Basically, all compressors fall into one of two categories: piston type and rotary vane type. As the name implies, piston type compressors have one or more (up to ten) pistons arranged in either an inline, axial, radial or vee configuration.Rotary’vane compressors have no pistons.

Piston type compressors go through an intake stroke and a compression stroke for each cylinder. On the intake stroke, the refrigerant from the low side (evaporator side) of the system is drawn into the compressor. The intake of refrigerant occurs through reed valves. These one-way valves control the flow of refrigerant vapors into the cylinder.During the compression stroke, the gaseous refrigerant is compressed.

This increases both the pressure and the temperature of the heat-carrying refrigerant.The outlet (discharge) side reed valves then open to allow the refrigerant to move into the condenser. The outlet reed valves may be considered the beginning of the high side of the system.

The engine systems that are surveyed are those that are most commonly used,namely ignition and fuelling, plus emission control. A major purpose of these system surveys is to identify common ground in order to focus on the components of the systems that can realistically be tested with the aid of reasonably priced tools, rather than the more exotic systems that require specialized test equipment.

By examining three ignition systems it should be possible to pick out certain elements that are commonly used. In the process of examining a number of other systems we shall see that certain basic principles are common to several types of systems that are used on vehicles. In effect, there is a good deal of knowledge that can be transferred across a considerable range of technology.

Electronic ignition systems make use of some form of electrical/electronic device to produce the electrical pulse that switches the ignition coil primary current ‘on and off ’, so that a high voltage is induced in the coil secondary winding in order to produce a spark in the required cylinder at the correct time.There are several methods of producing the basic ‘triggering’ pulse for the ignition, but three of these methods are more widely used than the others. It is the ignition systems that are based on the use of these three methods that are now dealt with in some detail.