A carburetor mixes the fuel and air before intake into the engine. This is called emulsifying the gasoline. An electronic fuel injection system injects the fuel into the engine while it is a liquid. When we think of the essential ingredients in the operation of an engine, we automatically think of fuel. However, air is essential as well, regardless if the fuel is emulsified or not. Air causes the fuel to be oxidized, which generates heat and in turn, causes the engine to run. The means by which air is directed in an electronic fuel injection system is more efficient than a carburetor simply because the electronic fuel injection system's components are smaller. The fuel-to-air ratios - and how they are controlled--have a direct effect on efficiency, emissions and power of the engine. The bottom line is that the fuel- to-air ratios are less effectively controlled with carburetors and much more effectively controlled with electronic fuel injectors.
Knowledge of fuel injector
1. How does a fuel injector work
Simply put, the fuel injector supplies the fuel for combustion which makes the engine run. The amount of fuel needed to be delivered to the engine at any given moment, called fuel metering, is determined by an electronic device, hence the name "electronic fuel injection". However, mechanical devices previously were used in fuel metering. With more current designs, a device called an engine control unit measures how much fuel to inject into the engine. With the aid of an eternal pump, the fuel injector "sprays" fuel into the air flow of the engine.
2. How to know if an injector is bad
In a multi-port fuel injection system, each cylinder has its own fuel injector. The fuel injectors need fuel delivered to them at a certain pressure -- commonly 32 to 44 p.s.i.,depending on the year, make and model of your vehicle. If the fuel pump is bad, all the injectors will seemingly malfunction, as there won't be enough pressure to keep the engine running properly. If the engine is misfiring, there is most likely a problem with one or more injectors or the injector circuits, if the ignition system is working properly.
3. How to Test Injectors
All modern vehicles are equipped with a fuel injection system. Fuel is pulled from the fuel tank by the fuel pump using vacuum. The fuel then passes through the fuel filter and is sent to the fuel injectors. During the intake stroke of the engine the fuel is sprayed into the cylinders with a mixture of air. The compression stroke then compresses the mixture which causes the engine to fire. During the lifetime of an engine an injector may fail. You may save time and money by testing the injectors yourself.
4. How to check the electrical part of the fuel injectors
Fuel injectors act like electrically controlled firing nozzles that receive a pulse signal to inject and fire a precise amount of fuel into the intake manifold. Multiport fuel injectors deliver individual shots into each cylinder. Fuel injectors can cause a variety of problems, including surging, stalling, misfiring, hesitation, flooding and no-start conditions. The ECM, or engine control module, sends an electronic signal to the fuel injector, which must read and transfer an electrical pulse to ignite the fuel. A vehicle owner can perform a few tests to determine whether the electrical part of the injector is functioning properly.
5. What causes leaking injector
Fuel pumps create pressure in fuel lines. The pressurized fuel is forced into the head of the fuel injector held in place by O-rings. A solenoid in the injector charges and triggers a brief opening of the fuel injector valve. The fuel passes through the injector valve and is pushed through nozzles into a fine mist that is ignited during combustion. Leaking injectors create fire hazards, degrade performance and potentially damage engines.
6. Signs & symptoms of a leaky fuel injector
Fuel injectors are more than simple nozzles used to spray gas into your engine. Injectors use a very fine needle and seat valve to meter fuel; if that needle valve gets bent or something goes wrong in the injector's electromagnet or return spring system, the injector can hang open and provide your engine with a constant spray of fuel that it doesn't need.
R-134a refrigerant
Production of chlorofluorocarbons (CFCs) has been phased out (Refrigerant like R-10, R-11, R-12) due to their potential to deplete the ozone layer which is 3 mm thick and filtering UV rays emitting from sun.Environmentally acceptable replacement compounds are therefore needed for use in existing medium and low temperature refrigeration applications.R134a is also known as Tetrafluoroethane (CF3CH2F) from the family of HFC refrigerant. With the discovery of the damaging effect of CFCs and HCFCs refrigerants to the ozone layer, the HFC family of refrigerant has been widely used as their replacement.
Refrigerant R134a or HFC-134a is a commercially available hydro fluorocarbon (HFC) refrigerant for use as a long-term replacement for R-12 in new equipment and for retrofitting medium temperature CFC-12 systems.
It is now being used as a replacement for R-12 CFC refrigerant in the area of centrifugal, rotary screw, scroll and reciprocating compressors. It is safe for normal handling as it is non-toxic, non-flammable and non-corrosive.
Currently it is also being widely used in the air conditioning system in newer automotive vehicles. The manufacturing industry uses it in plastic foam blowing. Pharmaceuticals industry uses it as a propellant.
It exists in gas form when expose to the environment as the boiling temperature is -14.9°F or -26.1°C.
Detection of Leaks
When you suspect a leak of R-134a in your air conditioning system, detection can be done by using one of the following 5 methods. The simplest method and cost effective is by the use of soap solution. Workshops may use more sophisticated equipments to do this.
