What’s the Different Between Diesel and Petrol Injector?


Fuel injection is the most essential part of the smooth running of a car. Whether petrol or diesel, every car needs the right quantity of fuel and air mixture to fulfill its range of demands. In this article, you will know about fuel injectors, how it works and what is the difference between a petrol injector and a fuel injector.

What is a Fuel injector and what is its purpose?

Fuel injectors are small devices installed in an engine that spray fuel into the car’s engine. These are controlled by valves that open or close many times in a second. These are designed for the optimum supply of fuel, its equal distribution, and proper combustion. They also help the engine run with great efficiency and reduced emission. There is either one or more than one injector for each cylinder that is responsible for the equal distribution of petrol or diesel. These injectors should be cleaned after a while for efficient functioning. Several companies such as Midland Auto Care are providing fuel injector cleaning service UK.

Difference between Diesel Injector and Petrol Injector

The purpose of the fuel injector is to control the volume of fuel delivered to the combustion chamber. The primary difference between diesel injector and petrol injector is how the injector sprays the fuel into the chamber. A petrol injector sprays a metered amount of fuel into the cylinder while a diesel injector operates at high pressure. Let’s know the difference between both in detail.

Diesel Fuel Injection

Many diesel engines use direct injection where the diesel is injected into the cylinder that is filled with compressed air. While other diesel engines use an indirect injection system where the fuel is injected into the pre-combustion chamber. A spring controls the valve and lifts it off while spraying the fuel into the cylinder. It works under very high pressure and sprays the fuel in a highly atomised form. When the pressure drops, the needle valve closes and stops the injection. Modern diesel injectors force the diesel through a very small nozzle of almost 0.25mm2 size. The pressure of the nozzle opening ranges from 140 to 210 kg/cm2.

Diesel fuel injectors come in different sizes and conditions such as OEM, used injectors, refurbished injectors, and remanufactured injectors. Diesel fuel injectors are pretty complicated as it has a high micron filter on the top inlet which has small-sized holes on the bottom for better atomising of the fuel. 

Petrol Fuel Injection

The modern petrol injection system uses indirect injection. During the process of injection, the fuel from the fuel tank is sent under pressure to the engine by a pump, where the fuel is distributed to each cylinder evenly. This injection varies from system to system and is injected either into the inlet manifold or inlet port. It makes sure that the fuel comes out in a fine spray. This fuel mixes with the air which is passing through the inlet or port. The fuel mixed with air enters the combustion chamber and results in the smooth running of an engine. A single injector for all the cylinders is pretty common. Otherwise, there is one injector for every two cylinders.

Modern petrol injectors are different in construction than diesel injectors. The direct-injection engine generates a mixture of air and fuel inside the combustion chamber. The high-pressure injectors inject the fuel into the combustion chamber and improve the cooling of a combustion chamber. Also, it enables the higher efficiency of an engine because of high compression.

Why are injectors so Important?

Fuel injectors are the most important component of an engine. Most of the failures of injectors are caused by the mixing of water with fuel. It disrupts the lubricating qualities of diesel fuel and the internal parts start to wear down more quickly. This can cause the complete failure of the injector. In diesel engines, the opening, and closing of the injector valve work with the same rpm as the diesel engine. When the water is added with fuel, the injectors get carbon and dirt due to the bad air cleaner. This carbon build-up has a significant impact on the life of fuel injectors.

What are the signs of faulty fuel injectors?

The build-up of carbon and debris on the injectors develops some faults, which result in the performance of the fuel injectors that affect the performance of the engine. Mechanical issues, electrical issues, and clogged debris can also be the cause of faulty injectors. However, check for some signs and symptoms that might indicate the faulty fuel injector. Here are the symptoms of the faulty fuel injector.

Engine Warning Light

Check engine light is the common sign of a faulty engine. Which appears on the dashboard of a car. Light can be checked on because of some other reasons as well. However, you should get your vehicle checked by a professional in case of noticing that light. The light triggers when there is too much fuel or little fuel delivered by an injector.

Vibration in Engine

The vibration in the engine after pressing the accelerator pedal can be a symptom of the faulty injector. The reason can be most probably a clogged or blocked nozzle. This blockage can lead to misfiring or a drop in acceleration. This is the reason why it is important to keep your fuel injectors clean.

Poor Fuel Economy

Poor fuel economy is the other noticeable symptom of the faulty fuel injector. Damaged or clogged fuel injectors can drop the fuel economy to an extent and also cause fuel leakage. The reason is that less fuel reaches the engine because of blockage or clogged nozzles.

Keep your fuel injectors clean and maintained by taking your vehicle for servicing every month. Whether your car has a petrol engine or diesel engine, fuel injector maintenance is very essential. It can reduce the emissions from the engine, keep the environment clean and keep your car in good condition.

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