Fuel-Injector Sorts

The present short article will be the initial inside a series about automotive fuel-injectors. It is assumed the reader features a basic understanding of what an injector is and it really is part inside the injection system of a automobile, as well as standard expertise about fuel-injection system terminology.

Automotive fuel-injectors look to be all the identical however they differ in shape, size and capacity to flow fuel.

The most popular injector would be the top-feed form. You will discover o-ring injectors that happen to be usually inserted inside a metallic or plastic fuel rail. A further kind could be the rubber-hose injector.

In this kind of injector a rubber hose is straight attached towards the injector inlet.


There are actually generally two sort of side-feed injectors. The very first kind of injector is utilized in MPFI (Multi-Port Fuel-Injection) systems. This injector fits inside the fuel rail. The second, is employed in TBI (Throttle-Body Injection) systems and ordinarily fits inside an injector pod. TBI systems are often confused with electronic carburetors.

This is not the case. TBI are full-electronic EFI (Electronic Fuel-Injection) systems. They use injectors as opposed to carburetors that rely on pressure differential, venturi, jets, metering rods, power valves, chokes, floats, etc.

TBI EFI makes use of none of these. The only similarity is that fuel is discharged, and travels via, the intake manifold.


Direct fuel-injection is actually a fuel-injection technologies that allows gasoline engines to utilize fuel much more efficiently, resulting in larger power levels, cleaner emissions, and elevated fuel-economy.

In a widespread MPFI system (whether batch or sequential fire) fuel is sprayed towards the intake valve inside the cylinder head ports. This benefits within a much more precise fuel-metering compared with all the preceding TBI setup.

Direct Fuel-Injection goes a step further by putting the injector straight in the combustion chamber, just like a spark-plug. Gone will be the days of 43psi of fuel-pressure because a direct fuel-injection program uses pressures as higher as 2500psi. This higher fuel stress is necessary to overcome internal cylinder stress in systems that meters fuel throughout the compression stroke (pretty comparable to a diesel engine).

The truth is this sort of fuel-injection mimics the intake stroke of a Diesel engine as a result the 30% benefit in fuel-economy in comparison to equivalent displacement gasoline engines.

This type of injection is referred to as stratified injection, exactly where some amounts of fuel are injected through the compression stroke achieving super lean ratios of 69:1 and an increase in fuel-economy up 30% greater compared to a classic sequential-fire fuel-injection technique.

Now you realize the fundamental and most common form of automotive fuel-injectors. In future articles I will speak about injector service and maintenance ranging from basic flush to ultrasonic cleaning.

Keep tuned for far more about fuel-injectors! Spot your comments and happy wrenching!

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