How fuel injection systems work
fuel injection diagram courtesy of kewengineering.co.uk
Cars need a mixture of fuel and air to create the combustion reactions which ultimately let them move. However, engines can only work best at certain ratios of gasoline to air. So how does your car create this proper ratio each time a piston fires? The answer is the fuel injection system.
The brains of fuel injection is the engine control unit (ECU), which is a computer that calculates how much fuel and air to deliver to the engine cylinders at a given time. A four-stroke engine only allows air and fuel into each cylinder at certain points in their cycles, so the ECU must calculate discrete portions of air and fuel to inject into each cylinder. This ratio varies based on road and vehicle conditions, as well as your actions behind the wheel; for example, if you are trying to accelerate.
The ECU opens the fuel injector to allow fuel and air in by applying an electrical current to the solenoid coil. As long as a pulse is applied to the coil, the injector remains open and fuel can enter. The length of this pulse is determined by the calculations performed by the ECU. Oxygen sensors elsewhere in the car make sure that the right amounts of fuel and air are entering the injection system, and allow the ECU to make real-time corrections.
After fuel and air enter the fuel injection system, the high pressure of their entrance forces them through a small nozzle and out of a spray tip into the engine. This high pressure, combined with a high speeds, turns the fuel and air into a vaporized mixture, since engine combustion cannot take place if the gasoline is still in liquid form. The fuel-air mixture then travels through the engine's air stream and enters the cylinders at specific intake times, where it can provide energy to keep your car moving.
—Seth Berger
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We was working on our mechanical injection air 'thingey' when my cousin spilld a vokda drink (the engine was running!) The engine immediatly began racing rpms upward.
So we went to Hughes grocery store and bought two 1/2 gallons of cheap Vodka and poured them into the gas tank
Be careful if you ddo this, vokda is hard on the paint job--we found out the hard way.
Anyway, the car ran bitchen' like I haad racing gas or something.
Then it threw a rod and we haven't driven our 450 Mercedes since. (SAD FACE)
Thanks great article above.
Capt. Billy