Recognizing the conditions of the test cell vs. real world application introduces a whole gamete of variables affecting the fuel supply/delivery to the engine.
In a manufacturers test cell, if you ever have the chance to go on a tour, you will recognize optimal engine conditions. Optimal engine conditions equal optimal engine performance. Optimal engine performance consists of optimal fuel supply. Manufactures' tests vary slightly from one manufacture to the other but are configured with these basics:
- Fuel tank is usually at least 10 feet above the engine
- Fuel tank is stationary
- Return fuel is returned to a separate tank
With the optimal fuel supply achieved, the fuel injection system can perform the job for which it was designed, keywords, optimal performance. That is to deliver virtually pure fuel to the injectors at the proper pressure; the injectors can then deliver the proper amount of fuel at the proper time into the cylinder for a more complete combustion. Understand fuel injection systems were designed to inject a predetermined amount of fuel at a predetermined time.
Give thought to the real world applications. As you might have noticed, we are unable to raise our fuel tanks higher than they are.
- Fuel tanks are usually below the engine and separated from the engine by 5 – 15 feet
- Vehicles are in motion
- Hot return fuel is routed into the fuel supply tank