Part of Lesson Plan: **Fuel system delivery (updated) by Sergio Marquez
Activity Overview / Details
While lecturing students will follow on text book ( Thomson Delmar Learning, "Automotive Technology: A Systems Approach," 4th edition ), pages 691-712
I will start by explaining the layout and flow of the fuel system, refer to fig. 27-1. The flow starts from the Fuel Tank were the fuel is stored, explain fuel tank construction (ex. fuel tanks are made of pressed corrosion resistant steel, aluminum or molded polyethylene plastic. aluminum and plastic are the most common. they are made in a way that alows them to expand and contract with the changes of internal temperatur and pressure) then it's sucked or pushed by a fuel pump and this could be electric or mechanical fuel pump, electric pumps are the most common. At this point explain the components that pickup the fuel from the tank and how the fuel sending unit work, (ex. the strainer, fuel pump, sending unit) refer to fig. 27-6 and fig. 27-30.
Once the fuel travels out of the tank at a high pressure, the fuel flows through a steel or a flexible nylon lines to a fuel filter, many of the fuel filter are found under vehicle and some are at or near the engine. At this time take the time to explain fuel filter construction, (ex. Fuel filters are made of pleated paper element mounted inside of eather a metal or plastic case) refer to fig. 27-19.
Fuel travels out of the fuel filter through more fuel lines all the way to the engine, where it enters a fuel pressure regulator and any excess fuel is returned to the fuel tank through a fuel return line. I will explain the fuel regulator functions (eg. pressure regulators are controlled by engine vacuum). Refer to fig. 27-1. Once the fuel goes through the pressure regulator, it goes into a fuel rail where the fuel injectors are connected. Then the fuel enters the fuel the injectors and ultimetly in to the cylinders when opend by the PCM/ECM (computer).