Introduction to Electronic Fuel Systems Topics covered in this presentation: Types of Electronic Fuel Systems Fuel Injection Timing, Open Loop and Closed Loop Modes Wiring Diagrams and Schematics ClassAct SRS enabled.

Types of Electronic Fuel Systems Electronic Fuel (petrol) Injection (EFI) Computer (ECU / ECM / PCM) operates solenoid controlled fuel injectors. Computer Controlled (feedback) Carburettors Computer operates mixture control solenoid and/or fuel shutoff valve. Electronic Diesel Injection Computer operates fuel metering solenoids. Electronic Fuel Injection is the most common type of fuel system in use. Next >

Question 1 Which is the most common type of fuel injection system? A) Electronic Fuel Injection B) Computer Controlled Carburettors C) Electronic Diesel Injection Correct Answer = A

Single and Multipoint EFI Systems Fuel injection systems classified by point of injection. ECU Single Point Fuel Injection (Throttle Body Injection - TBI) Injector located inside throttle body, sits on top of inlet manifold. Fuel in Air in Throttle valve Injector sprays fuel from above throttle valve. Injector Inlet manifold Throttle body ECU controls injector opening. Next >

Question 2 In a single-point fuel injection system, where is the injector located? A) In the inlet manifold B) Next to the inlet valve C) Before the air filter Correct Answer = D D) In the throttle body

Single and Multipoint EFI Systems Multipoint Fuel Injection ECU Injector located in each branch of inlet manifold, below throttle valve. Fuel in Air in Injectors x 4, x6, x8 etc. Inlet manifold Throttle valve Injectors spray fuel directly into each port. ECU controls opening of injectors. Next >

Question 3 What controls the opening of the injectors in an EFI system? A) The throttle valve B) The air pressure C) The ECU Correct Answer = C D) The pressure in the inlet manifold

Fuel Injection Timing Describes when fuel is sprayed into the inlet manifold. Intermittent (or modulated) Injectors controlled independently of inlet valve position. Timed (or sequential) Injectors controlled in time with inlet valves. Continuous Injectors open all the time, fuel pressure is controlled. Next >

Question 4 In which method of fuel injection timing is the fuel supplied in time with the inlet valves? A) Continuous B) Sequential C) Modulated Correct Answer = B D) Intermittent

Fuel Injector Opening Relationships Simultaneous Injection (all together). Sequential Injection (one at a time). Next >

Fuel Injector Opening Relationships Group Injection (Injectors of Vee engine operating in A and B banks). A B Next >

ECU Open & Closed Loop Operation Engine cold, ECU operates in open loop mode. Uses preprogrammed values to control engine. Engine at operating temperature, ECU operates in closed loop mode. It uses data from the oxygen and other sensors to control engine. Next >

Question 5 How many different modes does the ECU operate in? Enter your answer and press SEND. Correct Answer = 2

Typical Fuel System Sub-Systems 1. Fuel Supply System Supplies clean fuel to fuel metering system (fuel pump, filters, pipes). 2. Air Supply System Supplies controlled clean air to engine (air filter, ducting). 3. Fuel Metering System Controls amount of fuel (and air) entering engine (injectors, pressure regulator, throttle valve). Next >

Fuel System Diagrams and Schematics Fuel System Block Diagrams - 1 System and subsystem blocks Each block represents a system. Lines represent connections between systems. Arrows represent direction of flow. Direction of information flow/control Connection lines Next >

Fuel System Diagrams and Schematics Fuel System Block Diagrams - 2 System and component blocks Connection lines Each block represents a component. Lines represent connections between systems. Arrows represent direction of flow. Direction of information flow/control Next >

Fuel System Diagrams and Schematics Fuel System Schematic Diagrams Wiring Components Fuel pipes Next >

Question 6 Fuel system schematic diagrams show: 1. Components 2. Fuel pipes 3. Wiring 4. Connector numbers Which of these are correct? Correct Answer = C A) 1, 2 and 4 C) 1, 2 and 3 B) 2, 3 and 4 D) 1, 3 and 4

Fuel System Diagrams and Schematics Fuel System Wiring Diagrams Wire size Connector number Component symbol Wire colour Wire Next >

Question 7 Fuel system wiring diagrams show wire size, wire colour and wire connector number. Is this true or false? Answer True or False. Correct Answer = T

Summary You should be aware of: Types of Electronic Fuel Systems Fuel Injection Timing, Open Loop and Closed Loop Modes Wiring Diagrams and Schematics End >