Electronic fuel injection system [EFI]

This presentation is about complete description of EFI system. How it works.

1. EFI (Electronic Fuel Injection)

2. Group Members 1- Khdija Hassan BMEF14M001 2- M.Saleem BMEF14M003 3- Mohsin Ikram BMEF14M007 4- Ghulam Mustafa BMEF14M008 5- Moeed Ahsan BMEF14M009 6- Hafiz Zia- ur - Rehman BMEF14M030 7- M.Talha Hanif BMEF14M033

3. Contents Introduction Air Induction System Input (Sensors) ECU/M( Electronic Control Unit/Module) Output (Actuators)/Fuel Delivery System Advantages/ Disadvantage

4. INTRODUCTION The Electronic Fuel Injection system fitted to most modern vehicles combines sophisticated computer controls with a high pressure fuel delivery system to provide optimum power and fuel efficiency. It uses the Electronic Sensors for Precise metering of fuel. The system is controlled by an electronic control unit ( ECU ). Replacement for Carburetor. Not engine vacuum, is used to feed fuel into engine. Pressure is used from an electric fuel pump.

5. Types of EFI System Single Point Injection System Multi Point Injection System Direct Injection System Indirect Injection System

6. Single Point Injection It is also called TBI. Injector located inside throttle body . Injector sprays fuel from above throttle valve. ECU controls injector opening

7. Multi Point Injection System Injector located in each branch of inlet manifold, below throttle valve . Injectors spray fuel directly into each port. ECU controls opening of injectors

8. D irect Injection Injector is fixed to the top of combustion chamber. Fuel is injected above Piston head . Smaller combustion space, better thermal efficiency.

9. Indirect Injection Indirect Injection System has a small swirl chamber above the cylinder. Fuel is injected in swirl chamber . Higher compression ratio needed to aid starting.

10. Conventional/ Carburetor Engine 1- Difference of Pressure 2- Vanturi . 3 - Float chamber.

11. Conventional/Carburetor Engine The air induction system consists of the air cleaner, air flow meter, throttle valve, air intake chamber, intake manifold runner, and intake valve. When the throttle valve is opened, air flows through the air cleaner, through the air flow meter (on L type systems), past the throttle valve, and through a well tuned intake manifold runner to the intake valve. Air Induction System

12. Air Induction System

13. Air Cleaner : The Air Cleaner is a functional part that purifies vehicle intake air used for engine combustion . Air Cleaner Element : The Air Cleaner Element ( or Air Filter) is placed inside the Air Cleaner to eliminate dust , carbon and other pollution contained within the intake air from reaching the engine. Air Induction System

14. Airflow meters are basically mass flow meters, as they determine the air velocity and air pressure by measuring the mass flow of a medium, which is air in this case. Air Induction System

15. The throttle body is the part of the air intake system that controls the amount of air flowing into an engine's combustion chamber. It consists of a bored housing that contains a throttle plate that rotates on a shaft. When the accelerator is depressed, the throttle plate opens and allows air into the engine. When the accelerator is released, the throttle plate closes and effectively chokes-off air flow into the combustion chamber. This process effectively controls the rate of combustion and ultimately the speed of the vehicle. The throttle body is usually located between the air filter box and the intake manifold, and it is usually located near the mass airflow sensor. Air Induction System

16. Sensors ( Inputs)

17. Intake Air Temperature Sensor It measures the temperature of the air entering the engine.

18. Throttle Position Sensor A  throttle position sensor  (TPS) is a  sensor  used to monitor the throttle position of a vehicle.

19. Camshaft Position Sensor This sensor is responsible for telling the ECU the current position of the camshaft.

20. Manifold Absolute Pressure Sensor It senses the difference between atmospheric pressure and the engine vacuum pressure.

21. Vehicle Speed Sensor It is used for reading the speed of a vehicle's wheel rotation/speed.

22. Coolant Temp Sensor It is used to measure the “ temp ” of the engine coolant of an IC Engine. How does it work? ECU sends out regulated voltage to the coolant sensor. Voltage drops across it changes according to the temp because its RESISTANCE changes. Voltage drop is measured by the ECU and carry out adjustments according to this. Locations : on the bottom of the radiator.

23. Mass Air Flow Sensor It is to measure the amount of air entering the engine or  the air flow . How does “Hot Wire Sensor” work? Const. voltage is applied to the wire, heated by the current produced by the applied voltage, and it is placed in the position of the air stream. As the air flows, its temperature drops, as a result of this resistance also drops. It allows the more current to draw through it to maintain the initial temperature. Location: The MAF Sensor is located either on the air cleaner box or along the pipe going from the air cleaner to the throttle body .

24. Oxygen Sensor It is used to measures the proportion of  oxygen  (O 2 ) in the exhaust. How does “O 2 Sensor” work? It actually compares the amount of oxygen that is present in exhaust gas and the ambient air. Location: These are  located within the exhaust stream, there is at least one oxygen sensor located before the catalytic converter and typically one in each exhaust manifold.

25. Knock Sensor It is used to detect the “VIBRATIONS” produce by the Engine Knocking. How does it work? It is a piezoelectric sensor. That changes the vibrations sense by it into the voltage signal. Location: This sensor is normally bolted onto the main-body of the engine.  

26. Crankshaft Sensor It is responsible for telling the exact location of the crankshaft as well as the RPM of the engine.  How does it work? It is positioned so that the teeth on the reluctor wheel are in contact with the tip of the sensor. As crankshaft rotates sensor produces a voltage signal corresponding to the teeth. Locations: It is located at the bottom of the engine somewhere close to the crankshaft.

27. Electronic Control Unit(ECU)

28. It’s a type of electronic control unit that controls a series of actuators on an IC engine to ensure optimal engine performance.

29. Memory maps:

30. Functions: Control of air/fuel ratio Control of idle speed Variable valve timing(VVT) Ignition timing Waste gate control Speed limit

31. Fuel Delivery System and Actuators( OutPut ). Fuel Tank/Filter Fuel pump Fuel Rail/Relay & Return Line Fuel pressure regulator Fuel injectors Valves Spark Plug

32. M ounted inside or near the fuel tank M ay range anywhere from 8 to 80 lbs . R elay sends a signal to the ignition switch All other actuators and components in the injection system depend on powering the Relay. Fuel Pump and Relay

33. Fuel pressure regulator means of regulating fuel pressure according to engine vacuum mounted on the fuel rail that supplies the injectors . has a simple spring-controlled vacuum diaphragm with a vacuum connection to the intake manifold The excess fuel pressure is shunted through a bypass port back to the fuel tank

34. Fuel injector Output actuators such as fuel injectors are devices that are activated by the ECU with reference to the engine’s load and condition it is in . A spring-loaded solenoid pintle valve Pulse width common problem

35. Valves Allow the intake of different fluids involved in the injection of air, the mixture, and the fuel. Canister valve:  A key component for the  emission control system . Thanks to the movement of this valve, vapours contained in the fuel tank are transported into the engine, – IAC (Idle Air Control) Valve:    adjust the engine idling revolutions , managing and regulating the influx of air towards the combustion chamber

36. Spark plug This spark plug is used to ignite the charge inside the engine by applying high voltage across the terminal of electrode

37. Advantages Over Conventional System Improved atomization. Fuel is forced into the intake manifold under pressure. Better fuel distribution . Lower emissions. Lean efficient air-fuel mixture reduces exhaust pollution. Better cold weather drivability . Precise metering of fuel to each cylinder and increased air flow can result in more horsepower output.