MULTI POINT FUEL INJECTION SYSTEM of Automobiles.pptx

different designs and types of fuel injection system. useful for basic study.

1. MULTI POINT FUEL INJECTION SYSTEM BY SUVANJAN BHATTACHARYYA ASST. PROFESSOR MECHANICAL ENGINEERING DEPARTMENT MCKV INSTITUTE OF ENGINEERING HOWRAH.

2. INTRODUCTION In petrol engine carburetor is used for supplying air fuel mixture to the cylinder. In response to the recent demand for cleaner exhaust emission improved drivability and mileage, carburetor is not sufficient. In the place of carburetor MPFI system is used in Cars. MPFI system injects fuels into individual cylinders based on commands from engine control module. The MPFI gives higher output, faster throttle response under varying driving conditions.

3. INTRODUCTION Contd … To reduce or eliminate detonation. To prevent fuel loss in case of scavening in two-stroke engine.

4. TYPES OF INJECTION SYSTEM The main purpose of the Multi-point fuel injection system (MPFI) is to supply a proper ratio of gasoline and air to the cylinder. These systems function under two basic arrangements, namely (i) PORT INJECTION (ii) THROTTLE BODY INJECTION

5. COMPONENTS OF MPFI The system have four major components (i) Air intake system (ii) Fuel delivery system (iii) Electronic control system (iv) Emission control system

6. AIR INTAKE SYSTEM It includes (a)air filter, (b)throttle body, (c)intake manifold, and (d)finally drawn into the combustion chamber. It also consists of throttle valve, T P Sensor, which detects the throttle valve opening.

7. FUEL DELIVERY SYSTEM It includes – (a) Fuel Pump (b) Fuel filter (c) Injector Fuel Pump – ECM controls its operation and centrifugal pump is used to pump the fuel. Injector – Each cylinder have one injector. It injects the fuel into the inlet manifold according to the single from ECM.

8. ELECTRONIC CONTROL SYSTEM The electronic control system consists of various sensors which detect the state of engine and driving condition. ECM also controls the timing of fuel injection according to the signals from various sensors. Injection time is calculated on the basis of engine speed.

9. PORT INJECTION In port injector arrangement, the injector is placed on the side of the intake manifold, near the intake port. The injector sprays gasoline into the air, inside the intake manifold.

10. PORT INJECTION Contd … The gasoline mixes with the air in a reasonably uniform manner. This mixture of gasoline and air then passes through the intake valve and enters into the cylinder. Every cylinder is provided with an injector in its intake manifold. If there is six cylinders, there will be six injectors.

11. PORT INJECTION Contd …

12. PORT INJECTION Contd …

13. THROTTLE BODY INJECTION SYSTEM The throttle body is similar to the carburetor throttle body, with the throttle valve controlling the amount of air entering the intake manifold.

14. THROTTLE BODY INJECTION SYSTEM Contd… The injector is placed slightly above the throat of the throttle body. The injector sprays gasoline into the air in the intake manifold where the gasoline mixes with air. Then this mixture passes through the throttle valve and enters into the intake manifold. The fuel injection can be either timed or continuous .

15. THROTTLE BODY INJECTION SYSTEM Contd… In the timed injection system, gasoline is sprayed from the injectors in pulse. And, in the continuous injection system, gasoline is sprayed continuously from the injector. In both PORT INJECTION system and THROTTLE BODY injection system, the amount of gasoline injected depends upon the engine speed and power demands.

16. ADVANTAGES OF MPFI More uniform A/F mixture will be supplied to each cylinder, hence the vibration from the engine equipped with this system is less, due to this the life of the engine components is more and improved. Immediate response to the engine in case of sudden acceleration or deceleration. Due to more accurate A/F mixture is going into the cylinder, the emission level is low.

17. ADVANTAGES OF MPFI Contd… The mileage of car will be improved. It reduce wastage of fuel by the use of sensors and other control system.

18. D- MPFI SYSTEM The D-MPFI system is the manifold fuel injection system. In this type, the vacuum in the intake manifold is 1 st sensed. It then sensed the volume of air by its density. As the air enters into the intake manifold, the manifold pressure sensor detects the intake manifold vacuum and sends the information to the ECU (Electronic Control Unit). Then speed sensor also sends information about the rpm of the engine to the ECU.

19. D- MPFI SYSTEM Contd … Then the ECU in turn sends the commands to the injector to regulate the amount of gasoline supply for injection. When the injector sprays fuel in the intake manifold the gasoline mixes with the air and the mixture enters the cylinder.

20. L- MPFI SYSTEM The L-MPFI system is a port fuel-injection system. In this type the fuel metering is regulated by the engine speed and the amount of air that actually enters the engine. This is called air-mass metering or air-flow metering.

21. L- MPFI SYSTEM Contd… As air enters into the intake manifold, the air flow sensor measures the amount of air and sends information to the ECU. Similarly, the speed sensor sends information about the speed of the engine to the ECU. The ECU processes the information received and sends exact commands to the injector, in order to regulate the amount of gasoline supply for injection. When injection takes place, the gasoline mixes with the air and the mixture enters the cylinder.

22. MPFI SYSTEM.