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1 FUEL INJECTION SYSTEMS. 2 Types of Fuel Injection Systems Port fuel injection. (PFI/MPFI) Port fuel injection. (PFI/MPFI) Throttle Body Fuel Injection.

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Presentation on theme: "1 FUEL INJECTION SYSTEMS. 2 Types of Fuel Injection Systems Port fuel injection. (PFI/MPFI) Port fuel injection. (PFI/MPFI) Throttle Body Fuel Injection."— Presentation transcript:

1 1 FUEL INJECTION SYSTEMS

2 2 Types of Fuel Injection Systems Port fuel injection. (PFI/MPFI) Port fuel injection. (PFI/MPFI) Throttle Body Fuel Injection. (TBI) Throttle Body Fuel Injection. (TBI) Mechanical or CIS injection system. Mechanical or CIS injection system Corvette 1 st fuel injection (Manual) 1958 Corvette 1 st fuel injection (Manual)

3 3 Electronic Injection System Electronic Parts Electronic Parts Computer (PCM): Computer (PCM): logic device. logic device. Sensors : Sensors : input data to the computer. input data to the computer. Actuators : Actuators : output devices the computer operates. output devices the computer operates. Mechanical Parts Fuel tank. Fuel pump. Fuel filter and lines. Injector or injectors. Fuel rail. Pressure regulator.

4 4 Electronic Parts Electronic Parts Computer (PCM) - logic device. Electronic Parts Computer (PCM) - logic device. Sensors Sensors input data to the computer. input data to the computer. Actuators Actuators output devices the computer operates output devices the computer operates

5 5 Fuel Filter and Fuel Lines Sock on gas pump Inline Screen in injector

6 6 Fuel Rail & Pressure Regulator The rail - pipe that fills the injectors. Pressure regulator controls the pressure to injectors. Pressure adjusted for changes in intake manifold vacuum. Some are mechanical but newer cars use an electronic system.

7 7 Fuel Injectors Injectors Injectors electrically operated valve. electrically operated valve. Fuel pump Fuel pump pumps fuel to injector from fuel tank pumps fuel to injector from fuel tank holds pressure against e injectors valve. holds pressure against e injectors valve. Computer triggers valve with electrical signal called a pulse. Computer triggers valve with electrical signal called a pulse. (pulse width) (pulse width)

8 8 Fuel Injector Parts O Ring seals fuel rail intake manifold. Solenoid inside, note electrical connection. Pintle Needle at spray end where fuel shoots out.

9 9 How the Injector Fires The computer grounds the injector to turn it pulse -- Pulse width The computer grounds the injector to turn it pulse -- Pulse width Pulses timed by crankshaft sensor (CKPS). And/or camshaft sensor (CPS). Pulses timed by crankshaft sensor (CKPS). And/or camshaft sensor (CPS). Three ways to fire the injectors: Three ways to fire the injectors: 1. Group 1. Group 2. Gang injection 2. Gang injection 3. Sequential injection 3. Sequential injection

10 10 Sensors

11 11 Electronic Sensors (Inputs) MAP Manifold Absolute Pressure MAP Manifold Absolute Pressure MAF Mass Air Flow MAF Mass Air Flow ECT Engine Coolant Temperature ECT Engine Coolant Temperature IAT Intake Air Temperature IAT Intake Air Temperature TPS Throttle Position Sensor TPS Throttle Position Sensor VSS Vehicle Speed Sensor VSS Vehicle Speed Sensor O2 Exhaust Oxygen Sensor O2 Exhaust Oxygen Sensor CKP Crankshaft Position CKP Crankshaft Position CMP Camshaft Position CMP Camshaft Position KS Knock or Detonation Sensor KS Knock or Detonation Sensor

12 12 Manifold Absolute Pressure Sensor (MAP) Measures difference between atmospheric pressure and intake manifold vacuum. Measures difference between atmospheric pressure and intake manifold vacuum.

13 13 Mass Air Flow Sensor (MAF) Measures mass of air entering intake manifold.

14 14 Throttle Position Sensor (TPS) Measure throttle angle for PCM. Measure throttle angle for PCM. Electronically: its a potentiometer. Electronically: its a potentiometer. The voltage signal changes as resistance in pot. changes. The voltage signal changes as resistance in pot. changes.

15 15 Engine Coolant Temperature Sensor (ECT) Measure engines coolant temperature. Measure engines coolant temperature. Sensor mounted in engines water jacket. Sensor mounted in engines water jacket.

16 16 Intake Air Temperature (IAT) Works like CTS - measures - temperature of intake air. detect intake air temperature achieving the precise control of the A/F ratio.

17 17 Vehicle Speed Sensor (VSS) Monitors VEHICLE SPEED NOT ENGINE SPEED

18 18 Oxygen Sensor (O2 or HO2S) Measure the amount of oxygen in the exhaust stream. Measure the amount of oxygen in the exhaust stream. Low voltage <.45 is a lean signal. Low voltage <.45 is a lean signal. High voltage >.45 is a rich signal. High voltage >.45 is a rich signal /newer use two O2 sensors /newer use two O2 sensors. Some O2 sensors are heated. ( HO2S) Some O2 sensors are heated. ( HO2S)

19 19 Crankshaft Position Sensor (CKP) Uses Notches in crankshaft

20 20 Camshaft Position Sensor (CMP)

21 21 Knock Sensor (KS) Senses detonation which the engine is running. PCM will retard spark when detonation is detected.

22 22 Computer Actuators (Outputs) Fuel Injectors Fuel Injectors IAC Idle Air Control IAC Idle Air Control Fuel Pump Relay Fuel Pump Relay CANP Canister Purge CANP Canister Purge EGR Regulator EGR Regulator Cooling Fan Relay Cooling Fan Relay Torque Converter Torque Converter MIL-Malfunction Indicator Lamp MIL-Malfunction Indicator Lamp


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