25-08-2017, 09:32 PM
FUEL INJECTION SYSTEMS
FUEL INJECTION SYSTEMS.ppt (Size: 587 KB / Downloads: 124)
Types of Fuel Injection Systems
Port fuel injection. (PFI/MPFI)
Throttle Body Fuel Injection. (TBI)
Mechanical or CIS injection system.
1958 Corvette 1st fuel injection (Manual)
Electronic Injection System
Electronic Parts
Computer (PCM):
logic device.
Sensors :
input data to the computer.
Actuators :
output devices the
Electronic Parts
Electronic Parts Computer (PCM) - logic device.
Sensors
input data to the computer.
Actuators
output devices the computer operates
Fuel Filter and Fuel Lines
Sock on gas pump
Inline
Screen in injector
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
How the Injector Fires
The computer grounds the injector to turn it “pulse” -- “Pulse width”
Pulses timed by crankshaft sensor (CKPS). And/or camshaft sensor (CPS).
Three ways to fire the injectors:
1. Group
2. Gang injection
3. Sequential injection
Electronic Sensors (Inputs)
MAP Manifold Absolute Pressure
MAF Mass Air Flow
ECT Engine Coolant Temperature
IAT Intake Air Temperature
TPS Throttle Position Sensor
VSS Vehicle Speed Sensor
O2 Exhaust Oxygen Sensor
CKP Crankshaft Position
CMP Camshaft Position
KS Knock or Detonation Sensor
Manifold Absolute Pressure Sensor (MAP)
Measures difference between atmospheric pressure and intake manifold vacuum
Oxygen Sensor (O2 or HO2S)
Measure the amount of oxygen in the exhaust stream.
Low voltage <.45 is a lean signal.
High voltage >.45 is a rich signal.
1996 /newer use two O2 sensors.
Some O2 sensors are heated. ( HO2S