This document discusses electronic fuel injection (EFI) systems. It explains that EFI systems are more precise, reliable, and cost-effective than carburetor systems. EFI provides the correct air-fuel ratio, reduces exhaust pollution, and increases engine power. It then describes different types of fuel injection systems, including single-point and multi-point as well as indirect and direct injection. Various sensors that provide input to the engine control unit (ECU) are also outlined, such as oxygen, throttle position, engine temperature, inlet air temperature, and crankshaft position sensors.

1. KARTHICK S
III-MCT
12BMT017

2.  Replacement for carburetor.
 EFI very precise, reliable & cost effective.
 EFI provide correct A/F ratio.
 Reduce exhaust pollution.
 Increased engine power.

3.  Single or Multi-point injection
 Indirect or Direct injection

4.  Injector located inside
throttle body.
 Injector sprays fuel from
above throttle valve.
 ECU control injector
openings.

5.  Injector located below
Throttle valve.
 Injector sprays fuel
Directly to ports.
 ECU controls opening.

6.  Injector is fixed to the top
of combustion chamber.
 Fuel is injected above
Piston head.
 Smaller combustion space,
better thermal efficiency.

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

8.  Control electrical systems in motor vechile.
 Determines the amount of fuel, ignition timing
and other parameters.

9. Delivery system consists of:
1. Electrical fuel pump
2.Pressure regulator
3. Fuel Injector

10.  Sensors are electrical device.
 It will change resistance with change in
condition.
 Monitors operating condition and report to
Ecu.

11.  Oxygen sensor
 Throttle position sensor(TPS)
 Engine Temperature sensor(ETS)
 Inlet Air Temperature Sensor
 Crank Shaft Position sensor

12.  Measure oxygen content
 Mounted on exhaust system
 Output voltage changes with change in oxygen
content.
 Lean mixture decreases voltage
 Rich mixture increases voltage

13.  Variable resistor connected to throttle plate.
 Change in throttle angle =change in resistance.
 Based on resistance , ECU richens or leans the
mixture.

14.  Monitors the temperature of engine.
 Exposed to engine coolant.
 Engine cold = low resistance = rich mixture
 Engine hot = high resistance = lean mixture

15.  Measure the temperature of air entering the
engine.
 Cold air = more Fuel for proper A/F ratio.

16.  Detects engine speed
 Change injector timing and position
 Higher engine speed = more fuel