Fuel Injection systems in SI engines

Eeshan Bashir

Types of fuel injection system used in the SI engine

• Gasoline Direct Injection.• Port fuel injection– Single Point Fuel injection system.– Multipoint fuel injection system.

Gasoline Direct Injection• The gasoline is highly pressurized and injected

via a common rail fuel line directly into the combustion chamber of each cylinder.

Advantages of GDI

• Up to 15% lower fuel consumption and CO₂ emissions with the same power output

• Enhanced responsiveness and greater driving dynamics in combination with downsizing, turbocharging, and scavenging

• Torque increased by up to 50% at low engine speeds

• Higher specific power output Higher downsizing ratios

SCHEMATIC

SENSORS USED IN GDI

• High-pressure sensor in Rail• Hot-film mass air-flow sensor HFM• Knock sensor• Lambda sensor• Crankshaft speed sensor• Low-pressure sensor for tank pressure• Air-pressure and boost-pressure sensor• Accelerator pedal position sensor• Camshaft position sensor• Exhaust gas temperature sensor• Coolant temperature sensor

Actuators

• High-pressure solenoid injector• High-pressure pump• High-pressure injector• Ignition coil• Fuel-supply module FSM• Electronic throttle body• Spark Plug• Ignition Coil• Pressure regulator

Electronic Control Unit

• Total control of the actuators and run engine under optimal conditions

• High integration and compactness by in vehicle custom IC

• High speed processing • Waterproof structure• Integrated with injection

driver unit

Sensor: Airflow Meter

• Meter to measure the amount of air taken into the engine in order to calculate the quantity for fuel injection.

Sensor: Turbo Pressure sensor• Pressure sensor to measure the pressure of

turbocharged intake air.

Sensors: Manifold Absolute Pressure sensor• The sensor measures the manifold absolute pressure

to provide accurate air-fuel ratio control in conjunction with the results of measurements from the air-flow meter.

Sensor: Accelerator pedal Module

• An accelerator pressure module detects the amount of pedal depressions

• Hall effect sensor for long life and durability

Fuel Pressure Sensor• A fuel pressure sensor is designed to measure

and optimize the pressure of the fuel supplied to the high pressure injector.

Sensor: Camshaft Position Sensor

• Camshaft position sensor are used to determine accurate position of the crankshaft generally they are hall effect type sensors

Sensor: Cam Position Sensor

• Compact and high-performance cam position sensor to meet the needs for cleaner vehicle emissions and higher fuel efficiency

Sensor: Knock Sensor

• Detects vibration(engine knock) caused by abnormal engine combustion and controls the ignition timing to keep it as close to the knock limit as possible.

Sensor: Lamda Sensor

• This is a high response oxygen detecting sensor that helps to maintain the airfuel ratios.

Sensor: Exhaust gas Temperature Sensor.

• This thermistor type temperature sensor can detect the exhaust gas temperature of automobiles accurately.

Sensor: Coolant temperature sensor

• Sensor that measures the temperature of the engine coolant temperature.

Actuator: Electric Variable Cam Timing• Continuous variable cam timing control combined

with an electric motor contributes to low fuel consumption, low emission, and high output of engines.

Actuator: Electronic Throttle Body• The electronic throttle body opens and closes the

throttle value electronically based on how far the driver depresses the accelerator pedal, the electronic throttle opens and closes electronically.

Actuator: High pressure Injector

• The compact, lightweight, and high response injector is designed for direct injection gasoline engines.

Actuator: High pressure Pump

• A high pressure pump is designed to pressurize, meter and supply fuel with high efficiency. The pump is driven by engines camshaft.

Actuator: Fuel Pump

• Highly efficient, compact and low-noise fuel pump to meet the needs for lower vehicle electric power consumption and larger vehicle cabin.

Actuator: Ignition Coil(Stick Coil)

• The compact ignition coil can be mounted directly in a plug hole.

Actuator: Spark Plug

• The spark plug is used to ignite the charge inside the engine by applying high voltage across the terminals of the electrodes.

Actuator: Exhaust gas recirculation value

• EGR helps in improving economy of the vehicle and reduce the temperature thereby reducing the Nox emissions.

Actuator: pressure regulator

• This actuator is responsible for maintaining a certain pressure in the rail based on the speed and load on the engine.