Technology Decoded: Multi-Point Fuel Injection (MPFi)

This technology is used in Gasoline/petrol Engines. Initially carburetors were replaced by Single Point Fuel Injection (SPFi) that involves only one injector for all cylinders which often led to maldistribution of fuel among cylinders.  Due to this reason SPFi and carburetors were efficiently replaced by MPFi, which offers optimum air-fuel ratio distribution among cylinders.

Background/Development:

• Bosch developed the first automotive direct injection system for gasoline engines in 1952.
• Bendix Corporation developed the first commercial electronic fuel injection (EFI) system in 1957.

Technology Explained: 

In MPFi, there is a separate injector for each cylinder that leads to optimum air-fuel ratio distribution among all the cylinders. Each injector is connected to fuel rail and is placed near to intake valve of cylinder. In SPFi, an injection valve is just above the throttle valve. Other insights are discussed below:    

1. As the engine runs, the pump sends fuel from tank through regulator to injectors at constant high pressure.

2. In MPFi, each injector is under the control of Electronic Control Unit (ECU). Various sensors like mass air flow sensor, throttle position sensor, oxygen sensor, engine speed sensor etc. are located on the engine.

3. These sensors detect the operating conditions of engine like temperature of engine, speed of engine, load on engine, level of oxygen in the exhaust and many other variable factors which are important in smooth running for an engine.

4. Data from these sensors are fed into ECU, which further processes this information and after deciding the timing and duration of fuel injection, ECU sends pulses to control the operation of injectors accordingly. In this way, each cylinder is fed with required amount of fuel only which leads to improved fuel economy. 

Advantages:

• It leads to equal air-fuel ratio distribution among all cylinders.
• It also reduces fuel consumption and emission levels of vehicle.
• Less vibration.
• Improved mileage.

Watch this video for better understanding of MPFi:

Also Read: Technology Decoded: Carburetor