FUEL INJECTION SYSTEM

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FUEL INJECTION SYSTEMS: 

FUEL INJECTION SYSTEMS

Introduction : 

Introduction Fuel injection system is a well-designed mechanism for admitting fuel into an I.C. engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s. A fuel injection system is designed and calibrated specifically for the type(s) of fuel it will handle. Most fuel injection systems are for gasoline or diesel applications. The basic function of a fuel injection system is to inject fuel to the engine cylinders in proper quantity , at correct time and at a pre-determined rate .

History and Development: 

History and Development Herbert Akroyd Stuart developed the first system laid out on modern lines with a highly accurate 'jerk pump' to meter out fuel oil at high pressure to an injector. This system was adapted and improved by Robert Bosch and Clessie Cummins for use on diesel engines — Rudolf Diesel's original system employed an 'air-blast' system using highly compressed air. Fuel injection was in widespread commercial use in diesel engines by the mid-1920s. Because of its greater immunity to wildly changing g-forces on the engine, the concept was adapted for use in gasoline-powered aircraft during World War II, and direct injection was employed in some notable designs like the ’Junkers Jumo 210’, the ’Daimler-Benz DB 601’, the ‘BMW 801’, and later versions of the ’B-29 Super-fortress’.

Objectives Of Fuel Injection System: 

Objectives Of Fuel Injection System The injection system of the compression ignition engine should fulfill the following objectives consistently and precisely: Meter the appropriate quantity of fuel, as demanded by the speed of, and the load on, the engine at the given time. Distribute the metered fuel equally among cylinders in a multi-cylinder engine. Inject the fuel at the correct time (with respect to crank angle) in the cycle. Inject the fuel at the correct rate (per unit time or crank angle degree). Inject the fuel with the correct spray pattern and sufficient atomization as demanded by the design of the combustion chamber. Begin and end injection sharply without dribbling.

There are two major divisions of Fuel Injection systems: Solid Injection systems , which inject only the liquid fuel through the injectors. Air Injection systems , which inject air along with the liquid fuel. However, the air injection systems have proved to be less efficient and costlier than other systems and hence, is now obsolete. The commonly used types of Solid Injection system are: Individual pump system : This consists of a separate metering and compression pump for each cylinder. Common rail system : A single pump for compressing the fuel, plus a metering element for each cylinder.

Individual Pump Fuel Injection System: 

Individual Pump Fuel Injection System As shown in the adjoining figure, the fuel is drawn from fuel tank by means of a fuel feed pump which is operated from the injection pump camshaft. The fuel is then passed through a filter and there-by to the fuel injection pump. The filter prevents any abrasive matter in the fuel flow towards the injection pump, which would otherwise result in poor starting, irregular idling and deterioration in performance due to decreased fuel delivery from the injection pump. Fig .: Individual Pump Injection System using in-line injection pump

PowerPoint Presentation: 

The fuel injection pump then injects definite quantity of fuel into each cylinder in turn, according to the firing order, through the injectors fitted on them. The injection pump is gear driven from the engine camshaft so that it is driven at half the engine speed. Also a governing device is placed at the side of the injection pump to provide automatic speed control. Any excess fuel after lubrication of injector nozzle is returned to the fuel tank. The most successful working of this system is found in Swaraj Mazda SL engine.

COMMON RAIL DIRECT INJECTION SYSTEM: 

COMMON RAIL DIRECT INJECTION SYSTEM

HISTORY : 

HISTORY The common rail system was developed in the late 1960s by Robert Huber of Switzerland and the technology further developed by Dr. Marco Ganser The common rail fuel system is developed for heavy duty vehicles and turned it into practical use of this system mounted on the Hino Rising Ranger truck and sold for general use in 1995.

COMMON RAIL DIRECT INJECTION SYSTEM : 

COMMON RAIL DIRECT INJECTION SYSTEM In this system the unit injectors is employed on each cylinders. The unit injectors are operated by rocker arms. The fuel taken from the fuel tank by feed pump then passed through filter and common rail and same quantity of fuel is injected in each cylinder

MODERN COMMON RAIL SYSTEM: 

MODERN COMMON RAIL SYSTEM

PowerPoint Presentation: 

This system is the similar to the common rail injection system. In modern CRS the injector are operated by ECU(electronic control unit) The fuel from the fuel tank is pumped by a low pressure electric fuel pump through a filter, to the high pressure pump, which builds up the high pressure in the common rail with the help of a pressure regulator valve which is controlled by an ECU through pressure sensor. Thus the fuel pressure in the rail is independent of engine speed. The injector receives its operation signal from the ECU. The main component of the system are the low pressure pump, the high pressure pump the common rail ECU, the injector.

Advantages of CRS(common rail system): 

Advantages of CRS(common rail system) It increases fuel economy. It lowers emission. It delivers less noisy operation. The system can be easily integrated in wide variety of engines. It is relatively simple in construction & needs less maintenance.

MULTI POINT FUEL INJECTION SYSTEM: 

MULTI POINT FUEL INJECTION SYSTEM

INTRODUCTION: 

INTRODUCTION MPFI- a technology used in petrol engines Uses a small computer to control the car’s engine In MPFI engine one fuel –injector is installed near each cylinder ,that is why it is called multi point fuel injection. Before MPFI system, there was a technology called “ Carburetor”

PowerPoint Presentation: 

The computer in the MPFI system decides what amount of fuel to inject System also learns from the drivers driving habits MPFI system makes engine fuel efficient

FUNDAMENTALS OF FUEL INJECTION: 

FUNDAMENTALS OF FUEL INJECTION MPFI Systems can either be: Sequential Simultaneous Group These techniques result in better ‘power balance’ amongst the cylinders, higher output from each one of them, along with faster throttle response

PowerPoint Presentation: 

'Sequential' is the best from the above considerations of power balance/output “ Sefi ’’-Sequential Electronic Fuel Injection - technically is the best of the above variants of MPFI The ‘on-board’ ECU primarily controls the Ignition Timing and quantity of fuel to be injected

VARIOUS INJECTION SYSTEM : 

VARIOUS INJECTION SYSTEM

PowerPoint Presentation: 

The injector is placed on the side of the intake manifold near the intake port Every cylinder is provided with an injector in its intake manifold

Throttle Body Injection System : 

Throttle Body Injection System

D-MPFI System : 

D-MPFI System

L-MPFI System : 

L-MPFI System

ADVANTAGES : 

Improved fuel consumption Better for the environment Better performance ADVANTAGES

PowerPoint Presentation: 

THANK YOU ALL