CRDICOMMON RAIL DIRECT INJECTION

BY: SAHAL M MANSURI

ANDJOSHI MAULIK

CRDI Modern & clean diesel system

INTRODUCTION

The common rail system of fuel injection was used in marine diesel engines during the early and mid-19th century.

The common rail system of fuel injection is a simple and efficient system.

The recent trend in the automobile industry is the usage of common rail direct fuel injection systems in some modern vehicles.

Some of the engines in the automobile sector introduce this common rail system of injection not only in diesel engines, but also in petrol/gasoline engines.

WHY IT IS CALLED CRDI?

It is a new technology and it is called common rail direct injection because there is only one plunger in the pump which supply fuel to the rail from where fuel is injected to the different nozzles (injectors).

DEMAND ON MODERN DIESEL ENGINE DEVELOPMENT

Low fuel consumption. Low pollution emission. Quiet running engine. Improved engine performance

COMMON RAIL FUEL INJECTION SYSTEM AND ITS FUNCTION

Provide the diesel engine with fuel. Generate the high pressure needed for fuel injection and distribute the fuel to the individual cylinders.

Inject precisely correct amount of fuel at exactly the right moment in time.

In contrast to other injection system Common rail fuel injection system is an accumulator injection system.

HOW DOES A CR SYSTEM FUNCTION?

COMMON RAIL FUEL INJECTION SYSTEM

Low Pressure Circuit

High Pressure Circuit

ECU With Sensors

WORKING OF CRDI.

Low –pressure circuit comprises of: Fuel tank . Pre-supply pump. Fuel filter And the respective connection lines.

High –pressure circuit comprises: High – pressure pump with pressure – control valve The high – pressure accumulator (Rail )with the

rail –pressure sensor Injectors, and The respective high – pressure connection lines.

WORKING OF CRDI

WORKING OF CRDIECU and sensorsThe common rail ECU evaluates the signals from the

following sensors. Crankshaft – speed sensor, Boost – pressure sensor. Camshaft sensor, Accelerator-pedal travel sensor. Air temperature sensor. Air – mass meter and Rail pressure sensor.

COMPONENTS OF CRDI PRE SUPPLY PUMP - electric - roller - gear Rail-pressure sensor (RDS). Injector High pressure pump. High- pressure accumulator (Rail). Pressure-control valve (DRV)

PRE SUPPLY PUMPThe electric fuel pump comprises of:1.Electric Motor2.Roller-Cell Pump3.Non Return Valve

The roller cell is driven by an electric motor.

Its rotor is mounted eccentrically and provided with slots in which movable rollers are free to travel.

PRE SUPPLY PUMP

PRE SUPPLY PUMP

Gear type fuel pump The drive gear wheel is

driven by the engine . Delivery quantity is

directly proportional to engine speed.

Shut off is by means of an electromagnet.

HIGH- PRESSURE PUMP The pump plunger moves downwards The inlet valve opens The fuel is drawn in to the pumping element

chamber(suction stroke) At BDC, the inlet valve closes The fuel in the chamber can be compressed by

the upward moving plunger.

PRESSURE-CONTROL VALVE (DRV)

Responsible for maintaining the pressure in the rail at a constant level.

RAIL-PRESSURE SENSOR(RDS)

Measures the pressure in the rail. Inputs the information to the ECU.

ECU WITH SENSORS

Common Rail is an EDC controlled injection system

The ECU controls & monitors the complete injection process

The sensors delivers all the measured values which are required in the process