Overview

Introduction Principle Working Features Scope for further development Conclusion

Introduction

The country among other things has seen an enormous development in engines used in cars also.

The Diesel engines have also undergone a sea change from the time Rudolf Diesel invented it way back in 1892.

Today Common Rail Direct Injection (CRDI) is the order of the day.

CRDI Engine

Principle Unlike in conventional diesel engines,

the fuel is fed into the common tube or rail and high pressure is maintained.

This allows fuel to combine with air much more efficiently.

It features high-pressure fuel rail feeding individual solenoid valves as opposed to low-pressure fuel pump feeding injectors.

Layout of a CRDI Engine

Working Solenoid valves make possible fine

electronic control over the injection time and amount, and the higher pressure that the common rail technology makes available provides better fuel atomization. In order to lower engine noise, the engine's electronic control unit can inject a small amount of diesel just before the main injection event ("pilot" injection), thus reducing its explosiveness and vibration, as well as optimizing injection timing and the process continues

Features Direct injector Spiral-shaped intake port Integrated port Air flow metering Multiple Pilot injection and

Post injection Powerful Microcomputer Newly-developed catalytic

converters Reduced noise levels

Direct injector

A fuel injector is nothing but an electronically controlled valve.

Spiral-shaped Intake port

Provides optimum swirl and even distribution of fuel.

Integrated port

Integrated port is used for exhaust gas recycling. There are three advantages to this system

• eliminates external pipes which are subject to vibration

• quicker engine warm-up• better combustion.

Air flow metering

It gives exact analysis of the air-mass that is being taken in.

Due to this metering system, the microcomputer that controls engine timing receives precise data.

Multiple Pilot injection and Post injection

Pilot injections is small doses of fuel made prior to the main injection which help to smoothen the sharp combustion character.

Post injection is a similarly small dose of fuel injected after the main injection to reduce particulates.

Powerful Microcomputer

The microcomputer regulates the amount of time the valves stay open and thus the amount of fuel injected, depending on operating conditions and how much output is needed.

Newly-developed catalytic converters

Besides electronically-controlled exhaust-gas recycling which contributes to lower nitrous oxide emissions, CRDI engines are equipped with catalytic converters near the motor and emission control devices on the underbody. These vouch for a high degree of efficiency.

Reduced Noise levels

The Electronic control and multiple injections reduced noise to a great extent

Scope for further development

Use of different fuels for zero emissions and better engine performance

By using different fuels and cetane improvers, maximum torque can be obtained

Lowering the cost Closed-loop control injection with ion

sensing technology

Conclusion

CRDI technology revolutionized diesel engines. It has changed the way one looks as diesel cars by providing the above said advantages.

Advantages-More power is developed-Increased fuel efficiency-More stability-Pollutants are reduced-Particulates of exhaust are reduced-Exhaust gas recirculation is enhanced-Precise injection timing is obtained-Pilot and post injection increase the

combustion quality-The powerful microcomputer makes the

whole system more perfect

Manufacturers of CRDI engine

The car makers refer to their common rail engines by their own brand names. Some of them are

BMW's D-engines Mahindra's CRDe Tata's DICOR Honda's i-CTDi Hyundai-Kia's CRDi etc

Acknowledgements

I would like to take this opportunity to thank my project supervisor (Mr. Shailesh Babu) and parents for their support and guidance

References

Automotive Mechanics by S Srinivasan. I C Engines by M.L.Malthur & Sharma. I C Engines by V. Ganesan. Automotive Engines by S Srinivasan. International Journal of Automotive

Technology Approaches to Automotive Emissions

Control Magazines: Auto week, Automobile India