Common rail direct injection

1. Common Rail Direct Injection
Submitted To-
Mr. Amit Kumar
Submitted By-
Yashwardhan Sahi
140970104064

2. Contents
 Introduction
 History
 Operating Principle
 Working of CRDI
 Components of CRDI
 Diff. b/w direct & indirect injection
 Advantages & Disadvantages
 Applications
 Acronyms of CRDI
 References
 Remarks

3. INTRODUCTION
CRDI (Common Rail Direct Injection)
CRDI stands for Common Rail Direct Injection meaning,
direct injection of the fuel into the cylinders of a diesel engine
via a single, common line, called the common rail which is
connected to all the fuel injectors.

4. Whereas ordinary diesel direct fuel-injection systems have to
build up pressure anew for each and every injection cycle, the
new common rail (line) engines maintain constant pressure
regardless of the injection sequence. This pressure then
remains permanently available throughout the fuel line. The
engine's electronic timing regulates injection pressure
according to engine speed and load. The electronic control unit
(ECU) modifies injection pressure precisely and as needed,
based on data obtained from sensors on the cam and
crankshafts. In other words, compression and injection occur
independently of each other. This technique allows fuel to be
injected as needed, saving fuel and lowering emissions.
More accurately measured and timed mixture spray in the
combustion chamber significantly reducing unburned fuel
gives CRDI the potential to meet future emission guidelines
such as Euro V. CRDI engines are now being used in almost
all Mercedes-Benz, Toyota, Hyundai, Ford and many other
diesel automobiles.

5. History
The common rail system prototype was developed in the late 1960s
by Robert Huber of Switzerland and the technology further
developed by Dr. Marco Ganser at the Swiss Federal Institute of
Technology in Zurich, later of Ganser-Hydromag AG (est.1995) in
Oberägeri. The first successful usage in a production vehicle began
in Japan by the mid-1990s. Modern common rail systems, whilst
working on the same principle, are governed by an engine control
unit (ECU) which opens each injector electronically rather than
mechanically. This was extensively prototyped in the 1990s with
collaboration between Magneti Marelli, Centro Ricerche Fiat and
Elasis. The first passenger car that used the common rail system was
the 1997 model Alfa Romeo 156 2.4 JTD, and later on that same
year Mercedes-Benz C 220 CDI.

6. Common rail engines have been used in marine and
locomotive applications for some time. The Cooper-Bessemer
GN-8 (circa 1942) is an example of a hydraulically operated
common rail diesel engine, also known as a modified common
rail. Vickers used common rail systems in submarine engines
circa 1916. Early engines had a pair of timing cams, one for
ahead running and one for astern. Later engines had two
injectors per cylinder, and the final series of constant-pressure
turbocharged engines were fitted with four injectors per
cylinder. This system was used for the injection of both diesel
oil and heavy fuel oil (600cSt heated to a temperature of
approximately 130 °C). The common rail system is suitable
for all types of road cars with diesel engines, ranging from city
cars such as the Fiat Nuova Panda to executive cars such as
the Audi A6.

7. Operating Principle
Solenoid or piezoelectric valves make possible fine electronic control over the fuel
injection time and quantity, and the higher pressure that the common rail technology
makes available provides better fuel atomisation. 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, thus reducing its explosiveness and vibration, as well as
optimizing injection timing and quantity for variations in fuel quality, cold starting
and so on.

8. Components of CRDI
1. PRE SUPPLY PUMP
The electric fuel pump comprises of:
• Electric Motor
• Roller-Cell Pump
• Non Return Valve
- electric
- roller
- gear
• Rail-pressure sensor (RDS).
• Injector
2. Pressure-control valve (DRV)
• Responsible for maintaining the pressure in the rail at a constant level.

9. 3. 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.
• High- pressure accumulator (Rail).
4. 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
• Rail-pressure-sensor(RDS)
• Inputs the information to the ECU.
• Measures the pressure in the rail.

10. Working of CRDI
• A high-pressure pump generates pressurised fuel. The pump
compresses the fuel at the pressures of about 1,000 bar or
about 15,000 psi. It, then, supplies the pressurised fuel via a
high-pressure pipe to the inlet of the fuel-rail.

11. From there, the fuel-rail distributes it to the individual injectors which
then inject it into the cylinder's combustion chamber.
Most modern CRDI engines use the Unit-Injector system with
Turbocharger which increases power output and meets stringent
emission norms. This improves engine power, throttle response, fuel
efficiency and controls emissions. Barring some design changes, the
basic principle & working of the CRDI technology remains
primarily the same across the board. However, its performance
depends mainly on the combustion chamber design, fuel pressures
and the type of injectors used.

12. Difference b/w Direct & Indirect
Injection
Direct Injection (DI)
1. Injection pressure is higher (21 kg/cm^2) in this case as compare to
IDI because fuel atomisation is solely depend upon pressure of
injection.

13. 2. This type of engines are easy to start in cold also.
3. Fuel injection nozzle have multiple holes as high atomisation and
mixing is required because swirling of air is less in this case.
4. Thermal efficiency is higher as compare to IDI engine.
Indirect Injection (IDI)
1. Injection pressure is low as compare to DI as most atomizing is
achieved using pressure of air from pre-combustion chamber.
2. Glow plug is required to start the engine in cold start.
3. Single orifice nozzle is used.
4. Heat losses are more due to large wall area so thermal efficiency get
reduced as compare to DI.
5. High compression ratio is possible in IDI as compared to DI.

14. Advantages & Disadvantages
Advantages
1. CRDI engines are advantageous in many ways. Cars fitted with this new engine
technology are believed to deliver 25% more power and torque than the normal
direct injection engine.
2. It also offers superior pick up, lower levels of noise and vibration, higher
mileage, lower emissions, lower fuel consumption, and improved performance.
3. In India, diesel is cheaper than petrol and this fact adds to the credibility of the
common rail direct injection system.
Disadvantages
Like all good things have a negative side, this engine also have few
disadvantages. The key disadvantage of the CRDI engine is that it is costly than
the conventional engine. The list also includes high degree of engine
maintenance and costly spare parts. Also this technology can’t be employed to
ordinary engines.

15. Applications
The most common applications of common rail engines are marine and
locomotive applications. Also, in the present day they are widely used in a
variety of car models ranging from city cars to premium executive cars.

16. Some of the Indian car manufacturers who have widely accepted the
use of common rail diesel engine in their respective car models are
the Hyundai Motors, Maruti Suzuki, Fiat, General Motors, Honda
Motors, and the Skoda. In the list of luxury car manufacturers, the
Mercedes-Benz and BMW have also adopted this advanced engine
technology. All the car manufacturers have given their own unique
names to the common CRDI engine system.
However, most of the car manufacturers have started using the new
engine concept and are appreciating the long term benefits of the
same. The technology that has revolutionized the diesel engine
market is now gaining prominence in the global car industry.

17. Acronyms used by different
manufacturers for CRDI
Acronym Company
CDI Mercedes Benz
CRDI Hyundai
CR4, DiCOR Tata
CRDE Mahindra
D BMW, Volvo
DDiS Suzuki
D-4D Toyota
DCi Renault, Nissan
DI-D Mitsubishi
i-CTDi, i-DTEC Honda
JTD Fiat
VCDi Chevrolet
TDCi Ford
TDI Volkswagen

18. REFERENCE
• www.google.com
• www.wikipedia.com
• www.seminarlinks.blogspot.com
• Textbook of Automobile Engineering

19. THANK YOU