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Thursday, September 30, 2010

CRDI engines

What is CRDI engines??

common rail direct injection (CRDI) , which is a fairly recent design for diesel engines that may also be suitable for passenger automobiles. Though originally intended for commercial use, this design is now in wide use around the globe.


WHY IS IT USED?? IS IT BETTER THAN PREVIOUS ENGINES??


This  method is chosen by more and more manufacturers and by individual users because it is fuel efficient as other diesel technologies were. However, CRDI has also provided a tremendous boost in diesel-engine performance. The improvement is mainly due to the common-rail design, which has tubes that connect all the injectors. These injectors are based on the direct-injection concept, as was the case in the past. But the common-rail design was quite a step forward.

 PRINCIPLE..

Fuel in the common tube or “rail” is under a set amount of pressure which causes the fuel to be “atomized” or broken down to its smallest particles. This allows the fuel to combine with the air much more efficiently. With proper direct injection, fuel use is highly efficient, with much less waste fuel escaping the system unused.



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.   The first passenger car that used the common rail system was the 1997 model Alfa Romeo 156 1.9 JTD and later on that same year Mercedes-Benz E 320 CDI.
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.
The engines are suitable for all types of road cars with diesel engines, ranging from city cars  to large family cars .
Common rail direct fuel injection is a modern variant of direct injection system for diesel engines. It features a high-pressure (1000+ bar) fuel rail feeding individual solenoid valves, as opposed to low-pressure fuel pump feeding Unit Injectors ( pump nozzles) or high-pressure fuel line to mechanical valves controlled by cams on the camshaft. Third generation common rail diesels now feature piezoelectric injectors for even greater accuracy, with fuel pressures up to 180 MPa / 1800 bar, although a new version of Delphis proven diesel common rail system will allow compliance with Euro 6 and US Tier 2 Bin 5 without costly next-generation injection technologies.
Solenoid or piezoelectric 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 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 ("pilot" injection), thus reducing its explosiveness and vibration, as well as optimising injection timing and quantity for variations in fuel quality, cold starting, and so on. Some advanced common rail fuel systems perform as many as five injections per stroke.
Common rail engines require no heating up time, and produce lower engine noise and lower emissions than older systems.
In older diesel engines, a distributor-type injection pump, regulated by the engine, supplies bursts of fuel to injectors which are simply nozzles through which the diesel is sprayed into the engine's combustion chamber. As the fuel is at low pressure and there cannot be precise control of fuel delivery, the spray is relatively coarse and the combustion process is relatively crude and inefficient.
In common rail systems, the distributor injection pump is eliminated. Instead an extremely high pressure pump stores a reservoir of fuel at high pressure up to 2,000 bar (200 MPa) in a "common rail", basically a tube which in turn branches off to computer-controlled injector valves, each of which contains a precision-machined nozzle and a plunger driven by a solenoid. Driven by a computer (which also controls the amount of fuel to the pump), the valves, rather than pump timing, control the precise moment when the fuel injection into the cylinder occurs and also allow the pressure at which the fuel is injected into the cylinders to be increased. As a result, the fuel that is injected atomises easily and burns cleanly, reducing exhaust emissions and increasing efficiency.




TERMS::

A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid coil. 



A CAM is a small oval rotating or sliding piece which is used to open or close valves in a cylinder of an engine.The timing of the valve depends on the speed of rotation and the length of the TIP. The shaft to which these CAM is attached for rotation is called a CAMSHAFT.
The functioning of a simple Cam is shown below.

 Piezoelectricity is the charge which accumulates in certain solid materials in  response to applied mechanical strain


The Delphi Unit Pump Diesel Common Rail (UPCR) System is an innovative engine management concept that leverages advanced common rail technology — a proven "green" strategy — for very small diesel engine programs.  The system offers manufacturers a cost-effective, robust solution to help them achieve optimal fuel efficiency and meet stringent emissions standards, such as Euro 4.
Key features of the Delphi Diesel UPCR System include fast solenoid diesel injectors and a common rail, a program-tailored engine control module (ECM), robust unit fuel pump with an inlet metering valve, as well as an efficient, low cost fuel filter.





Wednesday, August 25, 2010

DIESEL ENGINES



DIESEL ENGINES ::

INTRODUCTION:
 
 Diesel's story actually begins with the invention of the gasoline engine. Nikolaus August Otto had invented and patented the gasoline engine by 1876. This invention used the four-stroke combustion principle, also known as the "Otto Cycle," and it's the basic premise for most car engines today. In its early stage, the gasoline engine wasn't very efficient, and other major methods of transportation such as the steam engine fared poorly as well. Only about 10 percent of the fuel used in these types of engines actually moved a vehicle. The rest of the fuel simply produced useless heat.

I­n 1878, Rudolf Diesel was attending the Polytechnic High School of Germany (the equivalent of an engineering college) when he learned about the low efficiency of gasoline and steam engines. This disturbing information inspired him to create an engine with a higher efficiency, and he devoted much of his time to developing a "Combustion Power Engine." By 1892 Diesel had obtained a patent for what we now call the diesel engine.

HOW DIESEL ENGINE WORKS:

 The article How Diesel Engines Work describes the four-stroke diesel engines commonly found in cars and trucks. The article How Two-stroke Engines Work describes the small two-stroke engines found in things like chain saws, mopeds and jet skis. It turns out that diesel engine technology is often combined with a two-stroke cycle in the huge diesel engines found in locomotives, large ships and generating facilities.  

Understanding the Cycle
­ I­f you read How Two-stroke Engines Work, you learned that one big difference between two-stroke and four-stroke engines is the amount of power the engine can produce. The spark plug fires twice as often in a two-stroke engine -- once per every revolution of the crankshaft, versus once for every two revolutions in a four-stroke engine. This means that a two-stroke engine has the potential to produce twice as much power as a four-stroke engine of the same size.
The two-stroke engine article also explains that the gasoline engine cycle, where gas and air are mixed and compressed together, is not really a perfect match for the two-stroke approach. The problem is that some unburned fuel leaks out each time the cylinder is recharged with the air-fuel mixture. (See How Two-stroke Engines Work for details.)
It turns out that the diesel approach, which compresses only air and then injects the fuel directly into the compressed air, is a much better match with the two-stroke cycle. Many manufacturers of large diesel engines therefore use this approach to create high-power engines.
The figure below shows the layout of a typical two-stroke diesel engine:

At the top of the cylinder are typically two or four exhaust valves that all open at the same time. There is also the diesel fuel injector (shown above in yellow). The piston is elongated, as in a gasoline two-stroke engine, so that it can act as the intake valve. At the bottom of the piston's travel, the piston uncovers the ports for air intake. The intake air is pressurized by a turbocharger or a supercharger (light blue). The crankcase is sealed and contains oil as in a four-stroke engine.
The two-stroke diesel cycle goes like this:
When the piston is at the top of its travel, the cylinder contains a charge of highly compressed air. Diesel fuel is sprayed into the cylinder by the injector and immediately ignites because of the heat and pressure inside the cylinder. This is the same process described in How Diesel Engines Work.
The pressure created by the combustion of the fuel drives the piston downward. This is the power stroke.
As the piston nears the bottom of its stroke, all of the exhaust valves open. Exhaust gases rush out of the cylinder, relieving the pressure.
As the piston bottoms out, it uncovers the air intake ports. Pressurized air fills the cylinder, forcing out the remainder of the exhaust gases.
The exhaust valves close and the piston starts traveling back upward, re-covering the intake ports and compressing the fresh charge of air. This is the compression stroke.
As the piston nears the top of the cylinder, the cycle repeats with step 1.
­
­From this description, you can see the big difference between a diesel two-stroke engine and a gasoline two-stroke engine: In the diesel version, only air fills the cylinder, rather than gas and air mixed together. This means that a diesel two-stroke engine suffers from none of the environmental problems that plague a gasoline two-stroke engine. On the other hand, a diesel two-stroke engine must have a turbocharger or a supercharger, and this means that you will never find a diesel two-stroke on a chain saw -- it would simply be too expensive.




WORLDS TOP TEN FASTEST CARS


1. Bugatti Veyron: 267 mph, 0-60 in 2.5 secs. Aluminum, Narrow Angle W16 Engine with 1001 hp, base price is $1,700,000. Tested again on July 10, 2010, the Bugatti Veyron once again claimed its title as the fastest car in the world at 267 mph.

Manufacturer Bugatti Automobiles
Production 2005–present
Assembly Molsheim, Alsace, France
Predecessor Bugatti EB110
Body style(s) 2-door coupé
2-door roadster
Layout Longitudinal mid-engine,
permanent four-wheel drive
Engine(s) Standard:
8.0 L W16 quad-turbocharged 1,001 brake horsepower (746 kW; 1,015 PS)[1]
Super Sport:
1,184 brake horsepower (883 kW; 1,200 PS)[2]
Transmission(s) 7-speed DSG sequential
Wheelbase 2,710 mm (106.7 in)
Length 4,462 mm (175.7 in)
Width 1,998 mm (78.7 in)
Height 1,159 mm (45.6 in)
Kerb weight 1,888 kg (4,162 lb)
Designer Jozef Kaban[3]

2. SSC Ultimate Aero: 257 mph, 0-60 in 2.7 secs. Twin-Turbo V8 Engine with 1183 hp, base price is $654,400. Tested in March 2007 by Guinness World Records, The SSC Ultimate Aero was the fastest car in the world from March 2007 to July 2010 until recently it fell behind the Bugatti Veyron to take the #2 spot.
Manufacturer Shelby SuperCars
Production 2006–present
Assembly USA
Body style(s) 2-seat Berlinetta
Layout Rear mid-engine, rear-wheel drive
Engine(s) 6.35L V8
Length 4,470 millimetres (176 in)
Width 2,080 millimetres (82 in)
Height 1,090 millimetres (43 in)
Curb weight 1,292 kilograms (2,850 lb)
3. Saleen S7 Twin-Turbo: 248 mph, 0-60 in 3.2 secs. Twin Turbo All Aluminum V8 Engine with 750 hp, base price is $555,000. Smooth and bad-ass, will make you want to show it off non-stop.

Manufacturer Saleen
cost = £260,960
Production 2000–2004[1]
Assembly Irvine, California, United States
Successor Saleen S7 Twin Turbo
Class Sports car
Body style(s) 2-door coupé
Layout Rear mid-engine, rear-wheel drive[1]
Engine(s) 7.0 L naturally-aspirated V8
Transmission(s) 6-speed manual[2]
Wheelbase 106 in (2692 mm)
Length 188 in (4775 mm)
Width 78 in (1981 mm)
Height 41 in (1041 mm)
Curb weight 2,750 lb (1,247 kg)
Related Saleen S281
Designer Steve Saleen,
Phil Frank[3]
4. Koenigsegg CCX: 245 mph, 0-60 in 3.2 secs. 90 Degree V8 Engine 806 hp, base price is $545,568. Made in Sweden, it is aiming hard to be the fastest car in the world, but it has a long way to go to surpass the Bugatti and the Ultimate Aero.

Manufacturer Koenigsegg
Production 2006–present
Predecessor Koenigsegg CCR
Successor Koenigsegg CCXR
Class Sports car
Body style(s) 2-door roadster
Layout Rear mid-engine, rear-wheel drive
Engine(s) 4.7 L twin-supercharged V8[1]
Transmission(s) 6-speed manual
Wheelbase 2,660 mm (104.7 in)
Length 4,293 mm (169.0 in)[1]
Width 1,996 mm (78.6 in)[1]
Height 1,120 mm (44.1 in)[1]
Curb weight 1,180 kg (2,601 lb)[1]
Designer Sven-Harry Åkesson
5. McLaren F1: 240 mph, 0-60 in 3.2 secs. BMW S70/2 60 Degree V12 Engine with 627 hp, base price is $970,000. Check out the doors, they looks like bat wings, maybe Batman need to order one and paints it black 


Manufacturer McLaren Automotive
Production 1993–1998
(100 produced)
Assembly Woking, Surrey, England
Successor McLaren MP4-12C
Class Sports car
Body style(s) 2-door 3-seat coupé
Layout RMR layout
Engine(s) 60° 6.1 L BMW S70/2 V12
Transmission(s) 6-speed manual
Wheelbase 2,718 mm (107.0 in)
Length 4,287 mm (168.8 in)
Width 1,820 mm (71.7 in)
Height 1,140 mm (44.9 in)
Curb weight 1,140 kg (2,513 lb)
Designer Gordon Murray & Peter Stevens
6. Ferrari Enzo: 217 mph, 0-60 in 3.4 secs. F140 Aluminum V12 Engine with 660 hp, base price is $670,000. Only 399 ever produced, the price goes up every time someone crashes.


Manufacturer Ferrari
Production 2002–2004
400 produced
Predecessor Ferrari F50
Successor Ferrari F70
Class Sports car
Body style(s) 2-seat Berlinetta
Layout RMR layout
Engine(s) 6.0 L V12
Transmission(s) 6-speed semi-automatic
Wheelbase 2,650 mm (104 in)
Length 4,702 mm (185.1 in)
Width 2,035 mm (80.1 in)
Height 1,147 mm (45.2 in)
Curb weight 1,365 kg (3,010 lb)
Related Ferrari FXX
Designer Pininfarina
7. Jaguar XJ220: 217 mph, 0-60 in 3.8 secs. Twin Turbo V6 Engine with 542 hp, base price was $650,000. Made in 1992, this car still got what it takes to make the list.

Manufacturer Jaguar Cars
Production 1992–1994
(281 produced)
Predecessor Jaguar XJR-15
Class Sports car, supercar
Body style(s) 2-door coupé
Layout RMR layout
Engine(s) 3.5 L twin-turbocharged V6 [1]
Transmission(s) 5-speed manual[1]
Wheelbase 2,642 mm (104.0 in)[1]
Length 4,930 mm (194.1 in)[1]
Width 2,007 mm (79.0 in)[1]
Height 1,151 mm (45.3 in)[1]
Kerb weight 1,372 kg (3,024.7 lb)[1]
8. Pagani Zonda F: 215 mph, 0-60 in 3.5 secs. Mercedes Benz M180 V12 Engine with 650 hp, base price is $667,321. With a V12 motor, this baby can do much better.

Manufacturer Pagani
Production 1999–present
112 produced[citation needed]
Class Sports car, Supercar
Body style(s) Carbon Fibre Monocoque with Aluminum Sub-Frames, Carbon Fibre Roll Bar
Layout Rear mid-engine, rear-wheel drive layout
Engine(s) Mercedes Benz M180 V12 w/Pagani Intake, Exhaust, Management Systems
Top Speed 345.94 kph / 215 mph
Transmission(s) 6-Speed Manual w/Twin Plate Clutch
Wheelbase 2730 mm / 107.5 in
Length 4435 mm / 174.6 in
Width 2055 mm / 80.9 in
Height 1141 mm / 44.9 in
Curb weight 1274 kg / 2809 lbs

9. Lamborghini Murcielago LP640: 211 mph, 0-60 in 3.3 secs. V12 Engine with 640 hp, base price is $430,000. Nice piece of art, the design is very round and smooth.

Manufacturer Lamborghini
Production 2001-present
4,000+ built[1]
Assembly Sant'Agata Bolognese, Italy
Predecessor Lamborghini Diablo
Successor Lamborghini Jota (expected in 2012)
Class Sports car
Body style(s) 2-door coupé or 2-door roadster
Layout Mid-engine, four-wheel drive
Engine(s) 6.2 L V12 580 PS (427 kW; 572 bhp)
6.5 L V12 640 PS (471 kW; 631 bhp)
Transmission(s) 6-speed manual
6-speed E-gear semi-automatic
Wheelbase 104.9 in (2,664.5 mm)
Length 2002-06: 180.3 in (4,579.6 mm)
2007-present: 181.5 in (4,610.1 mm)
Width 2002-06: 80.5 in (2,044.7 mm)
2007-present: 81.0 in (2,057.4 mm)
Height 44.7 in (1,135.4 mm)
2007-present Roadster: 44.6 in (1,132.8 mm)
Curb weight 1,650 kg (3,638 lb)
Related Lamborghini Reventón
Designer Luc Donckerwolke
10. Porsche Carrera GT: 205 mph, 0-60 in 3.9 secs. Aluminum, 68 Degree, Water Cooled V10 Engine with 612 hp, base price is $440,000. The most powerful and most expensive Porsche  nearly made the list as #10.

Manufacturer Porsche
Production 2004–2006
(1,270 produced)
Assembly Leipzig, Germany
Predecessor Porsche 911 GT1
Successor Porsche GT1
Class Sports car
Body style(s) 2-door roadster
Layout Mid-engine, rear wheel drive[1]
Engine(s) 5.7 litre DOHC V10[1][2]
Transmission(s) 6-speed manual[2]
Length 4,623 mm (182.0 in)[1]
Width 1,930 mm (76 in)[1]
Height 1,168 mm (46.0 in)[1]
Curb weight 1,380 kg (3,000 lb)[1]
Related Porsche 918 Spyder