Common rail

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Direct rail direct fuel injection is a direct fuel injection system for diesel engines.

In diesel engines, this machine has a high-pressure valve (more than 100 liters or 10 MPa or 1,500 psi) that gives individual solenoid valves, compared to the injector of a low-pressure fuel unit (or pump nozzle). The generation of third-generation diesels now has piezoelectric injectors for precision enhancement, with fuel pressures up to 2,500 bar (250 MPa; 36,000 psi).

In gasoline engines, these are used in direct gasoline engine injection technology (GDI).

Video Common rail

Histori

The public rail system prototype was developed in the late 1960s by Robert Huber from Switzerland and further developed technology by Dr. Marco Ganser at Swiss Federal Institute of Technology in Zurich, then from Ganser-Hydromag AG (est.1995) in OberÃÆ'¤ geri.

The first successful use in production vehicles began in Japan in the mid-1990s. Dr. Shohei Itoh and Masahiko Miyaki of Denso Corporation, a Japanese auto parts manufacturer, developed a common rail fuel system for heavy duty vehicles and turned them into practical use on the ECD-U2 common rail system mounted on a Hino Ranger truck and sold for general use in 1995 Denso claimed the first commercial high-pressure common rail system in 1995.

The modern common rail system, while working on the same principle, is controlled by the machine control unit (ECU) which opens each injector electrically rather than mechanically. It was a prototype extensively in the 1990s with a collaboration between Magneti Marelli, Centro Ricerche Fiat and Elasis. After research and development by Fiat Group, the design was acquired by German company Robert Bosch GmbH for completion of development and refinement for mass production. In hindsight, the sale appears to be a strategic error for Fiat, as new technology proves to be very profitable. The company had little choice but to sell the license to Bosch, because he was in a bad financial condition at the time and lacked the resources to complete his own development. In 1997 they expanded their use for passenger cars. The first passenger car that used the common rail system was the 1997 Alfa Romeo 156 2.4 JTD 1997 model, and later in the same year Mercedes-Benz introduced it in their W202 model.

General rail machines have been used in marine and locomotive applications for some time. Cooper-Bessemer GN-8 (circa 1942) is an example of a common rail operated hydraulic diesel engine, also known as a modified common rail.

Vickers pioneered the use of common rail injection in submarine engines. The Vickers engine with the common rail fuel system was first used in 1916 in class G submarines. It used four push pumps to provide pressure up to 3,000 pounds per square inch (210 bar, 21 MPa) every 90 degrees of rotation to keep fuel pressure quite constant on the rails. Delivery of fuel to individual cylinders can be turned off via a valve in the injector line. Doxford Engines used a common rail system on its opposite piston marathon machine from 1921 to 1980, where reciprocating multi-cylinder fuel pumps produced about 600 bar (60 MPa, 8,700 psi) pressures, with fuel stored in bottle accumulators. Pressure control is achieved by using adjustable pump discharge stroke and "spill valve". The camshaft-operated mechanical timing valves are used to supply the Brice/CAV/Lucas spring injector, which is injected through the cylinder side into the space formed between the pistons. The start engine has a pair of timings cams, one for running forward and another for astern. Then the engine has two injector per cylinder, and the last series of constant pressure turbocharged engine is equipped with four injectors per cylinder. This system is used for injection of diesel oil and heavy fuel oil (600cSt is heated to a temperature of about 130 ° C).

Maps Common rail

Apps

The common rail system is suitable for all types of road cars with diesel engines, ranging from city cars (such as Fiat Panda) to executive cars (like the Audi A8). The main suppliers of modern common rail systems are Robert Bosch GmbH, Delphi, Denso, and Siemens VDO (now owned by Continental AG).

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Acronyms and branding used

Automotive manufacturers refer to their common rail machines under their own brand name:

• Ashok Leyland: CRS (used on U Truck and E4 Bus)
• BMW Group (BMW and Mini): d (also used in Land Rover Freelander as TD4 and Rover 75 and MG ZT as CDT and CDTi), D and < b> SD
• Chevrolet (owned by GM): VCDi (licensed from VM Motori)
• Chrysler CRD
• CitroÃÆ' Â «n: HDi , e-HDi and BlueHDi
• Cummins and Scania: XPI (developed under the joint venture)
• Cummins: CCR (Cummins pump with Bosch injector)
• Daimler: CDI
• Fiat Group (Fiat, Alfa Romeo and Lancia): JTD (also labeled as MultiJet , JTDm , and by manufacturer provided as TDi , CDTi , TCDi , TiD , TTiD , DDiS and QuadraJet )
• Ford Motor Company: TDCi (Duratorq and Powerstroke)
• Honda: CTDI and i-DTEC
• Hyundai and Kia: CRDi
• IKCO: EFD
• Isuzu: iTEQ
• Jaguar d
• Jeep: CRD
• Komatsu: Level3 , Level4 , 4D95 and higher HPCR - series
• Land Rover: TD4 , eD4, SD4, TD6, TDV6, SDV6, TDV8, SDV8
• Mahindra: CRDe , m2DiCR , mEagle , mHawk , mFalcon and mPower (Truck)
• Maserati: Diesel
• Mazda: MZR-CD and Skyactiv-D (produced by Ford and PSA Peugeot Citroen joint venture) and formerly DiTD
• Mercedes-Benz: CDI and d
• Mitsubishi: DI-D (especially on the recently developed 4N1 machine family)
• Opel: CDTI
• Porsche: Diesel
• Proton: SCDi
• PSA (Peugeot, Citroën and DS): HDi , e-HDi or BlueHDi (developed in collaboration with Ford) - See the HDi PSA machine
• Renault, Dacia and Nissan: dCi (Infiniti uses some dCi machines as part of the Renault-Nissan Alliance, branded d )
• SsangYong: XDi , eXDI, XVT or D
• Subaru: TD or D (since Jan 2008)
• Suzuki: DDiS
• Tata: 2.2 VTT DiCOR (used in large SUV classes like Safari and Aria) and CR4
• Toyota: D-4D and D-CAT
• Volkswagen Group (Volkswagen, Audi, SEAT and? koda): TDI (newer models use common rail, compared to previous unit injector units). Bentley calls their Bentayga diesel just Diesel
• Volvo: D , D2 , D3 , D4 and D5 (some produced by Ford and PSA Peugeot Citroen), Volvo Penta D-series engine

src: www.scania.com

Principles

Solenoid or piezoelectric valves allow good electronic control over the timing and quantity of fuel injection, and the higher pressure provided common rail technology provides better fuel atomization. To lower engine noise, the machine's electronic control unit can inject a small amount of diesel just prior to the main injection event ("pilot" injection), thus reducing explosion and vibration, as well as optimizing the time and quantity of injection for variations in fuel quality. , cold start and so on. Some advanced rail fuel systems perform as many as five injections per stroke.

The public rails require a very short heating time to be absent, depending on the ambient temperature, and produce engine noise and emissions lower than the older system.

Diesel engines have historically used various forms of fuel injectors. Two common types include unit injection systems and distributor/inline pump systems. While these older systems provide accurate fuel quantity and injection time control, they are limited by several factors:

• They are cam-driven, and the injection pressure is proportional to engine speed. This usually means that the highest injection pressure can only be reached at the highest engine speed and the maximum injection pressure that can be achieved decreases as engine speed decreases. This relationship is true with all pumps, even those used on common rail systems. With a unit or distributor system, injection pressure is attached to the instantaneous pressure of a single pumping event without the accumulator, and thus the relationship is more prominent and troublesome.
• They are limited in number and timing of injection events that can be ordered during a single combustion event. Although some injection events are possible with this older system, it is much more difficult and expensive to achieve.
• For a typical inline distributor/inline system, the initial injection occurs at a predetermined pressure (often referred to as: pop pressure) and ends at a predetermined pressure. This characteristic results from the "dumb" injector in the cylinder head that opens and closes at the pressure determined by the spring preload applied to the plunger in the injector. Once the pressure at the injector reaches a predetermined level, the lift and the lifting injection begin.

In common rail systems, high pressure pumps store fuel reservoirs at high pressure - up to above 2,000 bar (200 MPa; 29,000 psi). The term "common rail" refers to the fact that all fuel injectors are supplied by a common fuel rail that is no more than a pressure accumulator in which the fuel is stored at high pressure. This accumulator supplies several fuel injectors with high pressure fuel. This simplifies the purpose of a high-pressure pump because it only needs to maintain target pressure (mechanically or electronically controlled). Fuel injectors are usually controlled by the ECU. When the fuel injector is electrically activated, the hydraulic valve (consisting of nozzle and plunger) is mechanically or hydraulically opened and the fuel is sprayed onto the cylinder at the desired pressure. Because the fuel pressure energy is stored remotely and the injector is electrically driven, the injection pressure at the start and end of the injection is very close to the pressure in the accumulator (rail), resulting in a square injection rate. If accumulators, pumps and pipes are sized correctly, the pressure and rate of injection will be the same for each of the several injection events.

src: www.dieselcenter.com.au

See also

• Hydraulically enabled Hydraulic Unit Injection (HEUI)
• Direct Turbocharged Injection
• The unit pump
• Water sensor

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References

src: cdn.shopify.com

External links

• Brief Summary of CRDI Engine work
• Animation explains common rail functions

Source of the article : Wikipedia