Common rail direct fuel injection system is a really modern variant of direct fuel injection for petrol and diesel engines.
On diesel engines, it possesses a high-pressure (over 1,000 bar/15,000 psi) fuel rail feeding individual solenoid valves, dissimilar to low-pressure fuel pump feeding unit injectors . Third-generation common rail diesels now feature piezoelectric injectors for increased precision, with fuel pressures as long as 1,800 bar/26,000 psi.
In gasoline engines, it is usually used in gasoline direct injection engine technology.
The more common rail system prototype was developed along at the late 1960s by Robert Huber of Switzerland and also the technology further developed by Dr. Marco Ganser in conjunction with the Swiss Federal Institute of Technology in Zurich.
The very first successful usage in production vehicle began in Japan by way of the mid-1990s. Dr. Shohei Itoh and Masahiko Miyaki associated with the Denso Corporation, a Japanese automotive parts manufacturer, developed the most popular rail fuel system for heavy duty vehicles and turned it into practical use on their ECD-U2 common-rail system that come with the Hino Rising Ranger truck and sold for general use in 1995. Denso claims the first commercial high pressure common rail system in 1995.
Modern common rail systems, whilst anterior to the same principle, are governed by an electric train engine control unit (ECU) which opens each injector electronically in lieu of mechanically. I thought this was extensively prototyped inside of the 1990s with collaboration between Magneti Marelli, Centro Ricerche Fiat and Elasis. After development and research next to the Fiat Group, the design was acquired due to the fact German company Robert Bosch GmbH for completion of development and refinement for mass-production. In hindsight the sale seemed to be a tactical error for Fiat mainly because the new technology turned out to be highly profitable. The business enterprise had little choice but to dispose of, however, given that it what food was in a poor financial state when and lacked the resources to try and do development on its own. In 1997 they extended its use for passenger cars. The most important passenger car that used the common rail system was the 1997 model Alfa Romeo 156 2.4 JTD, and later on during that year Mercedes-Benz C 220 CDI.
Common rail engines occur to be used in marine and locomotive applications for a time. The Cooper-Bessemer GN-8 (circa 1942) is surely an example of a hydraulically operated common rail diesel engine, also referred to as a modified common rail.
Vickers used common rail systems in submarine engines circa 1916. Doxford Engines Ltd. (opposed piston heavy marine engines) made use of a common rail system (from 1921 to 1980) whereby a multi-cylinder reciprocating fuel pump generated a pressure of approximately 600bar when using the fuel being stored in accumulator bottles. Pressure control was achieved as a result of an adjustable pump discharge stroke and also a “spill valve”. Camshaft operated mechanical timing valves were used to supply the spring-loaded Brice/CAV/Lucas injectors which injected through to the area of the cylinder back into the chamber formed between the pistons. Early engines had a set of two timing cams, one for ahead running andf the other for astern. Later engines had two injectors per cylinder and therefore 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 as opposed to a temperature of approximately 130C).
The most popular rail set up is suitable for a lot of various kinds of road cars with diesel engines, which ranges from city cars like Fiat Nuova Panda to executive cars like the Audi A6.
Today the most popular rail system has brought in terms of a revolution in diesel engine technology. Robert Bosch GmbH, Delphi Automotive Systems, Denso Corporation, and Siemens VDO (now owned by Continental AG) is going to be main suppliers of modern common rail systems. The motor car makers make reference to their common rail engines by their own individual brand names:
BMW’s D-engines (also used active in the Land Rover Freelander TD4)
Cummins and Scania’s XPI (Developed under joint venture)
Cummins CCR (Cummins pump with Bosch Injectors)
Daimler’s CDI (and on Chrysler’s Jeep vehicles simply as CRD)
Fiat Group’s (Fiat, Alfa Romeo and Lancia) JTD (also branded as MultiJet, JTDm, Ecotec CDTi, TiD, TTiD, DDiS, Quadra-Jet)
Ford Motor Company’s TDCi Duratorq and Powerstroke
General Motors Opel CDTI and earlier DTI
General Motors Chevrolet VCDi (licensed from VM Motori; also branded as Ecotec CDTI)
Honda’s i-CTDi
Hyundai-Kia’s CRDi
IKCO’s EFD which is one of several members of the EF family. Supplier TBD
Isuzu’s iTEQ
Komatsu’s Tier3, Tier4, 4D95 and higher – HPCR series Diesel engines.
Mahindra’s CRDe
Mazda’s MZR-CD (1.4 MZ-CD, 1.6 MZ-CD manufactured by three way partnership Ford/PSA Peugeot Citroen) and earlier DiTD
Mitsubishi’s DI-D (recently developed 4N1 engine family uses next generation 200 MPa (2000 bar) injection system))
Nissan’s dCi, Infiniti uses dCi engines, but not branded as dCi.
Proton’s SCDi
PSA Peugeot Citroen’s HDI or HDi (1.4HDI, 1.6 HDI, 2.0 HDI, 2.2 HDI and V6 HDI developed under three way partnership with Ford)
Renault’s dCi and earlier dTi
SsangYong’s XDi (some of these engines are built by Daimler AG)
Subaru’s Legacy TD (as of Jan 2008)
Tata’s DICOR & CR4
Toyota’s D-4D
Volkswagen Group: The 6.0 V12 TDI, 4.2 TDI (V8), 2.7 and 3.0 TDI (V6), 1.6, 2.0 TDI (L4) and 1.2 TDI (L3) engines featured on current Seat, Skoda, VW and Audi models use common rail, instead of the earlier unit injector engines.
Volvo 2.4D and D5 engines (1.6D, 2.0D manufactured by Ford and PSA Peugeot Citroen), Volvo Penta D-series engines
Wartsila-Sulzer 14RT-flex96-C “largest reciprocating engine inside of the world” designed because of the Finnish manufacturer Wartsila
Solenoid or piezoelectric valves make possible fine electronic control over the fuel injection system serious amounts of quantity as well as the higher pressure that the common rail technology makes available provides better fuel atomisation. For you to lower engine noise, the engine’s electronic control unit can inject a small amount of diesel prior to when area of the injection event (“pilot” injection), thus reducing its explosiveness and vibration, and how optimising injection timing and quantity for variations in fuel quality, cold starting and similar matters. Some advanced common rail fuel systems perform as much as five injections per stroke.
Common rail engines require very short (< 1 s) or no heating up time in any respect and produce lower engine noise and emissions than older systems. Diesel engines have historically used various different types of fuel injection system. Two common types include the gps device injection system and therefore the distributor/inline pump systems (See diesel engine and unit injector for much more information). While these older systems provided accurate fuel quantity and injection timing control, we were holding limited by a number of factors: We were looking at cam driven and injection pressure was proportional to engine speed. This typically meant that the new highest injection pressure could only be achieved at all the highest engine speed as well as maximum achievable injection pressure decreased as engine speed decreased. This relationship is true with all pumps, even those used on common rail systems; along with the unit or distributor systems, however, the injection pressure is stuck just using the instantaneous pressure of a single pumping event with no accumulator as well as the relationship is a lot more prominent and troublesome. These people were limited involved in the number and timing of injection events that may be commanded by carrying out a single combustion event. While multiple injection events are possible these kind of older systems, without a doubt a lot more difficult and costly to achieve. For all the typical distributor/inline system, the start of injection occurred in a very pre-determined pressure (also known as as: pop pressure) and ended at about a pre-determined pressure. This characteristic resulted from "dummy" injectors active in the cylinder head which closed and opened at pressures determined by way of spring preload applied to the plunger in to the injector. As soon as the pressure in a very injector reached a pre-determined level, the plunger would lift and injection would start. In common rail systems, a high pressure pump stores a reservoir of fuel at high pressure - up to and above 2,000 bars (29,000 psi). The concept of a "common rail" means indisputable fact that every single fuel injectors are made available from a common fuel rail which can be just a pressure accumulator the spot that the fuel is stored at high pressure. This accumulator supplies multiple fuel injectors with high pressure fuel. This simplifies the goal of the high pressure pump in that hot weather only has something to maintain a commanded pressure any kind of target (either mechanically or electronically controlled). The fuel injectors can even be ECU-controlled. When the fuel injectors are electrically activated, a hydraulic valve (consisting of a nozzle and plunger) is mechanically or hydraulically opened and fuel is sprayed back into the cylinders at the desired pressure. Ever since the fuel pressure energy is stored remotely along with the injectors are electrically actuated, the injection pressure at the start and end of injection can be quite close to the pressure while in the accumulator (rail), thus producing a square injection rate. In most cases accumulator, pump and plumbing are sized properly, the injection pressure and rate is the same for every one of the multiple injection events.