Common Rail Diesel
This is the most modern stage in the evolution of gasoline and diesel engines with direct fuel injection. It differs from traditional diesel engines with a low fuel supply pressure in the presence of a ramp, where diesel fuel is supplied under high pressure (more than 1000 bar), which is further distributed between electric nozzles with solenoid valves. The third generation of Common Rail systems is characterized by the use of piezoelectric injectors to increase injection accuracy, quantitatively increase the injection phases, as well as increase the pressure of the fuel supply to the ramp (up to 1800 bar). A variation for gasoline engines is called Direct Injection (FSI, GDI, etc.)
Common Rail History
The prototype of the Common Rail system was developed in the late 60s by Robert Huber in Switzerland. Further, his technology was developed by Marco Ganser of the Swiss Federal Institute of Technology in Zurich. In the mid-1990s, Dr. Shohei Ito and Masahiko Miyaki from DENSO Corporation, Japan, developed the Common Rail system for commercial vehicles and implemented it in the ECD-U2 system, which was used on HINO Rising Ranger trucks, and then sold the technology to others in 1995 to manufacturers. Therefore, DENSO is considered a pioneer in adapting the Common Rail system to the needs of the automotive industry. Modern Common Rail systems operate on the same principle. They are controlled by an Electronic Control Unit, which opens each injector electronically, not mechanically. This technology has been developed in detail by the combined efforts of Magneti Marelli, Centro Ricerche Fiat and Elasis. After FIAT developed the design and concept of the system, it was sold to the German company Robert Bosch GmbH for the subsequent completion of the development of the mass product. In general, this was a big miscalculation of FIAT, as the new technology has become very profitable. But the Italian concern at that time was in a deplorable financial condition and did not have the resources to complete the work. Nevertheless, Italians were the first to use the Common Rail system in 1997 on the Alfa Romeo 156 1.9 JTD and only then it appeared on the Mercedes-Benz C 220 CDI.
Engines Common rail used in shipbuilding and for locomotives. Cooper-Bessemer GN-8 system representative of the modified Common Rail system, where hydraulic control is used.
The principle of direct injection
English word COMMON RAIL denotes an equally high pressure in the accumulator tube (ramp), which is distributed across all cylinders. A submersible electric or vacuum pump delivers diesel fuel from the tank through the fuel heater and filter to the high pressure pump. It is driven by the engine and directs the fuel under high pressure into the ramp. For the normal operation of some types of systems, it is not necessary to constantly maintain the highest pressure. The ramp tubes are the same length and end with injectors. A pressure regulator is also located on the ramp, which sends the excess fuel back to the tank through the cooler. Using the pressure sensor in the ramp, the Engine Control Unit can receive information about the pressure in the ramp and monitor it.
The main sensors used in the system are the ramp pressure sensor, air flow sensor, camshaft and crankshaft sensors, temperature sensors of the engine and incoming air, accelerator pedal position sensor, heating system.
The solenoids in the Common rail system should respond within half a second: these are the injectors, the pressure regulator valve in the ramp, the turbocharger valve and the exhaust gas recirculation valve.
Injectors are turned on at the command of the controller – the EDC block by means of a magnetic solenoid. The hydraulic pressure force allows you to open and close the injector, however, activation occurs from the control unit. Some injectors have piezocrystals. Under the influence of a magnetic field, they increase in size. In a Piezo Inline type injector, the crystal is close to the needle and therefore does not use mechanical parts to turn on the needle. In early systems, double injection was used – pilot and primary to prevent detonation. In modern systems, up to six injection phases are used. Each injector is manufactured and tested in the laboratory, where a specific code is assigned to it according to the measured data of its operation. After replacing the injectors, the code must be registered in the memory of the control unit using a scanner.
Reasons for crowding out traditional diesel engines:
Better environmental emission data, less noise, cheaper component production.
Common rail today
Currently, each manufacturer has its own abbreviation, which stands for COMMON RAIL system:
– BMW: D-engines (also used by Land Rover Freelander as TD4)
– Cummins and Scania: XPI (Joint Development)
– Cummins: CCR (Cummins Pump with Bosch Injectors)
– Daimler: CDI (for Chrysler and Jeep – CRD)
– Fiat: Fiat, Alfa Romeo and Lancia – JTD (also called MultiJet, JTDm, Ecotec CDTi, TiD, TTiD, DDiS, Quadra-Jet)
– Ford Motor: TDCi Duratorq and Powerstroke
– General Motors: Opel / Vauxhall – CDTi (manufactured by Fiat and GM Daewoo) and DTi for Isuzu
– General Motors: Daewoo / Chevrolet – VCDi (licensed from VM Motori also has the Ecotec CDTi brand)
– Honda: i-CTDi
– Hyundai and Kia: CRDi
– Mahindra: CRDe
– Maruti Suzuki: DDiS (manufactured under license from Fiat)
– Mazda: CiTD
– Mitsubishi: DI-D (recently developed a new generation of 4N1 with pressure
– in the injection system up to 2000 bar)
– Nissan: dCi
– PSA Peugeot Citroen: HDI or HDi (Volvo S40 / V50 uses engines from PSA 1.6D & 2.0D, also uses the JTD brand)
– Renault: dCi
– SsangYong: XDi (engines are assembled under license from Daimler AG)
– Subaru Legacy: TD (since January 2008)
– Tata: DICOR
– Toyota: D-4D
– Volkswagen Group: Engine 4.2 V8 TDI and the latest 2.7 and 3.0 TDI (V6) replaced the old electronic diesel engines. The 2.0 TDI engine is used on the Volkswagen Tiguan and Audi A4. New 2.0 TDI will also be available soon for Passat and in 2009 for Jetta.
– Volvo: 2.4D and D5
– Skoda: TDI
Description of the common rail accumulator fuel system, intake, exhaust and toxicity systems of the WL-C engines of Mazda BT-50 & Ford Ranger
Without keyword Air intake system The air intake system is used to supply air to the engine cylinders. The system consists of an air intake, an air…
Without keyword This article is an attempt to consider the types of fuel injection on this engine.. But only. Special thanks Alexander Pavlovich Chuvilin…
Without keyword 2.1. Fuel system Toyota first used the Common Rail scheme on a 1CD-FTV engine. Unlike a conventional diesel system with a distribution…
Common Rail Injector
Without keyword “Battery-type fuel equipment began to be used on main marine diesels since 1910 and was most widely used in the 50s. The first industrial…