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Compression-Ignition Engine Combustion
Published in Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong, Combustion Engineering, 2022
Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong
Because engine load is controlled by the amount of fuel injected, the injector must handle a volume of fuel that ranges over an order of magnitude. For a fixed amount of fuel injected per cycle and a fixed injection duration, ideally, the injection pressure must increase in proportion to the square of the engine speed. Alternately, a positive displacement fuel injection system can be used to meter the fuel. Modern diesel engines have adopted electronically controlled fuel injection systems, including the common rail system and the unit injector system. The common rail system separates the injector body from the fuel pressurization unit (i.e., a common fuel pump with a high-pressure fuel rail). The unit injector system combines the individual injector with the fuel pressurization unit. Both systems can achieve high fuel injection pressure (e.g., 1000–3000 atm) to overcome the high in-cylinder gas pressure and produce fine droplets. Traditionally, diesel fuel is injected once per engine cycle. Modern injection systems allow multiple injections in the same engine cycle with a very precise control on the quantity and timing of the individual fuel pulse. Injection flexibility facilitates improved performance, lower emissions, and better fuel tolerance. For example, it is possible to have a pilot injection where a small amount of fuel is injected prior to the injection of the rest of the fuel. The combustion resulting from the pilot injection is expected to set up favorable in-cylinder gas conditions for cleaner and more efficient combustion of the main injection. More than two fuel pulses in one engine cycle can be easily achieved in modern diesel engines.
Diesel fuel injection systems
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
Last but not least, a common rail system can deliver peak injection pressures in the region of 160MN/m2 (23 000 lbf/in2). These very high pressures, although not quite so high as may be attained with unit fuel injection, are now required for efficient atomization of the injected fuel oil, to achieve ultra low emissions and further improve fuel economy. A possible disadvantage of the common rail fuel injection system is that the fuel injectors have continually to seal against these very high pressures, whereas in other systems they are subject only to intermittent pressurization just prior to fuel injection.
Automotive Trends in Europe
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
Common rail engines are viewed as the future by most OEMs for diesel passenger cars and even for some truck diesel engines. Mercedes-Benz (Daimler Chrysler), Alfa Romeo, and PSA introduced common rail diesel engines in the mid-1990s and BMW introduced their first common rail engine, a V8, to power their luxury 5 and 7 series cars, in 1998. The notable exception was Volkswagen, but even they announced an Audi-developed 3.3L V8 common rail engine in 1999.
Experimental investigations on combustion and emission characteristic of GCI engine fuelled E20 blend
Published in Cogent Engineering, 2020
The experimental conditions for this study are summarized in Table 3. For the fully warmed-up engine conditions, the coolant temperature was maintained at 90°C. The intake air was naturally aspirated while the temperature was fixed at 165°C. The engine was filled with the gasoline-ethanol blend of 20% ethanol in vol (E20). The common-rail pressure was fixed at 400 bar. The timing of the first injection was fixed at −35 CAD ATDC. The mass proportion between the first and second injections was 30/70. The timing of the second injection, the EGR level, parameters of interest in the present study, were varied independently while other parameters were held constant.
Formation and development of cavitation in a transparent nozzle with double orifices on different planes
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Jinglong Ma, Hua Wen, Shuisheng Jiang, G. Jiang
The control system uses the Delphi Multec DCR1400 (Taian, China) high-pressure common-rail fuel injection system. A pressure sensor is installed on the common-rail pipe for feedback and pressure control. The fuel injection process is driven by a DB2000-75 oil pump test-bed (Taian, China), and the rotational speed is set to 250 rpm. All tests are conducted under a full load, as determined by the speed of the pump. Within this single system, the usage of different speeds implies that the flow velocity, injection pressure, and fuel injection advance angle differ. The higher the pump speed, the greater the injection pressure; when pressure is too high, the pulsation of the common-rail pipe increases, which leads to leaks and fractures. As a result, the pressure of the high-pressure common-rail pipe has a maximum of 160 MPa. The rotation angle of the signal plate and its signal collector can transmit rotational speed, TDCS (Top Dead Center Signal) and crankshaft angle signals to the ECU (Electronic Control Unit), which detects and controls the injection frequency and time. High-magnification cavitation images are obtained using a high-speed digital camera (VRI-VEO-710L, New Jersey, USA). The camera has a frame rate of 20000 frames per second and a pixel resolution of 20 × 480, with minimum exposure time of 1 µs. A long-distance microscope (QM-100, Questar, USA) obtains a proper experiment image. LEDs illuminate the cavitation development in the nozzle. For all measurements, back-lighting technology is adopted. For in-nozzle cavitation research, a transparent nozzle was manufactured from polymethyl methacrylate (PMMA) and bound to the body of the actual injector used for all experiments. The cavitation investigation of this paper uses a transparent nozzle to observe the effect of different injection conditions on cavitation. In order to complete this task, 0# diesel is used as the working fluid.
Effects of Adding Ethanol to Natural Gas-Air Mixture on Combustion and Emissions of Natural Gas-Diesel Dual Fuel Engine Based on GT-Power
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Mengyuan Zhang, Yunjing Jiao, Yuanli Xu, Xiaofan Xu, Baoxing Guo
A four-cylinder turbocharged diesel engine is modified to implement the NDDF or NG-ethanol-diesel ternary-fuel concept. The engine specifications are given in Table 1. NG and ethanol are supplied with air during the intake stroke to create NG-ethanol-air mixture in the cylinder. Diesel fuel is directly injected into the engine cylinder via a high-pressure common-rail system.