Effects of Plateau Environment on Combustion and Emission Characteristics of a Plateau High-Pressure Common-Rail Diesel Engine with Different Blending Ratios of Biodiesel

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B20 were higher and more uniform. When the altitude was 2000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B50 were higher and more uniform. Lastly, as the altitude increased, the maximum combustion temperature of D and B20 decreased, and combustion became more uneven. As the altitude increased, the maximum combustion temperature of B50 increased, and the combustion became more uniform. As the altitude increased, the fuel–air ratio and the mass fractions of OH and NO decreased. When the altitude increased, the soot concentration increased, and the distribution area was larger.

Study on the leakage of plunger pair under static condition in high-pressure common rail injector considering deformation effect

Plunger pair is the key component of high pressure common rail injector and its sealing performance is very important. Therefore, it is of great significance to study the leakage mechanism of plunger pair. Under static condition, the high-pressure fuel flow in the gap of the plunger pair caused the deformation of the plunger pair structure and the temperature rise of fuel. For a more comprehensive and accurate study, the effect of deformation, including elastic deformation and thermal expansion, the physical properties of fuel, including density, viscosity and specific heat capacity, as well as the influence of plunger posture in the plunger sleeve, including concentric, eccentric, and inclination condition, are considered in this paper. Firstly, the mathematical models including Reynolds equation, film thickness equation, non-isothermal flow equation, parametric equation of fuel physical property, and section velocity equation are established. The numerical analysis based on finite difference method for the solution of these models is given, which can simultaneously solve for the fuel film pressure distribution, temperature distribution, thickness distribution, distribution of fuel physical properties, and leakage rate. The models are validated by comparing the calculated leakage rates with the measurements. The effects under different posture of plunger are discussed too. Some of the conclusions provided good guidance for the design of high-pressure common rail injector.

Development of a Generic Dual Fuel ECU for Common Rail Diesel Engine Control

<p>Rising costs of diesel fuel has led to an increased interest in dual fuel diesel engine conversion, which can offset diesel consumption though the simultaneous combustion of a secondary gaseous fuel. This system offers benefits both environmentally and financially in an increasingly energy-conscious society. Dual fuel engine conversions have previously been fitted to mechanical injection systems, requiring physical modification of the fuel pump. The aim of this work is to develop a novel electronic dual fuel control system that may be installed on any modern diesel engine using common rail fuel injection with solenoid injector valves, eliminating the need for mechanical modification of the diesel fuel system. The dual fuel electronic control unit developed replaces up to 90 percent of the diesel fuel required with cleaner-burning and cheaper compressed natural gas, providing the same power output with lower greenhouse gas emissions than pure diesel. The dual fuel system developed controls the flow of diesel, gas, air, and engine timing to ensure combustion is optimised to maintain a specific torque at a given speed and demand. During controlled experimental analysis, the dual fuel system exceeded the target substitution rate of 90 precent, with a peak diesel substitution achieved of 97 percent, whilst maintaining the same torque performance of the engine under diesel operation.</p>

Development of a Generic Dual Fuel ECU for Common Rail Diesel Engine Control

<p>Rising costs of diesel fuel has led to an increased interest in dual fuel diesel engine conversion, which can offset diesel consumption though the simultaneous combustion of a secondary gaseous fuel. This system offers benefits both environmentally and financially in an increasingly energy-conscious society. Dual fuel engine conversions have previously been fitted to mechanical injection systems, requiring physical modification of the fuel pump. The aim of this work is to develop a novel electronic dual fuel control system that may be installed on any modern diesel engine using common rail fuel injection with solenoid injector valves, eliminating the need for mechanical modification of the diesel fuel system. The dual fuel electronic control unit developed replaces up to 90 percent of the diesel fuel required with cleaner-burning and cheaper compressed natural gas, providing the same power output with lower greenhouse gas emissions than pure diesel. The dual fuel system developed controls the flow of diesel, gas, air, and engine timing to ensure combustion is optimised to maintain a specific torque at a given speed and demand. During controlled experimental analysis, the dual fuel system exceeded the target substitution rate of 90 precent, with a peak diesel substitution achieved of 97 percent, whilst maintaining the same torque performance of the engine under diesel operation.</p>