Abstract. The paper aims at the development of fuel supply and electronic control systems for boosted high-and middle-speed transport engines. A detailed analysis of different ways of converting diesel engine to operate on natural gas was carried out. The gas diesel process with minimized ignition portion of diesel fuel injected by the CommonRail (CR) system was selected. Electronic engine control and modular gas feed systems which can be used both on high-and middle-speed gas diesel engines were developed. Also diesel CR fuel supply systems were developed in cooperation with the industrial partner, namely, those that can be mounted on middle-speed diesel and gas diesel engines. Electronic control and gas feed systems were perfected using modeling and engine tests. The high-speed diesel engine was converted into a gas diesel one. After perfection of the gas feed and electronic control systems, bench tests of the high-speed gas diesel engine were carried out showing a high share of diesel fuel substitution with gas, high fuel efficiency and significant decrease of NO х and СО 2 emissions.

The work was aimed at the development of gas supply, diesel fuel supply and electronic control systems for automobile gas diesel engines. Different ways of diesel engine conversion to operate on natural gas were analyzed. Gas diesel process with minimized ignition portion of diesel fuel injected by the CR system was selected. Electronic engine control and modular gas feed systems which can be used on high- and middle-speed gas diesel engines were developed. Diesel CR fuel supply system was developed in cooperation with the industrial partner. Simulation was used to obtain basic parameters and control methods of these systems. The base diesel engine was converted into gas diesel engine using the systems developed. Bench tests of the gas diesel engine demonstrated a high share of diesel fuel substitution with gas, high fuel efficiency and large decrease of NOх and СО2 emissions.

A method of fuel injection rate shaping of the Diesel engine common rail fuel system with common rail injectors and solenoid control is proposed. The method envisages the impact on control current of impulses applied to the control solenoid valve of the common rail injectors for variation of the injection rate shape. At that, the fuel is supplied via two groups of injection holes. The entering edges of the first group with the coefficient of flow, μ сB , were located in the sack volume and the entering edges of the second group (coefficient of flow, μ сH)on the locking taper surface of the nozzle body. The coefficients of flow, μ сB , and μ сH differ considerably and depend on the valve needle position. This enables to adjust the injection quantity by injection holes taking into account operating conditions of the Diesel engine and henceby the combustion chamber zones. Using the constant fuel flow setup , characteristic of the effective cross-section of the common rail fuel system injector holes was investigated. The diameter of injector holes was 0.12 … 0.135 mm. The excessive pressure at the entering edges varied from 30 to 150 MPa and more and the excessive pressure in the volume behind the output edgefrom 0 to 16 MPa.

Conversion of locomotive engines for operation on natural gas lowers considerably expenses for fuel and reduces exhaust emissions which makes it possible to omit large and expensive aftertreatment systems. The permanent need to raise the engine power requires a considerable increase of the boost pressure. This can be realized by using a high pressure turbocharger or a two-stage charging system. In the research, parameters of a high boosted D200 6-cylinder locomotive engine having D/S=200/280 mm are forecasted using a one-zone model developed in MADI. An analysis was carried out to explain why the 1st stage compressor of the two-stage charging system should be specially profiled to have its map tilted to the right. Calculations were performed for the gas diesel engine having a break mean effective pressure (BMEP) 2.7 MPa with one and two-stage charging systems. In both cases, close fuel efficiency was obtained, though for the two-stage charging system, the boost air pressure was higher. The engine with one turbocharger had no reserves for further power augmentation while the two-stage charging system enabled to increase the boost air pressure further. Therefore, parameters of the engine having a higher BMEP 3.2 MPa were calculated. In that case, not to exceed the peak combustion pressure, a retarded fuel injection was used which resulted in fuel efficiency drop by approximately 1.5%.

Fuel injection causes considerable oscillations of fuel pressure at the injector inlet. One of the reasons is hydraulic impact when the needle valve closes. For multiple injections, the previous injections affect the following. As both the fuel pressure in rail pac and the injection rate grow, the oscillations increase. The pressure oscillation range at the common rail injector inlet at pac=1500 bar is up to 350 bar, and at the rail pressure pac=500 bar, the amplitude decreases to 80 bar. Physical properties of the fuel are also important. As the viscosity of the fuel increases, its hydraulic friction grows which results in a rapid damping of pressure oscillations. The data for an injector operating on sunflower oil is presented. As compared with diesel fuel, the oscillations range decreases from 400 to 250 bar at the same operating mode. The influence of the interval between the impulses of a double injection on the injection rate of the second fuel portion was investigated. Superposition of two waves during multiple injections may result in amplification and damping of the oscillations. Simulation was performed to estimate the influence of fuel type and time interval Δτ between control impulses of a double injection on the injection quantity of the second portion at pressures of 2000-3000 bar. When the rail pressure pac grows, the oscillations and their impact on the injection process increase. For diesel fuel at pressure of pac=2000 bar, the variation in injection rates of the second portion is 2.36-4.62 mg, and at pac=3000 bar – 1.58-6.63 mg.