The advancement of modern injection systems of diesel engines is related to a constant increase in the injection pressures generated by injection pumps. This translates into an improvement of the engine operation indexes, including the emission-related ones. Such an approach brings a series of problems related to the design, construction and durability of the injection system. Therefore, the authors asked whether the current market trend in injection systems is the only appropriate path to be taken. When searching for the answer, the authors decided to propose an innovative concept consisting of dissolving exhaust gas in diesel fuel with the use of an injection pump. Such a saturated solution, when flowing out of the injection nozzle, begins the process of releasing the gas dissolved in the fuel. This has a positive impact on the atomization process, hence the process of combustion. The aim of this paper stems from the previously performed research. Due to the nature of the phenomenon, it was necessary to propose a new design for the injection pump. For correct selection of the dimensions of the pumping section, it was of key importance to determine the coefficient of solubility and the bulk modulus of the solution of diesel fuel and exhaust gas. Aside from the description of the applied method and the results of the direct measurements, this paper presents the yet undescribed results of the measurements of the coefficient of solubility of different concentrations of exhaust gas in diesel fuel. The authors also investigated the influence of the amount of exhaust gas dissolved in the fuel on the bulk modulus of the solution. The final part of the paper is a description of a proprietary design of a hypocycloidal injection pump. The application of the innovative drive allows a correct dissolution of exhaust gas in the fuel.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

The article presents a concept of improving operation of the engine with the effect of gas desorption from a solution with nucleation of gas bubbles. This concept consists in dissolving gas in diesel fuel until the solution is in equilibrium. At a later stage, the phenomenon is reversed, and the gas is released from the solution during its injection into the combustion chamber. The purpose of the study is to present the idea of the desorption effect along with a thermodynamic analysis of the process and to study its impact on the operation of a diesel engine. The article also describes the most important features of the injection pump adapted to employ the desorption effect, which is a proprietary, patented solution. The conducted engine preliminary tests concerned the most important parameters of the engine’s operation (indicated pressure course, pressure growth rate, heat release rate, etc.) and the emission of harmful compounds (PM—particulate matter, CO, HC, and NO_x—nitrogen oxides). A significant reduction of PM, CO, and HC, with a simultaneous increase in NO_x emissions obtained in tests, confirmed that the desorption effect facilitated engine operation.

Most high-pressure fuel pumps for compression-ignition engines manufactured today are cam driven. These pumps have numerous advantages, such as low energy consumption and limited production costs. However, a problem arising from the nature of the cam mechanism is an unfavorable distribution of forces in the camshaft-plunger-cylinder system of a delivery section. The authors have proposed an innovative pump design that eliminates most of the problems present in conventional solutions. The pump utilizes a gear-based hypocycloid drive. This paper focuses mainly on the strength analysis of the two critical components (countershaft and mount) of the subassembly under the highest load – simulations were carried out for different critical load states. The following procedure of estimating fatigue life was adopted for computations: the operational evolution of stresses will be systematized to the set of amplitude stresses and mean stresses by means of the “Rainflow” method. The results obtained in the work showed that the main factor determining change of stresses was the presence of clearances in the pump mechanism. It has been proved that the values of clearances have a negative influence on the power transmission in particular – their presence results in loads being carried by the countershaft and not by the support inter-operating with it. This may cause frictional wear of teeth, leading to the improper operation of the transmission. The analysis showed that the mount was designed correctly. This facilitates the use of less demanding constructional materials.

The main objective of the work was to develop a comprehensive model of energy consumption simulation of heavy duty vehicles using the VECTO simulation tool. The research issue was the impact of aerodynamic drag and rolling resistance on fuel consumption and emissions under various driving conditions described in four driving cycles: Urban Delivery, Regional Delivery, Urban, and Suburban. Each cycle differed in driving time, distance and average speed to represent different operational scenarios. The methodology involved defining vehicle parameters such as weight, aerodynamic coefficients and tyre rolling resistance. The main findings show that the impact of both aerodynamic drag and rolling resistance on fuel consumption can be efficiently modelled. It has been proven that the proposed modifications to aerodynamic drag and rolling resistance can reduce fuel consumption by more than 8%. The lowest fuel consumption was achieved in the Regional Delivery cycle, while the Urban cycle had the highest fuel consumption due to frequent vehicle stops. The results show that optimization of vehicle design and its performance can significantly improve energy efficiency and reduce emissions. A computational modelling tool such as VECTO can contribute to sustainable transport solutions and improve the efficiency of heavy duty vehicle.

Very strict requirements referring to emission standards, the pollution of which is closely related to the quality of the combustion process, forces the manufacturers to introduce new solutions in the field of fuel injection, as well as adapt existing to more stringent standards. A noticeable trend in self-ignition engines is the return to injectors with electromagnetic control, due to the longer durability of the control element in relation to injectors with piezoelectric control. The use of electromagnetic injectors, however, required the introduction of numerous changes, resulting in a reduction in the number and weight of moving elements, which allowed to achieve greater precision of control and multiplication of the fuel dose. Due to the wide range of injector work pressures, it is necessary to determine the delay between the coil override and the beginning of the injection process, so that it is possible to precisely control the supply of fuel at each point of the engine's operation. In order to characterize the delay as a function of fuel pressure, the authors used the photoelectric effect. At the moment when the fuel stream interrupts the light source in the photoactive element, there is a voltage drop, on the basis of which it is possible to determine the actual start of the injection. The authors managed to show that the increase in fuel pressure in the reservoir significantly reduces the response time of the injector. Using the waveform curves, the relationship between the increase in the fuel dose for the measured cross section and the voltage drop in the photoactive element was also determined. It was also found, that the method basing on the use of a radiation source and a photoactive element can be used in the diagnostics of injectors to identify damaged friction pairs needle - body.