Is it possible to turn a diesel engine into a less pollutant device?

The current tendency in the eastern part of Europe is to modify old diesel engines with the purpose of improving characteristics in terms of horsepower and torque, but also to reduce the generated pollution. The diesel engines are still in use, against to the tendencies of renouncing to their support, at least in larger urban & industrial areas, where the pollution level, especially the particulate matter (particles PM10, PM2.5) and ozone concentrations, also the NOx are supposed to be generated mostly by diesel engine vehicles. The paper presents results concerning the influence of modifying the diesel engine control unit’s parameters, such as injection quantity, start of injection, intake air pressure and all the others correlated for better performance. The article brings into attention possibilities to reduce the exhaust pollution concentrations, correlated by simultaneous ways of improving the external characteristics of the engine by modifying the engine control unit’s parameters. Measurement results of a compression ignited internal combustion engine before and after the retrofitting, by reparametrization, meaning changing the parameters are presented and discussed.

A Hybrid Taguchi-Regression Algorithm for a Fuel Injection Control System

The fuel injection system is one of the key components of an in-cylinder direct injection engine. Its performance directly affects the economy, power and emission of the engine. Previous research found that the Taguchi method can be used to optimize the fuel injection map and operation parameters of the injection system. The electronic control injector was able to steadily control the operation performance of a high-pressure fuel injection system, but its control was not accurate enough. This paper conducts an experimental analysis for the fuel injection quantity of DI injectors using the Taguchi-Regression approach, and provides a decision-making analysis to improve the design of electronic elements for the driving circuit. In order to develop a more stable and energy-saving driver, a functional experiment was carried out. The hybrid Taguchi-regression algorithm for injection quantity of a direct injection injector was examined to verify the feasibility of the proposed algorithm. This paper also introduces the development of a high-pressure fuel injection system and provides a new theoretical basis for optimizing the performance of an in-cylinder gasoline direct injection engine. Finally, a simulation study for the fuel injection control system was carried out under the environment of MATLAB/Simulink to validate the theoretical concepts.

Multi-objective Optimization of High-Speed Solenoid Valve for Biodiesel Electronic Unit Pump

Background: A larger response delay of a high-speed solenoid valve will cause inaccurate fuel injection timing and imprecise cycle injection quantity, resulting in diesel engine emission and increased fuel consumption. Objective: Biodiesel as an ideal alternative fuel has exceptional advantages in energy conservation, emission reduction, and low-carbon environmental protection; however, matching with Electronic Unit Pump (EUP) and its impacts on solenoid valve operation need to be further studied. Method: In the present work, a numerical model of EUP fueled with biodiesel was established in an AMESim environment, which was validated by the experiment. Then, combined with the Design of Experiments (DOE) method, key parameters influencing the solenoid valve response delay were predicted: armature residual air gap, spring preload, poppet valve half-angle, valve needle diameter, and poppet valve diameter. Finally, taking the response delay time of solenoid valve as targets, multi-objective optimization model for high-speed solenoid valve was established using NSGA-II (non-dominated sorting genetic algorithm-II) genetic algorithm in modeFRONTIER platform. Results: The optimized results showed that the delay time of the solenoid valve closing is reduced by 6%, the opening delay time is reduced by 20.8%, the injection pressure peak is increased by 1.8MPa, which is beneficial to accurate injection quantity and the application of biodiesel in diesel engines.

Simulation studies on the boot shape injection of a giant magnetostrictive injector

Giant magnetostrictive injector using giant magnetostrictive material acting an electronic controlled injector may be one new promising injector to acquire adjustable injection rates while maintaining large injection quantity. An electronic controlled injector driven by a giant magnetostrictive actuator was designed through combining the driving requirement and output characteristics of the material. To promote responding speed of the coil current, the driving voltage with open-hold-fall type waveform was employed just like using in an electromagnetic injector. Simulation model for the injection characteristic of the injector was established using AMEsim software and verified using experimental results collected by the single injection meter. From simulation and experimental results, designed giant magnetostrictive injector showed good performances as maximum spray rate of 4.5 L/min and minimum spray pulse width of 0.21 ms, and realized the boot shape injection when generated by the designed voltage wave. Furthermore, duration time and amplitude of the pilot spray part in a boot shape injection were respectively adjusted through changing the dwell time and opening time. The boot shape injection reached by the giant magnetostrictive injector can reach quite accurate control of fuel injection and then promote fuel efficiency effectively.

Novel Determination of Anti-Hypertensive Combination; Benidipine Hydrochloride and Nebivolol Hydrochloride by High Performance Chromatographic Method

This research work was designed to establish and validate a novel stability indicating RP-HPLC method for the combined determination of Benidipine hydrochloride (BHE) and Nebivolol hydrochloride (NHE) in bulk and tablets, dependent on ICH guidelines.The assay method to analyse BHE and NHE was optimized with isocratic elution using acetonitrile: 0.1M acetate buffer (45:55, pH 5.1), Lichrospher ODS RP-18 column and flow pace of 1 ml/min. Total time for single run was 14 min. The injection quantity was 20μl, and was detected at 249nm. The method was verified on a concentration series of 1.25-10μg/ml (NHE) and 1.0-10μg/ml (BHE) for precision, accuracy and linearity. The LOD values were 0.059µg/ml and 0.028µg/ml for NHE and BHE, respectively. The LOQ values were 0.196µg/ml for NHE and 0.094µg/ml for BHE. The recovery percentages were 98.60-100.11% (BHE) and 98.94-101.50% (NHE) with relative standard deviation 0.250-0.694% (BHE) and 0.183-0.400% (NHE). The method was also observed to be efficient, and was sufficiently specific to measure BHE and NHE in the presence of stress-produced degradation products.

ANALYSIS OF THE PRE-INJECTION CONFIGURATION IN A MARINE ENGINE THROUGH SEVERAL MCDM TECHNIQUES

The present manuscript describes a computational model employed to characterize the performance and emissions of a commercial marine diesel engine. This model analyzes several pre-injection parameters, such as starting instant, quantity, and duration. The goal is to reduce nitrogen oxides (NOx), as well as its effect on emissions and consumption. Since some of the parameters considered have opposite effects on the results, the present work proposes a MCDM (Multiple-Criteria Decision Making) methodology to determine the most adequate pre-injection configuration. An important issue in MCDM models is the data normalization process. This operation is necessary to convert the available data into a non-dimensional common scale, thus allowing ranking and rating alternatives. It is important to select a suitable normalization technique, and several methods exist in the literature. This work considers five well-known normalization procedures: linear max, linear max-min, linear sum, vector, and logarithmic normalization. As to the solution technique, the study considers three MCDM models: WSM (Weighted Sum Method), WPM (Weighted Product Method) and TOPSIS (Technique for Order Preference by Similarity to Ideal Solution). The linear max, linear sum, vector, and logarithmic normalization procedures brought the same result: -22º CA ATDC pre-injection starting instant, 25% pre-injection quantity and 1-2º CA pre-injection duration. Nevertheless, the linear max min normalization procedure provided a result, which is different from the others and not recommended.

Injection control strategy of diesel engine based on speed segment PID and operating parameter adaptation

Aiming at the problems of low precision, poor anti-interference and poor follow-up in the control parameters for the diesel engine fuel injection system, this paper studies the control method of the high-pressure common rail electronic control fuel injection system of the diesel engine, constructs the high-pressure common rail fuel injection control system based on the ECU, and establishes the speed segment PID control model of fuel injection quantity, common rail pressure, fuel injection timing and fuel injection rate by using MATLAB/Simulink. The fuel injection quantity and timing are simulated. In order to realize all-round and flexible control of the diesel engine under different working conditions, and to achieve the desired optimal performance in all aspects, the optimization control method of the injection law for the diesel engine is studied. The diesel engine fuel injection control strategy based on speed segment PID and operating parameter adaptation is proposed to realize precise control of the common rail pressure, injection quantity, injection timing and injection rate under different working conditions. The simulation calculation and bench test show that the maximum fluctuation of rail pressure at idle speed is only 5 MPa, and the time to reach stability is only 1.25 s, which greatly improves the control accuracy, anti-interference and follow-up ability of the injection parameters.

Research on the correlation between fuel injection quantity and key structural parameters for the fuel system of marine diesel engines

In order to demonstrate the relationship between the fuel injection quantity and the structural parameters of the fuel system for large marine diesel engines, an AMESim model of a double-valve controlled fuel system is proposed. The accuracy of the model is validated in view of fuel injection quantity and system pressures. The correlation analysis is performed to illustrate the effects of single parameters and the interactions between different parameters on the fuel injection quantity. Considering the high calculation cost of the simulation model, the prediction model between the fuel injection quantity and the structural parameters for each working condition is obtained based on D-optimal design of experiments and the response surface methodology in this article. For the maximum deviation between the calculated and predicted fuel injection quantity is only 4.27%, the prediction models could be used for further analysis. And the results show that the diameters of high-pressure fuel tube (HPFT), small and big ends of pressure amplification piston (PAP) are the key single parameters. The absolute values of their correlation coefficients are between 0.77 and 0.87, between 0.22 and 0.43 and between 0.14 and 0.26 respectively. The correlation coefficients for the other parameters are all relatively small. For interactive parameters, the absolute values for all the correlation coefficients are less than 0.1. And the interactions between the diameters of big and small diameters of PAP, between the diameter of small end of PAP and the diameter of HPFT, between the diameter of HPFT and the pre-tightening force of needle spring influence the fuel injection quantity relatively obviously.

Effects of Two Pilot Injection on Combustion and Emissions in a PCCI Diesel Engine

The effects of two pilot injections on combustion and emissions were evaluated in a single−cylinder turbocharged diesel engine, which operated in premixed charge compression ignition (PCCI) modes with multiple injections and heavy exhaust gas recirculation under the low load by experiments and simulation. It was revealed that with the delay of the start of the first pilot injection (SOI−P1) or the advance of the start of second pilot injection (SOI−P2), respectively, the pressure, heat release rate (HRR), and temperature peak were all increased. Analysis of the combustion process indicates that, during the two pilot injection periods, the ignition timing was mainly determined by the SOI−P2 while the first released heat peak was influenced by SOI−P1. With the delay of SOI−P1 or the advance of SOI−P2, nitrogen oxide (NOx) generation increased significantly while soot generation varied a little. In addition, increasing Q1 and decreasing the second pilot injection quantity (Q2) can manipulate the NOx and soot at a low level. The advance in SOI−P2 of 5 °CA couple with increasing Q1 and reducing Q2 was proposed, which can mitigate the compromise between emissions and thermal efficiency under the low load in the present PCCI mode.

Optimization of NOx emission control based on high sulfur coal combustion

Combined with the operation of an 800MW supercritical boiler burning high sulfur coal, in order to control the emission of nitrogen oxides, the optimization adjustment of ammonia injection and NOx emission reduction based on combustion adjustment is proposed. According to the test of the inlet and outlet of denitration system under 800 MW condition, the parameters of NOx, O2, NH3, wind speed and so on at the inlet and outlet of denitration system are tested, and the ammonia injection manual valve is adjusted according to the test results. After adjustment, the NOx distribution at the outlet of denitration system is uniform, and the ammonia injection quantity is reduced. After adjustment, the flow field under 800 MW and 500 MW conditions is tested, and the flow field distribution under the two conditions is uniform. The adjustment test has achieved the expected effect.