Analysis of the Emissions and Performance of a Diesel Engine Using Pumpkin Seed Oil Methyl Ester with Different Injection Pressures

Biodiesel fuel is a potential alternative energy source for diesel engines due to its physiochemical characteristics relatively similar to those of traditional diesel fuel.In this study,the performance,emission,and combustion features of a mono cylinder DI diesel engine are assessed using 20%Pumpkin seed methyl ester(PSOME20)and considering varying injection pressures(200,220,240,and 260 bar).The considered Pumpkin seed oil is converted into pumpkin biodiesel by transesterification and then used as fuel.The findings demonstrate that the Brake Thermal Efficiency(BTE)of PSOME20 can be raised by 1.68%,and the carbon monoxide(CO),hydrocarbon(HC),and smoke emanations can be lowered,while oxides of nitrogen(NOx)emissions are increased at an injection pressure(IP)of 240 bar compared to the standard IP of 200 bar.The cylinder pressure and the Heat Release Rate(HRR)become higher at 240 bar,whereas the ignition delay is shortened with respect to PSOME20 at a normal IP of 200 bar.

Mechanism and optimization of fuel injection parameters on combustion noise of DI diesel engine

Combustion noise takes large proportion in diesel engine noise and the studies of its influence factors play an important role in noise reduction. Engine noise and cylinder pressure measurement experiments were carried out. And the improved attenuation curves were obtained, by which the engine noise was predicted. The effect of fuel injection parameters in combustion noise was investigated during the combustion process. At last, the method combining single variable optimization and multivariate combination was introduced to online optimize the combustion noise. The results show that injection parameters can affect the cylinder pressure rise rate and heat release rate, and consequently affect the cylinder pressure load and pressure oscillation to influence the combustion noise. Among these parameters, main injection advance angle has the greatest influence on the combustion noise, while the pilot injection interval time takes the second place, and the pilot injection quantity is of minimal impact. After the optimal design of the combustion noise, the average sound pressure level of the engine is distinctly reduced by 1.0 d B(A) generally. Meanwhile, the power, emission and economy performances are ensured.

Influence of Pre-injection Control Parameters on Main-injection Fuel Quantity for an Electronically Controlled Double-valve Fuel Injection System of Diesel Engine

A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment.The accuracy of the model is validated through comparison with experimental data.The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed.In the spill control valve mode,main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time.In the needle control valve mode,main-injection fuel quantity increases with rising multi-injection dwell time;this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths.Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes;the variation in main-injection quantity is in the range of 1 mm3.

Injection Strategy in Natural Gas–Diesel Dual-Fuel Premixed Charge Compression Ignition Combustion under Low Load Conditions

Dual-fuel premixed charge compression ignition (DF-PCCI) combustion has been proven to be a viable alternative to conventional diesel combustion in heavy-duty compression ignition engines due to its low nitrogen oxides (NOx) and particulate matter (PM) emissions. When natural gas (NG) is applied to a DF-PCCI engine, its low reactivity reduces the maximum pressure rise rate under high loads. However, the NG–diesel DF-PCCI engine suffers from low combustion efficiency under low loads. In this study, an injection strategy of fuel supply (NG and diesel) in a DF-PCCI engine was investigated in order to reduce both the fuel consumption and hydrocarbon (HC) and carbon monoxide (CO) emissions under low load conditions. A variation in the NG substitution and diesel start of energizing (SOE) was found to effectively control the formation of the fuel–air mixture. A double injection strategy of diesel was implemented to adjust the local reactivity of the mixture. Retardation of the diesel pilot SOE and a low fraction of the diesel pilot injection quantity were favorable for reducing the combustion loss. The introduction of exhaust gas recirculation (EGR) improved the fuel economy and reduced the NOx and PM emissions below Euro VI regulations by retarding the combustion phasing. The combination of an NG substitution of 40%, the double injection strategy of diesel, and a moderate EGR rate effectively improved the combustion efficiency and indicated efficiency, and reduced the HC and CO emissions under low load conditions.

Investigation of Performance and Combustion Characteristics of DI Diesel Engine Fuelled with Ternary Fuel Blend at Different Injection Pressure

The depletion of fossil diesel fuels, global warming concerns and strict limits on regulated pollutant emissions are encouraging the use of renewable fuels. Biodiesel is the most used renewable fuel in compression ignition (CI) engine. The majority of literature agrees that the particulate matter (PM), unburnt total hydrocarbons (THC) and carbon dioxide (CO) emission from biodiesel are lower than from conventional diesel fuel. One of the most important reasons for this is the oxygen content of the biodiesel. This induces a more complete and cleaner combustion process. In addition to this the absence of aromatic compounds in biodiesel leads to particulate matter reduction with respect to diesel fuel. The potential emission benefits induced by the presence of oxygen in fuel molecules has increased the interest in using the bio-alcohols fuel blends in CI engines such as ethanol. Although alcohols are more suitable for blending with diesel fuel, properties like lubricity, viscosity, stability, heating value and cetane number of diesel-alcohol (Diesohol) still require improvement. One of the techniques is addition of biodiesel which can improve all of these properties forming diesel-biodiesel-alcohol (ternary) blends. The blends of diesel-biodiesel-ethanol can be used in the existing CI engines without any major modifications and most significant result of using this blend is the lower emission with almost the same performance as of diesel fuel alone. The present study focused on investigation of performance and combustion characteristics of ternary fuel blend in DI diesel engine operating at different injection opening pressure (IOP). The different injection opening pressures are: 180 bar, 200 bar and 220 bar.

Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance

In order to investigate the effects of fuel injection distribution on the scrarnjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combustor performances. In addition, an irmer-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.

Fuel Spray Dynamic Characteristics of GDI High Pressure Injection System

In order to improve the fuel consumption and exhaust emission for gasoline engines,gasoline direct injection（GDI） system is spotlighted to solve these requirements.Thus,many researchers focus on the investigation of spray characteristics and the fuel formation of GDI injector.This paper presents a complete numerical and experimental characterization of transient gasoline spray from a high pressure injection system equipped with a modern single-hole electric controlled injector in a pressurized constant volume vessel.The numerical analysis is carried out in a one-dimensional model of fuel injection system which is developed in the AVL HYDSIM environment.The experimental analyses are implemented through a self-developed injection rate measurement device and spray evolution visualization system.The experimental results of injection rate and spray dynamics are taken to tune and validate the built model.The visualization system synchronize a high speed CMOS camera to obtain the spray structure,moreover,the captured images are taken to validate the injector needle lift process which is simulated in the model.The reliability of the built model is demonstrated by comparing the numerical results with the experimental data.The formed vortex structure at 0.8 ms is effectively disintegrated at 6.2 ms and the spray dynamics become rather chaotic.The fuel flow characteristics within injector nozzle extremely influence the subsequent spray evolution,and therefore this point should be reconsidered when building hybrid breakup GDI spray model.The spray tip speed reach the maximum at 1.18 ms regardless of the operation conditions and this is only determined by the injector itself.Furthermore,an empirical equation for the spray tip penetration is obtained and good agreement with the measured results is reached at a certain extent.This paper provides a methodology for the investigation of spray behavior and fuel distribution of GDI engine design.

EFFECTS OF INJECTION STRATEGY ON D.I. DIESEL ENGINE COMBUSTION

Experiments are conducted to develop an understanding of how split injections can affect the combustion and emission characteristics of a D.I. diesel engine with a common-rail injection system. The ratio of the amount of fuel injected between two injection pulses and the injection interval is varied keeping the injected fuel quantity constant. Results show that under the 70D90-10 injection pattern, the engine achieves the lower NOx-smoke emissions and BSFC compared with the single injection pattern. The heat release rate and the temperature show that the split injections increase the initial premixed burn and retards the diffusion burn. With the balance of these two effects, the maximum in-cylinder temperature decreases while the 50% heat release point is held at almost the same crank angle. Therefore, both NOx emission and BSFC are improved while keeping the smoke emission at the same level.

Influence of Diesel Engine Intake Throttle and Late Post Injection Process on the Rise of Temperature in the Diesel Oxidation Catalyst

In order to effectively implement DPF(Diesel Particulate Filters)regeneration control,thermal management of exhaust products before and inside Diesel Oxidation Catalyst(DOC)is necessary.In the present study,the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests.The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC;in particular,with intake throttle valve opening at 20%,temperature before DOC can be increased by about 170℃ with respect to the full opening.An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC,however its impact on the exhaust temperature before DOC is relatively limited.As the late post injection quantity increases,Hydrocarbon(HC)emissions also grow;in the present work it is shown that with a proper injection quantity,a considerable temperature increase inside the DOC can be obtained with relatively low HC emission.More specifically,with the intake throttle valve at 30%and DOC reaching ignition temperature as the late post injection quantity is increased,the exhaust temperature after DOC can be made larger than 550℃,adequate for DPF active regeneration.

Design of speed controller for electronic fuel injection gasoline generator based on feed-forward PID control

As for the application of electronic fuel injection （EFI） system to small gasoline generator set, mechanical speed controller cannot be coupled with EFI system and has the shortcomings of lagged regulation and poor accuracy, a feed-forward control strategy based on load combined with proportional-integral-differential （PID） control strategy was proposed, and a digital speed controller applied to the electrical control system was designed. The detailed control strategy of the controller was intro- duced. The hardware design for the controller and the key circuits of motor driving, current sampling and angular signal captu- ring were given, and software architecture was discussed. Combined with a gasoline generator set mounted with EFI system, the controller parameters were tuned and optimized empirically by hardware in loop and bench test methods. Test results show that the speed deviation of generator set is low and the control system is stable in steady state; In transient state the control system responses quickly, has high stability under mutation loads especially when suddenly apply and remove 100% load, the speed deviation is within 8% of reference speed and the transient time is less than 5 s, satisfying the ISO standard.

Effect of equivalence ratio on diesel direct injection spark ignition combustion

Aviation heavy-fuel spark ignition(SI)piston engines have been paid more and more attention in the area of small aviation.Aviation heavy-fuel refers to aviation kerosene or light diesel fuel,which is safer to use and store compared to gasoline fuel.And diesel fuel is more suitable for small aviation application on land.In this study,numerical simulation was performed to evaluate the possibility of switching from gasoline direct injection spark ignition(DISI)to diesel DISI combustion.Diesel was injected into the cylinder by original DI system and ignited by spark.In the simulation,computational models were calibrated by test data from a DI engine.Based on the calibrated models,furthermore,the behavior of diesel DISI combustion was investigated.The results indicate that diesel DISI combustion is slower compared to gasoline,and the knock tendency of diesel in SI combustion is higher.For a diesel/air mixture with an equivalence ratio of 0.6 to 1.4,higher combustion pressure and faster burning rate occur when the equivalence ratios are 1.2 and 1.0,but the latter has a higher possibility of knock.In summary,the SI combustion of diesel fuel with a rich mixture can achieve better combustion performance in the engine.

STRUCTURE PARAMETERS DESIGN AND PERFORMANCE TEST OF FUEL INJECTION SYSTEM

Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.

STRATEGY FOR DIESEL ROTARY ENGINE WITH COMMON RAIL INJECTION SYSTEM

A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development focuses on the applied fuel injection and ignition strategies, especially concerning the combustion configurations of injectors, ignition source, and combustion chamber. The prototype engine, equipped with Bosch common rail system and high performance electronic control unit （ECU）, is designed correspondingly. Studies show that the integration of a common rail injection system and the main and pilot duel injectors configurations, assisted with glow plug ignition device and flexible ECU, represents a promising approach to improve the potential of the low compression ratios diesel rotary engine. Currently the engine can run at 6 kr · min^-1 steadily and the power is about 68 kW/（4 kr ·min^- 1）.

Measurement and analysis of cycle fuel injection quantity for electronic unit pump

The cycle fuel injection quantity is accurately measured for electronic unit pump （EUP） operating at high, middle and low speeds by using displacement method based on EFS instantaneous mono-injector qualifier. On the basis of the experi- mental data about fuel injection quantity and fuel pressure, the variation of inconsistency in fuel injection quantity of EUP and the influence factors in different operating conditions are concluded. The results show that the inconsistency is lowest in maximum torque condition, while on the start and maximum power conditions, it is higher.

A numerical investigation into the effect of altering compression ratio, injection timing, and injection duration on the performance of a diesel engine fuelled with diesel-biodiesel-butanol blend

Using renewable fuels for diesel engines can reduce both air pollution and dependence on fossil fuels.A computer simulation was constructed to predict the performance,combustion characteristics,and NOx emissions of a diesel engine fuelled with diesel-biodiesel-butanol blends.The simulation was validated by comparing the modelling results against experimental data and a good agreement between the results was found.The fuels used for the validation were diesel(B0),biodiesel(B100),diesel-biodiesel blend(B50),and two diesel-biodiesel-butanol blends with 45%diesel-45%biodiesel-10%butanol(Bu10)and 40%diesel-40%biodiesel-20%butanol(Bu20)by volume.Experimental results showed that the addition of butanol reduced NOx emissions but deteriorated the engine performance.The aim of the current work was the numerical optimization of the different parameters to enhance the engine performance while using butanol to decrease NOx emissions.The engine compression ratio(CR)varied from 14 to 24,in increments of 2.Fuel injection timing(IT)was reduced from 30°before top dead centre(bTDC)to 5°bTDC in increments of 5°.Also,the fuel injection duration(IDur)was extended from 20°to 50°in increments of 10°.Results showed that the increase in the CR improved engine performance for the two investigated fuels,Bu10 and Bu20.The maximum engine brake power(BP),thermal efficiency(BTE),and minimum brake-specific fuel consumption(BSFC)of 1.46 kW,32.3%,and 0.273 kg/kWh respectively,were obtained when the Bu10 fuel was injected under the optimum conditions of 24 CR,15°bTDC IT,and 40°IDur.Under these optimum conditions,the BP,BTE,and BSFC improved by 3%-3.5%for Bu10 and Bu20 fuel blends compared with the base engine conditions of a CR of 22,30°IDur,and 10°bTDC IT.The heat release rate during the premixed phase increased when the IT was advanced,while the mixing-controlled combustion phase was enhanced when the IT was reduced.NOx emissions increased with increasing CR,while both an increase in IDur at constant IT and the reduction of the IT decreased the engine NOx emissions.Under the optimum conditions,the NOx emissions for Bu10 and Bu20 were further decreased by 2.2%and 0.9%,respectively,compared with the experimental results under base engine conditions.Reducing the IT from 15°to 5°bTDC at a CR of 24 and IDur of 40°caused the NOx emissions for Bu10 and Bu20 to decrease by 16%.When the IDur was increased from 20°to 50°at a CR of 24 and an IT of 15°bTDC,the NOx emissions for Bu10 and Bu20 decreased by 12.3%and 11.8%,respectively.The addition of butanol to the diesel-biodiesel blend under optimum conditions showed results that were comparable to those of pure diesel,with a decrease in NOx emissions.

Investigation on combustion and emission characteristics of diesel polyoxymethylene dimethyl ethers blend fuels with exhaust gas recirculation and double injection strategy

As a kind of renewable and high oxygen content fuel,polyoxymethylene dimethyl ether(PODE)can be added in diesel to realize energy saving and emissions reduction.To evaluate the combustion and emission characteristics of a diesel engine fueled with diesel and diesel/PODE mixtures,exhaust gas recirculation(EGR)and main-pilot injection strategies with various injection timings were applied.PODE was blended with diesel by volume to form mixtures which were marked as D100(pure diesel),D90P10(90%diesel+10%PODE),and D80P20(80%diesel+20%PODE).The results showed that the ignition delay(ID)and combustion duration(CD)of D80P20 were the shortest because of the highest cetane number(CN)and high oxygen content of PODE,indicating more concentrated heat release.At low and medium loads,D80P20 achieved the highest peak heat release ratio(PHRR)and peak combustion temperature(PCT)among the three fuels,and it was 14.3%and 3.6%higher than those of D100.PODE blending with diesel can significantly reduce particulate matter(PM)and D80P20 has the lowest PM emissions at all loads.Compared with D100,both PM and nitrogen oxide(NO_(x))emissions of PODE blends decreased simultaneously with 20%EGR at all loads.With the increase of pilot-main interval,the ID and CD of all test fuels increased,while the NO_(x)and PM emissions decreased.The conclusions of the present research provide a state of the application in light-duty engines fueled with diesel/PODE blends in future work.

Numerical Investigation of the Effects of Rate-Shaped Main Injection on Combustion and Emission in an OPOC Two-Stroke Diesel Engine

The effects of various split injection strategies on the opposed-piston opposed-cylinder(OPOC)diesel engine combustion and emission characteristics have been studied numerically using AVL-Fire CFD tools.The five rate-shaped main injections were used in split injection strategies.The results show that ignition delay from a rectangular injection rate is the shortest.Maximum pressure of the trapezoid injection rate is the largest.And the NOx emission of the rectangular injection rate is the largest.Meanwhile,the soot emission of the trapezoid injection rate is the least among the five injection rates.

An experimental study on RP-3 jet fuel injection on a common rail injection system

RP-3 jet fuel could be an alternative fuel for diesel engines.In this study,the injection characteristics of RP-3jet fuel under single and split injection strategies were investigated and compared with diesel fuel.The experimental results indicate that RP-3 jet fuel has slightly shorter injection delay time than diesel fuel,but this difference is negligible in actual engine operations.Further,although the lower density and viscosity of RP-3 jet fuel lead to higher volumetric injection rates and cycle-based injection quantities,the cycle-based injection mass and the mass injection rates at the stable injection stage of RP-3 jet fuel are close to or slightly lower than those of diesel fuel.Based on these experimental observations,it could be concluded that fuel physical properties are the secondary factor influencing the injection characteristics in both single and split injection strategies,as RP-3 jet fuel and diesel fuel are taken for comparison.

Research on High Pressure Gas Injection As a Method of Fueling, Disruption Mitigation and Plasma Termination for Future Tokamak Reactors

High-pressure gas injection has proved to be an effective disruption mitigation tech- nique in DIII-D tokamak experiments. If the method can be applied in future tokamak reactors not only for disruption mitigation but also for plasma termination and fueling, it will have an attractive advantage over the pellet and liquid injection from the viewpoint of economy and engineering design. In order to investigate the feasibility of this option, a study has been carried out with relevant parameters for conveying tubes of different geometrical sizes and for different gases. These parameters include pressure drop, lagger time after the valve＇s opening, gas diffusion in an ultra-high vacuum condition, and particle number contour.

Mathematical Model for the Injector of a Common Rail Fuel-Injection System

The paper describes a Diesel fuel injection process. Computer simulation was carried out together with measurement of the Common Rail accumulator fuel-injection system. The computer simulation enables the observation of the phenomena from rail pressure, being the input data for injection parameters calculations, to the injection rate. By means of computer simulation, the pressure values in specific sections of the injection nozzle may be computed, the needle lift, injection rate, total injected fuel, time lag from injector current to first evidence of injection process and other time-lags between various phases of the injection process. The injection rate provides input data for spray computer simulation. Measurements of injection and combustion were carried out within a transparent research engine. This engine is a single-cylinder transparent engine based on the AUDI V6 engine, equipped with a Bosch Common Rail Injection System. The comparison between the computed and measured injection parameters showed good matching.