Common Rail Diesel Engine Research Articles

Comparison of Single and Multiple Injection Strategies in a Butanol Diesel Dual Fuel Engine

A turbocharged three cylinder automotive common rail diesel engine was modified to operate in the n-butanol diesel dual fuel mode. The quantity of butanol injected by the port fuel injectors and the rail pressure, injection timing, and number of injection pulses of diesel were varied using open engine controllers. Experiments were performed in the dual fuel mode at a constant speed of 1800 rpm at varying brake mean effective pressure (BMEPs). Butanol to diesel energy share was varied, and the injection timing of diesel was always set for highest brake thermal efficiency (BTE). Single pulse injection (SPI) and two pulse injection (TPI) of diesel were evaluated. In SPI, with increase in the butanol to diesel energy share, the BTE remained unchanged. At high loads and high amounts of butanol, the heat release rate (HRR) variation indicated that butanol auto ignited before diesel with both SPI and TPI of diesel. NO emission always decreased because of reduced temperatures due to evaporation of butanol. Butanol also reduced the smoke levels except at high loads. HC levels were always higher. With optimized injection parameters, TPI of diesel resulted in lower NO, similar smoke, and BTE with lesser rate of pressure rise as compared to SPI of diesel in the dual fuel mode at high loads. On the whole, the SPI mode is suitable for low to medium outputs and the TPI mode is suitable for high outputs.

Effects of dilute gas on combustion and emission characteristics of a common-rail diesel engine fueled with isopropanol-butanol-ethanol and diesel blends

Isopropanol-butanol-ethanol (IBE) can be used in engines as an alternative fuel to eliminate the high recovery and separation costs in the production of butanol and also to avoid the corrosivity and low flash point of acetone in acetone-butanol-ethanol (ABE). In this respect, this study is aimed to investigate the performance, combustion and emissions of a single-cylinder, common-rail diesel engine fueled with IBE and diesel blends. Two blends of butanol and diesel fuel, denoted as IBE15 (15% IBE and 85% diesel in volume) and IBE30 (30% IBE and 70% diesel in volume) were tested. Additionally, the experiments in this study were conducted at different diluted gas ratios to achieve low NOx emission. The experimental results show that when the intake charger is gradually diluted, the start of combustion and combustion center for all the tested fuels are remarkably delayed. Compared with pure diesel, the brake thermal efficiency (BTE) for IBE15 is always higher. Butt for IBE30, the BTE is lower than that of pure diesel when the flow rate of the dilute gas is less than 30 L/min. For all the tested fuels, NOx emission reduces while CO and HC emissions increase with the increase of dilute gas. Soot emission for pure diesel and IBE15 drastically increases as the dilute gas increases. However, the increase of dilute gas does not cause the soot emission of IBE30 to significant increase. That is to say, IBE30 coupled with a proper EGR ratio has the potential to reduce NOx and soot emissions simultaneously.

Effects of injection timing and injection pressure on performance and exhaust emissions of a common rail diesel engine fueled by various concentrations of fish-oil biodiesel blends

To evaluate the performance and emissions of a test engine fueled by biodiesel blends produced from fish processing by-products, the experimental and simulation methods were used to investigate the effects of injection pressure and timing on engine operation and correlation of these effects with varying fish-oil concentrations in the biodiesel blends. Consequently, commercial diesel fuel blended with different concentrations of fish-oil biodiesel including B0, B10, B20, B30, B40 and B50 (corresponding to 0%, 10%, 20%, 30%, 40%, and 50% of biodiesel in blend) were used for the test engine. Compared to B0, the average reduction in brake power of the biodiesel fuels was reduced proportionally with the biodiesel ratio in the fuel blends. The brake specific fuel consumption (BSFC) and NOx emissions increased together with a reduction in soot, HC and CO emissions as the percentage of biodiesel increases. Moreover, the engine characteristics depend on operating parameters such as injection timing and injection pressure as also mentioned in many previous studies. When increasing injection timing, the brake power initially increases until reaching a maximum value and then decreases slightly for all types of fuels tested. Meanwhile, the effect of injection pressure differs depending on the pressure range and biodiesel blends.

Reducing volatile organic compound emissions from diesel engines using canola oil biodiesel fuel and blends

Volatile organic compounds (VOCs), a group of environmental pollutants, are emitted in large quantities when fossil fuel is burned in automobiles. This research investigates the VOCs in the exhaust emissions from a common rail diesel engine fueled with canola oil biodiesel fuel (COBF), conventional diesel fuel (CDF), and B20 (20% COBF blended with 80% CDF by volume) at various engine loads (30 Nm, 80 Nm, 130 Nm) and a constant engine speed of 1500 rpm. The results indicate that the regulated emissions (CO, HC, PM) were reduced obviously when COBF and B20 were used in a CRDI diesel engine, and a larger number of VOCs (about 30 types) are emitted with CDF and the quantity emitted is greater than with B20 and COBF. The total VOC emissions (TVOC) of B20 were lower than those with the other test fuels at all experimental conditions. In addition, this paper presents a simple approach for sampling VOC emissions from diesel engines, uses a gas chromatography/mass spectrometry (GC/MS) analysis, and also confirms that COBF blended with CDF in a volume fraction of 20–80 is an excellent alternative fuel based on VOC emissions.

A control method of fuel distribution by combustion chamber zones and its dependence on injection conditions

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, ??B, were located in the sack volume and the entering edges of the second group (coefficient of flow, ??H) - on the locking taper surface of the nozzle body. The coefficients of flow, ??B, and ??H 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 hence - by the combustion chamber zones. Using the constant fuel flow set-up, 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 edge - from 0 to 16 MPa.

CO2 concentration from turbocharged common rail diesel engine dually fueled with compressed biomethane gas controlled at optimum ratio

The objectives of this study are to investigate the carbon dioxide (CO2) concentration from the compressed biomethane gas (CBG) and diesel dual-fueled diesel engine and to compare the CO2 concentration produced from the dual-fueled and the diesel-fueled engines. The duration of CBG injection was controlled by following the optimum ratio of the CBG obtained from the previous study. During the test, the engine speed was varied from 1,000 to 4,000 rpm and the engine torque was maintained to be 25, 50, 75 and 100% of the maximum engine torque. Experiment was divided into two parts consisting of the dual-fueled and the diesel-fueled modes. From the dual-fueled mode, when the engine speed increased, the CO2 concentration decreased. Because the optimum ratio of the CBG and the volumetric efficiency decrease during the high engine speed range, the proportion of the diesel increases, the incomplete combustion occurs. The unburned carbon oxidizes to be the CO in higher proportion than the CO2, thus, the CO2 consequently decreases. From the CO2 comparison, the dual-fuel mode produced the CO2 nearly the same as that of the diesel-fuel mode during the low engine torque. On contrary, the dual-fuel mode had higher CO2 concentration during the high engine torque.

Numerical Study on Performance Improvement by Changing of Fuel Injection Timing of Common Rail Diesel Engine for using Electric Generation for Waste Engine Remanufacturing

Numerical Study on Performance Improvement by Changing of Fuel Injection Timing of Common Rail Diesel Engine for using Electric Generation for Waste Engine Remanufacturing

Hydrocarbon impact on NO to NO2 conversion in a compression ignition engine under low-temperature combustion

Compression ignition engines can employ high rates of exhaust gas recirculation to realize low-temperature combustion in order to reduce the NOx emissions. However, a substantial increase in NO2 contribution to the NOx emissions is also observed. The relationship between this NO to NO2 conversion is also affected by the hydrocarbons originating mainly from the fuel. This can have important consequences for the design of the exhaust after-treatment system. Therefore, this article presents an empirical investigation of the impact of hydrocarbon emissions on the in-cylinder NO–NO2 conversion process. First, engine motoring tests are performed with propane and NO gases dosed into the engine intake manifold. Engines with different compression ratios are employed to study the effect of in-cylinder temperature and intake HC–NO ratio on the NO–NO2 conversion process. Next, the hydrocarbon impact on the NOx survivability at different engine combustion modes is investigated using a common-rail diesel engine test platform with independent control of exhaust gas recirculation, intake boost, and exhaust back pressure. Results show that the existence of hydrocarbon has a strong promotion effect of converting NO to NO2. During compression test, NO–NO2 conversion rate can reach 95% under certain intake HC–NO concentration ratio, and the minimum HC–NO concentration ratio to sustain a high NO–NO2 conversion rate is sensitive to peak in-cylinder temperature; engine combustion results also show that hydrocarbon not only can promote the in-cylinder NO–NO2 conversion process, but also has the potential of decreasing the total NOx emissions under low-temperature combustion mode.

Injection strategies for reducing smoke and improving the performance of a butanol-diesel common rail dual fuel engine

In dual fuel engines auto-ignition of the inducted butanol creates a high temperature environment prior to the injection of diesel. This results in enhanced smoke emissions. This work was aimed at controlling the smoke level in a butanol diesel common rail turbocharged dual fuel engine through multiple fuel injections. Experiments were performed on a three cylinder turbocharged common rail diesel engine at a speed of 1800 rpm and BMEPs corresponding to 75% and 100% of full load (BMEP of 11.8 bar). Port fuel injectors along with dedicated circuitry were employed to control the quantity and timing of butanol introduction into the intake air. An open engine controller was used to vary the rail pressure, injection timing and number of pulses of the diesel that was directly injected into the combustion chamber. The injection timing of diesel was always set for best efficiency. First the effect of Main plus Post Injection (MPI) of diesel at a fixed butanol to diesel energy share (BDES) of 30% was evaluated at different post injection quantities and main to post offsets. Subsequently the influence of BDES was studied at a fixed post injection quantity and offset from the main injection. Finally Pilot plus Main Injection (PMI) of diesel, Main plus Post Injection (MPI) of diesel and Main plus Two Post Injections (MPTPI) of diesel were compared in the dual fuel mode. MPI resulted in improved brake thermal efficiency (BTE) and drastically reduced the smoke level because of enhanced mixing by the momentum of the post injected fuel. NO and CO2 were also reduced. Using high BDES values along with optimised post injection quantities and main to post offsets reduced the smoke level. PMI of diesel resulted in lower BTE and higher smoke, while the only advantage was reduced NO levels. MPI was better than MPTPI with respect to all the parameters. On the whole, in a dual fuel engine that uses butanol and diesel the main plus post strategy is effective in improving energy efficiency, reducing smoke and also in increasing the amount of butanol that can be utilized.

Effect of direct water injection during compression stroke on thermal efficiency optimization of common rail diesel engine

The increasingly strict emissions regulations put forward higher request of NOx emissions control to diesel engines. Water addition is considered to be an effective way to reduce NOx emissions. However, most studies around the world concerned mainly about the effect of water addition on NOx reduction. The effect of water addition on diesel engine efficiency was not paid as much attention as on emissions. A series of experiments were carried out on test bench based on a two cylinder diesel engine with the modifications of adding common rail system and direct water injection system. The effects of direct water injection on diesel combustion and indicated thermal efficiency optimization were studied and the mechanism of thermal efficiency improvement due to compression stroke water injection was revealed. The influences of water injection duration and water injection timing are also studied. Results showed that, compression stroke direct water injection is beneficial to thermal efficiency. Under test conditions up to 4.08% indicated thermal efficiency enhancement is achieved. The thermal efficiency enhancement is mainly attributed to the reduction of negative compression stroke’s work due to the heat absorption of water evaporation and the increment of positive power stroke’s work due to the addition of working fluid. For small water injection duration, earlier injection timing in the compression stroke leads to higher thermal efficiency, while injection at late stage in the compression stroke is more suitable for larger water addition quantity. Thermal efficiency rises at first until reaches its peak value, and then drops with increasing water injection duration. Further increasing water injection duration deteriorates combustion and has negative impact on thermal efficiency. The highest thermal efficiency enhancement is achieved under 0.4ms water injection duration and 180°CA BTDC water injection timing condition.

Thermophysical properties of rapeseed oil methyl esters (RME) at high pressures and various temperatures evaluated by ultrasonic methods

Investigation of the high-pressure thermophysical properties of biofuels, e.g., bulk modulus, surface tension, and viscosity is of paramount importance in fuel injection systems in diesel engines. Another crucial and dangerous phenomenon that may occur in biofuels at high pressures is phase transition (solidification), which can drastically increase the viscosity of the biofuel. This effect may hamper proper operation of the engine, especially under cold-start conditions. Unfortunately, the availability of high-pressure thermophysical properties of biofuels is still limited. The goal of this paper is to investigate the impact of high pressures on thermophysical properties of biofuels on the example of rapeseed fatty acid methyl esters (RME) in a wide range of pressures (0.1to250MPa) and temperatures (5to20°C). To this end we employed innovative ultrasonic techniques, i.e., the Bleustein-Gulyaev surface acoustic waves for measuring RME viscosity, and ultrasonic bulk compressional waves for measuring sound velocity in RME and consequently evaluating RME thermophysical parameters, e.g., bulk modulus and surface tension. The viscosity of the measured RME displayed an abrupt increase at pressures: 260 MPa (t=20°C), 230 MPa (t=15°C), 190 MPa (t=10°C), and 130 MPa (t=5°C). Evidently it was a signature of the phase transition (solidification) occurring in the RME. The discovered high viscosity high-pressure phase in RME can be very detrimental for operation of modern common rail Diesel engines. Therefore, the results of research presented in this paper should be interesting for engineers and designers working with modern common rail Diesel engines using biofuels.

Investigation on Combustion and Emission Performance of a Common Rail Diesel Engine Fueled with Diesel/Biodiesel/Polyoxymethylene Dimethyl Ethers Blends

Polyoxymethylene dimethyl ethers (PODEs) are an excellent blend for diesel due to their high cetane number, high oxygen content, and low viscosity. Combustion and emission characteristics are investigated based on experimental tests on a turbocharged, in-line 6-cylinder, common rail diesel engine. Results show that combustion starts earlier with PODE blending at low and partial loads. With pilot and main injection, the peak combustion pressures and peak heat release rates of diesel/biodiesel/PODE blend fuels increase due to large amounts of reactive radicals formed in the pilot heat release stage. With an increase in load, a slight decrease in both peak combustion pressure and peak heat release rate is observed. At low loads, the CA10s, CA50s, and CA90s of diesel/biodiesel/PODE blend fuels advance, and both rapid combustion and late combustion phases shorten. At medium and high loads, CA10s advance, CA50s remain unchanged, and CA90s clearly advance. Rapid combustion phases increase very little, whereas th...

Performance of a common rail diesel engine using biodiesel of waste cooking oil and gasoline blend

High viscosity, high pour point and low volatility are the major application blocks for biodiesel. In this study gasoline is mixed with biodiesel and they can be soluble with each other at any proportion. Combustion and emission characteristics are investigated on a turbocharged, in-line 6-cylinder, common rail diesel engine. Results showed that pour points, viscosities and distillation temperatures obviously decrease with gasoline ratio. Peak combustion pressures of biodiesel/gasoline blend fuels increase slightly. Ignition delays, peak heat release rates and combustion temperatures increase at partial and medium loads. HC and CO emissions increase at partial and medium loads and drop at high loads. NOX emissions of blend fuels grow by 4.2% and 6.7% compared with biodiesel averagely at 1400r/min, while soot emissions decline by 31.6% and 38.6%. For ultrafine particles (<220 nm), diameters to peak number concentration of blend fuels are smaller than that of biodiesel. Number concentrations decrease by 30% and 49% averagely compared to biodiesel. Especially, gasoline plays a significant reduction role on ultrafine particles at low and medium loads and soot emissions at high loads.

Effects of hydrogen addition to the intake air on performance and emissions of common rail diesel engine

Abstract This paper reports an investigation of the engine performance and emissions of an engine burning hydrogen-enriched diesel fuel. Hydrogen was chosen as the secondary fuel for its renewability in the long term and overall sustainability as a fuel. A four-cylinder, four-stroke, 1.461-L diesel engine with a common rail injection system was used for our tests. The cylinder pressures, rate of heat releases (ROHRs), brake specific energy consumptions (BSECs), brake thermal efficiencies (BTEs), exhaust gas temperatures (EGTs), and exhaust emissions were investigated under 50 Nm, 75 Nm and 100 Nm engine loads at 1750 rpm. Diesel fuel was injected directly to combustion chamber while hydrogen was continuously inducted into the intake manifold at two different flow rates while the original settings of the engine's electronic control unit were preserved. Results showed that hydrogen enrichment decreased HC and CO2 emissions and ROHRs, and increased EGTs and cylinder pressures under all conditions we tested. NOx emissions decreased with a 20 lpm flow rate and increased with a 40 lpm flow rate. Hydrogen also had a positive effect on BSEC and BTE, especially with low engine loads. Overall, hydrogen enrichment increases efficiency and reduces carbon-based emissions, all without major engine modifications.

Effect of exhaust gas recirculation rate on performance, emission and combustion characteristics of a common-rail diesel engine fuelled with n-butanol–diesel blends

ABSTRACTIncreasing fears of fossil fuel attenuation and tough emission protocols compel the research community to explore alternative renewable fuels for diesel engines. Butanol is desirable among renewable fuels due to its properties favorable to diesel engines. This study focused on the suitability of exhaust gas recirculation (EGR) and optimum injection timing on the performance, combustion and exhaust emission characteristics of common-rail direct-injection (CRDI) engine fueled with n-butanol-blended diesel using experimental and computational fluid dynamics (CFD) simulation. Various EGR rates and injection timings are considered for different butanol–diesel blends (0, 10, 20 and 30%). Obtained simulation results are validated with experimental data and found to be in good agreement. For all EGR rates and blends, nitrogen oxide (NO) emission is reduced drastically, whereas carbon monoxide (CO) and soot emissions are decreased moderately, with increase in n-butanol–diesel blends. The CO and soot emissions increase with EGR rate due to oxygen deficiency as well. Brake thermal efficiency is reduced by approximately 1% for neat diesel (Bu0) with increase in EGR rates. Soot emission for Bu30 (15 ° Before top dead centre (BTDC) is decreased by 23, 25, 24 and 26% for 0, 10, 20 and 30% EGR rates, respectively, compared to Bu0 (12° BTDC).

Performance, emission, and combustion characteristics of twin-cylinder common rail diesel engine fuelled with butanol-diesel blends.

Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NOx), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NOx, and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel.

Effects of different aromatics blended with diesel on combustion and emission characteristics with a common rail diesel engine

Aromatic hydrocarbons are thought to be the important components of diesel surrogate fuel. The studies on the effects of different aromatic hydrocarbons on diesel combustion process are of great significance. In this paper, experimental study was carried out on a modified single cylinder diesel engine to analyze the influences of different aromatics blended with diesel on the combustion and emission characteristics. Four typical aromatics (toluene, n-butylbenzene, tetralin and 1-methylnaphthalene) were selected and blended with commercial diesel fuel in 30% volume fraction to form the test fuels, respectively. Studies showed that the blending of aromatics resulted in the higher density and lower viscosity compared with traditional diesel fuel. Toluene lowered the distillation temperature of the mixed fuel to a large extent. The increases in both the ignition delay and the peak values of heat release rate were found in the experiments. The combustion duration was shortened especially for the multi-ring aromatics. It also increased maximum pressure rise rate remarkably at medium and high loads. As for the pollutant emissions, the higher CO emissions were detected at low loads for aromatics/diesel blends. The CO emissions of the multi-ring aromatics were higher than those of the single-ring aromatics and commercial diesel. HC emissions of the multi-ring aromatics were higher than those of diesel, while the single-ring aromatics had similar HC emissions to those of diesel. Blending aromatics leaded to the higher NOx emissions at medium-high loads. Smoke emissions were improved due to the longer ignition delay. The peak value of particle number/size distribution curve was shifted to the small-size sides after blending aromatics, in which the single-ring aromatics showed higher particle emissions than multi-ring aromatics.

Common Rail 디젤기관에서 연료 분사량 변화에 따른 기관 성능에 관한 실험적 연구

Common Rail 디젤기관에서 연료 분사량 변화에 따른 기관 성능에 관한 실험적 연구

커먼레일 디젤엔진의 흡배기밸브 타이밍 개선을 통한 연비절감에 대한 수치해석적 연구

커먼레일 디젤엔진의 흡배기밸브 타이밍 개선을 통한 연비절감에 대한 수치해석적 연구

Optimum ratio of compressed biomethane gas as dual fuel in turbocharged common rail diesel engine

During the world faced a crude oil price crisis, the selling price of all fuel types increased considerably. Commercial carriers that use vehicles installed with the turbocharged common rail diesel engine (TCRD Engine) attempted to find methods to reduce the fuel cost. One of the many alternative methods was the use of compressed biomethane gas (CBG) together with diesel, which was called as the dual fuel. In general, the amount of CBG supplied into the engine is mostly adjusted to be in the highest ratio without taking care of the influences on the engine and the environment. In order to introduce a guideline to adjust the CBG dual fuel correctly, this study has been conducted with objectives as follows: (i) to study the optimum ratio of CBG on unmodified TCRD engine, (ii) to describe the effect of critical factors on the optimum duration of CBG injection, and (iii) to analyze the fuel cost and the economical break-even point. The test was conducted on a 2.5L, four-cylinder, four-stroke, TCRD Engine in which the crankshaft end was coupled to the hydraulic dynamometer for measuring and controlling the torque to be constant as the reference torques obtained from the use of the pure diesel. The study found that the trend of variation in the optimum ratio of CBG significantly depended on the trend of the optimum duration of CBG injection, that is, increasing in low engine speed ranges, being constant at relatively high values during medium to high engine speeds, and, finally, decreasing to reach the lowest at the highest engine speed that the CBG can be supplied safely. The critical factors to define the optimum ratio of CBG consisted of smoke opacity in exhaust gas, exhaust gas temperature, and engine knock, which dominated differently for each of the different values of engine speed and torque. The analysis on fuel consumption and fuel cost showed that although the brake specific fuel consumption (BSFC) of the CBG and diesel dual fuel was higher than that of diesel, the fuel cost of the dual fuel was less than that of diesel because of the lower price of the CBG. This study also presented that CBG could be safely used as a dual fuel in unmodified TCRD engines if suitable critical factors to limit the optimum ratio of CBG were defined. Moreover, CBG was confirmed as suitable for use as the dual fuel with diesel without modification of the engine except the installation on the gas supply system. Therefore, these results can be followed to promote a decrease in the overall cost in the use of the TCRD engine in commercial transportation with high effectiveness and safety to the engine and the environment.