Common Rail Direct Injection Research Articles

Paradigm analysis of performance and exhaust emissions in CRDI engine powered with hydrogen and Hydrogen/CNG fuels: A green fuel approach under different injection strategies

An engine with common-rail direct injection diesel uses Hydrogen and hydrogen-enriched CNG to investigate their possible usage. The engine's air intake manifold delivers hydrogen/CNG and hydrogen mixes. Different injection pressures (three) and at higher load are used to test out the different engine output parameters. In dual and single-fuel operations with diesel, dual-fuel operations produce higher in-cylinder pressure (73.39 bar) and shown better combustion. Due to induction of dual fuel, there is large variability in ignition delay and combustion duration compared to pure diesel. Enriching hydrogen reduces specific fuel usage. Significant reduction in engine pollutants is observed in dual fuel mode compared to diesel fuel. Hydrogen substitutes reduce THC and CO2 emissions by 30–35% and 3–4% respectively. Dual-fuel operations emit less smoke (5–10%) in different injection pressure than diesel. At all injection pressure the different combustion parameters, performances (37.2% better than D100) and emissions like NOx, CO2, and smoke are better for all dual-fuel than diesel at rated load for the different fuel approach type two (DFA2).

Experimental investigation of the influence of ethanol and biodiesel on common rail direct injection diesel Engine's combustion and emission characteristics

This study aims to characterize the effect of oxygenated biofuels in diesel engine combustion, thermal efficiency, and emission by blending different percentages of ethanol and biodiesel with fossil fuel derived diesel. In this research, 5% and 10% by weight of bioethanol were added to commercial B10 (10% biodiesel and 90% diesel), B20 (20% biodiesel and 80% diesel) and B100 (100% biodiesel) and experimented on using a 3 L four-cylinder common rail diesel engine. The experiment was performed under three engine speeds of 1000 rpm, 1500 rpm, and 2000 rpm with three constant engine torques of 56 Nm, 84 Nm, and 140 Nm. The results show that ethanol-biodiesel-diesel ternary blended fuels are higher in premixed combustion pressure and net heat release rate (NHRR) peaks. The cumulative heat release of ethanol blended fuels is also higher for ethanol blended fuels. The fuel consumption increased with the ethanol and biodiesel percentage in the blended fuels due to the lower heating value while the brake thermal efficiency did not decrease. It was clearly observed that the particle emission could be reduced by more than 50% when ethanol and biodiesel percentage increased.

Experimental Investigation on Effects of Fuel Injection Timings on Dimethyl Ether (DME) Energy Share Improvement and Emission Reduction in a Dual-Fuel CRDI Compression Ignition Engine

The impacts of different fuel injection timings (base (15BTDC) and retarded (12BTDC)) on a single cylinder common rail direct injection (CRDI) compression ignition (CI) engine under dual fuel mode (DME-diesel) was examined at the maximum torque with the engine speed of 2200 rpm. The diesel (liquid) fuel was directly injected into the engine’s cylinder at the end of the compression stroke and Dimethyl ether (gas) fuel was injected into the intake system of the engine during the suction stroke. The maximum DME energy share (DME ES) with base injection timing (15BTDC) under controlled auto-ignition (CAI) is limited to 52%. Delayed injection timing prevents knock occurrence to a certain extent due to the lower peak combustion pressure and temperature. The DME energy share (DME ES) without knocking is extended to 58% with delayed injection timing (12BTDC). Three stages of combustion (low-temperature region, high-temperature region and diffusion combustion region) were observed under DME-diesel mode. The low-temperature region (LTR) occurs at the temperature range from 700–900 K whereas high-temperature region (HTR) was at the temperature beyond 1000 K. The cyclic variations with the coefficient of variation (COV) of the important parameters (peak in-cylinder pressure, peak rate of pressure rise and indicated mean effective pressure) were analyzed. NOx emission decreased along with zero smoke emission. However, the other emissions such as CO, HC increased marginally with retarded timing. The notable point emerged from this study is that the retarded injection timing is a promising strategy for enhancement of DME energy share with reduced emissions.

Experimental investigation of a novel quaternary blend for CRDI engine: performance, emission, and combustion characteristics

ABSTRACT The shortage-inflation of fossil fuels and aggravation of pollution intensity have initiated the search for innovative biofuel blends. Binary and Ternary fuels are studied for a long time. The use of biodiesel/vegetable oil up to 5–20% can replace fossil fuel with little modification in engine. However, to replace fossil fuel dependence up to 30–40% with little or no modification in engines is a challenge to researcher. This can be approached to evaluate a novel biofuel mix pattern called optimum Quaternary Blend by the experimental investigation. The main objective of the present research is to replace conventional Diesel with biofuels 30–40% with innovative fuel mix and lesser NOx-soot emission. In view of this, experimentally investigated combustion, emission, and performance behavior of single cylinder Common Rail Direct Injection (CRDI) engine fueled by quaternary blends combination of diesel (60–70 vol %), vegetable oil (Cotton Seed Oil – 5 vol% fixed), biodiesel (Mahua Biodiesel 5–25 vol %), and bio-alcohol (n-butanol 10–25 vol %). Further, to compare engine characteristics with D100% and D50B50%. Engine performance measures like brake thermal efficiency, specific energy consumption, emissions, and combustion characteristics such as rate of pressure rise (RPRR), combustion duration, CA50, CA90, mean gas temperature, combustion-chamber pressure, and net heat release rate are studied. It is noted that Diesel 60%, cotton seed oil 5% with mahua biodiesel 15–20%, and n-butanol 20–15% showed superior quaternary blend among all fuels. This optimum quaternary blend QB3-QB4 showed relatively higher brake thermal efficiency 8% more at lower specific energy consumption 10 MJ/kg about 29% less compared to other blends. Also, controlled combustion with rate of pressure rise 8.6 bar/deg CA about 14% less compared to other fuels. The NOx 10% less and smoke 2% less reported by optimum quaternary blends QB3 compared to other blends. However, CO emissions are noted least with marginal penalty in HC emissions.

Combustion and Emission Characteristics of a Diesel Engine Fueled with Crude Palm Oil Blends at Various Idling Speeds

At present, the preparation cost of biodiesel is still higher than that of diesel. Thus, directly using vegetable oil before transesterification can greatly reduce the cost. This study investigated the application characteristics of the direct use of crude palm oil (CPO) in a common rail direct injection (CRDI) diesel engine. In this study, the combustion characteristics, engine performance, and emission characteristics of the CRDI diesel engine operated with CPO0 (neat diesel fuel), CPO10 (10% CPO blended with 90% diesel fuel by volume), CPO30 (30% CPO blended with 70% diesel fuel by volume), and CPO50 (50% CPO blended with 50% diesel fuel by volume) at three idling speeds (750 rpm, 1500 rpm, and 2250 rpm) were evaluated. The results obtained from the experiment elucidate that combustion starts earlier by increasing the idling speed. The addition of CPO to diesel fuel resulted in a decrease in the peak in-cylinder pressure at all idle speeds and a decrease in the maximum heat release rate (HRRmax) at 750 and 1500 rpm, but an increase in HRRmax at 2250 rpm. On the other hand, increasing idle speed is beneficial for reducing carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), but it increases smoke emissions. In addition, adding 10% and 30% CPO to diesel fuel can reduce both HC, NOx, and smoke emissions simultaneously.

Comparison of ethanol/diesel fuel dual direct injection (DI2) strategy with reactivity controlled compression ignition (RCCI) in a diesel research engine

The dual direct injection (DI2) strategy is expected to cover the advantages of conventional diesel (CDI) mode while avoiding deficiencies of reactivity controlled compression ignition (RCCI) strategy such as high amount of incomplete combustion emissions and extremely high rate of pressure rise. Therefore, the present study focused on the comparison of combustion characteristics of these combustion modes in a diesel research engine, which was firstly operated under CDI mode at varying loadings and a constant speed of 2400 rpm to establish the reference data. Then, a low pressure port fuel injection (PFI) and high pressure gasoline direct injection (GDI) systems were activated to run on RCCI and DI2 modes, respectively, whereas test engine was already equipped with a common-rail direct injection (CRDI) system for conventional diesel fuel injection. Results showed that both direct and port injection methods increased the in-cylinder pressure (up to 9%) compared to conventional mode. In RCCI combustion, the rate of pressure rise increased more than direct injection and conventional mode. CDI exhibited higher thermal efficiency than RCCI and DI2 modes while both advanced modes were successful in reducing NOx and Smoke Opacity. However, significantly higher CO and unburned HC emissions were observed with both advanced modes in comparison to conventional one. Both CO and unburned HC emissions were reduced by direct injection of ethanol (DI2 strategy) at the rates of 16% and 35% compared with port injection method of RCCI strategy. This is an important finding of this study, which shows that the DI2 strategy has a potential to address a deficiency of RCCI and will bring it closer to its application to practical engines.

Study on interactive effects of CRDi engine operating parameters through RSM based multi-objective optimization technique for biofuel application

The current research focuses on the optimization of D+LPO (20% waste-based lemon peel oil and 80% diesel) fueled Common Rail Direct Injection (CRDi) engine fuel injection parameters for the optimum performance and emission characteristics. The foremost influential fuel injection parameters such as Injection Pressure (IP), Dwell Time (DT), Pilot Mass (PM) and Pilot Timing (PT) are considered to enhance the performance and decrease the emissions. Engine output responses like Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC), Hydrocarbons (HC), Carbon monoxide (CO), nitrogen oxides (NOx) and smoke emissions are modeled by using Response Surface Methodology (RSM). Analysis of Variance (ANOVA) disclosed that all the developed models are statistically significant with an R2 value of 0.9735 for BTE, 0.9719 for BSFC, 0.8517 for CO, 0.956 for HC, 0.9282 for NOx and 0.927 for smoke. Multi-objective optimization is performed using the desirability function approach to minimize the BSFC, HC, CO, NOx and smoke with maximum BTE. The D+LPO blend at IP 700 bar, PM 20%, PT 27°bTDC and 12° DT was predicted to be an optimum operating condition for this particular engine. Confirmatory tests were used to validate the predicted combination, and the prediction error was determined to be less than 5%.

Effect of injector nozzle parameters on fuel consumption and soot emission of two-cylinder diesel engine for vehicle

In this paper, a bench test of a two-cylinder diesel engine with high-pressure common rail direct injection (CRDI) system for the external characteristics was carried out. The shape of combustion chamber was determined by comparing the fuel economy and soot emission of diesel engines. Based on this result, the effects of different nozzle parameters attempted at reducing brake specific fuel consumption (BSFC) and smoke were investigated. The experimental results show that the improved combustion chamber with a high central convex platform can significantly reduce BSFC and it has little impact on smoke. The appropriate decrease of the nozzle tip penetration (NTP) as well as increase of nozzle-hole diameter contribute to reducing fuel consumption and soot emission. The BSFC at the spray angle of 156° is reduced by 16% at the engine speed of 4000 r/min compared with that at the spray angle of 150°. Comparative results on fuel consumption and smoke emission at all engine speeds reveal that the injector with 153° spray angle, 1.8 mm NTP, 6 injection holes and 0.12 mm nozzle-hole diameter is a better choice of the two-cylinder diesel engine.

Effect of biomethane substitution on combustion noise and performance of a dual fuel common rail direct injection diesel engine

AbstractRising pollution levels and stringent emission regulations have raised the requirement for the utilization of alternative green fuels as a sustainable energy source for engine applications. The economic and environmental benefits of using biomethane or renewable natural gas (>95% methane) in diesel engines have made it a promising solution. Sound levels caused by combustion noise, however, is an area of concern in the early stages of engine development process, and to the best of our knowledge studies related to the impact of gaseous fuel energy share on combustion noise in dual fuel diesel engines have not been reported in the literature. In the present work, experimental research on the combustion noise of a biomethane augmented dual fuel common‐rail direct injection (CRDI) diesel engine has been carried out with a correlational design of its performance and combustion characteristics at various engine operating conditions. Comparative results on combustion and performance characteristics of different fuel compositions at various engine loads revealed that there is a better utilization of gaseous fuel at full load conditions resulting in improved power output and reduced heat transfer losses. Cylinder pressure spectra derived from recorded in‐cylinder pressure were used for carrying out the quantitative analysis of sound levels. The results suggested that an increment in methane share is effective in controlling the sound pressure levels to 95 dB (at 1.5 Newton‐meter [Nm] and 13.5 Nm loading conditions) and it is lower than the diesel‐only operational levels at all loading conditions.

Enhancement of engine characteristics through zirconium nano particle addition and split injection parameter optimization for the adaptability of eucalyptus biofuel in diesel engine

The ever-growing demand for fuel sources, the rising prices of gasoline and diesel, and the harmful exhaust gases in the atmosphere are a few of the many reasons why biofuels need to be utilized. The use of eucalyptus oil as biodiesel in compression ignition (CI) engines shows promising results under numerous conditions, with properties such as high volatility and low viscosity and it innately emits lesser emissions during combustion. In a fully accelerated engine setup, key factors such as the performance and emissions of the engine are optimized using statistical techniques. The research involves a structured approach to investigating the capability of a 20% volumetric blend of eucalyptus oil (Eu20) mixed in diesel and is compared with a diesel under commensurable conditions. The ordered experimentations are performed on a common rail direct injection (CRDi) engine setup using the central composite design (CCD) along with Response Surface Methodology and desirability tests for easier calibration. All the optimal engine inputs are obtained from the developed multivariate regression model. Interaction effects are employed to identify the most influential factor through monitoring the interaction of two specific input factors on a single response. From the desirability tests, predicted with the highest desirability of 0.974, the optimal responses recorded are brake thermal efficiency (BTE) of 16.766%, brake specific fuel consumption (BSFC) of 0.516 kg/kW-hr, carbon monoxide (CO) of 0.17%, hydrocarbon (HC) of 16.22 ppm and oxides of nitrogen (NOx) of 77.565 ppm. Moreover, confirmatory tests are performed on the engine with responses having an error below 8%. From this experimentation, it has been found that the heating value of eucalyptus oil leads to lower BTE and higher fuel consumption rate even after the optimization. So that, to enhance the performance characteristics of the engine, the zirconium oxide (ZrO2) nanoparticles are mixed with the Eu20 at 50 and 100 ppm concentrations. While testing for the optimized parametric condition, the nanoparticle mixture sample delivers enhanced thermal efficiency and reduced fuel consumption rate than the Eu20.

Effect of injection timing on combustion, emission and particle morphology of an old diesel engine fueled with ternary blends at low idling operations

Currently, idling emissions and old vehicle emissions have attracted more and more attention. Many countries have made corresponding policies to limit these emissions. In this study, to investigate the combustion, engine performance, and emission characteristics of an old diesel engine fueled with diesel-palm biodiesel-ethanol (DPE) ternary blended fuels according to various multiple injection strategies under low idling conditions, a series of experiments were carried out on an old common-rail direct injection (CRDI) diesel engine. The engine speed and load were fixed at 750 rpm (the lowest speed) and 30 Nm, respectively. Two test modes of A (only pilot injection timing was variable) and B (only main injection timing was variable) were comparative studied. The experimental results show that the main-pilot injection timings and DPE ternary blends have significant impacts on the engine performance, combustion and characteristics. Overall, as the ethanol concentrations in DPE ternary blends increase, brake specific fuel consumption (BSFC), maximum heat release rate (HRRmax), ignition delay, carbon monoxide (CO) and hydrocarbon (HC) emissions increase, while nitrogen oxides (NOx) and smoke emissions are simultaneously reduced. The high volatility, high latent heat of evaporation and high oxygen content of ethanol may play a major role in reducing NOx and smoke emissions. In addition, the primary particle diameter of all tested fuels is distributed in a narrow range of 18–24 nm, and the addition of ethanol is beneficial to reduce the particle diameter.

A study on flexible dual-fuel and flexi combustion mode engine to mitigate NO, soot and unburned emissions

In the present study, an existing commercial light-duty automotive diesel engine is modified to a flexible dual-fuel engine (FDFE). The FDFE operates with different low and high reactivity dual fuel combinations under low temperature combustion (LTC) mode using combined multipoint fuel injection and common rail direct injection systems. The FDFE can smoothly transit between LTC and conventional diesel combustion (CDC) mode. FDFE combines SI and CI benefits and stands as a potential internal combustion engine for future hybrid electric options. In this study, the modified engine was operated in flexi fuel mode with methanol/diesel, methanol/biodiesel, methanol/dimethyl ether (DME), methanol/polyoxymethylene dimethyl ether (PODE), (methanol + Isobutanol blends)/diesel and (methanol + PODE blends)/diesel in LTC strategy at a different speed and torque conditions. This approach improved the brake thermal efficiency by 8%, decreased NO and soot emissions by more than 90% compared to CDC mode. The improvement in brake thermal efficiency reduced CO2 emissions compared to CDC mode. In the FDFE engine, combustion phasing and fuel energy input are maintained as same as in CDC mode to investigate the dual-fuel effects in LTC mode over a neat diesel mode. Experimental study with energy and exergy analysis was carried out to assess the technical suitability of the FDFE as compared to the conventional diesel engine. The results proved that without relying on the after- treatment systems and fossil fuels, it is possible to reduce the NO, soot, unburnt hydrocarbon, carbon monoxide and CO2 emissions from the diesel engine, paving the way for extending the life of the diesel engine.

Effect of Injection Parameters on the Performance of Compression Ignition Engine Powered with Jamun Seed and Cashew Nutshell B20 Biodiesel Blends

Renewable fuels are alternative resources that find use in the power generation, agricultural, and transportation sectors. The sustainable utility of these renewable fuels mostly addresses the socio-economic issues of a country and reduces its dependency on fossil fuels. In addition, being environmentally friendly allows them to handle global warming more effectively. Two B20 fuel blends were produced using methyl esters of cashew nutshell and jamun seed oils to test the performance of the common rail direct injection engine. To improve the engine performance, injection parameters such as nozzle geometry, injection time, and injector opening pressure are used. Improved brake thermal efficiency and lower emissions of smoke, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) were achieved with the help of advancing the injection timing, raising the injector opening pressure, and increasing the number of injector nozzle holes. In addition to reducing the ignition delay, extending the combustion duration, and increasing the peak pressure, the revised injection settings also boosted the heat release rates. At the maximum load, compared to CHNOB B20, JAMNSOB B20 showed a significant rise in the brake thermal efficiency (BTE) by 4.94% and a considerable decrease in smoke emissions (0.8%) with an increase in NOx (1.45%), by varying the injection timing, injection pressure, and nozzle geometry of the common rail direct injection (CRDI) engine.

Experimental investigation on effects of equivalence ratio on combustion with knock, performance, and emission characteristics of dimethyl ether fueled CRDI compression ignition engine under homogeneous charge compression ignition mode

This study deals with the effects of different equivalence ratios on combustion with a knock, performance, emissions of a DME fueled automotive CI engine under HCCI mode. The conventional common rail direct injection (CRDI) CI engine was modified to run with DME fuel (manifold injection) under HCCI mode. The experiments were conducted on the engine at different equivalence ratios at a constant speed of 1400 rpm. Two stages of combustion (low-temperature reaction (LTR) region and high-temperature reaction (HTR) region) were observed under HCCI mode. The LTR region occurs at the temperature range from 700 to 750 K. In contrast, the HTR region was at a temperature beyond 1000 K. The cyclic variations with the coefficient of variation (COV) of maximum in-cylinder pressure, indicated mean effective pressure with knock peak pressure and knocking intensity (KI) were analyzed for assessment of combustion stability. Based on the knocking intensity, the optimum equivalence ratio with controlled auto-ignition (CAI) was found as 0.55, with peak in-cylinder pressure of 70.87 bar and peak in-cylinder temperature of 1815 K. The COV for all the parameters and KI found below the limit value (COVlimit − 5% and knocklimit − 5 MW/m2) till 0.55 equivalence ratio and beyond the equivalence ratio, the knock occurred resulting in uncontrolled auto-ignition (UAI). Ultra-Low NOx (10–15 ppm) and zero smoke emissions with a considerable reduction in CO and HC emissions were observed at a higher equivalence ratio from DME fueled HCCI mode. However, CO and HC emissions were higher at lower equivalence ratio. This study shows that the simultaneous reduction of NOx and smoke emissions could be achieved in a DME fueled HCCI engine.

An experimental study on biodiesel production and impact of EGR in a CRDI diesel engine propelled with leather industry waste fat biodiesel

The purpose of the predominant endeavor is the way of through an experiment aspect for the reticular effect of exhaust gas recirculation (EGR) on combustion, performance, emissions besides energy characteristic of common rail direct injection (CRDI) engine fuelled with leather industry waste fat biodiesel and diesel blends. Biodiesel was converted by the transesterification process from the raw fat oil extracted with leather waste fat feedstock. This work takes advantage of blends of both like B10, B20, B30 along with engines that were run with various EGR rates (5%, 10%, and 15%) to evaluate engine outcome parameters. The maximum in-cylinder pressure was examined with the blend B20 with EGR 5% rate about 6.65% higher than pure diesel fuel. The high heat release rate (HRR) was ascertained with the blend B30 with EGR 10% rate about 23.81% higher than neat diesel fuel. The brake thermal efficiency (BTE) for the blend B10 with EGR 5% rate is higher than other test conditions but 4.2% let down associated with simple diesel fuel. The nitrogen oxides (NOx) were lesser than the clean diesel fuel at all test fuels, the highest NOx emission reduction was achieved in blend B30 with EGR 15% rate of about 87.59% than neat diesel fuel operation. The smoke opacity increased by raising the EGR level, the combination B30 with EGR 5% rate displayed low smoke opacity about 64.5% lower than neat diesel fuel. The hydrocarbon (HC) emission was lower than neat diesel at a low EGR rate, the blend B10 with EGR 5% rate displayed the lowest HC emission about 85.71% decreased then neat diesel operation. The carbon monoxide (CO) emission displayed lower than neat diesel at low EGR rate, the blend B10 with EGR 5% rate displayed the lowest CO emission about 50% than neat diesel. As of energy analysis, it was noted that the heat equivalent to brake power and heat lost to engine cooling water is higher in diesel fuel than biodiesel blends and the heat lost to exhaust gases and heat unaccounted loss were lower in diesel than biodiesel blend. Finally, the TOPSIS optimization study was carried out for finding the optimum input conditions which could result in improved combustion, performance, and reduced emissions. The B30% blend with EGR 15% at full load achieved 1st rank with 0.849 relative closeness value. So, this operating condition was projected as the best prospect for the application of a CRDI diesel engine.

Wavelet analysis for cyclic combustion dynamics of a multi-cylinder CRDI diesel engine fuelled with a blending of argemone biodiesel-diesel oil.

Higher cyclic variability in combustion adversely influences emissions, efficiency, and driveability of internal combustion engines. In this paper, we used wavelet transform techniques to investigate the dynamical characteristics of a combustion process in numerous combustion parameters of a 4-cylinder turbocharged common rail direct injection (CRDI) diesel engine fuelled with Argemone mexicana biodiesel (AGB)/diesel blended fuel. In addition, statistical analysis is described to validate the results of the wavelet spectrum methods for cyclic variation in the diesel engine. The results show that the cyclic variations in IMEP and Pmax are sensitive to the engine load and fuel properties. The coefficient of variation of both combustion parameters decreases as engine load increases for all tested fuels. Moreover, adding Argemone mexicana biodiesel (AGB) into diesel fuel up to 20% (AB20) reduces cyclic variations in combustion parameters at all tested engine loads. Furthermore, the global wavelet spectrum and wavelet power spectrum are utilized to identify the dominant oscillatory combustion modes. The cycle-to-cycle fluctuations in combustion parameters (i.e., IMEP and Pmax) exhibit multi-scale dynamics for all experimental conditions. Compared to long and intermediate oscillations in diesel fuel, AB10 and AB20 fuel showed short and intermittent period fluctuations. The findings of this experimental work will be helpful to optimize engine control strategies for AGB/diesel blended fueled multi-cylinder CRDI diesel engines.

Spray Behavior, Combustion, and Emission Characteristics of Jet Propellant-5 and Biodiesel Fuels with Multiple Split Injection Strategies

This study focuses on an analysis of the spray behavior, combustion, and emission characteristics of jet propellant-5 (JP-5) and biodiesel fuels with single-injection timing and multiple split injection strategies in a common rail direct injection (CRDI) single-cylinder diesel engine system. The analysis includes visualization of the spray and combustion. Multiple split injection strategies (e.g., double, triple, quadruple, and quintuple) were considered by equally distributing the fuel injection amount within the single-injection. Injection of biodiesel has a delayed start (0.2 ms) as well as shorter spray tip penetration compared with JP-5. As the fuel injection timing was approached to the top dead center (TDC), the engine performance and combustion efficiency improved. Retarding the injection timing contributed to an increase in carbon dioxide (CO2) (JP-5: max. 2.6% up, BD100: max. 1.5% up) and a decrease in carbon monoxide (CO) (JP-5: max. 93% down, BD100: max. 91% down) and nitrogen oxides (NOx) (JP-5: max. 83% down, BD100: max. 82% down). In comparison with JP-5, biodiesel showed disadvantages from the point of its combustion and emission characteristics for all injection timings. The quadruple-injection strategy, in which fuel injection was performed four times, showed excellent combustion, engine performance, and combustion efficiency. The CO2 emissions were highest with the quadruple-injection strategy (JP-5: 6.6%, BD100: 5.8%). The CO emissions of biodiesel decreased as the pulses of split injection extended, and a significant reduction of 83.8% was observed. NOx increased as the number of split injections increased (JP-5: max. 37% up, BD100: max. 52% up). JP-5 was a longer ignition delay than that of biodiesel from combustion flame visualization results. The final combustion in the multiple-injection strategy showed a typical diffusion combustion pattern.

Experimental evaluation of direct injection diesel engine performance and emissions with acacia biodiesel

Bharath’s sixth stage emission benchmark norms are stringent as per the global Emission norms, and their implementation is a great concern. The current Bharath stage VI emission norms were implemented on 1 April 2020. The aim of this work is to study the engine performance and emissions when the engine is fuelled by a new and unique bio-diesel. The engine selected for this experimentation is a Kirloskar , single-cylinder, 4-stroke and water-cooled, common rail direct injection (CRDi) diesel engine. The biodiesel was drawn from the Acacia seeds, which are available in plenty most of the places in South India, especially like Andhra Pradesh, Tamil Nadu and Karnataka . The oil was extracted from the dry acacia seeds and sent through a motorised expeller. The oil expelling efficiency is 19%, the available oil content is 220 ml, out of it 190 ml of oil was extracted, whereas with a hand-operated expeller, it was 16%; hence there is an improvement of 3%. The oil has been verified with FFA content and had 1.0%. FFA content single-step transesterification process is selected, which has yielded 97%. Experiments were conducted at 500 bar with a single injection, 500 bar with the main injection 15 degrees b TDC, pilot injection 23 degrees b TDC and 500 bar with B10 a single injection and 200 bar with the main 15 degrees b TDC, pilot injection 23 degrees b TDC. The results were observed when the engine was running with 15 degrees main injection and 23 degrees pilot injection strategy.

Effect of split injection strategies on diverse characteristics of a common rail direct injection diesel engine operating with diesel-palm oil-ethanol micro-emulsions

This study investigated the effect of pilot injection timing (PIT) and pilot injection quantity (PIQ) on the performance of a common rail direct injection (CRDI) diesel engine with two-stage injection system operating with diesel-palm oil-ethanol micro-emulsions. The results indicated that, at low engine load, the maximum in-cylinder pressure (Pmax) and peak of heat release rate (HRR) of D35P35E30 were highest, and those of D100 were lowest. At high engine load, the Pmax of D100 was highest, that of D60P30E10 was lowest, and the peaks of HRR were almost identical for all test fuels. The Pmax and peak of HRR were slightly increased with the advance of PIT. Increasing PIQ increased the first peak of HRR and reduced the second one. At low engine load, the coefficient of variation (COV) of Pmax and the indicated mean effective pressure (IMEP) presented a slight decrease for the micro-emulsions, but did for D100 at high engine loads. The brake specific fuel consumption (BSFC) of the micro-emulsions was higher, and the brake thermal efficiency (BTE) was also slightly higher when compared with diesel (D100). With the advance of PIT and the increase of PIQ, BSFC was increased, BTE was decreased, and hydrocarbon (HC) emissions were reduced. The variation of PIT and PIQ had little effect on the particle number concentration (PNC), but had evident effect on nitrogen oxides (NOx) emissions. It was concluded that the micro-emulsions can be used to reduce NOx and particulate matter (PM) simultaneously combined with injection strategy in a diesel engine.

The effect of tri-fuel blends on engine characteristics of a direct injection diesel engine with exhaust gas recirculation

ABSTRACT Biofuels are the most promising alternative to petro-diesel. In this work, the combined effect of mahua biodiesel and 1-Hexanol is studied on the engine characteristics. The concentration of both 1-Hexanol and mahua biodiesel is varied, 10%, 20%, and 30% each with diesel fuel. Common rail direct injection diesel engine is used in this study. Engine load is varied from 20% to 80% in step of 20%, the speed of the engine is constant throughout the experiment. Biofuel blends showed improved cylinder pressure and mean gas temperature at a higher engine load. At 60% load, 10H10M80D (10% 1-Hexanol/10% mahua biodiesel/80% diesel) showed 3.45% lower thermal efficiency and 6.11% higher fuel consumption compared to diesel. At 60% load, all the biofuel blends showed 50% lower carbon monoxide emission. At 60% load, 10H10M80D showed 33.33% lower hydrocarbon emission and 0.96% higher nitrogen oxide emission compared to baseline readings. The biofuel blends are less sensitive to exhaust gas recirculation (EGR) due to the oxygenated nature of biofuels. With 20% EGR, at 60% load, 10H10M80D showed 39.48% lower nitrogen oxide compared to no EGR. The results of 10H10M80D showed the best performance at all loads.