Common Rail Direct Injection Research Articles

Fuel Injection Strategy for Utilization of Mineral Diesel-Methanol Blend in a Common Rail Direct Injection Engine

AbstractMethanol fueled internal combustion (IC) engines have attracted significant attention due to their contributions in reducing environmental pollution and fossil fuel consumption. In this study, a single-cylinder research engine was operated on MD10 (10% (v/v) methanol blended with mineral diesel) and baseline mineral diesel to explore an optimized fuel injection strategy for efficient combustion and reduced emissions. The experiments were conducted at constant engine speed (1500 rpm) and load (3 kW) using two different fuel injection strategies, namely, single pilot injection (SPI) and double pilot injection (DPI) strategy. For each pilot fuel injection strategy, the start of main injection (SoMI) timing was varied from −3 to 6° crank angle (CA) before top dead center (bTDC). To examine the effect of fuel injection pressure (FIP), experiments were performed at three different FIPs (500, 750, and 1000 bars). Results showed that the MD10 fueled engine resulted in superior combustion compared with baseline mineral diesel, which was further improved by DPI at higher FIPs. The use of DPI strategy was found to be more effective at higher FIPs, resulting in higher brake thermal efficiency (BTE), lower exhaust gas temperature (EGT), and reduced oxides of nitrogen (NOx) emissions compared with SPI strategy. Detailed investigations showed that the addition of methanol in mineral diesel reduced particulates, especially the accumulation mode particles (AMP). Different statistical analysis and qualitative correlations between fuel injection parameters showed that higher FIP and advanced SoMI timings were suitable for particulate reduction from the MD10 fueled engine.

Significance of injection pressure on the overall performance of common rail direct injection engine using dairy scum oil methyl esters

The advantages of common rail direct injection engine, including more power, less noise and vibration, lower specific fuel consumption, precise injection timing and control over the mass of fuel injection, make the engine more popular and adoptable in all the transport vehicles by the automotive manufacturers across the world. The production and use of dairy products across the world is increasing rapidly and much of the scum obtained during the processing of dairy products is unused and discharged to atmosphere as a waste product which further leads to an adverse effect on the environment and grubby surroundings. The present study aims to use the dairy scum methyl esters in common rail direct injection engine for its adaptability and evaluate the engine performance in comparison with diesel fuel. Injection pressure is primarily the vital factor which persuades the performance of the engine, as the atomisation of the fuel depends on it. Hence, in the current study the injection pressure is augmented in the range 600–1000 bar by keeping the injection timing stable. The results revealed that the augmentation of pressure curved to raise the brake thermal efficiency and lessen the emissions.

Experimental analysis of a mini truck CRDI diesel engine fueled with n-Amyl alcohol/diesel blends with selective catalytic reduction (SCR) as a DeNOx technique under the influence of EGR

ABSTRACT The current work aims to investigate the compatibility of n-Amyl alcohol in a mini-truck common rail direct injection (CRDI) compression ignition (CI) engine with exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) as a DeNOx technique. The n-Amyl alcohol is a renewable biofuel it effectively mitigates the demand for fossil fuels and reduces greenhouse gas emission. Palladium and Rhodium coated SCR catalyst was used to reduce the nitrogen oxides (NOx) emission. For SCR of NOx ammonia was used as a reductant. From the experimental results, it was noted that with an increase in the percentage of alcohol in the blends, a slight drop in brake thermal efficiency (BTE) and higher brake specific energy consumption (BSEC) was observed. Both NOx and hydrocarbon (HC) emissions could be reduced with the use of n-Amyl alcohol and a combination of SCR and EGR techniques. The maximum reduction of NOx can be successfully achieved with the use of 40N60D (40% n-Amyl alcohol & 60% Diesel v/v) blend with SCR and 20% EGR at the slight cost of BTE. The engine can be successfully worked up to 40% of n-Amyl alcohol/diesel blends without causing any visible damage to the engine, with less NOx emissions. It is concluded that n-Amyl alcohol will be a sustainable next-generation biofuel for commercial vehicles.

Experimental investigation of algae biofuel–diesel blends on performance of a CRDI diesel engine

This paper presents the results of the investigations carried on a common rail direct injection (CRDI) diesel engine using algae biofuel–diesel blends. The algae biofuel–diesel blends considered were B10 and B15 (10% and 15% of algae biofuel are mixed with diesel on volumetric basis). The tests were conducted on CRDI diesel engine operated at a constant speed of 1500 rpm by varying the fuel injection pressure (FIP) from 600 to 1050 bar in steps of 150 bar. The results demonstrate that at high fuel injection pressure, i.e. 1050 bar, brake thermal efficiency (BTE) is highest and brake-specific fuel consumption (BSFC) is lowest when compared to other injection pressures. CO and HC emissions and smoke density significantly decreased with increase in injection pressures. However, NOx emissions are shown to be increased.

Artificial neural network approach on forecasting diesel engine characteristics fuelled with waste frying oil biodiesel

The present work investigates the influence of advanced injection strategy on a common rail direct injection assisted diesel engine characteristics fuelled with biodiesel and conventional diesel. Also, an artificial neural network is employed to forecast engine characteristics. Engine test is conducted under 100% load condition through an optimized nozzle opening pressure of 500 bar. Pre-injection timing is fixed permanently at 30 °CA bTDC, main injection timing varied from 15 °CA to 21 °CA bTDC and post-injection varied from 6 °CA bTDC to 6 °CA aTDC sequentially. However, the pre, main and post-injection quantities are changed respectively from 5% to 15%, 70% to 90%, and 5% to 15%. Minimum carbon monoxide, unburned hydrocarbon and smoke emission of 0.01% vol., 8 ppm and 1.59 FSN are achieved with pre-injection timing of 30 °CA, main injection timing of 21 °CA bTDC, and post injection timing of 6 °CA bTDC for B100-15%-70%-15%. Maximum brake thermal efficiency and nitric oxide emission of 34.3% and 1114 ppm are achieved in B100-5%-90%-5% at advanced injection timing and higher nozzle opening pressure. Artificial neural network models conform to experimental results having a lower root mean square error and correlation coefficient values in a range of 0.01 to 0.02 and 0.980 to 0.998 respectively. An artificial neural network is mostly preferred over other theoretical and empirical models to higher accuracy in predicting the output. Hence, multiple injection strategy fuelled biodiesel significantly decreased the emission and improved the performance compared to mechanical, single and split injection strategy.

저속 공회전시 커먼레일 디젤기관에서 디젤-팜오일 바이오디젤-에탄올 혼합연료의 연소 및 배기특성에 관한 연구

In this study, we investigated the effects of diesel-palm oil biodiesel-ethanol blends on combustion and emission characteristics in a 4-cylinder common rail direct injection (CRDI) diesel engine at low idling operations. The engine speed and engine load was 750 rpm and 40 Nm, while the main and pilot injection timing was respectively fixed at 2 °CA before top dead center (BTDC) and 20 °CA BTDC. The experimental results showed that the cylinder pressure increased with the increasing of palm oil biodiesel ratio from 20% to 100%. In addition, the peak value of cylinder pressure increased by 4.35% compared with pure diesel fuel when 5 vol.% ethanol oil added to diesel oil. Because the palm oil biodiesel and ethanol are the oxygenated fuel, the oxygen content played an important role in improving combustion. Based on the high oxygen content of biodiesel and ethanol, their mixing with diesel fuel effectively reduced PM emissions but increased NOx slightly, while CO and HC had no significant changes.

커먼레일 디젤기관에서 함산소 연료와 파일럿 분사시기의 변화가 연소 및 배기특성에 미치는 영향

In this study, the effect of various pilot injection timings on combustion and emission characteristics were investigated in a common-rail direct injection (CRDI) diesle engine fueled with diesel-ethanol blends. The engine speed and engine load were controlled at constant 1500rpm and 70Nm, respectively. The tested fuels were DE0 (pure diesel fuel), DE5 (5 vol.% ethanol blended with 95 vol.% diesel oil), DE10 (10 vol.% ethanol blended with 90 vol.% diesel oil) and DE15 (15 vol.% ethanol blended with 85 vol.% diesel oil). The main injection timing was fixed at 0°CA TDC (top dead center), while various pilot injection timings including 25°CA BTDC (before top dead center), 20°CA BTDC and 10°CA BTDC were selected as the experimental variable. The experimental results showed that various pilot injection timings had little effect on the peak value of cylinder pressure, but had great influence on the start of combustion. The peak value of heat release rate (HHR) increased with the increase of ethanol content. However, the peak value of HRR reduced as the pilot injection is delayed. The diesel fuel containing 10% ethanol had a highest peak value of combustion pressure compared with the others, while the pilot injection timing occurred at 25°CA BTDC. On the other hand, the exhaust emissions of DE10 was also the lowest compared with the others. In addition, with the increase of ethanol content in diesel the PM and NOx emissions reduced.

Effect of Mix waste cooking-oil biodiesel on performance and exhaust emissions of a CRDI engine

In fast-moving world, energy crisis and waste disposal are increasing day by day. To overcome the energy crisis, it is crucial that we consume less energy. The world contains potential resources to meet the demand of energy apart from electricity, highest demand among all sources. Hence to gear up the use of alternative methods from the wastes into an alternate fuel. The transportation is playing a major role in economic growth and globalization, but cause air pollution in all medium. In regard to crisis, biodiesel production from locally available mix waste cooking oil, which can be an major alternative to production of biodiesel apart from food resources. The aim of this paper is to extract the biodiesel from mix waste cooking oil using conventional methods and study the performance of B20 biodiesel blends with respect to best fuel injection time (IT), Injection opening pressure (IOP) and number opening holes in injector using common rail direct injection engine (CRDI). The experimental studies showed that waste cooking oil methyl ester (WCOME) at 27 deg before top dead centre and IOP 240 bar, B20 blend gives better results and 5 holes 0.3 mm injector nozzle give 31.7% Brake thermal efficiency, 37 HSU smoke, 37 ppm Hydrocarbon, 0.115% carbon monoxide of volume and reduce in 2% of nitrogen dioxide without any modification of engine.

The Effect of High Fuel Injection Pressure on CRDI Diesel Engine Fueled with Algae Biofuel

Experimental investigations were conducted to determine the performance & emission features of a common rail direct injection (CRDI) system using algae biofuel to aid diesel engine. The algae biofuel-diesel blends were taken in two different proportions, B10 & B15 (10% and 15% of algae biofuel is mixed with diesel on a volumetric approach). The tests were conducted on CRDI diesel engine at various injection pressures from 600 to 1050 bar with the difference of 150 bar. From the results it was exposed that at high fuel injection pressure (1050 bar), brake thermal efficiency (BTE) improved and brake specific fuel consumption (BSFC) reduced when related with other injection pressures. CO, HC &/smoke density significantly decreases with rise in injection pressures. However, NOx emissions are shown to be increased. At different load conditions, biodiesel algae are associated with higher exhaust gas temperatures.

Performance, emission and combustion characteristics of multi-cylinder CRDI engine fueled with argemone biodiesel/diesel blends

Present work dealt with the performance, emission and combustion characteristics of a 4-cylinder turbocharged, intercooled, common rail direct injection engine using argemone biodiesel-diesel blends. The physicochemical properties of biodiesel-diesel blends; AB10, AB20, AB30, AB50 and pure biodiesel were determined and compared with ASTM D6751. These blends were used for experimentation on 1.9L common rail direct injection (CRDI) engine at low load, part load and high load condition at a fixed rotational speed of 2000 rpm. It was observed that biodiesel blends perform better at part load and high load in comparison of low load condition. Maximum improvement of 5.58% in brake thermal efficiency (BTE) and 7.88% in brake specific fuel consumption (BSFC) were observed for AB20 at high load condition. Significant reduction in exhaust emissions (excluding NOx) were observed at part load and high load up to 30% blending of argemone biodiesel in diesel. At low load, less NOx emissions, higher HC and CO emissions were observed for all biodiesel-diesel blends. Also, no change in ignition delay was observed up to 20% blending of argemone biodiesel in diesel. AB30 and AB50 blends show a longer ignition delay in comparison of other tested blends. Higher in-cylinder pressure and heat release rate was found at all the test conditions except low load for AB20 blend. The 20% blending of argemone biodiesel can be used in engine to attain higher thermal efficiency with a penalty of higher NOx emissions. However, 30% blending of argemone biodiesel can be used to achieve almost similar brake thermal efficiency as that of petroleum diesel with less penalty of NOx emissions as imposed by AB20.

Experimental investigation of nano metal oxide blended Eucalyptus bio fuel on common rail direct injected diesel engine

An empirical study has been done using a mixture of aluminum oxide nanoparticles (ANPs) with Eucalyptus green fuel blend (EME20) in varied percentages to find out the impact of using it in a four stroke, single cylinder, common rail direct injection diesel engine. This research will detail about the experiments that have been conducted as well as the output of the investigation. The ANPs have been used in different proportions along with the Eucalyptus green fuel blend (EME20) utilizing an ultrasonicator and a homogenizer with cetyl trimethyl ammonium bromide (CTAB) as the cationic emulsifier. The tests have been done in a CRDI diesel engine at a constant speed of 1500 rpm using varied ANP-blended green fuel (EME20-ANP50 and EME20-ANP100) and the output have been contrasted with that of neat diesel and Eucalyptus green fuel blend (EME20). The investigative output shows a significant improvement in the break thermal efficiency and lesser hazardous pollutants (such as CO, HC and smoke) for the nanoparticles mixed in green fuel.

Assessment of combustion and exhaust emissions in a common-rail diesel engine fueled with methane and hydrogen/methane mixtures under different compression ratio

This study investigates the potential usage of the methane and hydrogen enriched methane in a turbocharged common-rail direct injection diesel engine. Methane and hydrogen/methane mixtures are sent through the air intake manifold of the engine. The engine is operated at four different loads and three different compression ratios. Results are compared amongst single diesel and dual-fuel operations at different compression ratios and load conditions. Compared to diesel, dual-fuel operations mostly generate higher and advanced peak in-cylinder gas pressure, more combustion noise, late pilot injection and start of combustion, advanced combustion center, substantial variations at ignition delay and combustion duration, a significant increase in cyclic variations at low and medium loads, and earlier heat release. Hydrogen enrichment decreases evidently specific fuel consumption. Concerning emissions, compared to diesel operation, dual-fuel operations produce higher total hydrocarbon (THC) and nitrogen oxides (NOx) but lower carbon dioxide (CO2). Hydrogen substitutions decrease THC and CO2 emissions of methane dual-fuel operations approximately between 9-29% and 1–32%, respectively. Smoke emission of dual-fuel operations is less than that of diesel at low and medium loads, whereas it sharply increases at high load. Knocking occurs at high compression ratio and load conditions with dual-fuel operations and dramatically increases with increasing hydrogen ratio. Decreasing the compression ratio notably reduces the combustion noise as well as some emissions, such as NOx, CO2 and smoke, for entire load ranges of dual-fuel and diesel operations.

Impact of fuel injection pressure on the engine characteristics of CRDI engine powered by pine oil biodiesel blend

Optimization of fuel injection strategies can maximize the utilization of biodiesel by addressing the issues concern with fuel consumption, engine performance, and exhaust gas emission. In the midst of the pervasiveness of plant-based biofuel, this paper focused on maximizing the pine oil biodiesel usage in a diesel engine having common rail direct injection (CRDI) system without any engine modifications. Pine oil derived from pine tree resins, has shown impressive fuel properties such as lower viscosity, flash point, boiling point and comparable calorific value to diesel. In this study, the impact of high fuel injection pressure on the engine characteristics of a diesel engine fueled by 30% pine oil biodiesel blend (P30) was analyzed. At standard 200 bar fuel injection pressure, the brake thermal efficiency (BTE) of P30 biodiesel blend was decreased compared to sole diesel. To improve the utilization and performance of the P30 blend, fuel injection pressure increased from 200 bar to 350 bar at a step of 50 bar. The results show that BTE and combustion characteristics are improved with an increase in injection pressure. The P30 fuel exhibits maximum BTE of 26.1% at 350 bar which is 6.9% higher the BTE of diesel at 200 bar. Exhaust emissions (CO, HC & Smoke) decreased gradually with increase in fuel injection pressure due to high atomization of fuel, faster evaporation, and formation of the better air fuel mixture. At 100% load condition, the P30 blend shows a maximum decrease in CO and HC emission at 300 bar, which is 16.6% and 13.1% less respectively compared to sole diesel at 200 bar injection pressure. The NOx is increased by about 9.4% for P30 blend at 350 bar when compared to that of Diesel at 200 bar. Thus, the blending ratio of pine oil biodiesel in the diesel can be extended by increasing the fuel injection pressure.

Experimental investigation on engine parameters variation in common rail direct injection engine fueled with biodiesel

Biodiesel is an alternative sustainable energy source and can be utilized in the compression ignition engine without any changes in the engine design. This research work focuses on the preparation of Calophyllum inophyllum methyl ester through two steps of transesterification process and its implementation in common rail direct injection diesel engines under various fuel injection strategies. At the initial stage of the current research work, two biodiesel blends of 10 vol% and 20 vol% with remaining quantity as diesel have been used as fuel in a diesel engine at a fuel injection pressure of 600 bar at 5%, 10% and 15% pilot injection variations. In the second stage, the study has been extended for the same strategies of injecting the fuel at the rates of 10% and 20% exhaust gas recirculation. All the experimental results are compared with diesel fuel at an injection pressure of 600 bar with 10% pilot injection. The experimental results revealed that an increase in the blend ratio of biodiesel enhances the combustion, performance characteristics and proliferation of pilot injection from 5 to 15% facilitates spontaneous and complete combustion. It is observed that 15% pilot injection quantity of 20 vol% Calophyllum inophyllum methyl ester blend has shown the best performance among the test samples with other injection strategies. The results also showed that the implementation of exhaust gas recirculation at 10% and 20% rates during diesel engine operation is evident in lower performance characteristics with a significant impact on oxides of nitrogen and carbon dioxide emissions.

Effect of Hydrogen Energy Share on a Hydrogen Diesel Dual Fuel Mode using a Common Rail Direct Injection System

This research work was aimed to investigate the maximum possible utilization of hydrogen energy in CI engine with diesel fuel replacement on energy share basis in hydrogen diesel dual fuel (HDDF) mode using common rail direct injection diesel engine. In HDDF mode, experiments were performed at two load conditions such as 3 and 5 bar of brake mean effective pressures (BMEPs). At a BMEP of 3 bar, the maximum hydrogen energy share (HES) could be reached to 50.1% without erratic engine operation, the level of NO, HC, CO and CO2 emissions were decreased up to 18%, 62%, 56% and 45% as compared with neat diesel case. However, there was no significant change in brake thermal efficiency (BTE) and smoke at high HES. At a BMEP of 5 bar, the maximum possible hydrogen energy share was nearly 40%, beyond this energy share severe knocking was noticed. NO emission was raised by 48%, whereas smoke and CO2 emission were decreased up to 20% and 24%. The brake specific HC emission was increased by 42% and there was no significant variation in CO emission with HES.

Influence of Fuel Injection Pressure on the Emissions Characteristics and Engine Performance in a CRDI Diesel Engine Fueled with Palm Biodiesel Blends

This experiment investigates the combustion and emissions characteristics of a common rail direct injection (CRDI) diesel engine using various blends of pure diesel fuel and palm biodiesel. Fuel injection pressures of 45 and 65 MPa were investigated under engine loads of 50 and 100 Nm. The fuels studied herein were pure diesel fuel 100 vol.% with 0 vol.% of palm biodiesel (PBD0), pure diesel fuel 80 vol.% blended with 20 vol.% of palm biodiesel (PBD20), and pure diesel fuel 50 vol.% blended with 50 vol.% of palm biodiesel (PBD50). As the fuel injection pressure increased from 45 to 65 MPa under all engine loads, the combustion pressure and heat release rate also increased. The indicated mean effective pressure (IMEP) increased with an increase of the fuel injection pressure. In addition, for 50 Nm of the engine load, an increase to the fuel injection pressure resulted in a reduction of the brake specific fuel consumption (BSFC) by an average of 2.43%. In comparison, for an engine load of 100 Nm, an increase in the fuel injection pressure decreased BSFC by an average of 0.8%. Hydrocarbon (HC) and particulate matter (PM) decreased as fuel pressure increased, independent of the engine load. Increasing fuel injection pressure for 50 Nm engine load using PBD0, PBD20 and PBD50 decreased carbon monoxide (CO) emissions. When the fuel injection pressure was increased from 45 MPa to 65 MPa, oxides of nitrogen (NOx) emissions were increased for both engine loads. For a given fuel injection pressure, NOx emissions increased slightly as the biodiesel content in the fuel blend increased.

Optimization of palm oil biodiesel blends and engine operating parameters to improve performance and PM morphology in a common rail direct injection diesel engine

In this paper, the characteristics of five palm oil biodiesel blends (B0, B10, B20, B30, and B100) have been tested in a common rail direct injection (CRDI) diesel engine with various EGR rates and pilot injection timings under 25% and 75% engine loads. The following were evaluated: combustion characteristics, including in-cylinder pressure, heat release rate (HRR), and mass fraction burned (MFB); engine performance parameters, including brake specific fuel consumption (BSFC) and coefficient of variation of the indicated mean effective pressure (COVimep); and emission characteristics, including CO, HC, NOx, PM and its morphology. By considering the combustion and emission characteristics, we found that the diesel engine fueled with B30 blend fuel with a 10% EGR rate, or with a pilot injection timing of 24° CA BTDC, can effectively reduce PM emissions and simultaneously keep NOx emissions at a low level. In addition, we found that the variations of the engine load and EGR rate, as well as the biodiesel blend ratio, have direct impacts on the PM particle diameter, shape, and other morphology.

Optimisation of nozzle geometry in the modified common rail direct injection biodiesel-fuelled diesel engine

The study of the experimental work focused on the optimisation nozzle geometry in the modified common rail direct injection (CRDI) diesel engine powered with palm oil methyl ester (POME) fuel. The CRDI diesel engine modified in terms of the toroidal re-entrant combustion chamber (TRCC) shape and nozzle geometry. The experiments are conducted with POME and diesel fuels (DF) at 80% and 100% loads, respectively. The parameters, such as compression ratio (CR) 17.5, speed 1500 RPM, fuel injection timing (IT) 10° BTDC and 900 bar injection opening pressure (IOP), are maintained constant. The selected fuel IT and IOP were optimised in our previous research. The experiments results revealed that the 7-hole nozzle injector improved in break thermal efficiency (BTE) by 1.5% and 1.3% for diesel and POME, respectively, as compared to the 6-hole injector. The average percentages of emissions are reduced up to 7.24% and 7.81% for diesel and POME fuels, respectively, except oxides of nitrogen (NOx). The peak pressure (PP) and heat release rate (HRR) are improved by 2.40% and 3.65%, respectively, for DF. The similar increased trend of PP and HRR is 2.53% and 4.10%, respectively, for POME in the modified CRDI diesel engine.

An experimental analysis of performance and exhaust emissions of a CRDI diesel engine operating on mixtures containing mineral and renewable components

The manuscript presents a comparative analysis of the performance and emission characteristics of a compression ignition engine equipped with a Common Rail injection system. The engine is fueled with diesel-biodiesel mixtures containing 25% and 50% share (by volume) of renewable components. Conventional diesel is used as a reference. Turkey lard and rapeseed oil are used as raw materials and subjected to the single-stage transesterification process to obtain methyl esters. The experiments are performed on a medium-duty, turbocharged, inter-cooled, Common Rail Direct Injection (CRDI) diesel engine. This study concentrates on one engine speed of 1500 rpm, typical for gen-set applications, and mid-load range from 100 Nm to 200 Nm. The scope of measurements covers the analysis of exhaust gasses concentration and engine efficiency parameters. In addition, the in-cylinder pressure measurements are performed in order to provide insight into the differences in combustion characteristics between examined fuel mixtures. The study reveals that the addition of the renewable component to fuel mixture positively affects a number of examined performance parameters as well as decreases the concentration of the examined toxic exhaust components, in the majority of cases.

A Study on Performance of Common Rail Direct Injection Engine with Multiple-Injection Strategies

Diesel engines are robust and reliable besides their good fuel economy. However, these engines produce higher exhaust emissions with fossil diesel and further these emissions level increases when operated on biodiesels. A common rail direct injection (CRDi) engine shows higher brake thermal efficiency (BTE) and lower emissions as compared to compression ignition mode (CI mode) of engine operation. This research paper revealed the results of diesel engine operated in CRDi mode with single injection (SI) and multi-injections (MI) of fuel using diesel and biodiesel of honne oil at 80% load. The CRDi engine operation with both SI and MI showed higher BTE and lower emissions as compared to CI mode. The peak pressure and heat release rate of a CRDi engine operation were lower as compared to CI mode. Overall, it could be concluded that biodiesel-powered CRDi engine with double injection and triple injection could reduce oxides of nitrogen (NOx) emissions by 40.8% and 50%, respectively, while smoke emission by 10% and 16.6%, respectively. However, there was a little penalty on BTE and brake-specific fuel consumption.