Re-entrant Combustion Chamber Research Articles

Impact of hydrogen-assisted combustion in a toroidal re-entrant combustion chamber powered by rapeseed oil/waste cooking oil biodiesel

This study investigates the performance and emission characteristics of biodiesel blends of rapeseed oil and waste cooking oil in a toroidal re-entrant combustion chamber (TCC) compression ignition engine. Hydrogen was allowed into the engine in dual fuel mode to enhance the engine performance. The presence of oxygen in the biodiesel and hydrogen induction increased the peak pressure and heat release rate significantly for all the engine loads. At a peak load of 4.88 kW, the maximum brake thermal efficiency (BTE) of 31.77% was recorded for the D70R20W10 (diesel 70%, rapeseed oil 20%, waste cooking oil 10%) biodiesel blend. Furthermore, hydrogen induction enhanced the BTE by around 3%. The biodiesel blending substantially lowered the emissions of unburnt hydrocarbons, carbon monoxide, and smoke opacity. Additionally, hydrogen supplementation facilitated 5–10% carbon monoxide reduction over biodiesel blends by enabling more complete oxidation. However, higher temperatures generated due to complete combustion resulted in more NOx formation. Thus, the authors propose that biodiesel blends of rapeseed oil, waste cooking oil, and diesel with hydrogen induction improve engine performance and reduce regulated emissions.

Influence of hydrogen-assisted combustion in compression ignition engines fueled with fuel blends of pine oil and waste cooking oil biodiesel using toroidal combustion chamber

In this research study, fuel blends of pine oil and waste cooking oil biodiesel (P/WCO) were examined for combustion analysis, engine performance, and emission characteristics tests. Improved combustion and engine performance were achieved using a toroidal re-entrant combustion chamber (TCC) and hydrogen supply as a dual fuel. The combustion behavior of fuel blends and hydrogen fuel was examined by varying the engine load at a constant speed. The results revealed that significant reduction in the specific fuel consumption for rich pine oil. Thus, a slightly lesser energy share from the fuel blends and a higher energy share from the hydrogen fuel was required for the engine to maintain the same brake power. Lower viscosity, higher flash point, and presence of oxygen in the pine oil enhance the combustion rate and brake thermal efficiency. Furthermore, hydrogen induction in the engine improves the flame velocity. A lesser crevice volume in the TCC can trap the unburnt fuel which can further increase the combustion efficiency. Thus, rich pine oil with the support of hydrogen induction in TCC causes advanced ignition, improved combustion, and more heat release during the combustion. The investigation results revealed that hydrogen induction increases the heat release rate and peak pressure by 7.4% and 2.67%, respectively. Similarly, the maximum of 24.55% increase in BTE and 18.22% reduction in BSFC was observed due to a constant 10 lpm hydrogen induction. Furthermore, hydrogen fuel significantly reduces the emissions such as CO, HC, CO2, and smoke. However, more NOx was generated due to more heat release rate during combustion. Thus, pine oil and waste cooking oil biodiesel blends with the support of hydrogen induction in TCC improve the engine performance and mitigate the toxic pollutants and can be a suitable alternative to diesel fuel.

Studies on Biodiesel and Hydrogen Powered Dual Fuel Common Rail Direct Injection Engine

Objectives: To evaluate the effect of hydrogen and used temple oil biodiesel (BTO) combination on the performance of Common Rail Direct Injection (CRDi) engine. To report the maximum possible flow rate (HFR) for knock free operation of the engine at a speed of 1500 RPM. Methods: Transesterification process was used to get BTO. was inducted through intake manifold. BTO was injected into engine cylinder using electronically controlled technique. Findings: The study revealed that the peak HFR was for BTO and 0.24 for diesel at an Injection Pressure (IP) of 800 bar and Injection Timing (IT) of before top dead center (bTDC). The Dual Fuel (DF) CRDi engine with Toriodal Reentrant Combustion Chamber (TRCC) shape yielded 6% to lower Brake Thermal Efficiency (BTE) with reduced exhaust gas emissions except 19 to higher oxides of nitrogen (NOx) at and 100% loads. Both Peak Combustion Pressure (PP) and Heat Release Rate (HRR) were 5 to 9% higher than BTO run diesel engine operation. Combustion Duration (CD) and Ignition Delay (ID) were 6 to 15% lower in DF CRDi operation with . Novelty: Diesel engine comes with hemispherical combustion chamber (HCC). Toriodal Reentrant Shaped Combustion Chamber (TRCC) was adopted in place of HCC which results better mixing of air and fuel. and BTO combination was used to power CRDi engine. Electronically controlled fuel injection system developed and fitted to conventional diesel engine. Keywords: Used temple oil biodiesel (BTO); Common rail direct injection (CRDi) engine; Toriodal reentrant combustion chamber (TRCC); Hydrogen flow rate (HFR); Hydrogen-biodiesel energy ratio (H2BER)

A Review of the Effects of Injection Strategy and Combustion Chamber Geometry Modification and a Single - Cylinder Diesel Engine

Diesel engines are extensively utilized in India's stationary power generation and agricultural pumping applications. Recent stringent government emission regulations necessitated modifications to existing engines. This study investigates a stationary, direct-injection, single-cylinder, 10 HP Diesel engine that initially did not comply with these norms. The original engine, featuring a hemispherical piston bowl and an injector with a finite sac volume, was modified to include a re-entrant combustion chamber and a sac-less injector. These modifications led to significant changes in emission levels. The study also highlights the critical influence of piston bowl shape on engine performance and emissions. Experimental and numerical analyses, including the use of multi-swirl piston bowls (MSB) and double-swirl piston bowls (DSB), revealed that these designs enhance in-cylinder swirl and turbulence, thereby improving the combustion process and reducing soot emissions by up to 81%. However, these modifications also increase NOx emissions due to elevated in-cylinder temperatures. Optimizing injection parameters could mitigate NOx emissions while maintaining engine performance. Thus, the proposed combustion chamber geometries and optimized injection strategies offer a promising approach to achieving compliance with stringent emission standards.

Improvement of diesel combustion with suppression of mutual fuel spray flame interactions with staggered nozzle hole arrangement and a spatially divided combustion chamber

A combination of a fuel injector with staggered nozzle hole arrangement with a combustion chamber divided into upper and lower layers by placing a lip at the middle of the side wall is proposed to improve diesel combustion with suppression of interactions among fuel spray flames. The fuel injector has twelve alternately arranged spray holes ( ϕ0.09 mm), staggered at two injection angles, 79° and 55° from the central axis of the injector. Two ordinary injectors with eight ( ϕ0.113 mm) and twelve ( ϕ0.092 mm) holes with an injection angle of 78° from the central axis with a conventional re-entrant combustion chamber were also examined as references. The experimental results showed that the improvements in thermal efficiencies and the reduction in smoke emissions can be established over a wide IMEP range with the proposed combination of the staggered nozzle hole injector and the divided combustion chamber. The exhaust loss is reduced with the combination of the injector and the combustion chamber while the cooling loss increases slightly. The rate of heat release from the combination of the injector and the combustion chamber has a more active main combustion and smaller afterburning than conventional systems. The three-dimensional CFD simulations showed that the combination of the injector and the combustion chamber can efficiently suppress the interactions among fuel spray flames at the combustion chamber wall after the impingement of fuel spray flames and also suitably distribute the fuel mixture, resulting in reductions in the afterburning and the smoke emissions. The slight increase in cooling loss with the proposed combination may be due to the increase in contact area of hot burned gas on the cylinder head; further improvements in thermal efficiency can be expected with optimization of the design factors related to the fuel injection and the combustion chamber configuration.

Experimental study on the effect of piston bowl geometry on the combustion performance and pollutant emissions of methane-diesel common rail dual-fuel engine

In dual-fuel operations, high methane substitution negatively affects combustion performance and creates high hydrocarbon (HC) and carbon monoxide (CO) pollutant emissions. Piston bowl geometry is proven an effective method for improving combustion performance and emissions. In the available study, combustion chamber geometry is experimentally indicated to succeed in dramatically reducing HC and CO pollutant emissions uncompromising nitrogen monoxide (NO) and smoke pollutant emissions.In this study, the effect of piston bowl geometry on the combustion performance and pollutant emissions of a single-cylinder methane-diesel common rail dual-fuel engine was studied experimentally. High-performance piston bowl geometries (Toroidal and Toroidal re-entrant) of conventional diesel operations were used versus original combustion chamber (OCC) geometry in diesel and dual fuel operation for enhancing combustion performance and reducing pollutant emissions. The experiments were conducted at constant 1850 r/min and five different engine loads. The methane energy fraction was set to 50% of the total energy fraction in dual fuel operations. Experimental results showed that the Toroidal re-entrant combustion chamber (TRCC) geometry reduced the long ignition delay period that was due to the methane addition and ensured more stable combustion at all torque conditions. In dual fuel operation, the TRCC geometry improved smoke, HC, and CO pollutant emissions by an average of 18%, 10%, and 3% for all loads, respectively, compared to the OCC geometry. However, NO pollutant emissions were an average of 2.5% higher than OCC geometry for the TRCC geometry. In sum, use of the TRCC geometry is an effective way for providing more complete combustion and reducing emissions under dual fuel operations at all torque conditions between 3 and 9 Nm.

Analysis of Improved In-Cylinder Combustion Characteristics with Chamber Modifications of the Diesel Engine

This study numerically analyses the effects of chamber modifications to investigate the improvement of in-cylinder combustion characteristics of the diesel engine using a computational fluid dynamics (CFD) approach. Five different modified chambers, namely, the double swirl combustion chamber (DSCC), bathtub combustion chamber (BTCC), double toroidal re-entrant combustion chamber (DTRCC), shallow depth combustion chamber (SCC), and stepped bowl combustion chamber (SBCC) were developed and compared with a reference flat combustion chamber (FCC). The effects of chamber modifications on temperature formation, velocity distribution, injection profiles, and in-cylinder turbulent motions (swirl and tumble ratio) were investigated. During the compression stroke, near top dead centre, the SCC showed a peak temperature of 970 K, followed by the FCC (968 K), SBCC (967 K), and DTRCC (748 K to 815 K). The DSCC and the SCC showed a high swirl ratio above 0.6, whereas the DTRCC and the BTCC showed a high tumble ratio of approximately 0.4. This study found that the SCC, BTCC, and DSCC have better combustion rates than the FCC in terms of temperature, heat release rate, and velocity distribution. However, the DTRCC showed poor temperature formation rates and rapid heat release rates (approx. 150 J/°CA), which can lead to rapid combustion and knocking tendencies. In conclusion, the DSCC and the SCC showed better combustion rates than the other chambers. In addition, turbulent motions inside the chambers avoided combustion in crevice regions. This study recommends avoiding chambers with wider bowls in order to prevent uneven combustion across the cylinder. Furthermore, split bowls such as the DSCC, along with adjusted injection rates, can provide better results in terms of combustion.

Effect of modified combustion chamber configuration and enhanced squish flow on improving thermal efficiency in jet-plume-controlled direct-injection near-zero emission hydrogen engines

In direct injection hydrogen engines, the Plume Ignition and Combustion Concept (PCC) developed by the authors has been applied to improve thermal efficiency and reduce NOx emissions under high-load operation. The PCC combustion method burns an optimized hydrogen jet plume that is ignited immediately upon completion of injection in the latter half of the compression stroke. In addition to optimizing the hydrogen jet configuration, this basic combustion concept was applied to burn a lean mixture and supercharging was used to recover the decline in power output due to combustion of a diluted mixture. As a result, a near-zero emission engine has been achieved that simultaneously provides high thermal efficiency, high power output and low NOx emissions at a single-digit ppm level. Various techniques have been applied to improve thermal efficiency further and achieve much lower NOx emissions close to a zero-emission target. These included the adoption of a re-entrant combustion chamber to reduce unburned hydrogen emissions, enhanced squish flow to promote better mixing of air and the hydrogen jet injected into the combustion chamber, and a narrower nozzle hole diameter to promote entrainment of air into the hydrogen jet. In this study, the effect of each of these measures was made clear experimentally and by analysis. This paper presents the results obtained.

Hydrogen and dual fuel mode performing in engine with different combustion chamber shapes: Modelling and analysis using RSM-ANN technique

This study investigates the impacts of hydrogen (H2) induction along with injected liquid honne biodiesel (BHO)/uppage biodiesel (BUO) as secondary pilot fuel in diesel engine. The effects of compression ratio (CR), hydrogen fuel flow rate (HFR) and different combustion chamber shapes in dual fuel (DF) mode were investigated. In the first phase of experiments, the effects of three different CR (15.5, 16.5, and 17.5) on engine efficacy and emission were presented. In the second phase, the effects of three HFR (0.1, 0.17, and 0.24 kg/h) on engine efficacy and emission, as well as the maximum possible HFR were reported. In the last phase, performance with different combustion chambers i.e., Hemispherical Combustion Chamber (HCC), Toroidal Reentrant Combustion Chamber (TRCC), and Toroidal Combustion Chamber (TCC) at maximum possible CR and HFR was highlighted. The study revealed that for knock free operation of the DF engine, the highest probable HFR was 0.24 kg/h at a CR of 17.5, fuel IT of 27obefore top dead center (bTDC) and injector opening pressure (IOP) of 250 bar. The toroidal re-entrant combustion chamber (TRCC) shape yielded 8%–12% better brake thermal efficiency (BTE) with lower emissions but 20–29% higher oxides of nitrogen (NOx) at 80% load in DF mode as contrasted to the single CI mode. Both peak pressure (PP) and heat release rate (HRR) were 12–15% higher. Response surface methodology (RSM) was used to design the experiments and to carry the optimization process. Artificial Neural Network (ANN) was used to forecast the performance and emission behaviors of the test engine. The findings demonstrated that RSM and ANN were excellent modelling techniques with good accuracy. In addition, ANN's prediction performance (R2 = 0.975 for BTE) was somewhat better than RSM's (R2 = 0.974 for BTE). Both the techniques were found to be successful in terms of agreement with experimental findings with ratios varying from 95% to 98% respectively. The prediction of BTE and NOx was also carried using different machine learning algorithms. It can be seen that R2 value for these models were slightly lower than ANN and RSM models indicating good predicting capability of ANN modelling.

Experimental Study on Effects of RCSL and RCTL Combustion Chamber for Combustion Process of Highly Intensified Diesel Engine

In order to optimize the combustion chamber of a highly intensified single-cylinder diesel engine, including improvement of the air utilization rate in the combustion chamber, optimization of the fuel/air mixture process, reduction of the soot emission in the cylinder, and obtainment of the optimal combustion performance parameters, a re-entrant combustion chamber with step-typed lip (RCSL) and a re-entrant combustion chamber with tilted lip (RCTL) were innovatively designed and the effects of the throat diameter on the combustion process was obtained through experiments. When the RCSL with a diameter of 72 mm worked, target for the Brake Mean Effective Pressure (BMEP) of 2.6 MPa could be achieved under the condition of excess air coefficient of 1.5~1.7. At the same time, this had the advantages of lower fuel consumption, lower exhaust temperature, lower smoke level, and shorter combustion duration. Under the same BMEP, the RCTL had lower fuel consumption, exhaust gas temperature and maximum combustion pressure, as well as faster heat release rate (HRR) and shorter combustion duration than the RCSL.

The Combined Effect of the Piston Bowl Geometry and Injection Fuel Pressure on the Compression Ignition Engine Characteristics

In this study, the combined effect of the piston bowl geometry and fuel injection pressures on combustion, performance and emission characteristics of compression ignition (CI) engine fueled with baseline Diesel (D100) and microalgae-biodiesel (MA100) was studied. In this paper, the comparison study for the two different piston bowl geometry, namely: hemispherical combustion chamber (HCC) and toroidal re-entrant combustion chamber (TRCC), was carried out with the various fuel injection pressures (200-240 bar) performed. A single-cylinder, direct injection, and four strokes were chosen to simulate the compression ignition (CI) engine by developing a zero-dimensional simulation model using Diesel-RK commercial software. The data was validated by comparing the results against experimental data, which showed that the results obtained from the numerical simulation were in good agreement with the experimental results. MPRR, EGT, HRR, BTE, and NOx exhibited an increase with increased fuel injection pressure, while an inverse trend was observed with ID, CO, and HC. When using MA100 biodiesel with HCC piston bowl geometry at fuel injection pressure (200 bar), the maximum predicted brake specific fuel consumption (BSFC) was 0.545 kg/kWh. A significant reduction of nitrogen (NOx) oxides emissions was also observed with low fuel injection pressures. In contrast, the emission characteristics such as hydrocarbons and CO were enhanced by increasing fuel injection pressure and modifying the piston bowl geometry.

Biodiesel Production Using Modified Direct Transesterification by Sequential Use of Acid-Base Catalysis and Performance Evaluation of Diesel Engine Using Various Blends

Biodiesel is a seemingly suitable alternative substitute for conventional fossil fuels to run a diesel engine. In the first part of the study, the production of biodiesel by modified direct transesterification (MDT) is reported. An enhancement in the biodiesel yield with a considerable reduction in reaction time with the MDT method was observed. The required duration for diesel and biodiesel blending was minimized including glycerol separation time from biodiesel in the MDT method. The development in the automotive sector mainly focuses on the design of an efficient, economical, and low emission greenhouse gas diesel engine. In the current experimental work Ceiba pentandra/Nigella sativa and diesel blends (CPB10 and NSB10) were used to run the diesel engine. A variety of approaches were implemented to improve the engine performance for these combinations of fuels. The fuel injector opening pressure (IOP) was set at 240 bar, the torriodal re-entrant combustion chamber (TRCC) having a six-hole injector with a 0.2 mm orifice diameter each, provided better brake thermal efficiency (BTE) with lower emissions compared with the hemispherical combustion chamber (HCC) and trapezoidal combustion chamber (TCC) for both CPB10 and NSB10. CPB10 showed better performance compared with NSB10. A maximum BTE of 29.1% and 28.6% were achieved with CPB10 and NSB10, respectively, at all optimized conditions. Diesel engine operation with CPB10 and NSB10 at 23° bTDC fuel injection timing, and 240 bar IOP with TRCC can yield better results, close to a diesel run engine at 23° bTDC fuel injection timing, and 205 bar IOP with HCC.

Effects of hydrogen flow rate, injection pressure and EGR on performance of common rail direct injection (CRDi) engine in dual fuel mode

PurposeThe different performance tests were conducted on diesel engine compression ignition (CI) mode and CRDi engine.Design/methodology/approachThe CI engine was suitably modified to CRDi engine with Toroidal re-entrant combustion chamber (TRCC) and was run in dual-fuel (DF) mode. Hydrogen (H2) was supplied at different flow rates during the suction stroke, and 0.22 Kg/h of hydrogen fuel flow rate (HFFR) was found to be optimum. Diesel and biodiesel were used as pilot fuels. The CRDi engine with DF mode was run at various injection pressures, and 900 bar was found to be optimum injection pressure (IP) with 10o before top dead center (bTDC) as fuel injection timing (IT).FindingsThese operating engine conditions increased formation of oxides of nitrogen (NOx), which were reduced by exhaust gas recycle (EGR). With EGR of 15%, CRDi engine resulted in 12.6% lower brake thermal efficiency (BTE), 5.5% lower hydrocarbon (HC), 7.7% lower carbon monoxide (CO), 26% lower NOx at 80% load as compared to the unmodified diesel engine (CI mode).Originality/valueThe current research is an effort to study and evaluate the performance of CRDi engine in DF mode with diesel-H2 and BCPO-H2 fuel combinations with TRCC.

Experimental and CFD analysis of Re-entrant Combustion Chamber on Diesel Enriched with Hydrogen

In view of global warming and diminution of sources for traditional fuels, investigators paid their attention towards finding the substitutes in all sectors such as agriculture, transportation and industries. One of the best alternative and unique option for overcoming these limitations is usage of hydrogen gas as fuel for petroleum-based engines. Further to have better quality of fuel and air mixture formation, a significant part is played by the geometry of the combustion chamber. To have quality burning of the fuel, an effort is targeted to investigate the impact of re-entrant chambers over the conventional type without and with hydrogen enrichment at distinct flows of diesel. Initially, experiments were conducted on toroidal chamber geometry of the piston bowl with diesel and with hydrogen enrichment. With a reduction of 30.65%, 44.11% and 18.78% in emission particulates of UHC, CO and smoke density correspondingly with addition of hydrogen as that of with diesel at peak load, further there is growth in NOx emissions about 10.16%. The variations of emission particulates with replacement of modified geometry, i.e. re-entrant type are detected as further reduced. To validate the reduction in emission trends, CFD simulations are carried out on fuel mass fraction and the findings presented.

Assessment of the impacts of combustion chamber bowl geometry and injection timing on a reactivity controlled compression ignition engine at low and high load conditions

The present paper aims to assess the impacts of diesel injection timing and two bowl geometries including re-entrant and wide-shallow combustion chambers on the combustion characteristics, emissions formation, and fuel consumption in a reactivity controlled compression ignition diesel engine under low and high load (five and nine bar indicating mean effective pressure) conditions. The results revealed that diesel injection at −60 CA ATDC under low load conditions significantly decreased soot and NOx emissions simultaneously for both piston bowl geometries. The use of the wide-shallow chamber decreased the period of the ignition delay and increased the engine operable load range as a result of more stable combustion under high-load conditions compared to the re-entrant chamber. Moreover, at all diesel injection timings, the indicated specific fuel consumption was decreased by nearly 4.8 and 6.6% under low and high load conditions, respectively when the wide-shallow combustion chamber was used since the heat transfer loss was lower than that of the re-entrant chamber. However, NOx emission under high load conditions at the center of the combustion chamber and more soot emission in the exhaust gas are two disadvantages of the wide-shallow chamber versus the re-entrant combustion chamber.

Study of diesel engine characteristics by adding nanosized zinc oxide and diethyl ether additives in Mahua biodiesel\u2013diesel fuel blend

This study deals with an experimental investigation to assess the characteristics of a modified common rail direct injection (CRDI) engine utilizing diesel, Mahua biodiesel, and their blends with synthesized zinc oxide (ZnO) nano additives. The physicochemical properties of diesel, diesel + 30 ppm ZnO nanoparticles (D10030), 20% Mahua biodiesel (MOME20), and Mahua biodiesel (20%) + 30 ppm ZnO nanoparticles (MOME2030) were measured in accordance to the American Society for Testing and Materials standards. The effects of modification of fuel injectors (FI) holes (7-hole FI) and toroidal reentrant combustion chamber (TRCC) piston bowl design on the performance of CRDI using different fuel blends were assessed. For injection timings (IT) and injection opening pressure (IOP) average increase in brake thermal efficiency for fuel blend D10030 and MOME2030 was 9.65% and 16.4%, and 8.83% and 5.06%, respectively. Also, for IT and IOP, the average reductions in brake specific fuel consumption, smoke, carbon monoxide, hydrocarbon and nitrogen oxide emissions for D10030 and MOME2030 were 10.9% and 7.7%, 18.2% and 8.6%, 12.6% and 11.5%, 8.74% and 13.1%, and 5.75% and 7.79%, respectively and 15.5% and 5.06%, 20.33% and 6.20%, 11.12% and 24.8%, 18.32% and 6.29%, and 1.79% and 6.89%, respectively for 7-hole fuel injector and TRCC. The cylinder pressure and heat release rate for D10030 and MOME2030 were enhanced by 6.8% and 17.1%, and 7.35% and 12.28%. The 7-hole fuel injector with the nano fuel blends at an injection timing and pressure of 10° btdc and 900 bar demonstrated the overall improvement of the engine characteristics due to the better air quality for fuel mixing. Similarly, the TRCC cylinder bowl geometry illustrated advanced ignition due to an improved swirl and turbulence. Also, the engine test results demonstrated that 30 ppm of ZnO nanoparticles in Mahua biodiesel (MOME2030) and diesel (D10030) with diethyl ether resulted overall enhancement of CRDI engine characteristics.

Influence of Combustion Chamber Geometry on the Combustion and Emission Characteristics of a Direct Injection Diesel Engine Operated on Renewable and Sustainable Fuel Derived from Diary Scum Waste

Present work discusses experimental investigation to study the effect of biodiesel blends and re-entrant combustion chamber on the performance, combustion and exhaust emissions. In the first phase of the work, diary scum oil methyl ester (DiSOME) biodiesel was produced by conventional transesterification process and is blended with conventional diesel fuel in steps of 20 (by volume). Further in the next phase of the work, influence of blended fuel properties and re-entrant combustion chamber (RCC) on the combustion and emission characteristics of a direct injection diesel engine has been investigated. Results of investigation showed that B20 operation with RCC provided increased thermal efficiency by 3-4% with 10% increased smoke, 10-20% decreased hydrocarbon (HC) and carbon monoxide (CO) and 8-10% increased nitric oxide (NOx) emission levels compared to B100 operation. Further increased cylinder pressure and heat release rate were observed with B20. However, Thermal efficiency and NOx emissions are comparatively lower and smoke, HC and CO emissions were found to be slightly higher than base line diesel operation.

Combustion parameters optimization of a diesel/natural gas dual fuel engine using genetic algorithm

The objective of this study is to optimize the diesel injection parameters, operating parameters and the combustion system of a diesel/natural gas fueled dual fuel engine simultaneously by applying the genetic algorithm. The indicated specific fuel consumption, NOx and CH4 emissions are selected as the optimization objectives. It is shown that almost all the solutions can meet the EURO VI emission limit of the Soot. However, only partial solutions satisfy the EURO V NOx emission limit. More open combustion chambers are chosen than the re-entrant combustion chamber on the Pareto front. A wide range distribution of the combustion bowl radius is found on the Pareto front. However, the diesel fuel spray angle, swirl ratio, EGR (Exhaust Gas Recirculation) rate and compression ratio are gradually concentrated near several optimal points. The response surfaces of ISFC, CH4 and NOx emissions for injection timing vs. EGR rate and spray angle vs. swirl ratio for all the calculated Pareto citizens are achieved.

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.

A comprehensive study on the effects of internal air jet piston on the performance of a JOME fueled DI diesel engine

In DI diesel engine, air-fuel mixing is a major parameter that affects the performance, emissions parameters and combustion characteristics. In-cylinder air motion and proper mixing of fuel have a strong effect on BTE, BSFC, UHC, CO, smoke and NOx emissions, because of improvement in the combustion of fuel. In this experimental investigation in order to enhance the performance of biodiesel-fueled diesel engine, the engine was tested using piston having internal air jets using 20% Jatropha Oil Methyl Ester-diesel blend (B20 JOME). For this purpose, the piston of the standard engine having Hemispherical Combustion Chamber (HCC) was reformed into Toroidal Re-entrant Combustion Chamber with internal air jets (TRCC-IAJ) that has the same volume as baseline HCC. The tests were performed at IMEP of 1.7, 3.2, 4.7, 6.2 and 7.7 bar with the standard injection timing and pressure. The test results show that the BTE and BSFC provide the best result for the modified piston compared to the original. The TRCC-IAJ reduced the smoke, CO and HC; while it showed the opposite effect with a sharp increase in NOx emissions. In overall, the results show that the modified piston TRCC-IAJ has improved the overall performance and emissions of the JOME-diesel blend.