Toroidal 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.

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.

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.

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.

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.

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.

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.

The impact of combustion chamber configuration on combustion and emissions of a single cylinder diesel engine fuelled with soybean methyl ester blends with diesel

The multi-dimensional computational fluid dynamics (CFD) simulation involving in-cylinder flow and combustion have been done to study the effect of soybean methyl ester and piston bowl configuration on performance, combustion and pollutant emissions from a single cylinder diesel engine. The baseline engine configuration consists of a hemispherical piston bowl. The investigation has been conducted for biodiesel blends with diesel and different piston bowl configurations such as Toroidal Re-entrant Combustion Chamber (TRCC), Re-entrant Combustion Chamber (RCC) and baseline Hemispherical Combustion Chamber (HCC) for same bowl volume to have constant compression ratio of 17.5. To simulate the in-cylinder flow and combustion process, AVL FIRE code was performed and experimental results of baseline hemispherical bowl have been used to validate the numerical model. The simulation results show that flow behaviour inside the combustion chamber strongly depends on the piston bowl configuration in diesel engine. The results obtained from the simulation for the fuel blends are compared with that of baseline diesel fuel. The brake specific fuel consumption is higher for biodiesel due to its lower heating value compared to baseline mineral diesel. However, significantly better results were obtained from engine having modified combustion chambers mainly due to better air movement and charge mixing.

Effects of tangential air passages to piston bowl on the performance of a DI diesel engine

ABSTRACT In this experimental study, the effects of providing tangential air passages to piston bowl for better fuel energy conversion in terms of engine performance were investigated using a DI (direct injection) diesel engine. For this purpose, the standard engine piston having Hemispherical Combustion Chamber (HCC) was modified into Toroidal Reentrant Combustion Chamber (TRCC) and then into Toroidal Reentrant Combustion Chamber with Tangential Air Passages (TRCC-TAP) that have the same volume as that of the baseline engine without modifying the compression ratio. From the experimental investigations, it was observed that piston having TRCC-TAP showed improvement in terms of BTE and BSFC by about 2.3% and 4.4%. Substantial improvements in reduction of emission levels particularly for CO, UBHC and smoke were also observed for TRCC-TAP by about 26.4%, 12.96% and 3.4% respectively compared to HCC. The combustion analysis too showed improved characteristics for TRCC-TAP compared to HCC at all loads of operation.

Optimization of Multiple Injection Strategy in Modified Common Rail Direct Injection Diesel Engine Powered with Palm Oil Methyl Ester

In this investigation, the common rail direct injection (CRDI) single cylinder four stroke diesel engine has made to modify in terms of toroidal reentrant combustion chamber (TRCC) shape and 7 holes CRDI nozzle injector. The current experimental study objective is to optimization of multiple injection strategy (MIS) in modified CRDI diesel engine powered with palm oil methyl ester (POME) B100 and diesel fuels. In the first phase of work, experiment results showed that slightly improved in brake thermal efficiency (BTE) and reduced emissions except oxides of nitrogen (NO_x) for POME fuelled engine operates under optimized MIS, fuel injection timing (IT) of -10° before top dead center (BTDC) and 600 bar injection pressure (IOP) in modified CRDI diesel engine. In the second phase of work, the performance of modified CRDI diesel engine is improved by increasing IOP from 600 bar to 900 bar at same MIS and fuel IT. The second phase of experiment results showed that percentage of increase in BTE by 2.47%, peak pressure (PP) by 13.69%, heat release rate (HRR) by 17.64%, NO_X by 11.70% and percentage of decreased in ignition delay (ID) by 29.62%, combustion duration (CD) by 13.79%, unburnt hydrocarbon (UBHC) by 19.04%, carbon monoxide (CO) by 14.28%, smoke level by 20.93% as compared to first phase of work in modified CRDI diesel engine fuelled with POME.

Effect of Injection Parameters: Injection Timing and Injection Pressure on the Performance, Emission and Combustion Characteristics of CRDI Diesel Engine Operate with Palm Oil Methyl Ester (POME)

This experimental study mainly focused on the investigation of CRDI diesel engine powered with palm oil methyl ester (POME) biodiesel and diesel fuels. The Toroidal Re-entrant combustion chamber shape (TRCC) and 6 holes CRDI injector were selected for experiment. The current research engine operated with constant CR 17.5 and speed 1500 rpm. In the first phase of work, the injection timing (IT) varied from -25 °BTDC to 5 °ATDC with interval of 5 degree during the experiments. The injection time-10 °BTDC has been optimized for higher engine efficiency. In the second phase of work, the injection opening pressure (IOP) has been varied form 600 bar to 1000 bar with increment of 100 bar interval during the experiments. The IOP of 900 bar has been optimized with constant fuel IT -10 °BTDC. Finally, the end results of experiments were reported that combined effects of IT (-10 °BTDC) and IOP (900 bar) enhanced the engine output in terms of brake thermal efficiency (BTE), also minimizing the pollutants using TRCC shape and 6-hole CRDI injector for CRDI diesel engine at 80% load.

Combustion characteristics, performances and emissions of a biodiesel-producer gas dual fuel engine with varied combustor geometry

This paper presents the overall performance, emission and combustion characteristics of the engine, when fuelled with biodiesel blends of Calophyllum Inophyllum methyl ester as injected fuel and babul wood chip derived producer gas as inducted fuel at constant injection timing (230bTDC), injection pressure (230 bar) and speed (1500 rpm). To improve overall performance, combustion and reduced emission characteristics of the engine, the combustion chamber was varied with 5 different geometries. Experimental results revealed that Toroidal re-entrant combustion chamber had higher Exhaust Gas Temperature and Brake Thermal Efficiency by 20.75% and 6.37% than that of HCC, while Brake Specific Fuel Consumption was reduced by 4.49% at optimal loading condition. However, engine overall performance of TrCC was found to be comparable with Hemi-spherical chamber and other designed combustion chambers. Similarly, comparing exhaust emissions, Oxide of Nitrogen and Carbon dioxide were on its higher side by 19.90% and 27.20% than normal HCC. On the contrary, carbon monoxide, Hydrocarbon and Smoke opacity for TrCC were found to be 76.12%, 33.71% and 38.67% lower than HCC. From the above study, it is finally concluded that converted renewable fuels with TrCC might be utilized as an alternative fuel without any exhaust related problems.

Achieving high performance and low emission in a dual fuel operated engine with varied injection parameters and combustion chamber shapes

The present paper describes the effect of injection parameters and combustor geometry on performance, emission and combustion characteristics of a turbo-charged diesel (TDI) engine operated in dual fuel mode with calophyllum inophyllum oil methyl ester and babul wood chip generated producer gas. The experimentation were carried out at varied injection timing (IT) (19–24°bTDC), injection pressure (IP) (180–240 bar) in steps of 10 bar and five different combustion chambers (CC) were investigated individually to achieve better performance. Experimental results revealed that at an advanced IT and IP of 24°bTDC and 230 bar, brake thermal efficiency (BTE) showed an overall reduction of 6.35%, while an increment of about 5.68% and 10.88% in brake specific fuel consumption (BSFC) and exhaust gas temperature (EGT) respectively. During the emission analysis, carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOX) and smoke opacity were measured to be 20%, 26.77%, 12.16% and 26.53% lower than conventional fuel. Moreover, toroidal re-entrant combustion chamber (TrCC) was also found to have superior performance, emission and combustion characteristics over the other configurations of combustion chambers. TrCC delivered a performance enhancement of 6.4%, 4.49% and 20.76% in terms of BTE, BSFC and EGT, while and emission level improvement of 34.48%, 33.71% and 38.67% in terms of CO, HC and smoke opacity. However, NOX emission level was deteriorated by 26.66% in compared to standard engine. Based upon the above results, engine with modified TrCC, advanced IT (24°bTDC) and IP (230 bar) enhances the existing performance, emission and combustion characteristics of a TDI engine operated in dual fuel mode, provides freedom from conventional fuel thereby enhancing sustainable energy and its security.

Improvement of ternary fuel combustion with various injection pressure strategies in a toroidal re-entrant combustion chamber.

The present experimental work focuses on the influence injection pressure and toroidal re-entrant combustion chamber in a single cylinder diesel engine fuelled with ternary fuel (diesel-biodiesel-ethanol) blend. Ternary fuel (TF) is prepared by blending 70% diesel, 20% biodiesel, and 10% ethanol blends and its fuel properties were investigated and compared with diesel fuel. Since the physic-chemical properties of TF are well behind the diesel fuel, it is proposed to be blended with 20ppm alumina nano additives which act as an ignition enhancer and catalytic oxidizer. The resulting fuel mixture (TF + 20ppm alumina additive) is named as high performance fuel (HPF). Experimentations were conducted on HPF subjected to various injection pressures of 18MPa, 20MPa, 22MPa, and 24MPa respectively and are operated in toroidal re-entrant chamber geometry (TG) at an injection timing of 22 obTDC. From experimentation, it was identified that, for TG-HPF, higher injection pressure of 22MPa ensued highest BTE (Brake Thermal Efficiency) of 35.5% and lowest BSEC (Brake Specific Fuel Consumption) of 10.13MJ/kWh owing to the pooled effect of higher swirl formation, improved atomization enhanced evaporation rate, and better air-fuel mixing. Emission wise TG-HPF operated at 22MPa lowered the HC (hydrocarbon), CO (carbon monoxide), and smoke emissions by 18.88%, 7.19%, and 5.02%, but with marginally improved NOx (oxides of nitrogen) and CO2 (carbon dioxide) emissions by 3.92% and 3.89% respectively. In combustion point of view, it is observed that injection pressure increased the cylinder pressure, heat release rate (HRR), and cumulative heat release rate (CHRR) by 5.35%, 5.08%, and 3.38% respectively indicating improved combustion rate as a result of enhanced atomization, evaporation, and high turbulence inducement. Overall, it is concluded that operating the ternary fuel at 22MPa injection pressure at toroidal re-entrant combustion chamber results in improved performance and minimized emissions.

Effect of combustion geometry on combustion, performance and emission characteristics of CI engine using simarouba oil methyl ester

Present study investigates the effect hemispherical (HCC), cylindrical (CCC), toroidal (TCC) and toroidal re-entrant (TrCC) type combustion chamber (CC) geometry on the characteristics of combustion, performance and exhaust emissions from the engine using Simarouba Oil Methyl Ester (SuOME) and to compare with base engine operated with diesel fuel. Simarouba oil biodiesel is prepared by 2 stage transesterification using methanol and KoH. 4-stroke naturally aspirated single-cylinder water-cooled direct-injection diesel engine with different optimized injection parameters of injection pressure to 240 bar, injection timing to 270bTDC, 6 hole injector of 0.2 mm diameter, and loading condition at rated speed of 1500 rpm were used for testing. Ignition delay (ID), combustion duration (CD), peak pressure (PP), brake thermal efficiency (BTE), exhaust gas temperature (EGT) and exhaust emissions (HC, CO, smoke opacity and NOx) were measured to estimate the behaviour of the diesel engine running on SuOME with different combustion geometry. Results were indicated that, use of SuOME reduces the engine performance with increased emissions compared to fossil diesel conventional fuel. However use of toroidal re-entrant CC gave the better combustion and performance with reduced emission except NOx comparing with other combustion chamber design.

Combined effects of piston bowl geometry and spray pattern on mixing, combustion and emissions of a diesel engine: A numerical approach

In the present work the combine effects of spray angle and the piston bowl geometry on mixing, combustion and emission characteristics of a direct injection diesel engine have been analyzed numerically. The piston bowl geometry is one of the most important factor that affect the air fuel mixing and combustion and emissions in a direct injection diesel engine. Four spray angles 150°, 155°, 160° and 165° and three different piston bowl geometries namely Toroidal Re-entrant Combustion Chamber (TRCC), Toroidal Combustion Chamber (TCC) and the baseline Hemispherical Combustion Chamber (HCC) have been considered for the same compression ratio of 17.5 and with same chamber volume for all three cases. To simulate the in-cylinder flow and combustion computational fluid dynamics (CFD) modeling based AVL FIRE code was performed and experimental results of the baseline hemispherical bowl were used to validate the numerical model. Simulation results show that spray angle significantly affects the mixing and combustion process for all three bowl geometries and the engine having TRCC type of combustion chamber gives better performance.

Combined impact of injection pressure and combustion chamber geometry on the performance of a biodiesel fueled diesel engine

Improved thermal efficiency, reduction in fuel consumption and pollutant emissions from biodiesel fueled diesel engines are important issues in engine research. To achieve these, rapid and perfect air-fuel mixing are the most important requirements. The mixing quality of biodiesel spray with air can be improved by selecting the best injection parameters and better design of the combustion chamber. Experiments were performed using a DI (direct injection) diesel engine equipped with a conventional jerk type injection system and pistons having HCC (hemispherical combustion chamber) and TRCC (toroidal re-entrant combustion chamber) geometries. The combined effect of varying, injection pressure and combustion chamber geometries, on the combustion, performance and exhaust emissions, using a blend of 20% POME (pongamia oil methyl ester) by volume in diesel were evaluated. The test results showed that improvement in terms of brake thermal efficiency and specific fuel consumption for TRCC operated at higher injection pressure. Substantial improvements in reduction of emissions levels were also observed for TRCC operated at higher injection pressure. However improved combustion, due to better air motion inside the cylinder and high pressure injection, increased the oxides of nitrogen (NOx). Increasing injection pressure decreased ignition delay, and increased peak in-cylinder pressure and maximum heat release rate.