Piston Shape Research Articles

Numerical investigation of in-cylinder gas motion dynamics in a heavy-duty direct injection hydrogen internal combustion engine

Mixture homogenization is one of the most important parameter for hydrogen internal combustion engines (H2ICE) to achieve near-zero NOx emissions and stable combustion, especially when premixed combustion strategy is used. On the other hand, inhomogeneities are inevitable due to the limited duration for mixing. This is more prominent in H2ICEs; those adopts low pressure direct injection (LPDI) system. Optimizing an engine to achieve higher level of homogeneity requires profound understanding of in-cylinder gas motion and mixing dynamics.To establish deeper comprehension of gas motion inside the cylinder, a 13-L LPDI H2ICE was modelled, and effect of different parameters were investigated by a holistic 1D-3D simulation methodology. While boundary conditions of operating point were obtained from the 1D simulations, different swirl numbers (SN), piston shapes and injector cap designs were simulated with 3D-CFD. Simulation results were analyzed based on uniquely defined parameters like homogeneity index (HI) and symmetricity of motion (SOM), as well as standard parameters like turbulence kinetic energy (TKE), and 3D visualizations of equivalence ratio iso-surfaces. Analysis showed that, there is a negative correlation between SN and HI under investigated conditions. Moreover, it was found that piston shapes which are promoting the tumble motion, improved average TKE by 31% and HI by 28% over base piston. This study aims to be a reference for the in-cylinder gas motion design of ultra-lean LPDI H2ICEs, where the target is retrofitting an existing diesel engine and attaining the best HI, SOM and TKE values at rated power conditions.

Computational analysis of piston shape effects on in-cylinder gas flow, fuel-charge mixing, and combustion characteristics in a two-stroke rod-less spark ignition opposed-pistons engine

Compared with the traditional in-cylinder direct-injection spark ignition engine, the side-injection and side-spark-ignition characteristics of the two-stroke opposed-piston engine increase the ignition kernel offset and flame propagation distance. Increasing the flame propagation speed can to some extent solve the drawbacks caused by the non-central arrangement of spark plugs. The combustion chamber structure plays a crucial role in gas flow, fuel-charge mixing, and combustion characteristics. Therefore, three pistons were designed and comparatively analyzed in this study. The results show that: The pancake piston is beneficial to maintaining the intake swirl strength due to its simple and smooth spherical arc structure. The swirl strength of the pit and pit-guided piston decreases obviously, and the tumble strength can be maintained well. Compared to pancake and pit-guided pistons, the average TKE for the pit piston increased by approximately 25%, with a more concentrated distribution at the spark timing. The pancake piston exhibits the best scavenging performance, reducing the residual exhaust gas ratio by 2.1% and fresh air loss by 3.3% to the pit piston. A stable ignition core can be formed at the spark timing, but significant differences are observed in the flame propagation process for three pistons. Compared to the pit-guided piston, the pit piston has a 0.3% decrease in the indicated thermal efficiency, but a 13.1% decrease in combustion duration, which reduces knock tendency.

Piston geometry and stroke optimization for high efficiency propane spark ignition engines

Propane has unique properties and offers interesting characteristics for high-efficiency spark ignition engines. Its high volatility reduces or completely eliminates fuel-wall wetting and facilitates fuel air mixing. Furthermore, propane has a research octane number of 112 and a high octane sensitivity of 15. Finally, its laminar flame speed is on the same order as that of conventional gasoline, and it exhibits high dilution tolerance. Modern spark ignition internal combustion engines rely on fast combustion rates and high dilution to achieve high brake thermal efficiencies. To accomplish this, high stroke-to-bore ratios and high geometric compression ratios have been used in new engine designs. Therefore, propane’s relatively high laminar flame speeds, high knock resistance, and dilution tolerance make it an excellent candidate fuel for modern spark ignition engines. The objective of this work is to co-optimize the piston geometry and the engine stroke to maximize the efficiency of a spark-ignition engine fueled with propane. 3D computational fluid dynamics (CFD) simulations employing the extended coherent flamelet model were used to study the parametric effects of piston shape and stroke length. A piston geometry based on high performing pistons was parameterized using four controlling parameters. The piston geometry and engine stroke design space was explored using deterministic and quasi-random sampling techniques. A Gaussian process regression model was built using the simulation data to explain the results observed.

Design of Magnetorheological Fluid Damper with Optimal Damping Force

This article focuses on designing and analyzing of an optimal Magnetorheological Fluid Damper (MRFD) having varying piston shape channeled into the piston of the MRFD. A finite element approach has been employed to investigate the impact of piston material, piston shape, MR fluid gap and pole length on the generated magnetic field density, yield stress along with damping force. Taguchi L18 orthogonal array has been exercised to obtain the optimal damping force. The Analysis of Variance (ANOVA) results investigate the contribution of the selected parameters and depict that the MR fluid gap is the most predominant factor which affects the damping force, making a contribution of 77.56%, followed by piston material which contributes 12.40%, pole length with a contribution of 8.23% and piston shape has negligible contribution of 0.07%. Taguchi predicts the optimized model for the selected parameters as A2B2C1D3 which has been validated by carrying out the analysis using ANSYS Maxwell software v. 16. The damping force of 1053 N has been obtained for the optimal MR damper model which is based on the prediction of the Taguchi results.

Enhancing ammonia engine efficiency through pre-chamber combustion and dual-fuel compression ignition techniques

In pursuit of unleashing ammonia’s potential in internal combustion engines, an extensive computational study was conducted to explore the effects of two advanced combustion techniques: pre-chamber combustion (PCC) and dual-fuel compression ignition (DF−CI) on a heavy-duty ammonia engine. In the PCC mode, hydrogen was introduced into the pre-chamber (PC) to generate distributed reacting jets, with a small energy fraction of 0.5%. The case featuring a slightly narrower PC throat (diameter of 5.4 mm) yielded the highest indicated thermal efficiency (ITE) of 50.4%, owing to the rapid distribution of reacting jets and advanced combustion phasing. Further increase in hydrogen energy fraction and reduction in throat diameter resulted in a lower ITE because of the enhanced wall heat transfer loss. The DF−CI mode also exhibited significant potential for achieving high efficiency. Through a systemic optimization of parameters such as diesel injection timing, spray included angle, injection pressure, swirl ratio, and piston shape, a significantly enhanced ITE of 50.3% was attained, 7.2% higher than the baseline scenario. The improvement was primarily attributed to the promoted mixing of diesel with air. Among the design parameters, the swirl ratio and spray included angle exhibited the most significant impact on the engine performance. Overall, both the PCC and DF−CI modes were found to yield high ITE and low ammonia emissions. However, because 20% of the diesel energy fraction was utilized to mitigate ammonia slip in the DF−CI mode, notably higher greenhouse gas emissions (carbon dioxide of 96 g/kW-h) were generated than in the PCC mode. In this regard, the ammonia-hydrogen PCC mode should be a more promising solution to achieve zero-carbon emissions for future ammonia engines.

Numerical study of piston bowl geometries on PFI-HCCI engine performance

Homogeneous charge compression ignition (HCCI) is an advanced combustion strategy proposed to provide higher efficiency and lower emissions than conventional compression ignition. However, there are still tough challenges in the successful operation of HCCI engines. Among these challenges, homogeneous mixture preparation and combustion phase control plays a vital role in determining the efficiency and emissions. Piston bowl geometry significantly enhances the process by improving the flow, turbulence, and mixing for the combustion. The study utilised experimental and numerical simulation methods to analyse HCCI combustion in port fuel injection (PFI) mode and evaluate the effect of piston geometries on engine performance. For this purpose, the different pistons bowl geometries (Baseline model, SQC, and CCC) with the same volume, compression, and equivalence ratio were numerically tested in a four-stroke, single-cylinder, YANMAR diesel engine. The numerical simulation results provide adequate assurance to proceed with the study with different piston geometries design. Compared to SQC and CCC, the Baseline model produced significantly higher cylinder pressure, temperature, and heat release rate. Different piston shape designs influenced the formation of air-fuel mixing, thereby affecting the time and location of onset combustion. The present investigation offered the significant role of piston geometry for the control mechanism of PFI-HCCI combustion, that is a vital part in demonstrating HCCI combustion.

Trade-off study and the influence of different fuel injection strategies to enhance the engine characteristics powered with ternary fuel in CRDI diesel engine.

The effects of a diesel engine combustion chamber geometries (PB1, PB2, PB3) and fuel injection pressure (FIP) (500, 750, and 1000 bar) with ternary fuel are discussed in this paper. It is observed that at maximum load as the FIP increased, the PB3 surpasses the PB1 and PB2 in brake thermal efficiency (4.86%) and hydrocarbon (7.2% decrease). However, a minor reduction in NOx (3%) is seen with increased FIP in the PB2. The NHRR (net heat release rate), peak pressure (in-cylinder), and ROPR (rate of pressure increases) all considerably increase with an enhancement in FIP in the case of PB3 by 2.96%, 3.86%, and 1.98%, respectively. It is discovered that altering the fuel injection pressure and piston shape concurrently offers a viable substitute for raising engine output and reducing emissions.

Effects of spray pattern and piston shape on in-cylinder flow in a two-cylinder spray-guided gasoline direct-injection optical engine

In gasoline direct-injection engines, in-cylinder flow plays an important role in terms of fuel atomization, mixture, turbulence, combustion, and emission. The in-cylinder flow is affected by the air–fuel interaction and piston shapes, and it is required to understand and optimize these influences. In this study, visualization of in-cylinder flow was performed depending on the piston shape and spray pattern using particle image velocimetry measurements in a two-cylinder optical engine with high-compression ratio and spray-guided direct-injection. Effects of these parameters were evaluated quantitatively by calculating average flow speed, average tumble ratio, and average turbulent kinetic energy. The mixture was confirmed using numerical simulation. The piston shape had no significant effect on the structure and strength of the in-cylinder flow. The 7-hole injector with asymmetrical spray patter was more effective to enhance the turbulence than the 10-hole injector with symmetrical spray pattern. As the injection timing was delayed up to before top dead center 120°, the average turbulent kinetic energy after fuel injection increased by up to 574 % in the 7-hole injector. However, considering stratification and possible knock region, ideal mixtures were found in the injection timing range of before top dead center 270° to 210° in both injectors.

Mechanical Analysis of Downsized Automobile Piston through Simulation

Engine downsizing technology benefits the environment in terms of emission gases and also reduces the usage of fuel in automobiles. Reducing the number of pistons and or their dimensions is among the most suitable techniques for engine downsizing. However, reducing the size of the pistons will cause another issue to with withstanding the applied forces generated due to combustion gases during combustion. Therefore, in this research work, the automobile piston was analyzed through simulation using ANSYSv17.2 after a 10% stroke reduction in its dimension. Further, to advance the novelty of this research work; 02-different automobile piston shapes: and hollow and toroidal combustion chambers (HCC & TCC) were reduced for investigating mechanical analysis. For mechanical analysis: maximum principal stresses, Von-Misses stresses, and total deformation before and after downsizing were analyzed. The results revealed that the maximum principal stresses, Von-Misses stresses, and total deformation were increased by 42%, 33.5%, 41.4%, 26.7%, 14.1%, and 8.2% after downsizing the HCC and TCC pistons respectively. Additionally, TCC offered better resistance to applied forces as compared to HCC. However, the increased values were within the maximum ultimate stress of the material, and it can be concluded that the 10% by stroke downsizing is under safe mode.

Effects of piston crown designs on in-cylinder flow and mixture formation in gasoline direct injection engine under the lean burn condition

In this study, the effects of piston shapes on in-cylinder flow characteristics and mixture formation in the lean condition was analyzed using the PIV method and CFD (CONVERGE v2.4). The four-piston geometries were concave, flat, convex, and base pistons, and the pistons were mounted on a GDI engine with transparent quartz. To quantify in-cylinder flow characteristics, the mean velocity, tumble ratio, turbulent kinetic energy, and tumble center were calculated. In addition, to analyze the effects of the difference in piston shapes in detail, the velocity fraction was calculated by dividing the cylinder area into three. In-cylinder flow was compared for the case without injection and the case with injection. There were four timed injections at C.A. 420°, 480°, 540°, and 600°, and the mixture characteristics were investigated in the cases of 480° and 600° injection. In the intake process and early compression process, there was no significant difference in the quantitative values for the shape of the piston regardless of the presence or absence of injection. However, the effects of the piston crown designs increased in the later compression process. As a result, the highest turbulent kinetic energy was found using a flat piston with a relatively high tumble ratio and swirl ratio in the absence of injection. The mixture formation was similar for all piston crown designs when injected at the crank angle of 480°. However, when the crank angle of 600° was injected, a stagnant fuel area was formed using the base-type piston, so it was difficult to secure sufficient fuel near the center of the cylinder.

Numerical study to improve the combustion and thermal efficiencies of off-gas/synthesis gas-fueled HCCI-engine at different loads: Piston-shape and crevice design

This numerical work aims to improve combustion efficiency and thermal efficiency by modifying the piston shape and crevice volume ratio of the HCCI engine operated under excessively lean air-fuel mixture conditions for power generation employment. The baseline piston, optimized for the diesel engine, gives strong reverse squish flow during the expansion stroke, causing a reduction in the efficiency of the engine. Therefore, the flow field in the squish area of the piston bowl should be weakened to facilitate auto-ignition at different points to boost the burning rate. Hence, the baseline piston shape was modified by bringing down the piston bowl depth and reducing the squish area ratio from 34% to 5% with a constant compression ratio. Crevice volume ratio Vcrevice/VTDC is also optimized for the HCCI engine to achieve high performance. All calculations are executed at MBT conditions by changing the inlet temperature of the mixture. Finally, the computational model results are validated with literature data. The results indicate that combustion phasing advances by changing the piston shape, and it also reports that the highest engine combustion efficiency of about 96%, 97%, and 99% are achieved by changing the piston shape and reducing the 40% crevice volume ratio of the engine, at low load, medium load, and high loads, respectively. The results also show that thermal efficiency is improved from 40% to 46% at low load while enhancing from 36 to 38.5% at 10 bar IMEP, respectively.

Effects of piston shapes and swirl ratios on combustion and emissions of a micro diesel pilot-ignition natural gas engine

To improve the performance of a micro diesel pilot-ignition (DPI) natural gas (NG) engine, four groups of pistons were designed and the effects of piston shapes and swirl ratios were discussed based on computational fluid dynamics (CFD) simulation.

Development and Characterization ofAgro-AlliedRice Husks andGroundnut ShellWaste Briquettes

Briquetting of agro-residues can alleviate some of the problems of energy shortage being encountered world-wide. The briquettes are essentially manufactured to provide cheap energy to the various sectors. Most importantly, to the domestic households that are finding it difficult to purchase the other sources of energy because of their cost. In this research the briquettes wereproduced in a briquetting screw press –BSP, using a manually operated piston and cylindrical shape Mould. The individual materials weremixed thoroughly in a ratio of rice husk: groundnut shell (RH:GS) as follows: 100:00; 70:30; 50:50;30:70; and 00:100.A fixed quantity of each mixture wereseparately hand-fed into a manually operated closed-end piston press to compact the briquettes. Thereafter, the briquettes wereejected and placed on drying racks and left in the sun for drying. The moisture content, ash content, volatile matter, fixed carbon, ignition time,flame propagation time, calorificvalue and water boiling test were investigated to determine the physical and thermal properties of the briquettes produced. The results of the investigation showedthat moisture content of the briquettes ranged from 3.96 –5.65%, the calorific value ranges from 130, 63.56–141, 62.87kJ/kg, the range of ash content is 6.10 -9.32 %, for fixed carbon is 7.67 -20.20 %, the ignition time ranges from 238-270sec and the rangesfor water boiling test time is 10.57m, –13.37m. These values satisfactorily comparewell with values obtained by other researchers in the literature. Therefore, the rice husk -groundnut shell briquettes are good alternative source of thermal energy for cooking. It is an economical and also an environmental friendly source of energy and waste disposal.

Effects of piston shape and nozzle specifications on part-load operation of natural gas–diesel dual-fuel RCCI engine and its application to high load extension

• Effects of piston shape and multi-angle nozzle were evaluated for DF RCCI operation. • Enhanced air utilization w/multi-angle nozzle reduced combustion and HT losses. • The highest GIE of RCCI improved as 51.8 % by hardware modifications. • Intake air amount could be increased by lowering CR (from 17 to 15) at the maximum load. • The maximum load of RCCI could be extended from 81 (reference) to 101 kW of BP. In this study, the effects of modifications of both the piston shape and injector nozzle are experimentally investigated for high load extension of a natural gas–diesel dual-fuel reactivity-controlled compression ignition (RCCI) engine. First, a bathtub shape with a reduced compression ratio is applied to the modified piston which was reported to improve the flame propagation in squish volume, the cooling loss, and the air induction rate under the same limit of in-cylinder pressure from previous studies. In addition, a multiangle two-layer injector is used to extend the maximum load, which has been proven to be effective for unburned hydrocarbon emissions and gross indicated efficiency in part-load operation in our previous study. The experiments are conducted under both 1200 rpm part-load operation (approximately 1950 J/cylinder per cycle of fuel input energy) and 1800 rpm maximum load operation. The objectives are to comprehensively evaluate the effects of the modifications on natural gas–diesel RCCI operation and verify the effects of all load conditions. The experimental results reveal that the changes in the piston—reduction in the compression ratio and a bathtub piston shape—are effective for both NOx and smoke emissions as the diesel injection timing is advanced. Although the multi-hole double layer (combined narrow and wide injection) has less effect on emissions compared to that of the change in piston, it affects the mixing process inside the cylinder, thus retarding the combustion phasing, prolonging the combustion duration, and eventually reducing the cooling loss. Both modifications are highly effective for advanced diesel injection timing corresponding to RCCI operation, which extends high-load operation from 80.9 to 101 kW of brake power, relatively 24.8 % increase, by adopting both the piston and injector modifications. Based on the modifications, the mass fraction of natural gas is suggested to be approximately 80 %. A higher fraction causes the variation in the maximum in-cylinder pressure to be extremely sensitive to allow robust operation. In contrast, if it is lower, the amounts of both NOx and smoke emissions exceed the emission standard levels (0.4 g/kWh and 15 mg/kWh for NOx and smoke emissions, respectively, corresponding to Stage-V of non-road engine operation).

Combined effects of nozzle hole variation and piston bowl geometry modification on performance characteristics of a diesel engine with energy and exergy approach

This experimental work aims to address the challenges of waste management. Biomass waste is converted into useful fuel and considered as a replacement to conventional fuel in CI engines. In this context, the grape marc and grape pomace are crushed and further processed to produce grapeseed oil. The grapeseed oil is further trans esterified to produce grapeseed seed oil methyl ester. The present study aims in examining the effect of varying piston shapes and nozzle profile on energy and exergy rates of a CI engine run with grapeseed oil methyl ester (GSME) blended with cerium oxide nano particles. The CeO2 nano particles were suspended in the base fuel at a concentration of 100 ppm and stability tests were conducted. The experiments were performed on a single cylinder, water cooled diesel engine with rated power of 5.2 kW. The research work includes two additional piston shapes namely, toroidal and shallow deep and two additional nozzle profiles viz. 4 hole and 5-hole nozzle. The hemispherical shape and 3-hole nozzle were considered as the standard one. Energy and exergy analysis were done on the experimental data to understand the exergy associated with cooling water, exhaust gas and unaccounted losses. The energy and exergy rates show that increase in nozzle hole number, decreases the destructive availability of the system. The exergetic efficiency of 32.8% is higher proving that toroidal shape and 5-hole nozzle profile is comparatively better and suitable for effective engine operation. HC, CO and smoke emissions reduced considerably by 14.4%–30% by the engine modification. Brake thermal efficiency was improved from 28.2% to 31.02% for CI engine with biodiesel. The paper addresses the gap in fuel modification clubbed with engine modification using biomass waste derived fuel. Exergy and energy analysis further add value to this current experimental work.

Analisis Peforma Dan Komsumsi Bahan Bakar Pada Honda Tiger 2006 Menggunakan Piston Standar Dan Piston Pro Neotech

the engine performance is very important at the automotive world, especially on 4-stroke motorcycles, where most people want the engine performance to be better and more economically. In this case to improve engine performance is done by changing the piston on the motor. With a different piston shape can increase the compression ratio. The purpose of this study is to determine changes in compression ratio, torque, power and fuel consumption, after replacing the piston. The test was carried out on a 2006 Honda Tiger, with a standard piston specification with a diameter of 64.5 mm (flat surface) and replaced with a 64.5 mm pro newtech piston (convex surface) by using Pertamax 92 fuel. The results obtained from the comparison of the compression value of 1, 6 : 1, 12.65 ft-lbs of torque, and 2.87 ft-lbs of power so that fuel consumption increases by 5.685%

Computational Investigation on the Performance Increase of a Small Industrial Diesel Engine Regarding the Effects of Compression Ratio, Piston Bowl Shape and Injection Strategy

This paper describes the simulative approach to calibrate an already extremely highly turbocharged industrial diesel engine for higher low-speed torque. The engine, which is already operating at its cylinder-pressure maximum, is to achieve close to 30 bar effective mean pressure through suitable calibration between the compression ratio, piston-bowl shape and injection strategy. The basic idea of the study is to lower the compression ratio for even higher injection masses and boost pressures, with the resulting disadvantages in the area of emissions and fuel consumption being partially compensated for by optimizations in the areas of piston shape and injection strategy. The simulations primarily involve the use of the 3D CFD software Converge CFD for in-cylinder calibration and a fully predictive 1D full-engine model in GT Suite. The simulations are based on a two-stage turbocharged 1950 cc four-cylinder industrial diesel engine, which is used for validation of the initial simulation. With the maximum increase in fuel mass and boost pressure, the effective mean pressure could be increased up to 28 bar, while specific consumption increased only slightly. Depending on the geometry, NOx or CO and UHC emissions could be reduced.

Understanding the effect of turbulent flow on the combustion cyclic variation in a spark ignition engine using Large-Eddy simulation

At the present, emission regulations have been tightened around the world in an effort to reduce emissions from internal combustion engine (ICE) vehicles. The one of the issues in the development of eco-friendly spark ignition (SI) internal combustion engines is a cycle-to-cycle variation (CCV) of combustion. Therefore, research on the CCV is also being actively carried out. Because the causes that affect the cycle deviation are various and complex, it is difficult to conduct detailed research on the source of the CCV through experimental studies. Therefore, the 3D simulation, especially large-eddy simulation (LES) approach is actively carried out.In the present study, the Lagrangian ignition model developed for LES is introduced. The Lagrangian particles were employed to realize the ignition channel and the secondary electric circuit model was implemented to predict the spark energy and the end of ignition time. And 30 LES cycles were performed to identify the cause of the CCV and validated against the experimental data. The vortex produced by wall flow on the secondary tumble plane was identified as an important factor. A new piston shape was designed to strengthen the vortex formation by wall flow. The result of new piston case showed the reduced combustion CCV than the base case. This research provides the guide how to investigate the sources of the combustion CCV and how to reduce the combustion CCV for the future engine development.

Design and optimization of a magnetorheological damper based on B-spline curves

Taking advantage of the magnetically controllable rheological properties of magnetorheological (MR) fluid, MR dampers are widely used in many engineering fields. Much effort has been made to improve the performance of MR dampers. Structural optimization is one of the popular methods to effectively improve the performance parameters of MR dampers. Most MR damper optimizations are focused on parts with regular shape, but shapes governed by equations can bring out more possibilities and further optimal results. Therefore, in this paper, a new MR damper is designed and optimized based on B-spline curves in order to maximize the controllable output damping force while saving the input power for the prosthetic knee. First, design principle of dividing the parts of the MR damper into two categories is introduced. Then, B-spline curves are used to form the piston shape, which is one of the crucial parts inside the magnetic circuit. Later, the optimal B-spline curve and other geometric parameters inside the magnetic circuit are obtained through simulation and optimization. Furthermore, the optimized MR damper is fabricated, assembled and tested. Finally, the proposed MR damper is compared with the ones in our previous work. Experimental results match well with the simulation ones. When working at the frequency of 1.0 Hz and the amplitude of 10 mm, the proposed MR damper has large maximum damping force and dynamic ratio, with acceptable equivalent damping. The proposed MR damper also performs better than the prototypes in our previous work in terms of maximum damping force, field dependent force, equivalent damping, dynamic range, and force-to-power ratio.

RETRACTED: Exploration over combined impacts of modified piston bowl geometry and tert-butyl hydroquinone additive-included biodiesel/diesel blend on diesel engine behaviors

Nowadays, the use of biodiesel for diesel engines has been attracting researchers aiming to improve engine characteristics although the engine performance could be decreased while utilizing biodiesel. In this aspect, optimizing the piston bowl geometry is one of the useful approaches to enhance the efficiency of the biodiesel-powered diesel engine. In this study, the standard piston of an existing diesel engine was modified into two different combustion bowls, namely Symmetrical Stepped Curved-V (SSCV) and Symmetrical Spline-V (SSV), to evaluate the CI engine performance powered with mixtures of sesame-originated biodiesel, diesel fuel, and tert-butyl hydroquinone (TBHQ) additive through two-stage experiment. In the first phase, experiments were carried out on two modified piston bowls powered by diesel and S20 (20% sesame biodiesel + 80% diesel fuel). Resultantly, SSV piston revealed superior engine characteristics to SSCV piston and standard piston due to enhanced air–fuel mixing and more complete combustion of SSV piston-based engine. Indeed, SSV piston operation exhibited an 8.68% of increased brake thermal efficiency (BTE), 6.54% of curtailed brake-specific fuel consumption (BSFC), 4.76% of lowered carbon monoxide (CO), 4.84% of decreased unburnt hydrocarbon (HC), and 2.22% of lowered smoke opacity but with increased nitrogen oxide (NOx) by 14.14% in comparison to diesel. In the 2nd phase, to control the NOx emission effectively, a TBHQ additive was added to the S20 sample at different proportions (500 mg and 1000 mg) to analyze the test engine behaviors with modified piston shapes. As a result, S20 + 500 mg TBHQ at 100% load improved BTE by 5.79% and reduced BSFC by 4.36% in the case of SSV piston. Moreover, it curtailed emissions of CO, HC, NOx, and smoke opacity by 13.33%, 15.49%, 12.09%, and 9.44%, respectively, when equated with diesel. Overall, S20 + 500 mg TBHQ could be thought of as a possible alternative fuel on SSV piston as it resulted in superior performance and emission characteristics in the existing standard engine. The current study's findings could pave the way for the development of diesel engines with modified piston geometry that is more efficiently compatible with biodiesel blends and additives.