Piston Crown Research Articles

Application of acetylene in multi-cylinder low heat rejection diesel engine fueled with ternary blend

The depletion of fossil fuels and environmental degradation have driven researchers worldwide to seek suitable alternative fuels for diesel engines. Internal combustion engines typically emit carbon monoxide (CO), hydrocarbon (HC), and smoke, contributing to environmental pollution. To address this issue, petroleum fuels can be substituted with alternative options like acetylene gas, hydrogen, CNG, or LPG. One effective strategy is to incorporate renewable fuels into diesel engines by partially or fully replacing diesel in a dual fuel mode (DFM). This research focuses on alternative renewable fuels for diesel engines like biodiesel and alcohol and its blends. The current research investigates the engine characteristics of diesel engines fueled with ternary blend (TB) fuel and different flow rates of acetylene in DFM. TB fuel was prepared using 70 % diesel, 20 % waste cooking oil biodiesel (WCOB), and 10 % methanol by volume. The induction of acetylene at different flow rates, such as 2, 4, and 6 lpm. Waste cooking oil is used to prepare biodiesel by transesterification. Partially stabilized zirconia (PSZ) is used to coat the cylinder head, piston crown, inlet, and exhaust valves with a thickness of 0.5 mm. The HC, CO, and smoke emissions are decreased by about 35.7 %, 29.8 %, and 21.6 %, respectively, for TB fuel with acetylene at 6 lpm at full load condition. The high calorific value of acetylene gas raised the in-cylinder temperature, significantly accelerating the combustion process. The heat release rate (HRR) and cylinder pressure are increased by 9.8 % and 6.8 %, respectively, at TB fuel with 6 lpm of acetylene induction. Acetylene induces rapid fuel combustion, resulting in increased energy transfer. The brake thermal efficiency (BTE) is improved by about 10.3 % for TB fuel with acetylene at 6 lpm and exhaust gas temperature (EGT) increased to 461oC at full load condition.

REFINING THE EMPIRICAL MODEL OF THE HEAT TRANSFER BOUNDARY CONDITIONS OF THE PISTON OF A HIGH-SPEED DIESEL ENGINE

The level of temperature of ICE pistons is a factor that greatly affects their reliability. Therefore, the need to simulate the temperature state of pistons with sufficient accuracy and minimal allocation of resources and time exists in research and during design. Primary approaches for determining the boundary conditions of the problem of thermal conduction of the piston on the basis of criterion equations, high-level mathematical models, and empirical models are considered. The latter ones have become widespread by virtue of simplicity and ease of use in practice; their usability is limited to a certain set of operating modes of one engine or a few ones of a similar design. On the basis of data from four series of experimental tests for a well-studied diesel engine 4ChN12/14 the existing empirical models of boundary conditions, suitable for identifying the temperature state of the piston only within the respective separate series separately, are refined in the paper. Processing of the data set on the measured temperatures in the control zones of the piston was performed, and linear function approximations were found that satisfactorily describe the effect of diesel power on the specified temperatures. The model of boundary conditions for a set of eighteen separate regions on the surfaces of the piston was proposed, which takes into account the dependence of the piston temperature state on the brake power of the ICE, the crank angle of the start of fuel injection, and the conditions of cooling the piston with oil. The influence of the heat insulation layer on the piston crown surface on the heat transfer was accounted for by introducing an additional thermal resistance term into the boundary condition equations. The model made obtaining the temperature field of the piston possible in simulation that is consistent with the results of all series of experiments in the control zones of the piston periphery, the edge of the combustion chamber, the vicinity of the groove of the first piston ring, the cooled surface opposite to the combustion chamber, and the piston skirt. The importance of a gradual change in the temperature of the oil and coolant during the transition of the internal combustion engine from one mode of operation to another regarding the temperature state of the piston is demonstrated. Taking the temperatures of oil from previous modes of operation into account is recommended during the analysis of engine transient processes.

Thermal analysis by numerical simulations of a multilayered coating applied on a heavy-duty diesel engine piston

A methodology to numerically study the impact of a thin, multi-layer coating applied on the piston crown surface of an internal combustion engine is proposed. It relies on a loose thermal coupling between 3D-RANS simulations of the combustion chamber and 3D conduction simulations of the piston. The approach allows to characterize the transient thermal behavior of the piston, which is crucial to capture the thermal swing effect of the coating, as well as its potential impact on the combustion, heat transfer and engine efficiency. This methodology is used to simulate the impact of a 200-µm, 3-layer coating, applied on the piston crown surface of a single-cylinder, heavy-duty Diesel engine, for one operating point. No gain in terms of efficiency is observed with the coated piston (the decrease in heat losses through the piston surface due to the coating is counter-balanced by an increase in heat losses through the non-coated cylinder head). However, the methodology proves capable of predicting a coherent thermal behavior of the coated piston (decrease in piston body temperature of 5 K, average bowl surface temperature swing amplitude of 60 K, <5 K temperature swing at the interface between the metallic substrate and the coating) and is able to provide insightful information regarding the impact of coating on volumetric efficiency, heat losses, combustion but also on the coating reliability itself, for a reduced computational cost compared to a fully coupled approach. It can then be employed to evaluate the effect of a coating applied not only on the piston but also on the cylinder head, which would certainly have a more significant impact on the engine efficiency.

Study on the integration of hydrogen in a multi-cylinder low heat rejection diesel engine using a ternary blend

Among alternative fuels, hydrogen (H2) holds significant promise as both a fuel and an energy carrier. It is expected to become a key alternative fuel in the near future to meet stringent pollution standards. H2 is used in internal combustion (IC) engines, gas turbines, and the aerospace industry due to its non-toxic and odorless nature, high calorific value (CV), and wide temperature range of combustibility. Additionally, it is a long-term renewable energy source that produces fewer pollutants. This study explores the impact of different H2 ratios on combustion behavior, engine performance, and emission characteristics in a dual-fuel compression ignition (CI) diesel engine. The current research focuses on the effect of TB of ethanol, Jatropha methyl ester, and diesel with the induction of H2 with different flow rates in diesel engine in dual fuel mode (DFM). The tests were performed at different engine loads, 25%, 50%, 75%, and 100% at a constant engine speed of 2500 rpm. H2 is inducted at different flow rates like 2, 4, and 6 Litres per minute (lpm). Partially stabilized zirconia (PSZ) is used to coat the cylinder head, piston crown, and valves with a thickness of 0.5 mm. The combined effect of TB fuel and H2 in a CI engine improves combustion and engine performance. At full load condition, brake thermal efficiency (BTE) is improved by 11.5% for TB fuel with H2 at 6 lpm, and exhaust gas temperature (EGT) increased by 12.7%. The cylinder pressure (CP) and heat release rate (HRR) are increased by 7.5% and 10.6% at TB fuel with 6 lpm of H2 induction. The utilization of H2 as an alternative energy source has significant consequences for the future of green energy production.

FEM Analysis And Design Optimization Of The Piston

The workings of an engine rely on the piston rod and/or connecting rod to transmit the force of the expanding gas in the cylinder to the crankshaft. Because of its critical role in engines, the piston is subject to inertial stresses and cyclic gas pressure, which may lead to fatigue damage in the form of side wear, fractures in the piston head or crown, and other issues. According to the research, the top of the piston experiences the highest level of stress, which is a major contributor to fatigue failure. This study uses finite element analysis to illustrate the stress distribution on an internal combustion engine's piston. It is the CAD and CAE programs that carry out the FEA. Examining and analyzing the distribution of thermal and mechanical stresses on the piston under real-world engine conditions during combustion is the primary focus. Predicting the component's critical area and greater stress using finite element analysis is also detailed in the paper. Created a structural model of a piston using CATIA software. We ran simulations and stress analyses with the help of ANSYS V14.5.

Performance analysis and optimization of thermal barrier coated piston diesel engine fuelled with biodiesel using RSM

The current research investigates diesel and simarouba biodiesel blends (10%, 20%, & 30% by volume) in conventional and Low Heat Rejection (LHR) diesel engines, each rated at 4.4 kW. While optimization techniques like Response Surface Method and Taguchi have been extensively studied, the impact of LHR and optimization on LHR engine performance and emissions is rarely explored. Converting the conventional engine to LHR involved applying 300 μm of stabilized zirconia to the piston crown to enhance combustion efficiency. Performance and emissions were analyzed at rated injection pressure (200 bar) and timing (23° before top dead center - btdc). Experiments were continued on LHR engine by varying injection timings (advancing - 26°btdc and retarding - 20°btdc). Advanced injection timing showed significant improvement in performance of Low heat rejection engine. MINITAB statistical tool is used to optimize engine performance using Response Surface Method. The 20% blend showed improved performance in both engines. The optimum values for Low heat rejection engine responses are 26.8%, 0.32 kg/kW-h, 0.018%, 59.59 ppm, and 1419.03 ppm for brake thermal efficiency, brake specific fuel consumption, carbon monoxide, and unburnt hydrocarbons, respectively. Confirmation experiments aligned well with model predictions, indicating the potential of LHR engines to enhance thermal efficiency and reduce emissions.

Estimation of Piston Surface Temperature During Engine Transient Operation for Emissions Reduction

Abstract Piston surface temperature is an important factor in the reduction of harmful emissions in modern gasoline direct injection (GDI) engines. In transient operation, the piston surface temperature can change rapidly, increasing the risk of fuel puddling. The prediction of the piston surface temperature can provide the means to significantly improve multiple-pulse fuel injection control strategies through the avoidance of fuel puddling. It could also be used to intelligently control the piston cooling jet (PCJ), which is common in modern engines. Considerable research has been undertaken to identify generalized engine heat transfer correlations and to predict piston and cylinder wall surface temperatures during operation. Most of these correlations require in-cylinder combustion pressure as an input, as well as the identification of numerous model parameters. These requirements render such an approach impractical. In this study, the authors have developed a thermodynamic model of piston surface temperature based on the global energy balance (GEB) methodology, which includes the effect of PCJ activation. The advantages are a simple structure and no requirement for in-cylinder pressure data, and only limited experimental tests are needed for model parameter identification. Moreover, the proposed model works well during engine transient operation, with maximum average error of 6.68% during rapid transients. A detailed identification procedure is given. This and the model performance have been demonstrated using experimental piston crown surface temperature data from a prototype 1-liter 3-cylinder turbocharged GDI engine, operated in both engine steady-state and transient conditions with an oil jet used for piston cooling turned both on and off.

Review on Performance and Emissions Characteristics of Compression Ignition Engine Fueling Non-Edible Vegetable Oil

The tremendous exhaustion of resources, a surprising price increase of petroleum fuel and worldwide ecological issues implement to find renewable fuel for compression ignition engine. Non-edible vegetable oils have proven consensus to opt as a replacement for diesel fuel due to comparable properties and less-pollutant characteristics. Using Unmixed Untreated Non-edible Vegetable Oil (UUNVO) in the CI engine matches the needs of a sustainable future and restricts the intensifying cost involved in biodiesel production. This paper aims to review the influence of various UUNVO (Karanja, Jatropha, Neem, Linseed, Mahua and Rubber Seed etc.) on the important performance parameters and emission level of diesel engine. UUNVO can be fuelled to the unmodified CI engine. However, the viscosity of UUNVO is reasonably higher compare to diesel fuel at room temperature, which deteriorates the engine performance and exhaust emission. Minor changes in the injection line for preheating the UUNVO and operating parameters are the way to improve it. It can clearly understand here that preheated UUNVOs typically increase NOx emissions and decrease PM, HC, and CO emissions level compared to standard diesel. UUNVO can substitute diesel fuel completely for short-duration operation. With the long-duration operation, UUNVO produces problems like poor engine performance, injector chocking, and erosion of piston crown, rings, cylinder liner, and other internal parts, and degradation of the lubricant. Problems raised due to durability can be minimized by controlling operational parameters.

Experimental Study on Macroscopic Spray and Fuel Film Characteristics of E40 in a Constant Volume Chamber

In the modern industrial field, there is a strong emphasis on energy-saving and emission reduction. Increasing the amount of ethanol in ethanol–gasoline blends has the potential to replace fossil fuel gasoline more effectively, improving energy efficiency and lowering emissions. The interaction between liquid fuel film generation on the piston crown and spray impingement in the combustion chamber in the setting of GDI engines has a substantial impact on particle emissions and engine combustion. In this study, 92# gasoline and ethanol by volume are combined to create the ethanol–gasoline blend E40. The spray characteristics and film properties of both gasoline and the intermediate proportion ethanol–gasoline blend E40 were researched utilizing a constant volume combustion platform and the schlieren method and refractive index matching (RIM) approach. The results show that, for 0.1–25 operating conditions, gasoline consistently displays greater macroscopic spray characteristic parameters than E40. This shows that gasoline fuel spray evaporation is superior to E40. Similar results are seen in the analysis of wall-attached fuel films, where the volume and thickness of the gasoline film are less than those of the E40 film under the given operating conditions. In contrast, E40 consistently exhibits stronger macroscopic spray characteristic values than gasoline under the 0.1–150 and 0.4–150 operating conditions, along with lower film thickness and volume. As a result, under these two operating conditions, E40 fuel performs better during spray evaporation.

Comparative analysis of material for flat & dome top piston for SI engine using ansys

Compared to other areas of the IC engine, the working condition of piston attracts the most attention rather than any part in IC engine due to its complexity. Pistons have undergone many significant material and topographic changes since their first industrial introduction to overcome these working conditions. It is being said that electric vehicles will take over the world, but until the Lithium-ion battery remains, there will always be a shortage for batteries. Taking this as an assumption and the fact that carbon neutral fuel is currently in development, our goal is to make the piston lighter and more durable to make it future ready. In this research article, our objective is to substantiate and analyze the stress distribution of the piston with various [1] piston crown designs, namely, [1] flat top and dome top; integrated with various synthetic and alloy materials, namely, Titanium alloy, [2] Aluminum alloy, [3] Super magnesium, and [4] 3D Graphene. [5] Static Structural and Steady state thermal analysis is performed on these pistons using ANSYS R2 2022 software, while designing is performed on AutoCAD 2020 software. This article presents and analyses [5] thermal stress analysis and damages due to pressure application. Results are displayed comparing based on [5,6,7] total deformation, Von-mises strain, Von-mises stress, strain energy, normal elastic strain, normal stress, total heat flux and directional heat flux. Result is concluded by comparing to find the most preferable material for the piston in an engine. The preference is given based upon weight reduction, strength, and future scope of the material.

Novel candidate of metal-based thermal barrier coatings: High-entropy alloy

To obtain compatible properties of low thermal conductivity and high thermal stability, Al0.6CoCrFeNiTi high-entropy alloy was designed as a novel candidate of metal-based thermal barrier coatings (MBTBCs). The corresponding high-entropy alloy coatings were fabricated by both high-velocity oxygen-fuel spraying (HVOF) and atmospheric plasma spraying (APS), and then the dependence of thermal insulation properties on microstructure was investigated. The both coatings exhibit a simple body-centered cubic (BCC) structure, but present obvious difference in microstructure and defect characters which relates to the evolution of in-flight particles. Benefit from the extremely low thermal conductivity, the APS-deposited coating can increase 13.24 °C of the surface temperature of piston crown and yield a temperature reduction of 19.00 °C along the thickness direction, which mean a positivity on enhancing the power efficiency of vehicle engines without sacrificing the strength of aluminum alloy components. In virtue of a decoupling method, the crucial effect of microstructure on thermal conductivity is disclosed, thus interpreting the excellent thermal insulation property of APS-deposited coating dominated by grain refinement and disordered BCC structure. The present results demonstrate a great potential of high-entropy alloy coatings as thermal barrier application and provide an inspiration for future works aiming to design these coatings to meet specific engineering needs.

Effect mechanism and quantitative analysis of injector faults on diesel engine performance

The nozzle deterioration, caused by carbon deposition, cavitation erosion, and other reasons, has a great influence on the power performance, emissions, and thermal load of the direct injection (DI) engine. To understand the manifold effects of nozzle fault on engines, a systematic explanation for the diverse fault phenomena and effect mechanism of nozzle abnormality on the engine performance is needed. The joint action of orifice diameter and fuel spread direction on the performance of a double-swirl diesel engine are numerically revealed and decoupled. The results show that the engine power performance is mainly affected by the change of orifice diameter, while the abnormal spray direction has a great influence on the emissions and the piston surface thermal load. Insufficient spray tilt angle leads to a more concentrated fuel distribution because the fuel of the faulty orifice is not effectively channeled and dispersed by the circular ridge, which causes a 15.29% increase in NOx and an 8.73% increase in soot emissions. Spray circumferential offset leads to increased soot, decreased NOx, and slightly decreased power due to asymmetric fuel distribution. Some fuel is directly injected and burned in the clearance between the piston crown and cylinder head due to the abnormal spray direction, which causes the maximum heat flux at the piston crown to be about 1.8 times that under normal state, greatly increasing the possibility of piston damage. In contrast, the spray circumferential offset mainly causes the position change of the thermal load, but not the magnitude change.

Thermodynamic analysis of heat transfer reduction in spark ignition using thermal barrier coatings

This work uses a 0D thermodynamic engine model coupled to a 1D surface temperature solver to study the potential of low thermal inertia thermal barrier coatings (TBCs) on combustion chamber surfaces to increase the efficiency of spark ignition engines. Under ideal conditions, coating the piston crown, head, and valve faces with a TBC with a thermal inertia of 640 J/m2 K s1/2 resulted in less than a 1% relative improvement in efficiency. Despite using a low thermal inertia coating to avoid open cycle charge heating, the reduction in closed cycle heat transfer, which is the pathway to increasing efficiency, increased knock propensity. Therefore, any efficiency gain through closed cycle heat transfer reduction in spark ignition is offset by the need to retard spark timing to counter knock. An exergy analysis of completely blocking heat transfer for a 10 crank-angle degree window showed that on a low compression engine, like those used for stoichiometric gasoline spark ignition, the maximum efficiency gain achievable was limited compared to a higher compression ratio engine. Furthermore, the high gas temperatures of stoichiometric operation mean that even state-of-the-art TBCs cannot elevate surface temperatures enough purely through temperature swing to achieve a significant reduction in heat transfer near top dead center, where work availability is highest. Overall, these results indicate that low thermal inertia TBCs are ill-suited for achieving an efficiency benefit in spark ignition through a heat transfer reduction pathway. Instead spark ignition TBC research should explore ways to use low thermal inertia TBCs to achieve open cycle charge cooling to reduce knock propensity.

Experimental investigations on SI engine with piston coatings and gasoline blends

Internal combustion engine fuel use is rising, gas prices are fluctuating, we are using less fossil fuels and natural resources, and we need to develop alternative fuels with lower carbon contents. This study compares several gasoline mixtures in a single-cylinder, two-stroke SI engine. The current experimental work provides a thermal barrier for gasoline mixtures containing ethanol, butanol, and propanol by 100-µm piston crown coatings of magnesium partially stabilized zirconium (Mg-PSZ). 20% ethanol and 80% gasoline, 20% butane and 80% gasoline, and 20% propane and 80% gasoline made up the fuel mixture samples. The following engine variables must be assessed in this experiment for coated and uncoated pistons: brake-thermal efficiency (BTH), specific fuel consumption (SFC), and HC and CO emissions. According to the experiment findings, employing E20 resulted in a 4% gain in thermal efficiency, a 1.78% decrease in specific fuel consumption, and a 2.0% and 2.4% decrease in HC and CO exhaust emissions. The results show that heat barrier coatings and gasoline blends (E20) may improve engine performance while lowering exhaust emissions.

The influence of thermal barrier coating (TBC) on diesel engine performance powered by using Mimusops elengi methyl ester with TiO2 nanoadditive

This current exploration aims for enhancing engine performance by using Mimusops elengi methyl ester 20% and 80% diesel with 25 ppm TiO2 [MEME20 + 25 ppm of titanium oxide] nanoparticle additive for the low heat rejection (LHR) engine. The coating of the piston crown was made with an insulation of two layers, initially, bond coat of nickel chromium aluminium yttrium (NiCrAlY) 50 µm and a topcoat 250 µm (5% yttrium + 2% neodymium oxide + 93% zirconium oxide) using the plasma spray coating technique. In comparison to diesel, the engine performance with MEME 20 + 25 ppm of titanium oxide resulted in enhancement in brake thermal efficiency (BTE) of 7.06% and a decrease in brake specific fuel consumption (BSFC) of 16.38%. The CO, HC and smoke values were curtailed by 35.66%, 31.8% and 19.66%, respectively, equated with diesel fuel. The NO x and EGT were increased by 22.23% and 9.33%, respectively, with full load at 1500 rpm.

Effect of Grooves on the Piston Crown in Improving the Performance of Diesel Engine

Effect of Grooves on the Piston Crown in Improving the Performance of Diesel Engine

Optimization and performance characteristics of low heat rejection engine powered by mahua bio diesel by Taguchi technique

The current study focuses on how a thermal barrier coated piston affects the diesel engine's efficiency and emission criteria. The top surface of the piston crown was completely coated with three varying configurations of thermal barrier coatings (TBC) materials, including 7% YSZ (LHR1), 2% Gd2O3 + YSZ (LHR 2), and 5% Gd2O3 + YSZ (LHR 3), all of which had a thickness of 0.25 mm. In addition, for all three combinations, the bond coat NiCrAlY, which was applied to the sample substrate using plasma spray method. An experimental performance investigation was carried out on a four-stroke, one-cylinder diesel engine fuelled with diesel and mahua bio diesel under various loading situations. A qualitative study was performed to establish the optimal condition using Taguchi's method in order to save time and money.

Effects of split diesel injection strategies on combustion, knocking, cyclic variations and emissions of a natural gas-diesel dual fuel medium speed engine

Accelerated by the harms and depletion risk of fossil fuels, transition to low-carbon or renewable fuels have become an urgent need for combustion engines to decarbonize transport sectors. Natural gas-diesel dual-fuel combustion is a promising method to achieve these goals by allowing the usage of natural gas in diesel engines. However, this concept has drawbacks of low combustion efficiency, high unburned hydrocarbon (HC) emissions and high cyclic variations at low engine loads. These drawbacks hinder the benefits of dual-fuel such as low NOx and soot emissions. To find solutions to these drawbacks, split diesel injections with variable injection timings and mass split ratios (ratio of first injection diesel mass to total diesel mass) were investigated experimentally and numerically on a medium speed marine engine at low load using constant natural gas and diesel amounts.Experimental results of the split injection were compared to single injection dual-fuel and conventional diesel operation. Single injection case resulted in slightly lower HC emissions and cyclic variations and higher NOx emissions than split cases in a narrow injection timing interval. Apart from that, split injections increased combustion efficiency and decreased cyclic variations in a broader timing interval. For split cases, early first injection timing prevented high premixed heat release peak, suppressed NOx emissions and knocking. Especially, using 70% split ratio with retarded second injections increased combustion efficiency, decreased knocking level and provided simultaneous reduction of HC and NOx emissions compared to lower split ratio cases. In short, despite not giving the minimum values at all conditions, split injection showed potential to find a remedy to high HC emissions and cyclic variations issues by keeping robust operation in a wider injection timing interval.The numerical results support the experiments in which better combustion and decreased HC emissions are attained using sufficiently early diesel injections. Simulations show that, compared to late single injection, early single injection dual-fuel case enables more homogeneous temperature distribution and better oxidization of methane near the cylinder wall and central region above the piston crown. Besides, split injection shows improved methane oxidation near the cylinder wall and inside top-land crevice volume.

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.

Emission control and reduction in the combustion chamber of an internal combustion engine

Introduction (problem statement and relevance). The task of emission control and reduction for internal combustion engines (ICE) is a relevant issue of the modern engine building. However, the catalytic converters potential is limited and almost exhausted. The paper authors study the possibility to partially reduce toxic emissions directly in the engine combustion chamber by means of the ceramic coating formed on the piston crown.The purpose of the paper is to study the influence of the coating formed by the method of microarc oxidation on the combustion chamber parts on the ICE exhaust toxicity.Methodology and research methods. The experimental method of research was applied. The research was carried out on the RMZ-551i engine. Engine tests were performed in various load modes: the rotation rate changed from 2000 to 6000 rpm, and the throttle opening amounted to 25, 50, 75 and 100% in each speed mode.Results. The paper presents experimental data proving the real possibility to decrease the ICE exhaust gas toxicity through formation of a ceramic coating on the piston crown. A relative decrease of carbon monoxide concentration in exhaust gases by 3.1% was noticed when using coatings on pistons compared to using standard pistons. Along with the decrease of CO amount, a relative increase of carbon dioxide (СО2) concentration by 2.1% is noticed.Practical significance. The provided experimental data obtained in the engine tests showed the possibility to partially reduce the amount of toxic components in exhaust gases directly in the combustion chamber by means of the coating on the piston crown formed by microarc oxidation method.