Homogeneous Charge Compression Ignition Engine Research Articles

Analysis of start-up behavior based on the dynamic simulation of an SOFC–engine hybrid system

A dynamic simulation model of a hybrid power generation system of a solid oxide fuel cell and a homogeneous charge compression ignition engine was developed to investigate the behavior of the system during the start-up process. The stack, reformer, catalytic burner, and heat exchanger were implemented as dynamic models based on physical equations. For the engine, an experimental data-based mapping model was developed. The dynamic model was simulated on a Matlab/Simulink platform. Individually developed component models were assembled as an integrated system model and operated at the system level. The hybrid system was designed to generate approximately 4 kW of electricity from the SOFC stack and 1 kW from the engine, resulting in a total system power of 5 kW, with an electrical efficiency of 50.6%. The integrated model was operated using a four-step start-up procedure for 50 h, during which the temperature and composition of the stream were observed in time. Based on this, the dynamic behavior of the system was analyzed at each stage throughout the entire start-up process from ambient to high operating temperature. Validation of key results suggests a close resemblance between the model and an actual system. Therefore, the proposed model is expected to exceed the limitations of the existing static model analysis method.

Prediction and control of knock at high load boundary for HCCI engine based on neural network

Homogenous Charge Compression Ignition (HCCI) have drawn lots of attentions due to its high efficiency and low emissions. But HCCI engines are prone to random abnormal combustion phenomena at load boundaries. In this paper, innovatively implement online prediction and control of knock at high load boundary for HCCI utilizing only cylinder pressure as the diagnostic parameter based on neural networks. The results show that the neural network model with previous cycle heat release, previous cycle crank angle at 50 % cumulative heat release (CA50), peak cylinder pressure during previous and current cycle negative valve overlap (NVO) as inputs can realize the prediction of 87.5 % early combustion cycle in the intake phase before the early combustion occurs, and the diagnosis accuracy is 89.4 %. The frequency of early combustion can be reduced from 2.3 % to 0.3 % with the help of prediction model combining water injection and fuel injection reduction control, and no knocking occurs. The high load boundary of the HCCI engine is expanded by 7.1 % from 0.366 MPa to 0.392 MPa at 1500 r/min with the help of this control strategy.

Effect of hydrogen sulfide content on the combustion characteristics of biogas fuel in homogenous charge compression ignition engines

The use of biogas fuel in homogeneous charge compression ignition (HCCI) engines has been promoted recently due to the environmental advantages. However, hydrogen sulfide (H2S) forms a non-environment friendly content and biogas impurity that its removal is associated with high costs. In this study, the effect of using biogas fuel in the HCCI engines under different operating conditions is investigated to shed light on the best scenarios of biogas combustion, even with the presence of H2S contents. A modified reaction mechanism is introduced by considering the reactions of H2S with other species in the air-fuel mixture. The new chemical kinetics model, and a multi-zone combustion approach, have been validated against experimental data from the literature and then used to simulate the HCCI combustion of biogas fuel. It was obtained that having up to 3.8% content of H2S in the intake charge can enhance the rate of heat release and combustion pressure. However, it had no significant effect on the in-cylinder temperature profile. Higher rates of H2S contents led to produce higher rates of sulfur oxides (SOx) emissions. Increasing the equivalence ratio (up to 0.50) results in a higher in-cylinder temperature and pressure as well as a higher SOx and nitrogen oxides (NOx) emissions. Also, the HCCI combustion is influenced by the intake temperature and pressure, where increasing those parameters leads to an increase in the in-cylinder temperatures and pressures, as well as the NOx emissions. However, SOx emissions are affected only when the intake temperature reaches over 400K and the intake pressure is over 1.5bar.

Analysis of the effects of lubricating oil viscosity and engine speed on piston-cylinder liner frictions in a single cylinder HCCI engine by GT-SUITE program

Engines with homogenous charge compression ignition (HCCI) are the low-temperature combustion models in which automatic oxidation reactions occur with the effect of in-cylinder pressure and heat at the end of preparation of homogenous air-fuel mixture and compression stroke within the cylinder by means of port injection or early direct injection. In-cylinder gas temperatures of such engines during the cycle are lower than conventional internal combustion engines. Therefore, they cause zero NOx and soot emissions. Moreover, the occurrence of combustion in very small crankshaft angles results in a decrease in heat losses observed in cylinder walls and an increase in thermal efficiency. Reducing mechanical friction is highly significant for increasing the effective productivity of HCCI engines. In internal combustion engines, 10% of total energy obtained from the fuel is spent on the heat emerging due to mechanical frictions. 20% of mechanical friction results from the friction occurring between piston ring and liners. In this article, frictional characteristics of compression ring (TOP) and piston skirt area have been examined for two different engine speeds and lubricants, by using technical properties of single-cylinder HCCI engine and in-cylinder pressure and temperature data obtained under full load by means of GT-SUITE software. As the increase in pressure, occurring inside the cylinder at the end of the exhaust stroke and at the beginning of intake stroke, increases ring pressure load in HCCI engines, higher level of piston ring frictions has been observed when compared to internal combustion engines with the same technical properties. Piston ring contact pressure force is a more effective parameter in terms of piston frictions, when compared to hydrodynamic pressure force. The use of lubricants with higher viscosity (SAE 10W-40) has enabled the piston to move more laterally. According to the analysis results, a maximum piston speed of 3.92 m/s for 800 rpm engine speed and 7.85 m/s for 1600 rpm engine speed has been obtained. Maximum friction power losses have been found as 63.84 W at 800 rpm engine speed and 85.91 W at 1600 rpm engine speed. Oil film thickness has obtained in the middle of the piston stroke in the intake, compression, power and exhaust strokes, respectively, 1.809, 1.674, 1.547 and 1.792 µm at 800 rpm engine speed and 1.101, 1.018, 0.932 and 1.119 µm at 1600 rpm engine speed.

NUMERICAL STUDY OF WATER ADDITION ON THE COMBUSTION CHARACTERISTICS IN AN HCCI ETHANOL ENGINE

Low-temperature combustion modes have attracted global attention in recent years, especially the homogeneous charge compression ignition (HCCI) mode. The HCCI combustion produces high-speed combustion, achieving relatively high thermal efficiencies while emitting low NOX and soot. However, due to the lack of direct control to start the combustion, one of the main challenges in this type of engine is to ensure that auto-ignition occurs close to the top dead center for a wide operation range. There are a few combustion phase control techniques to solve this limitation, and one of them is water injection. In this regard, this paper explores the influence of water concentration in an ethanol HCCI engine as a form of combustion phasing control. The work was conducted numerically using a zero-dimensional single-zone model with a chemical kinetic mechanism containing 56 species and 383 reactions. The numerical model results were well agreed with the reported experimental data. The water fraction ranged from 0 to 18% by mass at 3% intervals. The results demonstrate that water injection is an efficient strategy to control the combustion phasing by adjusting the charge reactivity. The increase in water fraction reduced in-cylinder pressure and heat release rates. Furthermore, the combustion phase was advanced, the combustion duration was extended, and thermal efficiency was about 44.3% with the increase in water concentration.

Study on homogeneous charge compression ignition combustion in argon circulated closed cycle hydrogen engine

It is important to improve thermal efficiency and to reduce harmful exhaust gas emissions in internal combustion engines. A closed cycle engine system that uses a monatomic molecular gas as the working fluid can be expected to have high thermal efficiency due to the high specific heat ratio of the gas. Several studies have been reported on closed cycle engines with conventional spark ignition or compression ignition. This research newly proposes an argon circulated closed cycle homogeneous charge compression ignition (HCCI) engine system fueled with hydrogen. In this engine system, effects of in-cylinder gas initial temperature and residual water in recirculated gas on combustion characteristics were investigated. The results show that the system with argon circulation has the wider range of operable conditions and the higher thermal efficiency compared to the case with air as the working fluid.

LES of HCCI combustion of iso-octane/air in a flat-piston rapid compression machine

Homogeneous Charge Compression Ignition (HCCI) engines promise better efficiency and cleaner emissions than conventional piston engines, but can be challenging to control. Rapid compression machines (RCM) provide a simplified configuration for investigating HCCI combustion behavior, which is necessary for effective control of engine ignition timing and peak pressures. In this study, we assess the utility of large eddy simulations (LES) for predicting HCCI combustion in a 3-D configuration. To this end, LES with finite-rate chemistry employing a 99-species iso-octane/air mechanism of two RCM operating conditions are performed. The RCM configuration under consideration was designed by Strozzi et al. (Combust. Flame, 2019) with a flat piston to introduce large amounts of thermal stratification representative of realistic HCCI engine conditions, through the generation of corner vortices. It is shown that the simulation provides reasonable agreement with temperature fluctuations (7% difference), as well as ignition delay in the short ignition case (1 ms difference), while the long ignition case (35 ms difference) highlights more substantial deficiencies that are still within the expected uncertainty from the employed chemical mechanism. Flame propagation modes predicted by LES agree with experimental observations: spontaneous ignition is seen in the short ignition case, while deflagration is more prominent in the long ignition case. Analysis of global and local quantities classify the short ignition case in a mixed ignition regime, and the long ignition case in the mild ignition regime. These results demonstrate the utility of FRC-LES for investigations of multimode combustion regimes of HCCI combustion in a 3-D configuration.

Optimization of operating conditions in a homogeneous charge compression ignition engine with variable compression ratio

Optimization of operating conditions in a homogeneous charge compression ignition engine with variable compression ratio

Experimental investigation on operating light-duty diesel engine using ethanol–gasoline blends in a homogeneous charge compression ignition combustion mode

The advanced diesel combustion mode of homogeneous charge compression ignition (HCCI) provides simultaneous lessening of soot and oxides of nitrogen (NOx) emissions. However, HCCI operations with low volatility and high reactivity diesel fuel require energy-intensive vaporizers and suffer from a restricted operating load range. In this work, high volatility, and low reactivity ethanol–gasoline blends were utilized as fuels in a port fuel injected light-duty diesel engine operated in HCCI mode to address this limitation. To study the effect of adding ethanol to the test fuels, its content was progressively increased from 10% to 60% by simultaneously reducing the gasoline content. 6% of an ignition improver, 2-ethylhexyl nitrate (2-EHN), was added to test fuels to attain stable HCCI combustion in the test engine at lower engine loads. A combined experimental and statistical approach was followed to characterize the HCCI engine combustion, performance and emissions. The impact of independent operating factors of ethanol–gasoline fuel blend composition and engine load on the various response parameters was estimated using multi-regression models developed based on the response surface method (RSM). The optimization of engine parameters was performed using the desirability approach of RSM to maximize performance and minimize emissions. The engine operating load range was extended from 23% (1.22 bar BMEP) to 86% (4.63 bar BMEP) with ethanol–gasoline–2-EHN-fuelled HCCI, which was a substantial improvement over the achievable load range only up to 38% (2.02 bar BMEP) with diesel-fuelled HCCI. All the multi-regression models developed were statistically significant at a 95% confidence level. The results showed that the indicated thermal efficiency improved, and soot and NOx emissions reduced with increased ethanol content in the test fuels. The test engine showed optimal working conditions when operated using 49% ethanol in the test fuels at 75% engine load. To benchmark the HCCI engine performance under optimal operating conditions, it was compared with conventional diesel combustion at 75% engine load. The NOx and soot emissions decreased by 76% and 98%, respectively, while indicated thermal efficiency increased by 20% for HCCI than conventional mode. The optimal fuel reactivity was determined at various engine loads by using the model equation developed for combustion phasing. According to the findings of this study, the fuel management strategy of using ethanol and gasoline blends is a viable method to enhance the performance and emission metrics of HCCI engines.

Research Directions for Homogenous Charge Combustion Ignition Engine

Homogenous Charge Combustion Ignition Engine (HCCI) technology is an advanced engine technology developed in 1989. Several attempts are being made for the performance improvement and field applications of HCCI engines. Simulation models and laboratory experiments confirm that the HCCI technology is superior to the conventional Internal Combustion engines. However, the HCCI research is in nascent stage today. Focused research is required to bring this technology in commercial use. This paper aims to investigate the future directions for study of Homogenous Charge Compression Ignition engines. Review articles from last ten years were studied in detail. The conclusions and future directions suggested by all papers are critically examined, tabulated and analyzed. Common conclusions are separately presented and the specific conclusions of the papers are compared so as to develop a methodology to carry out further research in the field of Internal Combustion engines.

Effects of intake charge temperature and relative air-fuel ratio on the deterministic characteristics of cyclic combustion dynamics of a HCCI engine

Homogenous charge compression ignition (HCCI) combustion can significantly reduce automotive pollution and increase the thermal efficiency of the engine. However, combustion phasing control is a major challenge in HCCI engines due to severe cyclic combustion variations. This study investigates the cyclic combustion dynamics of the HCCI engine using nonlinear dynamic methods such as return maps, recurrence plots (RPs), and recurrence quantitative analysis (RQA). Combustion stability and cyclic variations of HCCI combustion parameters were investigated on a modified four-stroke diesel engine. The experiments were conducted by varying relative air-fuel ratios ([Formula: see text]) and intake air temperatures ([Formula: see text]) at two engine speeds. In-cylinder pressure data of 2000 consecutive engine combustion cycles is logged for each test condition. In this study, deterministic characteristics of combustion phasing (CA50) and crank angle position of maximum cylinder pressure ([Formula: see text]) are investigated and compared by employing nonlinear dynamical methods. Return maps revealed that [Formula: see text] is having distinct and more frequently observed deterministic characteristics in comparison to CA50. Patterns in RPs showed a more persistent and sudden change in the combustion dynamics at higher engine speeds. Recurrence plot-based analysis found the existence of deterministic features in the combustion dynamics irrespective of the operating conditions. It was found using RQA parameters that the deterministic nature becomes stronger with a decrease in [Formula: see text] and any deviation in intermediate values of [Formula: see text]. Additionally, RQA measures advocate that CA50 has more deterministic characteristics at higher engine speed while [Formula: see text] at lower engine speed. Strong coupling and synchronization between [Formula: see text] and CA50 is indicated by cross-recurrence plots and CPR index when engine operated with a comparatively richer mixture.

Study on Chemical Kinetics Mechanism of Ignition Characteristics of Dimethyl Ether Blended with Small Molecular Alkanes

Dimethyl ether (DME)/C1-C4 alkane mixtures are ideal fuel for homogeneous charge compression ignition (HCCI) engines. The comparison of ignition delay and multi-stage ignition for DME/C1-C4 alkane mixtures can provide theoretical guidance for expanding the load range and controlling the ignition time of DME HCCI engines. However, the interaction mechanism between DME and C1-C4 alkane under engine relevant high-pressure and low-temperature conditions remains to be revealed, especially the comprehensive comparison of the negative temperature coefficient (NTC) and multi-stage ignition characteristic. Therefore, the CHEMKIN-PRO software is used to calculate the ignition delay process of DME/C1-C4 alkane mixtures (50%/50%) at different compressed temperatures (600–2000 K), pressures (20–50 bar), and equivalence ratios (0.5–2.0) and the multi-stage ignition process of DME/C1-C4 alkane mixtures (50%/50%) over the temperature of 650 K, pressure of 20 bar, and equivalence ratio range of 0.3–0.5. The results show that the ignition delay of the mixtures exhibits a typical NTC characteristic, which is more prominent at a low equivalence ratio and pressure range. The initial temperature of DME/CH4 mixtures of the NTC region is the highest. In the NTC region, the ignition delay DME/CH4 mixtures are the shortest, whereas DME/C3H8 mixtures are the longest. At low-temperature and lean-burn conditions, DME/C1-C4 alkane mixtures exhibit a distinct three-stage ignition characteristic. The time corresponding to heat release rate and pressure peak is the shortest for DME/CH4 mixtures, and it is the longest for DME/C3H8 mixtures. Kinetic analysis indicates that small molecular alkane competes with the OH radical produced in the oxidation process of DME, which inhibits the oxidation of DME and promotes the oxidation of small molecular alkane. The concentration of active radicals and the OH radical production rate of elementary reactions are the highest for DME/CH4 mixtures, and they are the lowest for DME/C3H8 mixtures.

A computational study to analyze the effect of equivalence ratio and hydrogen volume fraction on the ultra-lean burning of the syngas-fueled HCCI engine

This computational study investigates the equivalence ratio and hydrogen volume fraction effect on the ultra-lean burning of the syngas-fueled homogeneous charge compression ignition (HCCI) engine. In this research, low calorific syngas, composed of different compositions of H2, CO, and CO2, is used as a fuel in the HCCI engine that is operated under an overly lean air-fuel mixture. ANSYS Forte CFD package with Gri-Mech 3.0 chemical kinetics was used to analyze the in-cylinder combustion phenomena, and the simulation results were validated with experimental tests in the form of in-cylinder pressure and heat release rate at different equivalence ratios.The results indicate that changing the equivalence ratio produces a negligible change in combustion phasing, while it positively impacts the combustion and thermal efficiency of this syngas-fueled HCCI engine under lean conditions due to the high burning rate in the squish region. Moreover, an increased equivalence ratio increases MPRR due to the rich mixture combustion. The results also represent that the high-volume fraction of H2 in syngas fuel causes an advanced burning phase, improves the combustion performance of the HCCI engine at all equivalence ratio conditions, and causes slightly high NOx emissions.

The Start of Combustion Prediction for Methane-Fueled HCCI Engines: Traditional vs. Machine Learning Methods

In this work, 11 regression models based on machine learning techniques were employed to provide a fast-response and accurate model for the prediction of the start of combustion in homogeneous charge compression ignition engines fueled with methane. These regression models are categorized into linear and nonlinear types. Although the robust random sample consensus (RANSAC) model is a nonlinear type as well as SAM (simple algebraic model), the prediction accuracy is enhanced from 89.3% to 98.4%. Such accuracy is also achieved for the linear models, namely, ordinary least squares, ridge, and Bayesian ridge models. Indeed, due to the linear hypothesis (the correlation for the start of combustion prediction), the presented models have an acceptable response time to be used in real-time control applications like the electronic control units of the engines.

Enhancement of mixture homogeneity for DI-CI engine to achieve Homogeneous Charge Compression Ignition (HCCI) combustion characteristics: a numerical approach

ABSTRACT Homogeneous Charge Compression Ignition (HCCI) engine is a new mode of engine combustion concept used for decreasing emissions like NOx and soot and to meet stringent emission norms. A numerical and modeling analysis of the performance and emission characteristics of a DI-CI engine is presented in this paper. The numerical analysis was carried out using CONVERGE CFD software. In this paper, four different engine parameters were considered, i.e., Compression Ratio (CR) (14.5 to 19.5), Exhaust Gas Recirculation (EGR) (0 to 30%), Fuel Injection Pressure (FIP) (200 to 280 bar), and Start of Injection (SOI) (17 to 29° CA bTDC). Response Surface Methodology (RSM) was used for developing the design matrix in the given parameter ranges. Results were analyzed in terms of NOx, soot emissions, and Indicated Specific Fuel Consumption (ISFC) with an objective of lowering ISFC, soot, and NOx. The statistical analysis showed that CR of 18.9, SOI of 25.89° CA bTDC, EGR of 24.9%, and FIP of 262.45 bar predicted as an optimum combination of operation parameters set. From the ANOVA analysis, it is observed that CR and SOI are the most influencing parameters on the output response parameters. The mixture homogeneity (i.e., Target Fuel Distribution Index (TFDI)) of air-fuel was improved by 19.2% for optimum configuration as compared to baseline configuration.

Low-Temperature Oxidation of Di-n-Butyl Ether in a Motored Homogeneous Charge Compression Ignition (HCCI) Engine: Comparison of Characteristic Products with RCM and JSR Speciation by Orbitrap

Low-Temperature Oxidation of Di-<i>n</i>-Butyl Ether in a Motored Homogeneous Charge Compression Ignition (HCCI) Engine: Comparison of Characteristic Products with RCM and JSR Speciation by Orbitrap

A comparative study of PODE/gasoline and n-heptane/gasoline in a spark-assisted homogeneous charge compression ignition engine with dual-injection strategies and EGR

Homogeneous charge compression ignition (HCCI) has potential to improve thermal efficiency for gasoline engine due to the similar formation of mixture between HCCI and traditional spark ignition mode. High reactivity fuel combined with gasoline is used to achieve HCCI combustion with a relative low compression ratio. Polyoxymethylene dimethyl ethers (PODE) is a kind of low-carbon fuels with unique molecule structure, which is beneficial for carbon neutral. The intermediate products of PODE are different from those of long-chain alkane such as n-heptane and diesel. In this paper, the difference in spark-assisted HCCI (SA-HCCI) combustion combined with spark ignition and EGR between PODE/gasoline and n-heptane/gasoline under different operating conditions were investigated. The results illustrated that PODE/gasoline was more suitable for SA-HCCI combustion due to the positive relation between thermal efficiency and gasoline percentage, which can significantly improve the thermal efficiency while suppressing knock. Although the cetane number of PODE is greater than the n-heptane, the SA-HCCI combustion was more violent fueled with n-heptane/gasoline than that of PODE/gasoline. Low NOx and PM emissions are achieved for SA-HCCI combustion especially for PODE/gasoline. The advancing spark timing reduced the incomplete combustion and shortened the combustion duration, thus reducing the THC and CO emissions, especially fueled with PODE/gasoline. Although a low EGR rate can slightly improve the THC and CO emissions, violent combustion can be significantly improved. In general, high efficiency and low emissions could be achieved by PODE/gasoline and spark ignition combined with EGR. The brake thermal efficiency for SA-HCCI combustion fueled with PODE/gasoline increased by 30% compared with DISI mode under the same loads.

Syngas composition for improving thermal efficiency in boosted homogeneous charge compression ignition engines

Various syngas compositions were experimentally investigated in a homogeneous charge compression ignition (HCCI) engine to suggest an optimal composition that can maximize thermal efficiency. Intake boosting was also implemented to extend the high-load operating range over a wide range of equivalence ratios. The engine speed was selected as 1,800 rpm and the intake pressure was increased from 0.19 MPa to 0.26 MPa. The thermal efficiency improved by increasing the intake pressure, and incrementally increasing the equivalence ratio until the maximum pressure rise rate (MPRR) limit was reached. The increase in intake pressure also extended the engine load by increasing the syngas fuel input. The syngas composition was systematically varied to clarify the effects of H2 and CO contents on the combustion and emissions of the HCCI engine. H2 was increased from 30% to 50%, whereas the CO amount was reduced from 25% to 8% for maintaining a constant lower heating value (LHV). Although the intake temperature decreased with increasing the H2 content, the thermal efficiency improved. The increase in H2 content was more effective in enhancing combustion performance than the intake temperature reduction. The engine load also slightly increased owing to the improvement in the thermal efficiency. Furthermore, the CO emission also decreased. The NOX emissions remained low despite the enhanced combustion performance. The CO-absent fuel compositions were also evaluated to improve the thermal efficiency. The highest gross indicated thermal efficiency of 43.4% was recorded with a CO-absent fuel composition (50% H2 and 50% CO2). However, the achievable engine load reduced because the LHV was lower than that of CO-present syngas. In the case of CO-absent fuel compositions, it was difficult to operate the HCCI engine with an H2 content higher than 50% owing to its excessive MPRR. Therefore, a syngas composition with a high H2 content and a low CO content was favorable for high-load extension in the HCCI engine.

Experimental Investigations of Injection and Combustion Parameters of a Homogeneous Charge Compression Ignition (HCCI) Engine with a Multi-Injection Common Rail System

This work experimentally investigates the most imperative parameters that control the injection and combustion processes in a multi-injection HCCI Diesel engine namely; fuel-line pressure, timing of multi-injection events and the resulting in-cylinder pressure. These parameters in addition to the heat release rates are evaluated at different engine loads and speeds over up to 42 successive cycles. The main inter-relations of these parameters are also discussed. Results revealed that the maximum cylinder pressure and temperature in the HCCI engines are lower by 7% compared to similar conventional ones, which could lead to lower NOx emission. In addition, the fuel line pressure exhibits nearly the same major frequency of the waves, 850 to 950 Hz. Those results could be very useful for engine assessment, modeling, control, NOx reduction and power saving.

Exergy analysis in a HCCI engine operated with diethyl ether-fusel oil blends

Homogeneous Charge compression ignition (HCCI) combustion mode is a very interesting new combustion model with high efficiency, low nitrogen oxide (NOx), and soot emissions. In the present investigation, the performance of an HCCI engine operated with three fuel ratios, i.e., 40% diethyl ether and 60% fusel oil (D40F60), 60% diethyl ether and 40% fusel oil (D60F40), and 80% diethyl ether and 20% fusel oil (D80F20), at different lambda values and engine speeds was assessed from exergy indicators. The results indicate that the lambda variation allows observing the best performance zones when operating with fuel blends. From the comparison of the exergy indicators, it is concluded that the highest engine efficiency is obtained when operating with D40F60 at a lambda between 2.1 and 2.2. However, it was determined that the increase of diethyl ether in the blend decreases the HCCI engine performance. Also, greater stability of performance was recorded when operating with D80F20. A higher exergy destruction rate is observed between lambda 3.4 and 3.9 when operating with D80F20. The exergetic efficiency values varied from 5.34% to 23.85%. According to the results obtained, the lowest and highest value of exergy efficiency was recorded for the D80F20 and D40F60, respectively.