Homogeneous Charge Compression Ignition Engine Research Articles

Effect of Brown’s gas addition on combustion and emissions of homogeneous charge compression ignition engine

ABSTRACT The oxides of nitrogen (NO x ) and smoke emitted by widely used compression ignition (CI) engines of automobiles are among the major contributor to the environmental pollution. Several attempts are being made to reduce these exhaust emissions from automobiles. Low-temperature combustion (LTC) with homogeneous charge compression ignition (HCCI) is one of the strategies to reduce these engine exhaust emissions. The present work investigates the addition of Brown’s gas (HHO) in the intake manifold of a stationary common rail direct injection CI engine in HCCI mode. In the experiments, electronically assisted fuel injection system was used to maintain the injection pressure to 250 bars. The effect of HHO addition on the combustion and emissions was studied for different loads and injection advance. It was observed that the brake power, brake thermal efficiency, and brake-specific fuel consumption were improved by around 5% due to HHO addition. However, they were found to be decreased with increased injection advance. Moreover, a considerable reduction in NO x emission, i.e., 1–12 ppm was recorded for early injection mode. Thus, Brown’s gas addition with LTC strategy may result in reduced environmental pollution.

Biodiesels powered in-cylinder common rail direct injection (CRDi) Assisted Homogeneous Charge Compression Ignition (HCCI) engine

ABSTRACT Experimental tests were performed on homogeneous charge compression ignition (HCCI) with in-cylinder direct injection (DI) of diesel, biodiesel of Ceiba Pentandra oil methyl ester (CPOME) and biodiesel of Acid oil methyl ester (ACOME). Initially some trial experiments were conducted at different fuel injection timing (IT) to distinguish the HCCI operation from common rail direct injection (CRDI) operation. For this, heat release rate (HRR) analysis, trial experiments were conducted for 40 % Load. The cool flame always started at about 20° before top dead centre (bTDC) showing HCCI operation started with fuel IT advancement of 50° bTDC and more. HCCI engine showed lowered peak HRR and retarded one. Higher injection pressure (IP) lowered oxides of nitrogen (NOx) due to lower HRR. NOx of 42 ppm, 36 ppm and 34 ppm were achieved with diesel, ACOME and CPOME respectively at IP 900 bar and IT of 80° bTDC in HCCI mode. Lower smoke of 9 HSU, 15 HSU and 17 HSU was achieved with diesel, ACOME and CPOME respectively at the same operating conditions. Overall, it could be concluded that, IP 900 bar and IT of 80° bTDC are the best operating conditions to reduce NOx and smoke with slightly lower brake thermal efficiency (BTE) in HCCI mode.

The effect of direct water injection on a diesel-gasoline reactivity controlled compression ignition engine

Reactivity Controlled Compression Ignition (RCCI) combustion is a promising method to achieve ultra-low nitrogen oxide and soot emissions. However, the main problem of this strategy is the limited operating range, which is mainly caused by high pressure rise rate. In this study, the possibility of using direct water injection as an approach to decrease pressure rise rate is appraised. To that end, a Lagrangian-Eulerian approach is used to simulate a gasoline-diesel RCCI engine with the use of OpenFOAM. The effects of water injection timing and the mass ratio of injected water to diesel fuel on the engine performance are investigated. The study also includes the injection of water into a Homogenous Charge Compression Ignition (HCCI) engine to compare the effect of direct water injection on RCCI and HCCI methods. According to the results, the optimal case with the water injection timing of −10°ATDC and mass ratio of 3 achieves a 29% reduction in maximum pressure rise rate at the cost of a 1.4% decrease in engine power and a 1% increase in overall emissions. Sensitivity analysis shows that direct water injection has the most impact on maximum pressure rise rate and the lowest impact on gross indicated efficiency. A trade-off between maximum pressure rise rate and emissions can be achieved by adjusting spray angle or water injection timing in the RCCI concept. However, in the HCCI strategy, direct water injection invariably results in significantly increasing overall emissions regardless of the spray angle and water injection timing.

Operating range, combustion, performance and emissions of an HCCI engine fueled with naphtha

In this study, it was aimed that the effects of naphtha on homogeneous charged compression ignition (HCCI) combustion, performance, exhaust emissions and operating range were researched experimentally in an HCCI engine. The test engine was able to operate with HCCI mode between 800 and 2000 rpm and λ = 1.61–λ = 2.93 lambda values range at constant inlet air temperature of 60 °C. Pure n-heptane and naphtha, N25, N50 and N75 fuel blends were used as test fuels. Experiments showed that knocking tendency reduced with the increase of lambda. Similarly, more stable combustion was obtained with the addition of naphtha into n-heptane due to higher octane number. Test results showed that HCCI combustion was delayed when naphtha fraction increased in the test fuels. MPRR was obtained as 15.6 bar/°CA and 11.9 bar/°CA with n-heptane and naphtha respectively at λ = 2 and 1000 rpm. ITE increased from 29% to 37% with naphtha according to n-heptane at λ = 2 and 1000 rpm. On the contrary, HC and CO increased from 331 ppm to 411 ppm and 0.051% to 0.075% with naphtha compared to n-heptane at λ = 2 and 1000 rpm, respectively. It was also seen that Naphtha showed wider HCCI operating range according to n-heptane especially knocking zone.

Performance analysis of HCCI engine powered by tamanu methyl ester with various inlet air temperature and exhaust gas recirculation ratios

The extensive usage of petroleum as a fuel in a conventional engine produces harmful pollutants and also leads to global warming. CI engines have certain advantages over SI engines such that they have higher efficiency and emit lesser CO and HC, but they also have disadvantages such as high smoke and NOx. A homogeneous charge compression ignition engine (HCCI) is a better solution to minimize smoke and NOx simultaneously. The present study was performed comparing the conventional CI engine and HCCI mode of operation fueled with tamanu methyl ester (TME). The HCCI engine was run at various inlet air temperatures (IAT) (80 °C, 90 °C, and 100 °C) because tamanu methyl ester cannot be vaporized at room temperature. The results exhibited that TME operated CI engine noticed higher brake thermal efficiency (BTE) and fuel economy and also lesser carbon monoxide (CO) and unburned hydrocarbon (UBHC) emission than the HCCI engine. HCCI engine with enhanced IAT showed lower NOx and smoke emission than conventional engine. From the results, the optimum IAT was found to be 90 °C, so further experiments were carried out using the IAT 90 °C at various exhaust gas recirculation (EGR) ratios. The EGR associated HCCI engine produces ultra-lean NOx emission, but on the other hand, it shows slightly lower BTE, cylinder pressure and heat release rate than the engine operating without EGR. The results also exhibited that elevation of IAT beyond 100 °C leads to short HCCI combustion, tending to knock, thus leading to unstable operation.

An experimental investigation on combustion and performance characteristics of supercharged HCCI operation in low compression ratio engine setting

This study investigates the effects of boost pressure on combustion and performance of an early direct injection homogenous charge compression ignition (HCCI) engine at a low compression ratio (CR). A 2.0 L, four-cylinder, four-stroke, gasoline direct injection engine was converted to operate in early direct injection HCCI mode. In addition, a supercharger unit was developed for engine boosting. The experiments were performed at different intake manifold absolute pressures (MAP) from 1.0 to 1.6 bar at different engine loads using n-heptane fuel. The effects of boost pressure were investigated on HCCI combustion and engine performance characteristics using volumetric efficiency, in-cylinder pressure, heat release rate (HRR), maximum in-cylinder pressure and gas temperature, CA50 (crank angle by which 50% of the fuel is burnt), combustion duration, apparent combustion efficiency, indicated mean effective pressure (IMEP), brake mean effective pressure (BMEP), friction mean effective pressure (FMEP), indicated thermal efficiency (ITE), brake thermal efficiency (BTE), heat loss, exergy of heat loss, coefficient of variation of IMEP (COVIMEP), maximum pressure rise rate (MPRR) and ringing intensity (RI). The experimental results showed that high-efficiency HCCI operation is feasible at an engine compression ratio as low as 9.2 once the engine variables are properly optimized and an appropriate level of supercharging is utilized. An increase in indicated thermal efficiency was seen as boost pressure increased. In addition, combustion phasing advanced by increasing boost pressure or increasing air–fuel equivalence ratio values. Combustion events with CA50 2–3 °CA aTDC show the highest thermal efficiency especially at low boost pressure conditions. In addition, the pressure rise rate and ringing intensity increased by increasing air–fuel equivalence ratio and MAP. The test results also showed that HCCI operating range can be extended with the increase of intake manifold pressure especially at high load limits.

The kinetics of methane ignition in fuel-rich HCCI engines: DME replacement by ozone

Fuel-rich combustion of methane in a homogeneous-charge compression-ignition (HCCI) engine can be used as a polygeneration process producing work, heat, and useful chemicals like syngas. Due to the inertness of methane, additives such as dimethyl ether (DME) are needed to achieve ignition at moderate inlet temperatures and to control combustion phasing. Because significant concentrations of DME are then needed, a considerable part of the fuel energy comes from DME. An alternative ignition promotor known from fuel-lean HCCI is ozone (O3). Here, a combined experimental and modelling study on the ignition of fuel-rich partial oxidation of methane/air mixtures at Φ = 1.9 with ozone and DME as additives in an HCCI engine is conducted. Experimental results show that ozone is a suitable additive for fuel-rich HCCI, with only 75 ppm ozone reducing the fuel-fraction of DME needed from 11.0% to 5.3%. Since ozone does not survive until the end of the compression stroke, the reaction paths are analyzed in a single-zone model. The simulation shows that different ignition precursors or buffer molecules are formed, depending on the additives. If only DME is added, hydrogen peroxide (H2O2) and formaldehyde (CH2O) are the most important intermediates, leading to OH formation and ignition around top dead center (TDC). With ozone addition, methyl hydroperoxide (CH3OOH) becomes very important earlier in the compression stroke under these fuel-rich conditions. It is then later converted to CH2O and H2O2. Thus, ozone is a very effective additive not only for fuel-lean, but also for fuel-rich combustion. However, the mechanism differs between both regimes. Because less of the expensive additives are needed, ozone could help improving the economics of a polygeneration process with fuel-rich operated HCCI engines.

Influence of intermediate temperature heat release on autoignition reactivity of single-stage ignition fuels with varying octane sensitivity

This study investigates the effects of intermediate temperature heat release (ITHR) on autoignition reactivity of full boiling range gasolines with different octane sensitivity through intake temperature and simulated exhaust gas recirculation (EGR) sweeps in a homogenous charge compression ignition (HCCI) engine. To isolate the ITHR effects, low temperature reactivity was suppressed through the use of high intake temperature and low intake oxygen mole fraction. For quantification of ITHR, a new method was applied to the engine data by examining the maximum value of the second derivative of heat release rate. Combustion phasing comparisons of fuels with octane sensitivity showed that fuel with less octane sensitivity became more reactive as intake temperature and simulated EGR ratio decreased, while fuel with higher octane sensitivity had a reverse trend. For all of the fuels that were tested, the amount of ITHR increased as the intake temperature and oxygen mole fraction increased. These ITHR trends, depending on octane sensitivity, were almost identical with the trends of combustion phasing, showing that ITHR significantly affects fuel autoignition reactivity and determines octane sensitivity.

Numerical investigation on the effect of oxygen in combustion characteristics and to extend low load operating range of a natural-gas HCCI engine

The effect of increasing oxygen on extending the low load operating range and combustion and emission characteristics of a natural-gas homogeneous charge compression ignition engine with pre-chamber is studied numerically. There are five oxygen percentage selected to investigate the influence of oxygen in homogeneous charge compression ignition combustion. The five selected Oxygen percentages are 21% (pure air), 40%, 60%, 80% and 100% (pure oxygen), which have 0.3 (pure air), 0.158, 0.105, 0.079 and 0.063 (pure oxygen) equivalence ratios, respectively. 60% oxygen is the optimum amount due to the earliest start of combustion and CA50 in all cases that directly affect the indicated mean effective pressure and efficiency. It has the maximum pressure, temperature, and heat release rate compared to the other oxygen percentages. Increasing oxygen up to 60%led to producing more OH radicals, while more increasing oxygen, causes a lack of H atoms from the decomposition of the CH bond in natural-gas caused to reducing OH concentration. Increasing oxygen makes the temperature distribution more uniform and shorts the combustion duration. It also leads to drop the temperature for the start of combustion. CO and UHC drop with excess oxygen, the maximums decreasing for CO and UHC are almost 100% and the minimums are 50.11% for CO and 80.4% for UHC occurring in 40% oxygen. Oxygen can extend the load range to the dilute regions, 40% oxygen would expand about 47.33% while by 60%, 80%, and 100% oxygen it would expand about 65%, 73.67%, and 79% respectively.

Statement of Removal

Article title: Biodiesels powered in-cylinder common rail direct injection (CRDi) Assisted Homogeneous Charge Compression Ignition (HCCI) engine Authors: S.B. Nagesh, N.R. Banapurmath, T.K. Chandrashekhar, S.V. Khandal Journal: International Journal of Sustainable Engineering Version of Record Published Online: 08 July 2020 DOI: https://doi.org/10.1080/19397038.2020.1780335 Due to a publisher error, source files associated with a different published article (Reza Khalifeh & Hossein Esmaeili, 2020, Biodiesel production from goat fat using calcium oxide nanocatalyst and its combination with diesel fuel to improve fuel properties, International Journal of Sustainable Engineering, DOI: 10.1080/19397038.2020.1780336), were incorrectly used during the production stages of the above article. We have removed this incorrect version of Nagesh et al. and published the correct version under a new DOI using the correct source files. The correct version of the article can be found here: https://doi.org/10.1080/19397038.2020.1811012 We apologise to the authors for this error.

Combined effect of external mixture formation and cooled exhaust gas recirculation on engine performance and emissions characteristics of partially pre‐mixed charged compression ignition engine

AbstractThe present experimental study was aimed to investigate the combined effect of external mixture formation and cooled exhaust gas recirculation (EGR) on performance and emissions characteristics of partially homogeneous charge compression ignition (PCCI) engine. A conventional single‐cylinder four‐stroke compression ignition engine was modified to operate on PCCI mode with the supply of diesel fuel vapor via intake manifold during suction stroke. A Homogenous air‐fuel charge was produced by using a retrofit system to provide fuel vapor. The engine was operated in two modes, direct injection (DI)‐EGR and PCCI (DI‐fuel vapor‐EGR) mode, and then results were compared with DI (conventional) mode. Constant 10% EGR was maintained during DI‐EGR and PCCI modes. Compared to conventional mode, in PCCI mode at full engine load, NOx and smoke opacity were decreased by 2.39 g kW−1 hr−1 and 27% respectively, and the marginal penalty in HC and CO emissions by 0.4 and 0.1 g kW−1 hr−1 was observed. Brake thermal efficiency was slightly reduced by 2.5% compared to DI mode.

Elevated pressure low-temperature oxidation of linear five-heavy-atom fuels: diethyl ether, n-pentane, and their mixture

Abstract Diethyl ether (DEE) has been proposed as a biofuel additive for compression-ignition engines, as an ignition improver for homogeneous charge compression ignition (HCCI) engines, and as a suitable component for dual-fuel mixtures in reactivity-controlled compression ignition (RCCI) engines. The combustion in these engines is significantly controlled by low-temperature (LT) chemistry. Fundamental studies of DEE LT oxidation chemistry and of its influence in fuel-mixture oxidation are thus highly important, especially at elevated pressures. Elevated pressure speciation data were measured for the LT oxidation of DEE, of its similarly-structured linear five-heavy-atom hydrocarbon fuel (n-pentane), and of a mixture of the two fuels in a jet-stirred reactor (JSR) in the temperature range of 400–1100 K and at various pressures up to 10 bar. The pressure influence on the LT oxidation chemistry of DEE was investigated by a comparison of the measured profiles of oxidation products. The results for DEE and n-pentane were then inspected with regard to fuel structure influences on the LT oxidation behavior. The new speciation data were used to test recent kinetic models for these fuels [Tran et al., Proc. Combust. Inst. 37 (2019) 511 and Bugler et al., Proc. Combust. Inst. 36 (2017) 441]. The models predict the major features of the LT chemistry of these fuels well and could thus subsequently assist in the data interpretation. Finally, the LT oxidation behavior of an equimolar mixture of the two fuels was explored. The interaction between the two fuels and the effects of the pressure on the fuel mixture oxidation were examined. In addition to reactions within the combined model for the two fuels, about 80 cross-reactions between primary reactive species generated from these two fuel molecules were added to explore their potential influences.

Predictive simulation of single cylinder n-butanol HCCI engine

Homogeneous Charge Compression Ignition (HCCI) is a commonly research new combustion mode due to its advantages over conventional combustion in internal combustion engine such as higher thermal efficiency as well as lower particulate matter (PM) and nitrogen oxides (NOx) emission. However, combustion phasing control difficulty is the main challenge in order to achieve this HCCI combustion due to the absence of direct auto-ignition control. The aim of this study is to investigate the effects of engine load conditions, intake charge temperature and exhaust gas recirculation (EGR) rate numerically on the combustion characteristics of HCCI engine in a single-cylinder and four-stroke engine fuelled with n-butanol. Predictive one-dimensional engine cycle simulation with single-zone model is employed in this study. A chemical kinetic mechanism of n-butanol is used to in this model to capture the chemical reaction process during the combustion. It was found that these parameters play important roles towards the combustion phasing of the HCCI engine as well as the in-cylinder pressure. This HCCI model is able to predict the trend of the combustion characteristics comprehensively with the variation of these critical parameters resulting in a good agreement with previous HCCI studies.

Influence of intake air temperature control on characteristics of a Homogeneous Charge Compression Ignition engine for hydrogen-enriched kerosene-dimethyl ether usage

In this study, the high-speed of 2000 rpm and low-speed of 1000 rpm behaviors on the HCCI test engine at full load were examined experimentally by controlling the intake air temperature. The tests were carried out at 0.90 equivalence ratio for hydrogen-enriched kerosene-dimethyl ether mixture. In order to expand the usage of HCCI engines in daily life, their problems encountered at high loads and high speeds need to be solved. The main reason of these problems is the control of the start of combustion since there is no external combustion system in HCCI engines.The experimental results show that the intake air temperature directly affects engine performance and emissions. The intake air temperature control was led to shorter flame development time and better combustion stability. The in-cylinder pressure at 1000 rpm for 373 K is overall 6.82% and 4.07% higher than the 273 K and 298 K. The average heat release rate curve trends at 1000 rpm are overall 45.68% higher than 2000 rpm. The brake specific fuel consumption for 2000 rpm is about 5.29% higher than 1000 rpm. The differences between the two NOx trends are 35.4% maximum and 11.03% minimum for 1000 rpm and 2000 rpm. At high engine speed, the HC formation drops linearly from 488 ppm to 339 ppm with increasing air temperature. Also, the soot formation decreased with a slope of 1.58 times higher than 1000 rpm. Overall, the increase in intake air temperature at the tests positively affected in-cylinder pressure, CO, HC and soot.

Potential of range extender electric vehicles (REEVS)

Battery Electric Vehicles (BEVs) is a promising technology. However, it suffers from low range characteristics thus increasing the anxiety to prospect customers and hindering its market penetration. To overcome this challenge, a range extender that can generate additional power to charge the battery could be the solution. This brief review article will highlight the prospects and challenges of range extender technology for electric vehicles. A number of automobile manufacturers have launched their Range Extended Electric Vehicles (REEVs) models and the detailed comparison will be given. Several types of range extenders will be discussed, including the internal combustion engine, microturbine, and fuel cell. Lastly, this report will suggest the use of Low Temperature Combustion (LTC) i.e Homogeneous Charge Compression Ignition (HCCI) engine be utilised as range extenders for electric vehicles.

Effect of Injection Pressure on Performance and Emission Characteristics HCCI Engines

Homogeneous Charged Compression Ignition engine (HCCI) is a suitable replacement of conventional diesel engines as it provides higher thermal efficiency and low oxides of emission (NOx) and particulate emissions. In HCCI engine, direct controlling of ignition timing is not possible. But it can be controlled by varying the engine parameters such as fuel injection pressure, inlet air temperature and exhaust gas recirculation. In this study, HCCI engine is controlled with changing the injection pressure of the fuel and analysed for the effect of injection pressure of the fuel for emission and performance of Karanja methyl ester fuel. The experiments were conducted on HCCI engine with fuel injection pressures of 2 bar, 3 bar, 4 bar and 5 bar and the optimum fuel injection pressure is found out. The results show that, the brake thermal efficiency is increased when the injection pressure is increased due to better atomisation and fuel penetration and also resulted in low emissions (NOx, smoke) compared with diesel engine.

A 22:1 Compression Ratio Ammonia-Hydrogen HCCI Engine: Combustion, Load, and Emission Performances

The interest in ammonia as a high-density hydrogen carrier for long-term electricity storage is growing. A clean and efficient Combined Heat and Power (CHP) system is envisioned for power production from stored ammonia, to which Homogeneous-Charge Compression-Ignition (HCCI) engines are promising. Although recent studies showed a high equivalence ratio potential for ammonia HCCI engines, its resistance to auto-ignition forces the use of high intake temperatures, which limits the engine power density. Moreover, the feasibility of clean and highly efficient ammonia combustion has not been demonstrated. Therefore an HCCI test bench has been modified to reach an effective compression ratio of 22:1, which allowed operation from neat hydrogen up to 95%vol. ammonia. A full cartography of the ammonia-hydrogen load range, related efficiencies and emissions is obtained and the impact of the equivalence ratio (from 0.1 to 0.6), the intake temperature (from 50 ◦C to 240 ◦C) and Exhaust Gas Recirculation is assessed. Thanks to a reduced combustion intensity, ammonia allows a 50% IMEP increase compared to neat hydrogen, while maintaining equivalent combustion efficiencies. Using the ammonia-hydrogen blending ratio as a control parameter, the combustion timing and load control is broadened. The EGR impact was mixed: a positive reduction of NO emissions but a negative impact on NO2 and unburned emissions. Finally, the trade-off for the ideal ammonia-hydrogen blending ratio is discussed. To optimise the concept, boosted conditions with higher stroke-to- bore ratios must be aimed at.

Thermodynamic-CFD analysis of waste heat recovery from homogeneous charge compression ignition (HCCI) engine by Recuperative organic Rankine Cycle (RORC): Effect of operational parameters

Beside the percent of fuel, which is burnt to produce power by combustion, the rest of the fuel energy is waste heat that can be recovered. In the present study, a thermodynamic-computational fluid dynamics (CFD) analysis was performed to recover waste heat from the coolant system (water jacket) in a six-cylinder homogeneous charge compression ignition (HCCI) engine by Recuperative organic Rankine cycle (RORC). The CFD simulations were used to estimate the waste heat at different operating conditions and to investigate the effect of the important parameters including intake temperature, intake pressure, equivalence ratio, and engine speed. Thermodynamic study was performed for the RORC, in which the inlet heat in the evaporator of a cycle was calculated based on the CFD analysis, and then the power produced in RORC was obtained. Results indicate that the improvement in thermal performance of the hybrid system in the HCCI engine can be as high as 27.94%.

Enhancing the efficiency benefit of thermal barrier coatings for homogeneous charge compression ignition engines through application of a low-k oxide

Prior experiments reported by the authors have proven the hypothesis that achieving a dynamic temperature swing on the combustion chamber surface will lead to improved thermal and combustion efficiencies of the homogeneous charge compression ignition engine. A thin layer of yttria-stabilized zirconia, roughly 150 μm, was plasma sprayed on the piston top. It led to markedly advanced ignition and heat release in the gasoline homogeneous charge compression ignition engine, accompanied with reduced unburnt hydrocarbon and carbon monoxide emissions, improved combustion efficiency, and a higher thermal efficiency. A related computational study highlighted the critical role of coating thermal conductivity in achieving a desired dynamic response; hence, the second phase of experimental investigations focused on introducing structured porosity in the yttria-stabilized zirconia coating, as a means of reducing effective conductivity. Indeed, additional incremental improvements were observed, as well as limitations related to adverse effects of the surface roughness and the fuel interactions with the surface roughness and open pores. Erosion can also be a problem in a direct injection engine. Therefore, the third round of investigations focused on a material with a natively low conductivity (low-k), sprayed on the top of an Al piston in a relatively dense form, and in a way that yields a smooth surface. The objective was to capitalize on the low conductivity, while avoiding the pitfalls accompanying high-porosity formulations. The heat-storage capacity was limited by keeping the thickness relatively low. The results verify the paramount importance of thermal conductivity in the context of high “temperature swing” behavior and indicate a potential to improve the homogeneous charge compression ignition engine’s combustion efficiency roughly 1.5%, with the overall indicated efficiency improvement on the order of 5%, on a relative basis. In addition, the low-k oxide thermal barrier applied to the piston extended significantly the low-load homogeneous charge compression ignition operability limit.

Experimental Investigations to Extend the Operating Load Range of a Homogeneous Charge Compression Ignition Engine through Fuel Modifications

Experimental Investigations to Extend the Operating Load Range of a Homogeneous Charge Compression Ignition Engine through Fuel Modifications