Combustion Characteristics of HCCI in Motorcycle Engine

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Yuh-Yih Wu ◽  
Ching-Tzan Jang ◽  
Bo-Liang Chen
Keyword(s):  
Cylinder Head ◽  
Internal Combustion Engines ◽  
Peak Pressure ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Hcci Combustion ◽  
Lower Maximum ◽  
Intake Air Heating ◽  
Gas Recirculation ◽  
Motorcycle Engine

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system for internal combustion engines that reduces fuel consumption and exhaust emissions. This work studied a 150 cc air-cooled, four-stroke motorcycle engine employing HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. Kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and exhaust gas recirculation (EGR) rates. Combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for conducting a stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from cylinder pressure. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission of CO. However, EGR is better than λ for decreasing the peak pressure and MRPR without deteriorating the engine output. Advancing the timing of peak pressure causes high peak pressure, and hence increases MRPR. The timing of peak pressure around 10–15 degree of crank angle after top dead center indicates a good appearance for low MRPR.

Combustion Characteristics of HCCI in Motorcycle Engine

2009 ◽  
Author(s):  
Yuh-Yih Wu ◽  
Bo-Liang Chen
Keyword(s):  
Cylinder Head ◽  
Peak Pressure ◽  
Combustion Engine ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Gas Temperature ◽  
Hcci Combustion ◽  
Excess Air ◽  
Intake Air Heating ◽  
Motorcycle Engine

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system of internal combustion engine for reducing fuel consumption and exhaust emissions. This paper studied a 150 cc air-cooled four-stroke motorcycle engine operating HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. The kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and EGR rates. The combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from the cylinder pressure. Higher first stage ignition temperature causes higher peak cylinder gas temperature. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission CO. However, EGR is better than excess air for decreasing the peak pressure and MRPR without deteriorating the engine output.

scholarly journals A research into a gasoline HCCI engine

2010 ◽  
Vol 140 (1) ◽  
pp. 3-13
Author(s):  
Jacek HUNICZ ◽  
Andrzej NIEWCZAS ◽  
Paweł KORDOS
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Hcci Combustion ◽  
Permissible Range ◽  
Wide Range ◽  
Gas Recirculation ◽  
Direct Fuel Injection

Homogeneous charge compression ignition (HCCI) is nowadays a leading trend in the development of gasoline internal combustion engines. The application of this novel combustion system will allow to comply with future legislations concerning the exhaust emissions including carbon dioxide. This paper presents a design and implementation of a research engine with a direct fuel injection and the capability of HCCI combustion via an internal gas recirculation and a negative valves overlap (NVO). The technical approach used in the engine allowed an autonomous HCCI operation at variable loads and engine speeds without the need of a spark discharge. Experiments were conducted at a wide range of valve timings providing data which allowed an assessment of a volumetric efficiency and exhaust gas recirculation (EGR) rate. Permissible range of air excess coefficient, providing stable and repeatable operation has also been identified. The use of direct gasoline injection benefited in the improvement of the start of the combustion (SOC) and heat release rate control via the injection timing.

Improvements in Efficiency and Mixture Formation for an Innovative Diesel HCCI Concept

2009 ◽  
Author(s):  
E. Musu ◽  
R. Rossi ◽  
R. Gentili
Keyword(s):  
Combustion Process ◽  
Pressure Rise ◽  
Pollutant Emissions ◽  
Spontaneous Ignition ◽  
Exhaust Gas ◽  
Mixture Formation ◽  
Hcci Combustion ◽  
Gas Recirculation ◽  
Transfer Flow ◽  
Homogeneous Charge

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in dilute homogeneous mixtures. The combustion rate must be reduced by suitable solutions such as high rates of Exhaust Gas Recirculation (EGR) and/or lean mixtures. HCCI is considered to be a very effective way to reduce engine pollutant emissions, however only a few production engines have been built. HCCI combustion currently cannot be extended to the whole engine operating range, especially to high loads, since the use of EGR displaces air from the cylinder, limiting engine mean effective pressure, thus the engine must be able to operate also in conventional mode. This paper concerns a study of an innovative concept to control HCCI combustion in diesel-fueled engines. The concept consists in forming a pre-compressed homogeneous charge outside the cylinder and in gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the transfer flow rate, and high pressure rise rates, typical of standard HCCI combustion, can be avoided. This new combustion concept has been called Homogenous Charge Progressive Combustion (HCPC). This paper concerns CFD analysis focused on improving efficiency and reducing pollutant emissions considering a new HCPC engine configuration. Results show an indicated efficiency around 45% and a consistent reduction of soot emission compared to conventional diesel engine.

Effects of Intake Temperature on the Combustion Characteristics of HCCI Engine Fueled with n-Butanol

2014 ◽  
Vol 700 ◽  
pp. 651-654 ◽  
Author(s):  
Gang Li ◽  
Chun Hua Zhang ◽  
Ye Chong Shen ◽  
Ya Chong Shen ◽  
Jia Wang Zhou
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Combustion Stability ◽  
Maximum Heat ◽  
Hcci Engine ◽  
Hcci Combustion ◽  
P Rate

In order to study the influence of intake temperature on the combustion characteristics of HCCI engine fueled with n-butanol, the 2nd cylinder of a water-cooled, naturally aspirated and double-cylinders diesel engine was converted into HCCI combustion mode. The cylinder pressure (P), rate of pressure rise (dp/dφ), heat release rate (dQ/dφ) and cycle-to-cycle variations (CCV) were compared and analyzed by bench tests under the conditions with different intake temperatures at engine speed of 1000r/min, excess air coefficient of 2.5. The experiment results show that the peak pressure (Pmax), the peak rate of pressure rise and maximum heat release rate tend to rise and the peak arrives in advance with the increase of intake temperature. As the intake temperature rises, the coefficient of variation for Pmaxreduces and combustion stability increases.

Characterization of Partially Premixed Combustion With Ethanol: EGR Sweeps, Low and Maximum Loads

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Pert Tunestal
Keyword(s):  
High Efficiency ◽  
Pressure Rise ◽  
Premixed Combustion ◽  
Maximum Pressure ◽  
Pressure Rise Rate ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Partially Premixed ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) sweeps were performed on ethanol partially premixed combustion (PPC) to show different emission and efficiency trends as compared with diesel PPC. The sweeps showed that when the EGR rate is increased, the efficiency does not diminish, HC trace is flat, and CO is low even with 45% of EGR. NOx exponentially decreases by increasing EGR while soot levels are nearly zero throughout the sweep. The EGR sweeps underlined that at high EGR levels, the pressure rise rate is a concern. To overcome this problem and keep high efficiency and low emissions, a sweep in the timing of the pilot injection and pilot-main ratio was done at ∼16.5 bars gross IMEP. It was found that with a pilot-main ratio of 50:50, and by placing the pilot at −60 with 42% of EGR, NOx and soot are below EURO VI levels; the indicated efficiency is 47% and the maximum pressure rise rate is below 10 bar/CAD. Low load conditions were examined as well. It was found that by placing the start of injection at −35 top dead center, the efficiency is maximized, on the other hand, when the injection is at −25, the emissions are minimized, and the efficiency is only 1.64% lower than its optimum value. The idle test also showed that a certain amount of EGR is needed in order to minimize the pressure rise rate.

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

2017 ◽  
Vol 19 (10) ◽  
pp. 1005-1023 ◽  
Author(s):  
Jerald A Caton
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Thermodynamic Evaluation ◽  
Combustion Engines ◽  
Automotive Engine ◽  
Specific Heats ◽  
Cycle Simulation

The thermodynamic limitation for the maximum efficiencies of internal combustion engines is an important consideration for the design and development of future engines. Knowing these limits helps direct resources to those areas with the most potential for improvements. Using an engine cycle simulation which includes the first and second laws of thermodynamics, this study has determined the fundamental thermodynamics that are responsible for these limits. This work has considered an automotive engine and has quantified the maximum efficiencies starting with the most ideal conditions. These ideal conditions included no heat losses, no mechanical friction, lean operation, and short burn durations. Then, each of these idealizations is removed in a step-by-step fashion until a configuration that represents current engines is obtained. During this process, a systematic thermodynamic evaluation was completed to determine the fundamental reasons for the limitations of the maximum efficiencies. For the most ideal assumptions, for compression ratios of 20 and 30, the thermal efficiencies were 62.5% and 66.9%, respectively. These limits are largely a result of the combustion irreversibilities. As each of the idealizations is relaxed, the thermal efficiencies continue to decrease. High compression ratios are identified as an important aspect for high-efficiency engines. Cylinder heat transfer was found to be one of the largest impediments to high efficiency. Reducing cylinder heat transfer, however, is difficult and may not result in much direct increases of piston work due to decreases of the ratio of specific heats. Throughout this work, the importance of high values of the ratio of specific heats was identified as important for achieving high thermal efficiencies. Depending on the selection of constraints, different values may be given for the maximum thermal efficiency. These constraints include the allowed values for compression ratio, heat transfer, friction, stoichiometry, cylinder pressure, and pressure rise rate.

Effect of Engine Operating Parameters on Combustion and Emission Characteristics

1992 ◽  
Author(s):  
Jiang Lu ◽  
Ashwani K. Gupta ◽  
Eugene L. Keating
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Operating Parameters ◽  
Emission Characteristics ◽  
Pollutants Emission

Abstract Numerical simulation of flow, combustion, heat release rate and pollutants emission characteristics have been obtained using a single cylinder internal combustion engine operating with propane as the fuel. The data are compared with experimental results and show excellent agreement for peak pressure and the rate of pressure rise as a function of crank angle. The results obtained for NO and CO are also found to be in good agreement and are similar to those reported in the literature for the chosen combustion chamber geometry. The results have shown that both the combustion chamber geometry and engine operating parameters affects the flame growth within the combustion chamber which subsequently affects the pollutants emission levels. The code employed the time marching procedure and solves the governing partial differential equations of multi-component chemically reacting fluid flow by finite difference method. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution levels. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.

scholarly journals Impact of injection strategies on combustion characteristics, efficiency and emissions of gasoline compression ignition operation in a heavy-duty multi-cylinder engine

2018 ◽  
Vol 21 (8) ◽  
pp. 1426-1440 ◽  
Author(s):  
Buyu Wang ◽  
Michael Pamminger ◽  
Ryan Vojtech ◽  
Thomas Wallner
Keyword(s):  
High Temperature ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Pressure Rise ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
Direct Fuel Injection

Gasoline compression ignition using a single gasoline-type fuel for direct/port injection has been shown as a method to achieve low-temperature combustion with low engine-out NOx and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low-temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high-temperature combustion with reduced amounts of exhaust gas recirculation appears more practical. Furthermore, for high-temperature gasoline compression ignition, an effective aftertreatment system allows high thermal efficiency with low tailpipe-out emissions. In this work, experimental testing was conducted on a 12.4 L multi-cylinder heavy-duty diesel engine operating with high-temperature gasoline compression ignition combustion with port and direct injection. Engine testing was conducted at an engine speed of 1038 r/min and brake mean effective pressure of 1.4 MPa for three injection strategies, late pilot injection, early pilot injection, and port/direct fuel injection. The impact on engine performance and emissions with respect to varying the combustion phasing were quantified within this study. At the same combustion phasing, early pilot injection and port/direct fuel injection had an earlier start of combustion and higher maximum pressure rise rates than late pilot injection attributable to more premixed fuel from pilot or port injection; however, brake thermal efficiencies were higher with late pilot injection due to reduced heat transfer. Early pilot injection also exhibited the highest cylinder-to-cylinder variations due to differences in injector behavior as well as the spray/wall interactions affecting mixing and evaporation process. Overall, peak brake thermal efficiency of 46.1% and 46% for late pilot injection and port/direct fuel injection was achieved comparable to diesel baseline (45.9%), while early pilot injection showed the lowest brake thermal efficiency (45.3%).

Sign in / Sign up

Export Citation Format

Share Document