Combustion Characteristics of HCCI in Motorcycle Engine

Author(s):  
Yuh-Yih Wu ◽  
Bo-Liang Chen

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.

Author(s):  
Yuh-Yih Wu ◽  
Ching-Tzan Jang ◽  
Bo-Liang Chen

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.


Author(s):  
K Anand ◽  
R P Sharma ◽  
P S Mehta

Suitability of vegetable oil as an alternative to diesel fuel in compression ignition engines has become attractive, and research in this area has gained momentum because of concerns on energy security, high oil prices, and increased emphasis on clean environment. The experimental work reported here has been carried out on a turbocharged direct-injection multicylinder truck diesel engine using diesel fuel and jatropha methyl ester (JME)-diesel blends. The results of the experimental investigation indicate that an increase in JME quantity in the blend slightly advances the dynamic fuel injection timing and lowers the ignition delay compared with the diesel fuel. A maximum rise in peak pressure limited to 6.5 per cent is observed for fuel blends up to 40 per cent JME for part-load (up to about 50 per cent load) operations. However, for a higher-JME blend, the peak pressures decrease at higher loads remained within 4.5 per cent. With increasing proportion of JME in the blend, the peak pressure occurrence slightly advances and the maximum rate of pressure rise, combustion duration, and exhaust gas temperature decrease by 9 per cent, 15 per cent and 17 per cent respectively. Although the changes in brake thermal efficiencies for 20 per cent and 40 per cent JME blends compared with diesel fuel remain insignificant, the 60 per cent JME blend showed about 2.7 per cent improvement in the brake thermal efficiency. In general, it is observed that the overall performance and combustion characteristics of the engine do not alter significantly for 20 per cent and 40 per cent JME blends but show an improvement over diesel performance when fuelled with 60 per cent JME blend.


2013 ◽  
Vol 448-453 ◽  
pp. 3350-3353
Author(s):  
Jian Wang ◽  
Yu Wei Chen ◽  
Jian Sun ◽  
Sheng Ji Liu

Experiments were separately carried out on Liquefied Petroleum Gas (LPG) and gasoline as fuel for a spark ignition (SI) engine. According to the indicator diagram and the calculation of corresponding heat release, combustion characteristics of the two fuels were analyzed. The results showed that using LPG would lead to 7.64% power reduction and a little peak pressure reduction when the structures and ignition advance angle of the engine were remained. At rated speed and full load, the power of engine fueled with gasoline reaches the maximum when the excess air ratio is 0.90 and 0.76 fueled with LPG; when comparing the maximum power and specific heat consumption at different excess air ratios, we can see that the change of excess air ratio has a greater effect on the engine fueled with gasoline than that fueled with LPG; the specific heat consumption of both fuels decrease with the increase of load. Besides, under the same Фa, LPG has a shorter combustion delay period, faster combustion speed and shorter combustion period than gasoline.


Author(s):  
Yuh-Yih Wu ◽  
Hsien-Chi Tsai ◽  
Ta-Chuan Liu

Homogeneous charge compression ignition (HCCI) is a well-known technology that reduces the fuel consumption and exhaust emissions. This work implemented HCCI on a 150cc spark-ignition (SI) engine. The compression ratio of target engine was changed from 10.5 to 12.4 to enhance the compression temperature. In addition, a commercialized low-pressure injector was installed near the intake port for supplying fuel for HCCI operation. After the analysis of in-cylinder gas temperature, the dual fuel, with gasoline for the additive fuel and kerosene as the main fuel, was investigated in the small scale target engine. Experiments were executed through various excess air ratios, different gasoline additive ratios and then extension of engine load. Two-stage heat release, which provides energy to heat up the mixture during the compression stroke, was observed from HCCI combustion with kerosene fuel. The maximum rate of pressure rise (MRPR) could be reduced by increasing gasoline additive ratio of dual fuel without deteriorating the engine power output. By using the dual fuel method, the engine indicated mean effective pressure could be improved by a maximum percentage 23.9% and an average percentage 17.6% from just using kerosene fuel under the knocking limitation of MRPR equals to 4 bar/deg.


2015 ◽  
Vol 1092-1093 ◽  
pp. 508-511
Author(s):  
Jia Wang Zhou ◽  
Chun Hua Zhang ◽  
Gang Li ◽  
Ye Chun Shen

The combustion characteristics of an HCCI engine fueled with n-butanol were investigated on a modified two-cylinder, four stoke diesel engine. The experiments were conducted on the HCCI engine with λ of 2.0, 2.5 and 3.0, and the intake air temperature and engine speed were kept at 140 °C and 1000rpm, respectively. Effects of λ on combustion characteristics including in-cylinder pressure rise rate, heat release rate, CA05 and combustion duration of HCCI combustion engine are discussed in details based on the recorded in-cylinder pressure. The results indicate that in-cylinder pressure and the rate of pressure rise both decrease with the increase of λ, the maximum heat release rate also decreases with the increase of λ but occurs at late crank angles. In addition, as λ increases, the combustion phasing retards and combustion duration becomes longer.


2014 ◽  
Vol 1016 ◽  
pp. 577-581 ◽  
Author(s):  
Pavel Brabec ◽  
Aleš Dittrich

The paper deals with the load of the head of the engine. Head of SI engine, which has molded seat of intake and exhaust valve, is one of the most complex parts of the engine. It contains intake and exhaust ports, spark plugs, timing of the mechanism and channels for cooling and lubrication. Much of the final form of this component also contributes its load, which is both heat and mechanical. The biggest influence on the deformation of embedded saddles exhaust valve has a temperature distribution in the cylinder head. These temperatures are influenced by many factors, especially temperature and coolant flow, load and engine speed, which affect the combustion process and exhaust gas temperature (the engine mode is constantly changing, therefore the thermal load on the valve seats is different). In our paper we will only deal with the heat load of the cylinder head of the engine. Currently, the most common use of appropriate software tools for determining the distribution as voltage or temperature. The simulation results may not always be identical to the actual situation, so it is necessary to perform by verification. The paper described measurements of temperature on the inserted valve seats cylinder head of the engine.


2014 ◽  
Vol 700 ◽  
pp. 651-654 ◽  
Author(s):  
Gang Li ◽  
Chun Hua Zhang ◽  
Ye Chong Shen ◽  
Ya Chong Shen ◽  
Jia Wang Zhou

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.


Author(s):  
A. P. Shaikin ◽  
I. R. Galiev

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.


2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.


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