scholarly journals Characterisation of the combustion process in the spark ignition and homogeneous charge compression ignition engine

2018 ◽  
Vol 22 (5) ◽  
pp. 2025-2037
Author(s):  
Ante Vucetic ◽  
Mladen Bozic ◽  
Darko Kozarac ◽  
Zoran Lulic

Homogeneous charge compression ignition (HCCI) engine is a potential solution for reducing air pollution and for satisfying legal limits regarding the emissions from internal combustion engines. The HCCI engines have advantages of lower emissions of NOx and particulate matter, compared to the standard combustion modes, while on the other hand one of the major disadvantages is the difficulty of control of start of combustion, since the start of combustion is highly sensitive to the intake air temperature. Additional advantage of the HCCI engine is the ability to operate with wide range of fuels. In order to demonstrate this potential in this study the HCCI mode of operation is compared to the spark ignition mode of operation. The study aims to compare and characterise two different combustion modes on the same engine with different CR and different fuels at similar operating conditions. For that purpose the engine tests are performed at the same indicated mean effective pressures for the spark ignition and HCCI combustion mode at the same engine speed, while the tests are performed at three different engine speeds and three different loads. The measurements were performed on the experimental set-up that consists of single cylinder Diesel engine modified to enable operation in spark ignition and HCCI modes. The characterisation includes the comparison of in-cylinder pressure, temperature and rate of heat release obtained by spark ignition and homogeneous charge compression ignition combustion mode and presents comparisons of engine efficiencies and of emissions of HC, CO, and NOx.

Author(s):  
Chia-Jui Chiang ◽  
Anna G. Stefanopoulou

The goal of this paper is to identify the dominant factors that should be included in a control oriented model in order to predict the start of combustion in a homogeneous charge compression ignition (HCCI) engine. Qualitative and quantitative information on the individual effects of fuel and exhaust gas recirculation on the HCCI combustion is provided. Using sensitivity analysis around a wide range of operating conditions of a single-cylinder port-injection gasoline HCCI engine, we find that temperature is the dominant factor in determining the start of combustion. Charge temperature thus becomes the “spark” in a HCCI engine. Therefore, a model without the composition terms should be adequate for model based regulation of the combustion timing in a port-injection gasoline HCCI engine with high dilution from the exhaust.


Author(s):  
Xiaojian Yang ◽  
Guoming G Zhu

To implement the homogeneous charge compression ignition combustion mode in a spark ignition engine, it is necessary to have smooth mode transition between the spark ignition and homogeneous charge compression ignition combustions. The spark ignition–homogeneous charge compression ignition hybrid combustion mode modeled in this paper describes the combustion mode that starts with the spark ignition combustion and ends with the homogeneous charge compression ignition combustion. The main motivation of studying the hybrid combustion mode is that the percentage of the homogeneous charge compression ignition combustion is a good parameter for combustion mode transition control when the hybrid combustion mode is used during the transition. This paper presents a control oriented model of the spark ignition–homogeneous charge compression ignition hybrid combustion mode, where the spark ignition combustion phase is modeled under the two-zone assumption and the homogeneous charge compression ignition combustion phase under the one-zone assumption. Note that the spark ignition and homogeneous charge compression ignition combustions are special cases in this combustion model. The developed model is capable of simulating engine combustion over the entire operating range, and it was implemented in a real-time hardware-in-the-loop simulation environment. The simulation results were compared with those of the corresponding GT-Power model, and good correlations were found for both spark ignition and homogeneous charge compression ignition combustions.


Author(s):  
Hu Tiegang ◽  
Liu Shenghua ◽  
Zhou Longbao ◽  
Zhu Chi

Dimethyl ether (DME) is a kind of fuel with high cetane number and low evaporating temperature, which is suitable for a homogeneous charge compression ignition (HCCI) engine. The combustion and emission characteristics of an HCCI engine fuelled with DME were investigated on a modified single-cylinder engine. The experimental results indicate that the HCCI engine combustion is a two-stage heat release process. The engine load or air-fuel ratio has significant effects on the maximum cylinder pressure and its position, the shape of the pressure rise rate and the heat release rate. The engine speed has little effect. A DME HCCI engine is smoke free, with zero NOx and low hydrocarbon and CO emissions under the operating conditions of 0.25–0.30 MPa brake mean effective pressure.


Author(s):  
G Tian ◽  
Z Wang ◽  
Q Ge ◽  
J Wang ◽  
S Shuai

The hybrid combustion mode is an ideal operation strategy for a gasoline homogeneous charge compression ignition (HCCI) engine. A stable and smooth spark ignition (SI)/HCCI switch has been an issue in the research on multimode combustion. In this paper, the switch process has two key issues; the cam profile and throttle opening. With the developed two-stage cam system, the valve phase strategy can be switched within one engine cycle, from the normal cam profile for the SI mode to a negative valve overlap (NVO) profile for the HCCI mode, or vice versa. For a smoother and more stable switch, the throttle change was separated from the cam profile switch, which was called the stepped switch. The effect of throttle opening on HCCI combustion was studied, and the results showed that the concept of the stepped switch was reliable. With gasoline direct injection (GDI) the combustion mode switches from both SI and HCCI sides were smooth, rapid, and robust, without any abnormal combustion such as knocking and misfiring.


Author(s):  
Meshack Hawi ◽  
Mahmoud Ahmed ◽  
Shinichi Ookawara

Homogeneous charge compression ignition (HCCI) is a combustion technology which has received increased attention of researchers in the combustion field for its potential in achieving low oxides of nitrogen (NOx) and soot emission in internal combustion (IC) engines. HCCI engines have advantages of higher thermal efficiency and reduced emissions in comparison to conventional internal combustion engines. In HCCI engines, ignition is controlled by the chemical kinetics, which leads to significant variation in ignition time with changes in the operating conditions. This variation limits the practical range of operation of the engine. Additionally, since HCCI engine operation combines the operating principles of both spark ignition (SI) and compression ignition (CI) engines, HCCI engine parameters such as compression ratio and injection timing may vary significantly depending on operating conditions, including the type of fuel used. As such, considerable research efforts have been focused on establishing optimal conditions for HCCI operation with both conventional and alternative fuels. In this study, numerical simulation is used to investigate the effect of compression ratio on combustion and emission characteristics of an HCCI engine fueled by pure biodiesel. Using a zero-dimensional (0-D) reactor model and a detailed reaction mechanism for biodiesel, the influence of compression ratio on the combustion and emission characteristics are studied in Chemkin-Pro. Simulation results are validated with available experimental data in terms of incylinder pressure and heat release rate to demonstrate the accuracy of the simulation model in predicting the performance of the actual engine. Analysis shows that an increase in compression ratio leads to advanced and higher peak incylinder pressure. The results also reveal that an increase in compression ratio produces advanced ignition and increased heat release rates for biodiesel combustion. Emission of NOx is observed to increase with increase in compression ratio while the effect of compression ratio on emissions of CO, CO2 and unburned hydrocarbon (UHC) is only marginal.


2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad Izadi Najafabadi ◽  
Nuraini Abdul Aziz

Engine and car manufacturers are experiencing the demand concerning fuel efficiency and low emissions from both consumers and governments. Homogeneous charge compression ignition (HCCI) is an alternative combustion technology that is cleaner and more efficient than the other types of combustion. Although the thermal efficiency andNOxemission of HCCI engine are greater in comparison with traditional engines, HCCI combustion has several main difficulties such as controlling of ignition timing, limited power output, and weak cold-start capability. In this study a literature review on HCCI engine has been performed and HCCI challenges and proposed solutions have been investigated from the point view ofIgnition Timingthat is the main problem of this engine. HCCI challenges are investigated by many IC engine researchers during the last decade, but practical solutions have not been presented for a fully HCCI engine. Some of the solutions are slow response time and some of them are technically difficult to implement. So it seems that fully HCCI engine needs more investigation to meet its mass-production and the future research and application should be considered as part of an effort to achieve low-temperature combustion in a wide range of operating conditions in an IC engine.


2018 ◽  
Vol 20 (3) ◽  
pp. 304-326 ◽  
Author(s):  
Elliott A Ortiz-Soto ◽  
George A Lavoie ◽  
Margaret S Wooldridge ◽  
Dennis N Assanis

Advanced combustion strategies for gasoline engines employing highly dilute and low-temperature combustion modes, such as homogeneous charge compression ignition and spark-assisted compression ignition, promise significant improvements in efficiency and emissions. This article presents a novel, reduced-order, physics-based model to capture advanced multi-mode combustion involving spark ignition, homogeneous charge compression ignition and spark-assisted compression ignition operating strategies. The purpose of such a model, which until now was unavailable, was to enhance existing capabilities of engine system simulations and facilitate large-scale parametric studies related to these advanced combustion modes. The model assumes two distinct thermodynamic zones divided by an infinitely thin flame interface, where turbulent flame propagation is captured using a new zero-dimensional formulation of the coherent flame model, and end-gas auto-ignition is simulated using a hybrid approach employing chemical kinetics and a semi-empirical burn rate model. The integrated model was calibrated using three distinct experimental data sets for spark ignition, homogeneous charge compression ignition and spark-assisted compression ignition combustion. The results demonstrated overall good trend-wise agreement with the experimental data, including the ability to replicate heat release characteristics related to flame propagation and auto-ignition during spark-assisted compression ignition combustion. The calibrated model was assessed using a large parametric study, where the predicted homogeneous charge compression ignition and spark-assisted compression ignition operating regions at naturally aspirated conditions were representative of those determined during engine testing. Practical advanced combustion strategies were assessed relative to idealized engine simulations, which showed that efficiency improvements up to 30% compared with conventional spark-ignition operation are possible. The study revealed that poor combustion efficiency and pumping work are the primary mechanisms for efficiency losses for the advanced combustion strategies evaluated.


Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3557 ◽  
Author(s):  
M. Mofijur ◽  
M.M. Hasan ◽  
T.M.I. Mahlia ◽  
S.M. Ashrafur Rahman ◽  
A.S. Silitonga ◽  
...  

Strict emission regulations and demand for better fuel economy are driving forces for finding advanced engines that will be able to replace the conventional internal combustion engines in the near future. Homogeneous charge compression ignition (HCCI) engines use a different combustion technique; there are no spark plugs or injectors to assist the combustion. Instead, when the mixtures reach chemical activation energy, combustion auto-ignites in multiple spots. The main objective of this review paper is to study the engine performance and emission characteristics of HCCI engines operating in various conditions. Additionally, the impact of different fuels and additives on HCCI engine performance is also evaluated. The study also introduces a potential guideline to improve engine performance and emission characteristics. Compared to conventional compression ignition and spark ignition combustion methods, the HCCI combustion mode is noticeably faster and also provides better thermal efficiency. Although a wide range of fuels including alternative and renewable fuels can be used in the HCCI mode, there are some limitation/challenges, such as combustion limited operating range, phase control, high level of noise, cold start, preparation of homogeneous charge, etc. In conclusion, the HCCI combustion mode can be achieved in existing spark ignition (SI) engines with minor adjustments, and it results in lower oxides of nitrogen (NOx) and soot emissions, with practically a similar performance as that of SI combustion. Further improvements are required to permit extensive use of the HCCI mode in future.


2017 ◽  
Vol 12 (4) ◽  
pp. 102-110
Author(s):  
Nahedh Mahmood Ali

Many researchers consider Homogeneous Charge Compression Ignition (HCCI) engine mode as a promising alternative to combustion in Spark Ignition and Compression Ignition Engines. The HCCI engine runs on lean mixtures of fuel and air, and the combustion is produced from the fuel autoignition instead of ignited by a spark. This combustion mode was investigated in this paper. A variable compression ratio, spark ignition engine type TD110 was used in the experiments. The tested fuel was Iraqi conventional gasoline (ON=82). The results showed that HCCI engine can run in very lean equivalence ratios. The brake specific fuel consumption was reduced about 28% compared with a spark ignition engine. The experimental tests showed that the emissions concentrations were reduced by 91.27% for NOx, 85.99% for CO, 78.91% for CO2, and 83.56% for unburned hydrocarbons compared to the SI engine. HCCI engine produced little noise with about 26.68% less than SI engine.


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