Effect of agro-activities on drinking-water quality in Bangladesh (original) (raw)
SAE Technical Paper Series, 2008
The Homogeneous charge compression ignition (HCCI) is the third alternative for the combustion in the reciprocating engine. HCCI a hybrid of well-known spark ignition (SI) and compression ignition (CI) engine concepts and has potential of combining the best features of both. A two cylinder, four stroke, direct injection diesel engine was modified to operate one cylinder on the compression ignition by detonation of homogeneous mixture of ethanol and air. The homogeneous mixture of the charge is prepared by port injection of ethanol in the preheated Intake air. This study presents results of experimental investigations of HCCI combustion of ethanol at intake air temperature of 120 0 C and at different air-fuel ratios. In this paper, the combustion parameters, pressure time history, rate of pressure rise, rate of heat release, mean temperature history in the combustion chamber is analyzed and discussed. The HCCI operating region criteria is defined based on the cycle-to-cycle variation of indicated mean effective pressure (IMEP) and rate of pressure rise. The results presented in this study for air fuel ratio, which satisfies the HCCI operating region criteria. The results show that controlled HCCI combustion is possible with extremely low emission and high efficiency.
International Journal of Emerging Trends in Engineering Research (IJETER), 2021
The homogeneous charge compression ignition (HCCI) engine is the promising technology to reduce the pollutants without affecting its performance and it is also proved by the many studies. This study investigates the performance and emission characteristics of HCCI engine fuelled with diesel –waste cooking oil (WCO) blends and also analysed the effect of air temperature and fuel properties on HCCI engine combustion. The experimental investigation was conducted with single cylinder DI diesel engine and it was slightly modified to port injection system for premixing the charge. The electric air heater was adopted in suction pipe to preheat the inlet air. The experimental investigation conducted in two phases, in the first phase the conventional DI diesel engine was tested with different fuel blends such as B25, B50, B75 and B100 and notes the readings. In the next phase, HCCI engine was operated with same blend ratios. During the experimentation on HCCI engine, the suction air temperature was varied between 40⁰C to 90⁰C. From the experimental results, it was found that the HCCI engine has emitted low NOx and smoke emissions at 80⁰C of air temperature for all the blends. Whereas the HCCI engine emitted more carbon monoxide (CO) and hydrocarbon (HC) emissions due to lean mixture causes misfiring in the chamber. In addition, it is also noted that the value of CO and HC has been varied with diesel –WCO blends. The specific fuel consumption (SFC) is increased for diesel and biodiesel fuel in HCCI engine compared to compression ignition (CI) engine
Thermal Science
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...
Energy Conversion and Management, 2015
There is an urgent need to develop new combustion strategies such as homogeneous charge compression ignition (HCCI) mode to meet current and future emissions regulations. In this study, experiments and a coupled AVL-CHEMKIN CFD (computational fluid dynamic) model were adopted to compare combustion phasing, engine performance and emissions in term of equivalence ratio for both HCCI combustion engines with and without pre-combustion chamber to investigate the effect of pre-combustion chamber on HCCI combustion engine. Results revealed that with an equivalence ratio of 0.2, HCCI engine with pre-combustion chamber (comet MK.V) tolerates misfiring process, while HCCI engine without pre-combustion chamber (modified chamber) experiences a complete combustion. HCCI engine with modified chamber has higher combustion pressure, narrower heat release rate (HRR), more advanced start of combustion (SOC) and higher indicated mean effective pressure (IMEP) in comparison with comet MK.V chamber. For equivalence ratios between 0.2 and 0.5, the average increase in IMEPs is 49.3%. Furthermore, HCCI engine with modified chamber generates higher work per kg fuel compared to comet MK.V chamber. While a high level of nitrogen oxide (NO x ) emissions is produced by HCCI combustion with modified chamber, both carbon monoxide (CO) and hydrocarbon (HC) emissions decreased drastically. In terms of combustion phasing, engine performance and emissions, the HCCI engine with modified combustion chamber is preferred at low equivalence ratios (U < 0.3) compared with comet MK.V chamber.
Revista de Engenharia Térmica, 2020
Our dependence on fossil fuels coupled with concerns about harmful emissions have motivated researchers to look for renewable fuels that have clean combustion and for advanced combustion modes. In this context, homogeneous charge compression ignition (HCCI) is an emerging technology which offers an alternative to conventional spark ignition and compression ignition engines and can operate on renewable fuels. Low temperature combustion, which can result in low NOx emissions with high indicated efficiency, is the more important characteristic of this combustion mode. It’s main problem is the combustion timing control due to lack of direct ignition control, once HCCI flame initiation is based on charge thermal state. Thus, controlled auto-ignition (CAI) combustion mode has been proposed. Several methods were proposed for combustion phasing control, between them, the injection of water in the intake manifold. This work investigated the influence of water injection in the intake runner o...
Experimental Investigation on Performance of HCCI Combustion in Diesel Engine Fuelled with Diesel
International Journal of Science Technology & Engineering
The Homogeneous charge compression ignition (HCCI) combustion is an alternative to current engine combustion systems and research in HCCI is being carried out to use it as a method to reduce emissions. In this research performance and emission characteristics of HCCI combustion has been investigated experimentally. Experiment was performed in modified single cylinder diesel engine which has conventional mode of starting and then followed by HCCI mode. The basic requirement of the HCCI engines is homogeneous charge preparation, which is attained by using port fuel injection strategy. An external device was used for fuel vaporization and mixture formation.
A Technical Review of HCCI Combustion in Diesel Engine
The Homogeneous charge compression ignition (HCCI) combustion is an alternative to current engine combustion systems and research in HCCI is being carried out to use it as a method to reduce emissions. HCCI has the potential nearly to eliminate engine-out NOx emissions while producing efficiencies as in diesel engine, when a pre mixture of gas-phase fuel and air is burned spontaneously and entirely by an auto ignition process. Homogeneous Charge Compression Ignition (HCCI) engines promise high thermal efficiency combined with low levels of nitric oxide and particulate matter emissions. The purpose of this study is to summarise the alternative fuel effect for the HCCI engine combustion process.
International journal of engineering & technology, 2018
In this paper the emission characteristics and performance of various bio diesel fuels (Tyre pyrolysis oil (TPO), Micro algae oil and Pig animal fat oil) were experimented. A single cylinder, water cooled diesel engine was modified in to homogeneous charge compression ignition engine (HCCI) with adopted port fuel injection (PFI) technique. The effects of air fuel ratio, intake temperature, injection pressure and EGR rate exhaust emissions were explained in a broad manner. The analysis of the exhaust emissions are integrated to oxides of Nitrogen (NOx), Carbon Monoxide (CO), unburned hydro carbons (UHC), smoke and soot. The performance analysis was also included on specific fuel consumption and break thermal efficiency. The basic requirements for HCCI engine is the homogeneous mixture preparation of air and fuel. This mixture formation was done by adopting port fuel injection technique and external devices were also used for bio diesel vaporization and mixture preparation. The combustion processes were measured with different EGR system. The experimental results of different bio diesel fuels with HCCI engine mode were recorded and evaluated. A small increase in CO and HC emissions were observed with increasing bio diesel content due to slow evaporation rate of bio diesel. A significant reduction in NOx emissi on was also observed with respect to difference in bio diesel blends. Micro algae oil was found more stable compared with other bio diesel fuels due to the property of fuel vaporization and low heat releasing.
Homogeneous Charge Compression Ignition Engine ( New Concept of Pollution Free I . C . Engine ) Prof
2013
Homogenous charge Combustion ignition (HCCI) engines are being considered as an alternative to diesel engines. The HCCI concept involves premixing fuel and air prior to induction in to the cylinder (as is done in current sparkignition engine) then igniting the fuel –air mixture through the compression process (as is done in current diesel engines) As per the report of united state congress (2005), The HCCI engines might be commercialized in light duty vehicles by 2012 and by 2015 as much as half million barrels of oil per day may be saved. Because of the need of reduce worldwide fuel consumption, greenhouse gas emissions, there is strong interest in HCCI worldwide. This paper describes the results & operation of a single cylinder KOEL engine in HCCI mode. This experiment represents the first step towards the development of engine based on HCCI concept.