PERFORMANCE AND EMISSION ANALYSIS OF DIESEL ENGINE BY INJECTING DIETHYL ETHER WITH AND WITHOUT EGR USING DPF PROJECT REFERENCE NO. : 37S1036 COLLEGE BRANCH GUIDES : KS INSTITUTE OF TECHNOLOGY, BANGALORE : MECHANICAL ENGINEERING : NAGAPRASAD K S STUDENTS : HARISH N DEVAPPA H S MALLESHAPPA BADIGER MANJESH A Introduction: The intention of Rudolf Diesel to provide a new type of internal combustion engine operating with higher efficiency than conventional steam and Otto cycle engines, and that could be operated on many types of fuels. The engine cycle developed by diesel involves injection of fuel into a volume of air heated by compression. Over the course of history, the durable and efficient diesel engine has replaced other less efficient modes of power production, including steam engines in the railroad industry. A diesel engine or compressionignition (C.I.) engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber. Energy consumption is increasing globally in various forms for different purposes. To determine the potential of di-ethyl ether (DEE) for use as a transportation fuel, it is necessary to understand its engine and emissions performance characteristics, as well as what it might cost. Although DEE has long been known as cold-start aid for engines, knowledge about using DEE for other applications, such as a significant component of a blend, or as a complete replacement for diesel fuel is limited [9]. 1
Exhaust Gas Recirculation (EGR) is a pre-treatment technique, which is being used widely to reduce and control the oxides of nitrogen (NO x ) emission from diesel engines. EGR controls the NO x because it lowers oxygen concentration and flame temperature of the working fluid in the combustion chamber. However, the use of EGR leads to a trade-off in terms of soot emissions. Higher soot generated by EGR leads to long-term usage problems inside the engines such as higher carbon deposits, lubricating oil degradation and enhanced engine wear [6]. For many years, diesel engine manufacturers have been working extensively to develop after treatment technologies that are capable of significantly reducing the emission levels of each of the primary pollutants which are considered to be a risk to the environment and public wellbeing. The majority of these after treatment technologies have been designed with the most consideration being given to compounds such as particulate matter (PM), oxides of nitrogen (NO x ), carbon monoxide (CO), and hydrocarbons (HC). One primary after treatment technology commonly used to reduce the PM emission levels of diesel exhaust is the diesel particulate filter (DPF). There are a variety of DPFs available. For example, the DPF could be made of composite fibrous materials which utilize fine fibers as a means of particle filtration. The importance of CI engines is due to Its higher thermal efficiency than SI engines, and CI engine fuels being less expensive than SI engine fuels (petrol or gasoline). These factors make the running cost of CI engines much less than SI engines and hence make them attractive for all industrial, transport and other applications. Objectives of the project: To conduct the experiments on diesel engine using neat diesel with & without EGR at various loads. To conduct the experiments by injecting Di-ethyl ether at different proportions with diesel into the engine running with & without EGR at different loads. To measure the emission parameters with and without after treatment devicesdiesel particulate filter (DPF) based on the highest efficiency of the engine. 2
To compare the Performance and Emission of diesel engine by injecting neat diesel & Di-ethyl ether blends having EGR, DPF set up. Finally, to suggest the optimum operating condition for this existing diesel engine by considering all the parameters. Methodology: Exhaust Gas Recirculation Exhaust Gas Recirculation is an efficient method to reduce NOx emissions from the engine. It works by recirculating a quantity of exhaust gas back to the engine cylinders. Intermixing the recirculated gas with incoming air reduces the amount of available O2 to the combustion and lowers the peak temperature of combustion. Recirculation is usually achieved by piping a route from the exhaust manifold to the intake manifold. A control valve within the circuit regulates and times the gas flow. Uses of Exhaust Gas Recirculation First, exhaust gas recirculation reduces the concentration of oxygen in the fuel-air mixture. By replacing some of the oxygen-rich inlet air with relatively oxygen-poor exhaust gas, there is less oxygen available for the combustion reaction to proceed. Since the rate of a reaction is always dependent to some degree on the concentration of its reactants in the prereaction mix, the NO x -producing reactions proceed more slowly, which means that less NO x is formed. In addition, since there is less oxygen available, the engine must be adjusted to inject less fuel before each power stroke. Since we are now burning less fuel, there is less heat available to heat the fluids taking place in the reaction.the combustion reaction therefore occurs at lower temperature. Since the temperature is lower, and since the rate of the NOxforming reaction is lower at lower temperatures, less NOx is formed. Basic Parts of EGR There are 3 basic parts of EGR EGR Control Valve EGR Cooler EGR Transfer Pipe 3
Fig: 4.1 Relation between EGR ratio and load Fig: 4.2 Diesel Engine test rig and Exhaust gas recirculation system Diesel Particulate Filters (DPF) Diesel particulate traps are devices that physically capture diesel particulates to prevent their release to the atmosphere. Some of diesel filter materials which have been developed show quite impressive filtration efficiencies, frequently in excess of 90%, as well as acceptable mechanical and thermal durability. In fact, diesel traps are the most effective control technology for the reduction of particulate emissions with high efficiencies. More precisely, due to the particle deposition mechanisms utilized in these devices, traps are effective in controlling the solid fraction of diesel particulates, including elemental carbon (soot) and the related black smoke emission. It must be remembered that traps may have limited 4
effectiveness, or be totally ineffective, in controlling the non-solid fractions of PM, such as the SOF or sulfate particulates. For this reason, trap systems designed to control the total PM emission are likely to incorporate additional functional components targeting the SOF emission (e.g., oxidation catalysts) and sulfate particulates. Due to the low bulk density of diesel particulates, which is typically below 0.1 g/cm 3 diesel particulate filters can quickly accumulate considerable volumes of soot. The collected particulates would eventually cause excessively high exhaust gas pressure drop in the filter, which would negatively affect the engine operation. Therefore, diesel filter systems have to provide a way of removing particulates from the filter to restore its soot collection capacity. This removal of particulates, known as the filter regeneration, can be performed either continuously, during regular operation of the filter, or periodically, after a pre-determined quantity of soot has been accumulated. In either case, the regeneration of filter systems should be invisible to the vehicle driver/operator and should be performed without his intervention. In most cases, thermal regeneration of diesel filters is employed, where the collected particulates are removed from the trap by oxidation to gaseous products, primarily to carbon dioxide (CO2). The thermal regeneration, schematically represented in Fig5.1, is undoubtedly the cleanest and most attractive method of operating diesel filters. FILTERATION PM CO2 O2 NO HEAT Fig 5.1 Schematic of Particulate Filter with Thermal Regeneration. 5
Experimental Setup Compression ignition engine Experiments are conducted on a four stroke multi-cylinder, water cooled compression ignition engine. The specifications of the engine are shown in the specification table. Hydraulic Dynamometer Fig 6.1 Compression ignition engine Fig 6.2 Hydraulic dynamometer 6
The engine is loaded through a water dynamometer setup. The load is applied using this hydraulic dynamometer. EGR Connection Full experimental Set up Fig 6.3.5 EGR circuit connection Fig 6.4 Photograph of Diesel Engine test rig 7
Diesel Particulate Filter (DPF) DPF Arrangement Fig 6.5.1 Wall-Flow substrate Diesel Particulate Filter (DPF) Fig 6.5.2 DPF arrangement The Diesel Particulate Filter (DPF) is placed in the exhaust line of the CI engine. The exhaust gases from the silencer pass through the diesel particulate filter. Thus the exhaust gases containing the particulate matter gets filtered and clean gases passes to the atmosphere. DPF is loaded with precious metal and hence enhancing regeneration. 8
Results: The investigation of diesel engine performance is done by blending diesel with diethyl ether with and without EGR. The analysis is done in the sequence of comparison of performance obtained at different concentrations of diesel fuel with di-ethyl ether at different ratios of 20% and 30% for various EGR valve openings. The variation of brake thermal efficiency and exhaust gas temperature at different load has been presented and discussed. The engine speed is kept at a constant speed of 1200rpm with an EGR valve opening of 1/4, 1/2, 3/4, 1.The results were analyzed as follows. Performance characteristics of Neat Diesel with and without EGR at different loads running at 1200rpm. Performance characteristics of Diesel blended with 20% Di-ethyl ether with and without EGR at different loads running at 1200rpm. Performance characteristics of Diesel blended with 30% Di-ethyl ether with and without EGR at different loads running at 1200rpm. Comparison of Neat Diesel with Di-ethyl ether blends with and without EGR for 16 kg load at 1200rpm. Emission Measurement for 3/4 EGR valve opening at 16 kg Load. The comparison and performance of diesel engine at different loads for various valve openings and at different blending are shown clearly with the graphical representation of values for different parameters like brake thermal efficiency& exhaust gas temperature.the emission such as PM, NO x, HC, CO, CO 2 is also shown in comparison with neat diesel and diesel blending with 20% di-ethyl ether and 30% di ethyl ether 9
Performance characteristics of Neat Diesel oil with and without EGR at 1200rpm Comparison of Brake thermal efficiency v/s Load Fig A.1Brake thermal efficiency v/s Load The brake thermal efficiency was measured with load for all test turns with and without EGR at 2, 4, 8 and 12 kg loads. The efficiency has found to decrease gradually by recirculating the exhaust gas. This happens due to burnt gas occupying the engine cylinder which thereby reduces the availability of oxygen for combustion. The maximum brake thermal efficiency has been found to be 6.72% at 12 kgfor without EGR condition as shown in fig A.1 The minimum brake thermal efficiency for 12kg is with 3/4 EGR valve opening condition. 10
Comparison of Exhaust Gas Temperature v/s load Fig A.2 Exhaust Gas Temperature v/s Load The Exhaust Gas Temperature is compared with load for all the test turns with and without EGR for 0, 2, 4, 8 and 12 kg loads. It is found that Exhaust Gas Temperature reduces with the application of E.G.R which in turn reduces the NO x pollutant from the emission. Conclusions: After the investigation of diesel engine performance by blending diesel with diethyl ether (DEE) with and without EGR system, it is shown that no major modifications are required for EGR installation in the existing engine, except for the fuel. Even though the brake thermal efficiency of CI engine decreases with EGR system, The injection of DEE has drastically enhanced the efficiency for more than the normal performance with EGR system. It is also found that the exhaust gas temperature has decreased with exhaust gas recirculation for both diesel and DEE blends. Maximum brake thermal efficiency is found to be 4.93% for 30% DEE and ¾ EGR opening at 4KG load. At this optimum condition of engine, DPF will be attached to the engine exhaust and emission will be measured At this operating condition the exhaust gas temperature is found to be 114 deg.c which is lesser than neat diesel operation Particulate matter emission has been decreased at a larger 11
rate by the usage of DPF emission has been decreased to a minimum. There has been a decrease in PM emission of over 95% by the application of DPF Nitrogen oxides (NO x ) emission has considerably reduced with usage of both after treatment devices for with EGR condition. By all these results we can conclude that the after treatment devices are active in reducing the engine emissions and are necessary in attaining the emission norms. Scope for Future Work: Performance of the diesel engine can be studied for higher injection pressure and by increasing the injection advance. Effects of intake air heating and fuel preheating on performance of engine can be studied. The controlled quantity of Exhaust gas can be re-circulated to minimize nitrogen dioxide and nitric oxide emission. Electronic controlled EGR valve opening can be made, thereby controlling the flow precisely 12