Diesel Engine Using Blend Fuels

Abstract

Experimental study has been carried out to analyze engine performance and emissions characteristics for diesel engine using different blend fuels without any engine modifications. A total of four fuel samples, such as DF (100%diesel fuel), JB5 (5% jatropha biodiesel and 95% DF), JB10 (10% JB and 90% DF) and J5W5 (5% JB, 5% waste cooking oil and 90% DF) respectively were used in this study. Engine performance test was carried out at 100% load

keeping throttle 100% wide open with variable speeds of 1500 to 2400 rpm at an interval of 100 rpm. Whereas,emission tests were carried out at 2300 rpm at 100% and 80% throttle position. As results of investigations, the average torque reduction compared to DF for JB5, JB10 and J5W5 was found as 0.63%, 1.63% and 1.44% and average power reduction was found as 0.67%, 1.66% and 1.54% respectively. Average increase in bsfc compared to DF was observed as 0.54%, 1.0% JB10 and 1.14% for JB5, JB10 and J5W5 respectively. In case of engine exhaust gas emissions, compared to DF average reduction in HC for JB5, JB10 and J5W5 at 2300 rpm and 100% throttle position found as 8.96%, 11.25% and 12.50%, whereas, at 2300 and 80% throttle position, reduction was as 16.28%, 30.23% and 31.98% respectively. Average reduction in CO at 2300 rpm and 100% throttle position for JB5, JB10 and J5W5 was found as 17.26%, 25.92% and 26.87%, whereas, at 80% throttle position, reduction was observed as 20.70%, 33.24% and 35.57%. Similarly, the reduction in CO2 compared to DF for JB5, JB10 and J5W5 at 2300 rpm and 100% throttle position was as 12.10%, 20.51% and 24.91%, whereas, at 80% throttle position, reductions was

observed as 5.98%, 10.38% and 18.49% respectively. However, some NOx emissions were increased for all blend fuels compared to DF. In case of noise emission, sound level for all blend fuels was reduced compared to DF. It can be concluded that JB5, JB10 and J5W5 can be used in diesel engines without any engine modifications However, W5B5 produced some better results when compared to JB10.

Introduction

Unlimited use of the fossil fuels has led to global environmental degradation and health hazards. Reduction in engine emissions becomes a major task in engine development due to the increasing concern of environmental protection and more stringent emission norms. In addition to this more efforts are needed to reduce dependence on the petroleum fuels as it is obtained from limited reserves . It has been reported by the US department of energy that the world’s oil supply will reach its maximum production and midpoint of depletion sometime around the year 2020 . Legislations have been passed in many countries, requiring diesel to contain a minimum percentage of bio fuels. The Czech Republic proved to be the best, which insisted on 100% bio fuel use for transportation . The attractive characteristics of biodiesel include higher cetane number, non-toxic emissions, bio-degradability, absence of sulphur and aromatic compounds and excellent lubricity . Bio diesel is the fuel that can be produced from straight vegetable oils, edible and non-edible, recycled waste vegetable oils, and animal fat .

To evaluate the engine performance of different biodiesel blends, several experimental studies have been carried out around the world. Generally a slight power loss, reduction in torque and increased brake specific fuel consumption (bsfc) were observed in case of biodiesel fuelled engines. Besides it reduces the emissions of carbon monoxide (CO), hydrocarbon (HC), sulfur dioxide (SO2), polycyclic aromatic hydrocarbons (PAH), nitric polycyclic aromatic hydrocarbons (nPAH) and particulate matter (PM).

However, a majority of research results have indicated an increase in nitrogen oxides (NOx) . According to the study  conducted on six cylinders DI diesel engine, increase of biodiesel percentage in the blend involves a slight decrease of both power and torque. In particular, with pure biodiesel there was a reduction by about 3% maximum power and about 5% of maximum torque. Similar results were reported by Aydin and Bayindir  using cottonseed oil methyl ester (CSOME). However, a decrease of CO, NOx and SO2 emissions were observed in the same study. In many countries, the use of edible oil to

produce biodiesel is not feasible due to a big gap in the demand and supply of such oils for dietary consumption. Therefore, it should be concentrated on the inedible oils such as Jatropha curcas, M. indica, Ficus elastica, Azardirachta indica, Calophyllum inophyllum, neem, P. pinnata, rubber seed, mahua, silk cotton tree and tall oil microalgae whose potential availability can easily be found and these are very economical comparable to edible oils. The cost of feedstocks accounts about 60–80% of the total cost of biodiesel production. Therefore, the problem of high feedstock cost can also be mitigated by the

selection of non-edible vegetable oil for the production of bio diesel.

In Malaysia, biodiesel production is mainly palm oil based though it has taken some initiative to introduce jatropha production in mass level. Jatropha is also getting importance for a yield factor of 1.2 tons/ha with about 0.8 kg/m2 production of seeds per year. Jatropha is a potential second generation biodiesel feedstock, though it still requires more research and development . It has been also reported that among the vegetable oils, jatropha oil exhibits very good properties. It is a non-edible oil, its calorific value and cetane number are higher compared to many others. The jatropha plant can grow almost anywhere, even on gravely, sandy and saline soils. Its water requirement is very low . Based on the

studies available, jatropha oil is seems to be as one of the best substitutes to fossil diesel supply. In case of using waste cooking oil in diesel engines, it is found to be an alternative way of reducing the disposal of waste cooking oil and for abatement of the fuel crisis as well. Waste edible oil (WEO) can not be discharged into drains or sewers due to blockages and odour or vermin problems and may also pollute watercourse. It is also a prohibited substance and will cause problems if it is dumped in municipal solid waste landfill and municipal sewage treatment plants. Being cheap and easily available, waste cooking oil

seems like a good substitute for diesel, but its high viscosity is a major drawback. To overcome this problem, a small percentage, like 5%, can be blended and tested for engine compatibility.

Keeping in view the above facts, the main objective of the present study is to determine the suitability of using biodiesel derived from non-edible oil such as jatopha oil along with the use of WCO to investigate the effect of jatropha biodiesel addition (5% and 10% in volume) and JB + WCO (5%+5% in vol.) with conventional diesel fuel, on performance and emission characteristics of a DI diesel engine.

Experimental setup and experiments

The present study is conducted on an engine installed in the heat engine laboratory of Mechanical Engineering Department at University of Malaya.  A one-cylinder, four-stroke diesel engine is selected and is mounted on a test-bed.  Two fuel tanks, one for DF and

another for blend fuels were used for supplying the fuels to the test engine. The engine is coupled to an eddy current dynamometer. It can be operated at a maximum power of 20 kW at 2450 to 10000 rpm. The engine was first fuelled with DF to determine the baseline parameters and then, it was fuelled with blend fuels. In order to calculate mean values, each test was repeated three times.

Engine performance parameters have been measured are engine torque, brake power, and brake specific fuel consumption (bsfc). In this regard, test procedure was carried out to run a single cylinder diesel engine through DYNOMAX 2000 data control system. In order to carry out the performance test, engine was run at 100% load keeping throttle 100% wide open. Engine test conditions were monitored by Dynomax-2000 software. All engine performance data were measured at “Step RPM Test” mode (between 1500 and 2400 rpm with intervals of 100 rpm conditions). To examine the emission characteristics, a portable BOSCH exhaust gas analyzer (model ETT 0.08.36) was used to measure the

concentration of exhaust gases of the test engine such as hydrocarbon (HC) in part per million (ppm) while carbon monoxide (CO) and carbon dioxide (CO2) in percentage volume (%vol). While NOX emission was measured using AVL 4000 (Make: Graz/Austria) gas analyzer. The emissions of different pollutants were measured at 2300 rpm at 100% and 80% throttle position. To measure the noise level, NI Sound Level Measurement System was adopted. In this regard, the PCB 130 Series of Array Microphones (microphone model 130D20) was employed. Because of limited conditions, the measurement of engine

noise was carried on the engine test bed in engine testing laboratory. Sound level was measured at different brake mean effective pressure (bmep) such as 0.98, 1.48, 1.97, 2.46 and 2.95 bar respectively. Sound level was taken from five directions at 1 meter away from the test engine bed such as front, rear, left, right and top side. However, only front side was selected for this study, which produced the highest level of noise.