PERFORMANCE DIESEL DUAL FUEL ENGINE ON ADDITIONAL COCONUT SHELL OIL

Fuel alternative diesel was developed aiming to develop environmentally friendly alternative fuels in Indonesia. The purpose of this study was to determine the physical properties and quality of diesel produced from coconut shell liquid smoke, B20, and B40. The quality and physical properties of diesel in question were tested in terms of its Calorific Value, Viscosity, Density, and Cetane Number test. Based on the engine performance testing, the parameters sought were torque, power, and specific fuel consumption. In this case, the testing of the physical properties of diesel was conducted through the comparison of the fuel used, among others, the highest torque value was obtained at 32.415 Nm on diesel fuel for the engine shaft rotation of 1980 rpm with the mass load of 9.6 kg. Furthermore, fuel consumption specific was obtained from diesel fuel with the largest rotation of 3548 rpm using 337.4 g/kWh, while the lowest value was obtained from diesel B40 with a torque value of 24.702 Nm. In this case, the lowest mass fuel consumption specific (SFC)) was found in coconut shell oil mixture with the largest rotation of 1520 rpm using 40.9 g/kWh. The conclusion made was that the addition of coconut shell oil in diesel can reduce energy because the calorific value decreased, as evidenced by the addition of coconut shell oil causing the engine performance to decrease.


INTRODUCTION
Diesel is one of the alternative fuels that has the potential to be developed in facing the energy crisis. Until now, Indonesia is still facing problems in achieving development targets in the energy sector with the fact that Indonesia has become an importing country for crude oil and fuel oil. Efforts to deal with this energy crisis need serious attention to anticipate various socio-economic problems that will arise. In addition, many non-renewable resources will one day be sure to run out of petroleum and have a negative impact on the environment in the form of exhaust emissions that pollute the environment. Therefore, it is necessary to develop a substitute fuel that is renewable, more environmentally friendly, and affordable by the public.
Diesel fuel is one of the liquid fuels for diesel engines consisting of methyl esters or ethyl fatty acids made from some biological resources. Generally made through the reaction of methanolysis or ethanolization of vegetable or animal fatty oils with alcohol (methanol or ethanol), energy is one of the basic needs of all industrial and household needs in the social sphere. Along with population economic growth, regional development and annual development, the need for energy fulfillment in all sectors nationally is also getting bigger.
The results of a study by the Department of Energy and Mineral Resources explained that Indonesia's total energy consumption per capita is increasing every year by more than 5% [1] [2].
Coconut shell oil is produced from the condensation of the pyrolysis process, in which the steam resulting from burning coconut shells is either directly or indirectly are accommodated in a container [3]. During the burning of coconut shells, it undergoes pyrolysis that produces several mixtures of chemical compounds which are dominated by phenol, carbonyl, alcohol, hydrocarbons, and others [4] [5]. Based on the previous research [6] the effect of adding methanol has a real impact on the physical condition of the fuel. This is in accordance with another research project [7] that activated charcoal (coconut shell) has high phenol and methanol content. Furthermore, other studies [8], [9] emphasized that the alternative fuel used in diesel engines is a mixture of diesel with fuel derived from petroleum. Fuel petroleum has been regulated quite well by the American Society for Testing and Materials (ASTM) by calling it a diesel mixture [10], although the definition has not been clearly defined by the Indonesian government. The volume percentage of diesel (eg XX) that is mixed in the fuel to make the fuel is given the symbol BXX.
The mixing results in changes in both the physical and chemical properties of the diesel. The more mixture of coconut shell liquid smoke, the more aldehyde and phenol content will increase so that the mixed fuel will be flammable and will not produce the required energy. The testing of diesel engines with a mixture of coconut shell oil according to Vinukumar [11]. In addition, it is also very safe to increase engine performance and reduce emissions without changing and modifying the diesel engines. The mixture of coconut shell oil added to diesel has new diesel physical properties so that it can be studied. The comparison of the physical properties of Biosolar, B20, B40 and Coconut shell oil were further tested on a diesel engine [12] .

Equipment
In this case, the equipment used includes a diesel engine from a pump that has been designed to be tested with several additional measuring tools and braking methods. Figure 1 shows the diesel engine used.  The diesel used has a Cetane Number of 48 according to [13] and contains a maximum sulfur of 2,500 parts per million (ppm). This means that the diesel fuel produces environmentally friendly emissions and is economical in use. The coconut shell oil used is a product from Creanova Rahmah with Level E. The liquid smoke was then filtered for impurities using a home filter. Figure 2 shows the packaging of coconut shell oil from the industry.

Figure 2 Liquid Smoke of Coconut Shell
Some of the diesel blends used are presented in table 2. with the types used to test the physical properties and performance of the machine.

Testing Steps
The mixing was done by using a measuring instrument to determine the volume in milliliters in the diesel mixture. The coconut shell oil used was at a volume of 350 ml for each composition of B20 and B40 according to the specified ingredients.

Physical Properties Testing Physical
The properties testing was carried out through several methods, including the cetane number of fuel using the ASTM D613 method using the Cetane Rating Unit. In addition, a pycnometer was used to test the density of the fuel. Furthermore, the viscosity testing of the fuel was carried out using the ASTM D445 method using viscometer kinematic. The last physical property test was the calorific value of the fuel using a bomb calorimeter with an automatic 6400 isoperibol type from PARR. All tests of B20 and B40 fuel characteristics were carried out at the UPT Integrated Laboratory, Diponegoro University, Semarang.
Diesel Engine Performance Testing was conducted at the Energy Laboratory of Wahid Hasyim University, Semarang with through several steps. The first step is preparing the engine and fuel, then putting the diesel fuel into the fuel measuring cup. After that, the machine was started, the brake lever was turned on to give a certain load to the brake disc and record the load. Furthermore, the force meter or the hanging scale was read as a mass applied to the disk and recorded it. The next step is measuring the rotation of the shaft on the engine using a tachometer and recording it. The combustion process and fuel were then left for 30 seconds to decrease. Furthermore, the load on the engine was increased by turning the brake lever and the steps 5 and 6 were repeated. In addition, this whole experiment was also repeated using other fuels.
Fuel mixed coconut shell oil was analyzed on a diesel engine that has been made with the following parameters and equations used 1. Symbol (T) is Torque measure from dyno test unit Nm, force that works (F) at Newton [N] and distance pendulum r on meter unit. .

RESULTS AND DISCUSSION
Based on the tests that have been carried out to determine the characteristics of the sample materials of coconut shell liquid smoke, B20, and B40 which have been investigated in the laboratory to obtain the characteristic values of fuel diesel, the results are presented in table 3.  Density testing is a method to determine the quality of fuel oil to distinguish the characteristics of a fluid. Based on the tests carried out, the results can be seen in the graph Figure 3.1. The addition of coconut shell oil in diesel caused different densities. The addition of coconut shell oil increased the density value of the coconut oil shell in diesel, while the density of the fuel increased. In accordance with the previous research (Yustia, et al., 2020), it was stated that activated charcoal (coconut shell) has high phenol and methanol content.

FUEL VISCOSITY
In this case, value can be referred to as the level of viscosity of a fluid. The viscosity will have an impact on the level of ease of flow of fuel oil. The results of the viscosity test of the test sample can be seen in the following graph of  Based on the graph on Figure 3.2, the viscosity value of bio diesel tended to decrease. Diesel oil with the addition of composition to B40 and a mixture of coconut shell oil decreased very drastically. Very low viscosity values are not very good for the combustion process. Dilute oil will cause the injector inable to fog properly. The worst condition of the diluted oil is that the oil will exit the nozzle early before the fogging time.

FUEL
Cetane number is one of a number of measurable factors that indicate the overall characteristics and quality of diesel fuel. The cetane number of each diesel fuel is actually the average of all the cetane numbers of the various hydrocarbons found in that fuel. The flammability of diesel will affect the performance of a diesel engine. A fuel with a low cetane number can cause a diesel engine to run slower and have higher emissions due to inefficient combustion. In this case, the results of the test of the cetane number can be seen in the following graph of Figure 5. Based on the graph in figure 5, the cetane number value tends to be stable with the average Biosolar value, B20, B40 showing a not much decrease. In addition, coconut shell oil did not show a value, the standard minimum cetane number for diesel fuel ranging within the values of 40-51, B20, B40 can still achieve efficiency.

CALORIFIC VALUE OF FUEL
The calorific value of a fuel can be used as a parameter to determine the amount of heat produced during complete combustion. Heat is a form of energy, so from this value it can be seen the potential for energy conversion that can be produced. The heating value test results can be seen in the graph Figure 6.

Figure 6. Value LHV
Based on figure 6, the highest calorific value of diesel was at 1.0439 KCal/gram. When the composition was made into B20, the calorific value decreased to 0.7823 Kcal/gram. Type B40 oil and a mixture of coconut shell oil did not burn (miss firing).

ANALYSIS OF PHYSICAL PROPERTIES
Changes that occur will affect the quality of the fuel produced. The explanation that can be taken was based on the viscosity value, where mixing diesel with coconut shell oil reduced the viscosity of diesel fuel. The density of the fuel from the test results that the coconut shell oil mixture increased as the density value increased.
Mixing coconut shell oil in diesel fuel will affect the cetane number of diesel fuel. The more coconut shell oil mixed, the more it will increase. Therefore, the fuel mixture will be flammable and will not produce the required energy. The calorific value of the test results showed that the calorific value decreased with the addition of coconut shell oil volume into diesel. The decrease in calorific value means that coconut shell oil reduces the quality of diesel fuel in terms of the energy produced from the fuel.

PERFORMANCE OF DIESEL ENGINE WITH MIXED DIESEL FUEL
The relationship of power between mixing fuel diesel engine testing was obtained as shown in Figure 7. It is directly proportional to the increase in torque produced due to incubation, the power generated will also decreased with additional of coconut oil shell, its due to value caloric of coconut shell oil lower than diesel.
Torque results are based on differences in the fuel used, namely when the addition of coconut shell oil concentration in diesel will reduce the torque produced. This is because the torque was affected by the mass of the load which decreased as the concentration of coconut shell oil was added into diesel. Therefore, the torque obtained decreased as this will result in the power generated as well.  revealed that using diesel from coconut shell oil reduced the power produced, although it only had a slight difference from pure diesel. In addition, when the braking process means a decrease in the rotation of the engine shaft, the power generated increases in value from the initial start then when it decreases near stopping the power value will decrease. The test results also showed a decreased fuel consumption material fuel that is presented in Figure .8.  Figure 9 shows the relationship between the value of torque rotation on specific fuel consumption from diesel engine testing. Based on these results, as power increases due to braking and a decrease in rotation, fuel consumption will decrease. This is because power is inversely proportional to specific fuel consumption.
Comparison of the use of different fuels resulted in different fuel consumption in the test. As the concentration of coconut shell oil in diesel increased, the value of fuel consumption decreased. Comparison of the use of different fuels resulted in different fuel consumption in the test according to (Harsono & Siregar, 2015).
In accordance with the torque and power relationship, which is directly proportional to the increase in torque generated due to braking, the power generated will also increase, from the torque rotation results based on the difference in fuel used, namely when the addition of coconut shell oil in diesel will reduce the torque produced. This is because the torque is influenced by the mass of the load which decreases as the concentration of coconut shell oil added to diesel.

CONCLUSION
Based on the testing of the physical properties of the fuel with the addition of coconut shell liquid smoke, it can be concluded that the results of testing the physical properties of the fuel show that the addition of coconut shell oil will affect the fuel energy produced. This is because the heating value decreases and inhibits the combustion process in diesel engines, specifically the torque, power and fuel consumption parameters.