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Efforts to find alternative fuels and reduce emissions of CI engines have been conducted, one of which is the use of diesel hydrogen dual fuel. One of the goals of using hydrogen in dual-fuel combustion systems is to reduce particulate emissions and increase engine power. This study investigates the thermal efficiency and emission characteristics of a diesel-hydrogen dual fuel CI engine at various loads condition. The hydrogen was used as a secondary fuel in a single cylinder 667 cm3 diesel engine. The hydrogen was supplied to intake manifold by fumigation method, and diesel was injected directly into the combustion chamber. The results show that the performance test yielding an increase around 10% in the value of thermal efficiency of diesel engines with the addition of hydrogen either at 2000 or 2500 rpm. Meanwhile, emission analyses show that the addition of hydrogen at 2000 and 2500 rpm lead to the decrease of NOx value up to 43%. Furthermore, the smokeless emissions around 0% per kWh were occurred by hydrogen addition at 2000 and 2500 rpm of engine speeds with load operation under 20 Nm.

Range extender engine is one of the main components of the range-extended electric vehicle (REEV) and together with a generator to extend the mileage of the electric vehicle. The main component of REEV is an electric motor, battery, and generator set that consist of generator and engine. In this study, we compared two models of REEV performance with two different types of the engine by simulation. Single cylinder 499 cc gasoline engine and single cylinder 667 cc diesel engine are chosen as the object of this research especially relating to the utilization of the fuel consumption and CO2 emissions when fitted to an electric vehicle. The simulation was conducted by using AVL Cruise software and performed by entering the data, both experiment and simulation data, on all the main components of REEV. This simulation was performed in Japan 08 driving cycle. Based on the simulation, fuel consumption is reduced up to 35.59% for REEV with single cylinder diesel engine 667 cc compared to REEV with single cylinder gasoline engine 499 cc. The reduction of CO2 emissions from REEV with single cylinder 499 cc gasoline engine compared to REEV with single cylinder 667 cc diesel engine up to 30.47%.

This paper will discuss the feasibility and economic analysis of biogas energy as a supply for the diesel engine generator. The techno-economic analysis was performed by using three parameters which are Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PP) as the feasibility indicators of the biogas power plant project. Calculation of substitution was obtained from the comparison between data of diesel engine using diesel fuel and dual-fuel with biogas. Economic calculations include the substitution percentage of diesel fuel by biogas for dual-fuel. Meanwhile, the calculation of savings was based on the ratio of energy content between diesel fuel and biogas. The eventual outcome is determined using economic comparison between the use of diesel fuel and dual-fuel mode. Feasibility shows that the pilot plant of 1 to 6 kWh using diesel fuel and dual-fuel are not feasible while techno-economic parameter analysis shows that NPV0, IRRMARR, while PP is undefined. The biogas power plant project is feasible in some conditions such as there is no labor cost, and 5 and 6 kWh will be feasible under the assumption that expenses for machine maintenance is eliminated. However, even when applying both conditions where biogas is feasible, diesel fuel is still not.

The experimental investigation of 2nd generation bioethanol derived from EFB of oil-palm blended with gasoline for 10, 20, 25% by volume and pure gasoline were conducted on performance and exhaust emission tests of SI engine. A four stroke, four cylinders, programmed fuel injection (PGMFI), 16 valves variable valve timing and electronic lift control (VTEC), single overhead camshaft (SOHC), and 1,497 cm3 SI engine (Honda/L15A) was used in this investigation. Engine performance test was carried out for brake torque, power, and fuel consumption. The exhaust emission was analyzed for carbon monoxide (CO) and hydrocarbon (HC). The engine was operated on speed range from1,500 until 4,500 rev/min with 85% throttle opening position. The results showed that the highest brake torque of bioethanol blends achieved by 10% bioethanol content at 3,000 to 4,500 rpm, the brake power was greater than pure gasoline at 3,500 to 4,500 rpm for 10% bioethanol, and bioethanol-gasoline blends of 10 and 20% resulted greater bsfc than pure gasoline at low speed from 1,500 to 3,500 rpm. The trend of CO and HC emissions tended to decrease when the engine speed increased.

Modification of combustion system from indirect injection (IDI) to direct injection (DI) was carried out on the two cylinder diesel engine, followed with tests for performance and emission. The modification from IDI to DI was conducted on a two cylinder diesel engine by removing the pre-chamber from the inside of the cylinder head, replacing the injector and its position to the top of the combustion chamber directly and also replacing the original piston with a piston that has a bowl on the crown. Performance and emission tests were conducted on 1,500 rpm with loads that vary from 0, 10, 20, 30, 40, 50, to 60 Nm. The investigation results of the diesel engine modification from IDI to DI showed several interesting phenomena. Further research is needed in order to increase the engine performance and reduce its emission.

The experiment was conducted on a conventional direct injection diesel engine. Performance test was carried out to evaluate the performance and emission characteristics of a conventional diesel engine that operates on ethanol-diesel blends. The test procedure was performed by coupling the diesel engine on the eddy current dynamometer. Fuel consumption was measured using the AVL Fuel Balance, and a hotwire anemometer was used to measure the air consumption. Some of the emission test devices were mounted on the exhaust pipe. The test of fuel variations started from 100% diesel fuel (D100) to 2.5% (DE2.5), 5% (DE5), 7.5% (DE7.5), and 10% (DE10) ethanol additions. Performance test was conducted at 1500 rpm with load variations from 0 to 60 Nm by increasing the load on each level by 10 Nm. The addition of 5% ethanol to diesel (DE5) increased the average pressure of combustion chamber indication to 48% as well as reduced the specific fuel consumption to 9.5%. There were better exhaust emission characteristics at this mixture ratio than diesel engine which used pure diesel fuel (D100), the reduction of CO to 37%, HC to 44% and opacity to 15.9%.