Bilge Albayrak Çeper, S.Orhan Akansu, Nafiz Kahraman INVESTIGATION OF CYLINDER PRESSURE FOR H 2 /CH 4 MİXTURES AT DIFFERENT LOAD Dept. of Mechanical Engineering, Erciyes University Engineering Faculty, Kayseri, Turkiye International Conference on Automotive Technologies November 13 – 14, 2008

2 ABSTRACT In this study, an experimental study on the performance and exhaust emissions of a spark ignition engine fuelled with methane-hydrogen mixtures (100%CH 4, 10%H 2 -90%CH 4, 20%H 2 -80%CH 4, and 30%H 2 -70%CH 4 ) were performed at full load and 65% full load for different excessive air ratio. This present work was carried out on a Ford engine. This is a four- stroke cycle four-cylinder spark ignition engine with a bore x stroke of 80.6x88 mm and a compression ratio of 10:1. Experiments were made on a constant engine speed of 2000 rpm. CO, CO 2 and HC emission values and cylinder pressures were measured. The results showed that while the excessive air ratio increase, CO and CO 2 emission values decrease. International Conference on Automotive Technologies November 13 – 14, 2008

3 Why Natural gas –Hydrogen mixtures ? The energy system today is dominated by fossil fuels, which are abundant and relatively inexpensive. Burning of the fossil fuels generates waste materials, mainly emissions to the atmosphere in the form of combustion fuel gases and dust, as well as some ash and/or clinker. These waste materials have hazardous effects on the environment, some of them locally, others with more widespread or even global impact. Natural gas (NG) is an extremely important source of energy for reducing pollution and maintaining a clean and healthy environment. In addition to being a domestically abundant and secure source of energy, the use of NG also offers a number of environmental benefits over other sources of energy, particularly other fossil fuels. Natural gas is composed primarily of methane which dominates its emission characteristics. Methane mixes readily with air and has a high octane rating which makes it a very good spark-ignition engine fuel. International Conference on Automotive Technologies November 13 – 14, 2008

4 Traditionally, to improve the lean-burn capability and flame burning velocity of the natural gas engine under lean-burn conditions, an increase in flow intensity in cylinder is introduced, and this measure always increases the heat loss to the cylinder wall and increases the combustion temperature as well as the NOx emission. One effective method to solve the problem of slow burning velocity of natural gas is to mix the natural gas with the fuel that possesses fast burning velocity. Hydrogen is regarded as the best gaseous candidate for natural gas due to its very fast burning velocity, and this combination is expected to improve the lean-burn characteristics and decrease engine emissions. Why Natural gas –Hydrogen mixtures ? International Conference on Automotive Technologies November 13 – 14, 2008

5 The volumetric heat value of natural gas–hydrogen mixtures will decrease with the increase of hydrogen fraction in fuel blends, and this is due to the low volumetric heat value of hydrogen–air mixture compared to that of natural gas–air mixture at the stoichiometric condition. International Conference on Automotive Technologies November 13 – 14, 2008 Why Natural gas –Hydrogen mixtures ?

6 Experimental apparatus and test procedure Table 1. General specifications of the Ford engine The general specifications of the engine are shown in Table 1. A Cussons-P8601 brand hydrokinetic dynamometer was used for the tests. The schematic view of the test equipments is shown in Fig. 1Table 1Fig. 1 Bore80.6mm Stroke88mm Compression Ratio10:1- Exhaust valve opening55BBDC Exhaust valve closing50ATDC Intake valve opening13BTDC Intake valve closing47ABDC 1500 rpm spark timing18BTDC 2000 rpm spark timing30BTDC 3000 rpm spark timing38BTDC International Conference on Automotive Technologies November 13 – 14, 2008

7 1-Engine Chassis, 2- Hydrokinetic Dynamometer, 3- Engine, 4- Engine Cooling Unit, 5-Air Tank, 6- Control Unit, 7- Main Fuel Tank, 8- Regulator, 9- Fuel Select Key, 10-Fuel Tank, 11-Mass Flow meter, 12- Exhaust Gas Analyzer Figure 1. Experimental rig International Conference on Automotive Technologies November 13 – 14, 2008

8 The in-cylinder pressure was measured with AVL type 8QP500C water cooled piezoelectric pressure transducer. The transducer is connected to a Cussons Model 4441 charge amplifier, which provides a calibrated voltage signal for display on a Signal Processing Rack 4410 oscilloscope. After that signal are exhibits in picoscobe Selected profiles subsequently transferred to a personal computer system for further analysis. Before experiments, pressure transducer is calibrated regularly in a pressurized gas chamber and the amplifier output versus gas chamber pressure is plotted. An example calibration curve of pressure transducer and charge amplifier output is shown in Figure 2.. Figure 2 Calibration curved International Conference on Automotive Technologies November 13 – 14, 2008 Calibration

9 The experimental results in this investigation were obtained from four cylinders, four strokes, water cooled, fuel engines having 80.6 mm bore and 88 mm stroke with a compression ratio of 10. The fuel blends with different fractions were used which is 100/0, 90/10, 80/20 and 70/30 CH 4 /H 2 proportions by varying excessive air ratio for 2000 rpm at full load and 65% full load. The effects of most influential operating variables such as excessive air ratio on cylinder pressure, brake thermal efficiency, CO, CO 2 and HC emissions are tested. International Conference on Automotive Technologies November 13 – 14, 2008 Emission Parameters

10 Figure 3 Cylinder pressure values versus the Crank angle for different H 2 fraction at full load and 65% full load Cylinder Pressure International Conference on Automotive Technologies November 13 – 14, 2008

11 Figure 4 Cylinder pressure values versus the Crank angle for different H 2 fraction at full load and 65% full load. Cylinder Pressure International Conference on Automotive Technologies November 13 – 14, 2008

12 Figure 5 Variation of CO emissions versus EAR for different H 2 fraction at full load and 65% full load. International Conference on Automotive Technologies November 13 – 14, 2008 Emissions

13 Figure 6 Variation of CO 2 emissions versus EAR for different H 2 fraction at full load and 65% full load. International Conference on Automotive Technologies November 13 – 14, 2008 Emissions

14 Figure 7 Variation of HC emissions versus EAR for different H 2 fraction at full load and 65% full load. International Conference on Automotive Technologies November 13 – 14, 2008 Emissions

15 Figure 8 Brake thermal efficiency values versus the EAR for different H 2 fraction at full load and 65% full load. International Conference on Automotive Technologies November 13 – 14, 2008 Efficiency

16 Conclusions An experimental study on performance and emission of a spark ignition engine operating on CH4 with 0, 10%, 20%, and 30% (in volume) hydrogen enrichment was conducted. The main results are summarized as follows. The experimental measurements gave the results coherent with literature data. Increasing the EAR leads to a decrease in peak pressure values. Increasing with H 2 amount, peak pressure values are closing to TDC. HC, CO 2 and CO emissions values decrease with increasing hydrogen percentage. While at lean mixtures, CO 2 emission values are decreasing, at rich mixtures, CO 2 emission values are increasing. Increasing with EAR, CO emissions values are decreasing Brake thermal efficiency values increase, while increasing H 2 percentage. International Conference on Automotive Technologies November 13 – 14, 2008

17 Thank you. International Conference on Automotive Technologies November 13 – 14, 2008