Aerican J. o Engineering and Applied Sciences 1 (4): 338-346, 2008 ISSN 1941-7020 2008 Science Publications Nuerical Study on the Perorance Characteristics o Hydrogen Fueled Port Injection Internal Cobustion Engine Rosli A. Bakar, Mohaed K. Mohaed and M.M. Rahan Faculty o Mechanical Engineering, Autootive Excellence Center, University Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gabang, Kuantan, Pahang, Malaysia Abstract: This study was ocused on the engine perorance o single cylinder hydrogen ueled port injection internal cobustion engine. GT-Power was utilized to develop the odel or port injection engine. One diensional gas dynaics was represented the low and heat transer in the coponents o the engine odel. The governing equations were introduced irst, ollowed by the perorance paraeters and odel description. Air-uel ratio was varied ro stoichioetric liit to a lean liit and the rotational speed varied ro 2500 to 4500 rp while the injector location was considered ixed in the idway o the intake port. The eects o air uel ratio, crank angle and engine speed are presented in this study. Fro the acquired results show that the air-uel ratio and engine speed were greatly inluence on the perorance o hydrogen ueled engine. It was shown that decreases the Brake Mean Eective Pressure (BMEP) and brake theral eiciency with increases o the engine speed and air-uel ratio however the increase the Brake Speciic Fuel Consuption (BSFC) with increases the speed and air-uel ratio. The cylinder teperature increases with increases o engine speed however teperature decreases with increases o air-uel ratio. The pressure luctuations increased substantially with increases o speed at intake port however rise o pressure at the end o the exhaust stroke lead to reverse low into the cylinder past exhaust valve. The luctuation aplitude responded to the engine speed in case o exhaust pressure were given less than the intake pressure. The voluetric eiciency increased with increases o engine speed and equivalent ratio. The voluetric eiciency o the hydrogen engines with port injection is a serious proble and reduces the overall perorance o the engine. This ephasized the ability o retroitting the traditional engines with hydrogen uel with inor odiications. Key words: Hydrogen ueled engine, port injection, air uel ratio, engine speed, cranks angle, perorance characteristics INTRODUCTION In the recent days, there are two ain issues regarding the uels: availability and global cliate change. The status o the availability o the ossil uels is critical and the prices have been juped to levels that never been reached beore. Furtherore, the environental probles are serious and the politics all over the world applied severe conditions or the autootive industry. Researchers, technologists and the autoobile anuacturers are increasing their eorts in the ipleentation o technologies that ight be replaced ossil uels as a eans o ueling existing vehicles. Hydrogen, as alternative uel, has unique properties give it signiicant advantage over other types o uel. However, the widespread ipleentation o hydrogen or vehicular application is still waiting several obstacles to be solved. These obstacles are standing in the production, transpiration, storage and utilization o hydrogen. The ost iportant one is the utilization probles. Hydrogen induction techniques play a very doinant and sensitive role in deterining the perorance characteristics o the hydrogen ueled internal cobustion engine (H 2 ICE) [1]. Hydrogen uel delivery syste can be broken down into three ain types including the carbureted injection, port injection and direct injection [2]. The port injection uel delivery syste (PFI) injects hydrogen directly into the intake aniold at each intake port rather than drawing uel in at a central point. Typically, hydrogen is injected into the aniold Corresponding Author: M. M. Rahan, Autootive Excellence Center, Faculty o Mechanical Engineering, University Malaysia, Pahang, Lebuhraya Tun Razak, 26300 Gabang, Kuantan, Pahang, Malaysia 338
ater the beginning o the intake stroke. Hydrogen can be introduced in the intake aniold either by continuous or tied injection. The orer ethod produces undesirable cobustion probles, less lexible and controllable [3]. But the latter ethod, tied Port Fuel Injection (PFI) is a strong candidate and extensive studies indicated the ability o its adoption [3,4]. The calling sounds or adopting this technique are supported by a considerable set o advantages. It can be easily installed only with siple odiication [5] and its cost is low [6]. The low rate o hydrogen supplied can also be controlled conveniently [7]. External ixture oration by eans o port uel injection also has been deonstrated to result in higher engine eiciencies, extended lean operation, lower cyclic variation and lower NO x production [8,9]. This is the consequence o the higher ixture hoogeneity due to longer ixing ties or PFI. Furtherore, external ixture oration provides a greater degree o reedo concerning storage ethods. The ost serious proble with PFI is the high possibility o pre-ignition and backire, especially with rich ixtures [10-11]. However, conditions with PFI are uch less severe and the probability or abnoral cobustion is reduced because it iparts a better resistance to backire. Cobustion anoalies can be suppressed by accurate control o injection tiing and eliination o hot spots on the surace o the cobustion as suggested by [5]. Knorr et al. [12] have reported acceptable stoichioetric operation with a bus powered by liquid hydrogen. Their success was achieved by the ollowing easures: Foration o a stratiied charge by tied injection o the hydrogen into the pipes o the intake aniold with a deined pre-storage angle. At the beginning o the intake stroke a rich, non-ignitable ixture passes into the cobustion chaber Injection o hydrogen with a relatively low teperature o 0-10 C so that the cobustion chaber is cooled by the hydrogen and inally Lowering o the copression ratio to 8:1 A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 The present contribution introduces a odel or a single cylinder, port injection H2ICE. GT-Power sotware code is used to build this odel. The ain task o this odel is to investigate the perorance characteristics o this engine. The ephasis is paid or the trends with the air uel ratio and engine speed. The instantaneous behavior is also considered. MATERIALS AND METHODS One-diensional basic equations: Engine perorance can be studied by analyzing the ass and energy lows between individual engine coponents and the heat and work transers within each coponent. Siulation o one-diensional low involves the solution o the conservation equations; ass, energy and oentu in the direction o the ean low. Mass conservation is deined as the rate o change in ass within a subsyste which is equal to the su o i and e e ro the syste d dt : = (1) sub i e where, subscript i and e represent the inlet and exit respectively. In one-diensional low, the ass low rate ( ) is expressed as Eq. 2: = ρau (2) where, ρ is the density, A is the cross-sectional low area and U is the luid velocity. Energy conservation: The rate o change o energy in a subsyste is equal to the su o the energy transer o the syste. The energy conservation can be written in the ollowing ro: DE DW DQ = + (3) Dt Dt Dt E = The energy W = The work One o the ain conclusions drawn ro the Q = The heat experiental study o [10] was the possibility o Energy conservation can be expressed as Eq. 4: overcoing the proble o backire by reducing the injection duration. Sierens and Verhelst [13] DE DW exained DQ Dt Dt our dierent junctions o the port injection position Dt d(e) dv = p + (uel line) against the air low. Based on the results o i H + i H h e e ga(tgas T wall) (4) dt dt their CFD odel, the junction that gives the highest power output (Y-junction) was dierent ro the junction that gives the highest eiciency (45 junction). e = The internal energy Finally a coproise was suggested. H = The total enthalpy 339
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 h g = The heat transer coeicient T gas and T wall = The teperatures o the gas and wall respectively The heat transer ro the internal luids to the pipe wall is dependent on the heat transer coeicient, the predicted luid teperature and the internal wall teperature. The heat transer coeicient is calculated every tie step, which is a unction o luid velocity, thero-physical properties and the wall surace roughness. The internal wall teperature is given here as input data. Thereore, h g can be expressed as: 2 1 3 hg = Cρ UeCp Pr (5) 2 C = The riction coeicient U e = The eective speed outside boundary layer C P = The speciic heat Pr = The Prandtle nuber The riction coeicient is related to Renolds nuber which is expressed as Eq. 6: R ρu L v c c e = (6) In case that the wall surace is rough and the low is not lainar, the value o the riction coeicient then is given by Nikuradse s orula: C (rough) D = The pipe diaeter h = The roughness height 0.25 = 1D (2log 10( ) + 1.74) 2h 2 (10) Moentu conservation: the net pressure orces and wall shear orces acting on a sub syste are equal to the rate o change o oentu in the syste: ρu2 dxa 1 2 D 2 = dt dx 2 dpa + i i u + i eu 4C Cp ρu A (11) u = Fluid velocity D = The equivalence diaeter C pl = The pressure loss coeicient Dx = The eleent length. In order to obtain the correct pressure loss coeicient, an epirical correlation is used to account or pipe curvature and surace roughness, which is expressed as Eq. 12: ρ = The density U c = The characteristic speed L c = The characteristic length and v is the dynaic viscosity by: The riction coeicient or sooth walls is given 16 C =, where ReD < 2000 (7) Re D 0.08 C =, where ReD > 4000 (8) Re 0.25 D 1 2 pi 2 0.5ρu1 The Prandtle nuber is expressed as Eq. 9: This equation can be extended or the present our stroke engine to: η C p µ Pr = = (9) λ a 2pb BMEP = NVd (14) λ = The heat conduction coeicient µ = The kineatic viscosity and a is the theral P b = The brake power diusivity N = The rotational speed 340 C p 1 = The inlet pressure p 2 = The outlet pressure u 1 = The inlet velocity p = p (12) Engine perorance paraeters: The brake ean eective pressure (BMEP) can be deined as the ratio o the brake work per cycle W b to the cylinder volue displaced per cycle V d and expressed as: BMEP W V b = (13) d
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 Fig. 1: Model o single cylinder, our stroke, port injection hydrogen ueled engine Brake eiciency ( η b ) can be deined as the ratio o the brake power P b to the engine uel energy as: η = b b ( LHV) (15) = The uel ass low rate LHV = The lower heating value o hydrogen P The Brake Speciic Fuel Consuption (BSFC) represents the uel low rate per unit brake power output P b and can be expressed as Eq. 16 [14] : BSFC P = (16) The voluetric eiciency ( η v ) o the engine deines the ass o air supplied through the intake valve during the intake period, a, by coparison with a reerence ass, which is that ass required to perectly ill the swept volue under the prevailing atospheric conditions and can be expressed as Eq. 17: b Table 1: Hydrogen ueled engine paraeters Engine paraeter (Unit) Measure Bore () 100.000 Stroke () 100.000 Connecting rod length () 220.000 Piston pin oset () 1.000 Displaceent (liter) 0.785 Copression ratio 9.500 Inlet valve close IVC (CA) -96.000 Exhaust valve open EVO (CA) 125.000 Inlet valve open IVO (CA) 351.000 Exhaust valve close EVC (CA) 398.000 paraeters are used to ake the odel which is shown in Table 1. It is iportant to indicate that the intake and exhaust ports o the engine cylinder are odeled geoetrically with pipes. Several considerations were ade the odel ore realistic. Firstly, an attribute heat transer ultiplier is used to account or bends, roughness and additional surace area and turbulence caused by the valve and ste. Also, the pressure losses in these ports are included in the discharge coeicients calculated or the valves. The in-cylinder heat transer is calculated by a orula which closely eulates the classical Woschni correlation. Based on this correlation, the heat transer coeicient (h c ) can be expresses as Eq. 18 [15] : h 3.26B p T w 0.2 0.8 0.55 0.8 c = (18) a η v = ρ V where, ρ ai is the inlet air density. ai d (17) B = The bore in eters p = The pressure in kpa T = Teperature in K w = The average cylinder gas velocity in sec 1 Engine odel: A single cylinder, our stroke, port injection hydrogen ueled engine was odeled utilizing The cobustion burn rate (X b ) using Wiebe the GT-Power sotware. The injection o hydrogen was unction, can be expressed as Eq. 19 [16] : located in the idway o the intake port. The odel o n+ 1 the hydrogen ueled single cylinder our stroke port θ θi Xb = 1 exp[ a ] (19) inject engine is shown in Fig. 1. The speciic engine θ 341
θ = The crank angle θ i = The start o cobustion θ = Cobustion period a and n = Adjustable paraeters RESULTS AND DISCUSSION This search is categorized into three subsections. The irst part represents the eects o BMEP, BSFC, Brake eiciency and axiu cylinder teperature with the Air-Fuel Ratio (AFR). The second part deonstrates the instantaneous results i.e. variations o intake, exhaust port and cylinder pressure against the crank angle. The third part presents the eects o engine speed (RPM) on engine perorance. It is worthy to ention that one o the ost attractive cobustive eatures or hydrogen uel is its wide range o laability. A lean ixture is one in which the aount o uel is less than stoichioetric ixture. This leads to airly easy to get an engine start. Furtherore, the cobustion reaction will be ore coplete. Additionally, the inal cobustion teperature is lower reducing the aount o pollutants. Figure 2 shows the eect o air-uel ration on the brake ean eective pressure. The air-uel ratio AFR was varied ro stoichioetric liit (AFR = 34.33:1 based on ass where the equivalence ratio φ = 1) to a very lean liit (AFR =171.65 based on φ = 0.2) and engine speed varied ro 2500-4500 rp. BMEP is a good paraeter or coparing engines with regard to design due to its independent on the engine size and speed. I torque used or engine coparison, a large engine was always see to be better when considering the torque, however, speeds becoe very iportant when considered the power [17]. It can be seen that the decreases o the BMEP with increases o AFR and speed. It is obvious that the BMEP alls with a nonlinear behavior ro the richest condition where AFR is 34.33 to the leanest condition where the AFR is 171.65. The dierences o BMEP are increases with the increases o speed and AFR. The dierences o the BMEP are decreases 6.682 bar at speed o 4500 rp while 6.12 bar at speed 2500 rp or the sae range o AFR. This iplied that at lean operating conditions, the engine gives the axiu power (BMEP = 1.275 bar) at lower speed 2500 rp) copared with the power (BMEP = 0.18 bar) at speed 4500 rp. Due to dissociation at high teperatures ollowing cobustion, olecular oxygen is present in the burned gases under stoichioetric conditions. Thus soe additional uel can be added and partially burned. This increases the teperature and the nuber o oles o the burned gases in the cylinder. These eects increases the pressure were given increase power and ean eective pressure [15]. A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 Fig. 2: Variation o brake ean eective pressure with air uel ratio or various engine speeds Fig. 3: Variation o brake theral eiciency with air uel ratio Figure 3 shows the variation o the brake theral eiciency with the air uel ratio or the selected speeds. It is seen that the brake power (useul part) as a percentage ro the intake uel energy. The uel energy are also covered the riction losses and heat losses (heat loss to surroundings, exhaust enthalpy and coolant load). Thereore lower values o ηb can be seen in the Fig. 3. It can be observed that the brake theral eiciency is increases nearby the richest condition (AFR 35) and then decreases with increases o AFR and speed. The operation within a range o AFR ro 49.0428-42.91250 (φ = 0.7-0.8) give the axiu values or ηb or all speeds. Maxiu ηb o 31.8% at speed 2500 rp can be seen copared with 26.8% at speed 4500 rp. Unaccepted eiciency ηb o 2.88% can be seen at very lean conditions with AFR o 171.65 (φ = 0.2) or speed o 4500 rp while the eiciency was observed 20.7% at the sae conditions 342
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 with speed o 2500 rp. Clearly, rotational speed has a ajor eect in the behavior o ηb with AFR. Higher speeds lead to higher riction losses. Figure 4 show the behavior o the brake speciic uel consuption BSFC with AFR. The AFR or optiu uel consuption at a given load depends on the details o chaber design (including copression ratio) and ixture preparation quality. It varies or a given chaber with the part o throttle load and speed range [15]. It is clearly seen ro Fig. 4 that the higher uel is consued at higher speeds and AFR due to the greater riction losses that can occur at high speeds. It is easy to perceive ro Fig. 4 that the increases o BSFC with decreases in the rotational speed and increases the value o AFR. However, the required iniu BSFC were occurred within a range o AFR ro 38.144 (φ = 0.9)-49.0428 (φ = 0.7) or the selected range o speed. At very lean conditions, higher uel consuption can be noticed. Ater AFR o 114.433 (φ = 0.3) the BSFC goes up rapidly, especially or high speed. At very lean conditions with AFR o 171.65 (φ = 0.2), a BSFC o 144.563 g kw-h 1 was observed or the speed o 2500 rp while 1038.85 g kw-h 1 or speed o 4500 rp. The value BSFC at speed 2500 rp was observed around 2 ties at speed 4000 rp however around 7 ties at speed 4500 rp. This is because o very lean operation conditions can lead to unstable cobustion and ore lost power due to a reduction in the voluetric heating value o the air/hydrogen ixture. This behavior can be ore clariied by reerring to Fig. 3, where the brake eiciency reduced considerably at very lean operation conditions. Figure 5 shows how the AFR can aect the axiu teperature inside the cylinder. In general, lower teperatures are required due to the reduction o pollutants. It is clearly deonstrated how the increase in the AFR can decrease the axiu cylinder teperature with a severe steeped curve. The eect o the engine speed on the relationship between axiu cylinder teperatures with AFR sees to be inor. At stoichioetric operating conditions (AFR = 34.33), a axiu cylinder teperature o 2752.83 K was recorded. This teperature dropped down to 1350 K at AFR o 171.65 (φ = 0.2). This lower teperature inhibits the oration o NO x pollutants. In act this eature is one o the ajor otivations toward hydrogen uel. The intake port and exhaust port pressures distributions in ters o crank angle are shown in Figure 6 and 7 respectively. The instantaneous behavior is at the 150th cycle or Wide Open Throttle (WOT) Fig. 5: Variation o axiu cylinder teperature with air uel ratio Fig. 4: Variation o brake speciic uel consuption with air uel ratio or dierent engine speed 343 Fig. 6: Instantaneous intake port pressure distributions with crank angle or dierent speed
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 Fig. 7: Instantaneous exhaust port pressure distributions with crank angle or various engine speeds Fig. 8: Instantaneous cylinder pressure distributions with crank angle or various engine speed and stoichioetric operation. Figure 6 and 7 are very iportant to investigate the backire or pre-ignition occurrence in details. However, or the present case there is neither backire nor pre-ignition and this is the case o noral cobustion and shows typical results o pressure variation. The crank angle axis is divided into our parts to indicate the our strokes which take two cycles (720 ). The pressure sees to be like a series o pulses. Each pulse is approxiately sinusoidal in shape due to the single cylinder engine. The coplexity o the phenoena that occur is apparent. The aplitude o the pressure luctuations increases substantially with increasing engine speed. Fro Fig. 6, the axiu intake pressure was recorded 1.1144 bar at speed 4500 rp during the copression stroke while 1.00846 bar at speed o 2500 rp. At the suction stroke, when high intake vacuu is occurred, the curve is continuously inward and low pulsation is sall. For high speed, larger pulses can be seen. At high speeds ore uel is required and consequently ore vacuu in the intake port. A vacuu o 0.8681 bar was calculated in 4500 rp copared with 0.9897 bar at 2500 rp. The gas dynaic eects play a very iportant rule here. It distorts the exhaust low which is shown in Fig. 7. The rise o the pressure at the end o the exhaust stroke can lead to reverse low into the cylinder past the exhaust valve, however, the high vacuu in the beginning o the irst stroke is highly desired to banish the burnt gases out o the cylinder. At speed o 3000 rp, a axiu pressure o 1.213 bar and axiu vacuu o 0.639 bar were recorded. The response o luctuation o the aplitude to the engine speed in case o exhaust pressure sees to be less than the intake pressure. 344 Figure 8 shows the behavior o the cylinder pressure at the last cycle (150th cycle) or WOT and stoichioetric operation conditions. The behavior o the pressure ollows the cobustion phenoenon that occurs. The eect o the rotational speed on the instantaneous behavior o the cylinder pressure is inor. This curve can be divided into three parts or discussion purpose. The irst part corresponds the lae developent period which consues about 5% o the air uel ixture. Very little pressure rise is noticeable and little or no useul work is produced. The second part corresponds the lae propagation period which consues about 90% o the ixture. During this tie, pressure in the cylinder is greatly increased, providing the orce to produce work in the expansion stroke. The axiu values are 51.6 bar at speed o 4500 rp and 47.728 bar at speed o 2500 rp. These values are less than that o traditional gasoline uel about 70 bar with approxiately siilar conditions. The third part corresponds to lae terination period which consues about the rest o the ixture (5%). In general this behavior is like the behavior o the traditional gasoline uel, however, it is necessary to keep in ind that during the hydrogen cobustion, the lae velocity is rapid and the ain changes o cylinder pressure (the second part) occur in a shorter tie. Figure 9 shows the variation o the voluetric eiciency with the engine speed. In general, it is desirable to have axiu voluetric eiciency or engine. The iportance o voluetric eiciency is ore critical or hydrogen engines because o the hydrogen uel displaces large aount o the incoing air due to its low density (0.0824 kg 3 at 25 C and 1 at.). This reduces the voluetric eiciency to high extent.
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 Fig. 9: Eect o voluetric eiciency with the rotational speed or dierent equivalence ratio For exaple, a stoichioetric ixture o hydrogen and air consists o approxiately 30% hydrogen by volue, whereas a stoichioetric ixture o ully vaporized gasoline and air consists o approxiately 2% gasoline by volue [18]. Thereore, the low voluetric eiciency or hydrogen engine is expected copared with gasoline engine works with the sae operating conditions and physical diension. This lower voluetric eiciency is apparent in Fig. 9. Leaner ixture gives the higher voluetric eiciency. The axiu voluetric eiciency was observed 79.4% at lean conditions with AFR = 171.65 (φ = 0.2) while 62.4% at stoichioetric conditions. Higher speeds lead to higher voluetric eiciency because o the higher speeds give higher vacuu at the intake port and consequent larger air low rate that goes inside the cylinder. Further increase in engine speed leads toward the axiu value o ηv For the considered speeds and with equivalence ratios o 1, 0.8 and 0.6, the axiu η v was recorded at 4200 rp. For equivalence ratio o 0.4 and 0.2, the axiu η v was recorded at 3800 rp. At urther higher engine speeds beyond these values, the low into the engine during at least part o the intake process becoes chocked. Once this occurs, urther increase in speed do not increase the low rate signiicantly so voluetric eiciency decreases sharply. This sharp decrease happens because o higher speed is accopanied by soe phenoenon that have negative inluence on η v. These phenoenon include the charge heating in the aniold and higher riction low losses which increase as the square o engine speed. In act a lot o solutions were suggested to solve this proble. Furuhaa and Fukua [19] and Lynch [20] suggested and carried out tests with pressure boosting systes or hydrogen engines. White et al. [18] suggest direct injection (incylinder) or hydrogen. 345 Fig. 10: Variation o cobustion duration with engine speed or dierent equivalence ratio Figure 10 shows the cobustion duration as a unction o the engine speed or dierent equivalence ratio. As stated earlier, hydrogen cobustion velocity (1.85 sec 1 ) is rapid copared with that o gasoline (0.37-0.43 sec 1 ). Thereore short cobustion duration is expected. It is well established that the duration o cobustion in crank angle degrees only increases slowly with increasing speed or gasoline and diesel engines [15]. Figure 10 shows that this act is also true or hydrogen engines. The luctuation shown is very sall, however, it was enlarged in Fig. 10 with a very high scale. All the changes take place within a range o 0.0248. This is too sall value, especially i one knows that at 4500 rp, the crank shat rotates 27000 within 1 sec. CONCLUSION The present study considered the perorance characteristics o single cylinder hydrogen ueled internal cobustion engine with hydrogen being injected in the intake port. The ephasis was paid to the eects o engine speed, AFR. The instantaneous behavior was also studied. The ollowing conclusions are drawn: At very lean conditions with low engine speeds, acceptable BMEP can be reached, while it is unacceptable or higher speeds. Lean operation leads to sall values o BMEP copared with rich conditions Maxiu brake theral eiciency can be reached at ixture coposition in the range o (φ = 0.7-0.8) and it decreases draatically at leaner conditions The desired iniu BSFC occurs within a ixture coposition range o (φ = 0.7-0.9). The operation with very lean condition (φ<0.2) and high engine speeds (>4500) consues unacceptable aounts o uel Lean operation conditions results in lower axiu cylinder teperature. A reduction o
A. J. Engg. & Applied Sci., 1 (4): 338-346, 2008 around 1400 K can be gained i the engine works properly at (φ = 0.2) instead o stoichioetric operation Hydrogen cobustion results in oderate pressures in the cylinder. This reduces the copactness required in the construction o the engine. But, i abnoral cobustion like preignition or backire happens, higher pressures ay destroy the connecting rod and piston rings. Thereore, uch care should be paid or this point The low values o voluetric eiciency see a serious challenge or the hydrogen engine and urther studied are required In general, the behavior o the ost studied paraeters is siilar to that o gasoline engine. This gives a great chance to retroit gasoline engines with hydrogen uel with inor odiications. Further uture experiental work will be done to ephasize this siulation and get ore details. ACKNOWLEDGEMENT The researchers would like to express their deep gratitude to University Malaysia Pahang (UMP) or provided the laboratory acilities and inancial support. REFERENCES 1. Suwanchotchoung, N., 2003. Perorance o a spark ignition dual-ueled engine using splitinjection tiing. Ph.D. Thesis, Vanderbilt University, Mechanical Engineering. 2. Das, L.M., 1990. Fuel induction techniques or a hydrogen operated engine. Int. J. Hydro. Energ., 15: 833-842. DOI: 10.1016/0360-3199(90)90020-Y 3. Das, L., R. Gulati and P. Gupta, 2000. A coparative evaluation o the perorance characteristics o a spark ignition engine using hydrogen and copressed natural gas as alternative uels. Int. J. Hydro. Energ., 25: 783-793. DOI: 10.1016/S0360-3199(99)00103-2 4. Das, L., 2002. Hydrogen engine: Research and developent progras in Indian Institute o Technology (IIT), Delhi. Int. J. Hydro. Energ., 27: 953-965. DOI: 10.1016/S0360-3199(01)00178-1 5. Lee, S.J., H.S. Yi and E.S. Ki, 1995. Cobustion characteristics o intake port injection type hydrogen ueled engine. Int. J. Hydro. Energ., 20: 317-322. DOI: 10.1016/0360-3199(94)00052-2 6. Li, H. and G.A. Kari, 2006. Hydrogen ueled spark-ignition engines predictive and experiental perorance. J. Eng. Gas Turbines Power, ASME., 128: 230-236. DOI: 10.1115/1.2055987 7. Sierens, R. and S. Verhelst, 2001. Experiental study o a hydrogen-ueled engine. J. Eng. Gas Turbines Power, ASME, 123: 211-216. DOI: 10.1115/1.1339989 8. Yi, H.S., K. Min and E.S. Ki, 2000. The optiized ixture oration or hydrogen uelled. Int. J. Hydro. Energ., 25: 685-690. DOI: 10.1016/S0360-3199(99)00082-8 9. Ki, Y.Y., J.T. Lee and J.A. Caton, 2006. The developent o a dual-injection hydrogen-ueled engine with high power and high eiciency. J. Eng. Gas Turbines Power, ASME., 128: 203-212. DOI: 10.1115/1.1805551 10. Ganesh, R.H., V. Subraanian, V. Balasubraanian, J.M. Mallikarjuna, A. Raesh and R.P. Shara, 2008. Hydrogen ueled spark ignition engine with electronically controlled aniold injection: An experiental study. Ren. Energ., 33: 1324-1333. DOI: 10.1016/j.renene.2007.07.003 11. Kabat, D.M. and J.W. Heel, 2002. Durability iplications o neat hydrogen under sonic low conditions on pulse-width odulated injectors. Int. J. Hydro. Energ., 27: 1093-1102. DOI: 10.1016/S0360-3199(02)00007-1 12. Knorr, H., W. Held, W. Prü and H. Rüdiger, 1997. The an hydrogen propulsion syste or city buses. Int. J. Hydro. Energ., 23: 201-208. DOI: 10.1016/S0360-3199(97)00045-1 13. Sierens, R. and S. Verhelst, 2003. Inluence o the injection paraeters on the eiciency and power output o a hydrogen ueled engine. J. Eng. Gas Turbines Power, ASME., 125: 444-449. DOI: 10.1115/1.1496777 14. Blair, G.P., 1999. Design and Siulation o our Stroke Engines. 1st Edn., SAE International Society o Autootive Engineers Inc., Warrandale, Pa., USA., ISBN: 978-0-7680-0440-3, pp: 840. 15. Heywood, J.B., 1988. Internal Cobustion Engine Fundaentals. 1st Edn., McGraw-Hill, London, ISBN-10: 007028637X, pp: 930. 16. Ferguson, C.R. and A.T. Kirkpatrick, 2001. International Cobustion Engines: Applied Therosciences. 2nd Edn., John Wiley and Sons, Inc., New York, ISBN: 10: 0471356174, pp: 384. 17. Pulkrabek, W.W., 2003. Engineering Fundaentals o the Internal Cobustion Engines. 2nd Edn., Prentic Hall, New York, USA., ISBN: 10: 0131405705. 18. White, C.M., R.R. Steeper and A.E. Lutz, 2006. The hydrogen-ueled internal cobustion engine: A technical review. Int. J. Hydro. Energ., 31: 1292-1305. DOI: 10.1016/j.ijhydene. 2005.12.001 19. Furuhaa, S. and T. Fukua, 1986. High output power hydrogen engine with high pressure uel injection, hot surace ignition and turbocharging. Int. J. Hydro. Energ., 11: 399-407. DOI: 10.1016/0360-3199(86)90029-7 20. Lynch, F.E., 1983. Parallel induction: A siple uel control ethod or hydrogen engines. Int. J. Hydro. Energ., 8: 721-730. DOI:10.1016/0360-3199(83)90182-9 346