hydrogen fueled Internal combustion engines

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

Content 1. Abstract 2. Introduction 3. Problems with fossil fuels. 4. Why Hydrogen? 5. Combustive properties of Hydrogen. 6. Hydrogen combustion. 7. Hydrogen fuelled Diesel & SI engine. 8. Problems & Solution. 9. Engine design & modification. 10.Performance & emission characteristics.

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

Hydrogen fuelled internal combustion engines. Abstract: Increased population enhancing the demand of energy. Traditional fossil fuels are not able to satisfy so much longer. Depletion of fossil fuels and pollution from it are two main concerns in using it. Now there is need of alternative which will minimize our dependency on traditional fuels, maximize efficiency and satisfies stringent norms in the field of pollution & emission control. By resolving some safety issues and storage issues Hydrogen is best the solution for replacement of fossil fuels. Here we are going to discuss combustive properties of Hydrogen, direct use of Hydrogen in Internal Combustion Engines (ICE), problems & solutions in using Hydrogen in ICE. Keywords: Alternative energy, Hydrogen energy, Internal Combustion engines. Introduction: In the field of transportation, the fossil fuels playing vital role. Diesel and petrol are two main fuels in the world of automobiles. But the fact is these fuels are not going run longer. The power consumption is increasing exponentially at higher rate with the population while the availability of fossil goes on decreasing. There is imbalance. Along with this concern one more concern with the fossil fuel is pollution. These fuels introduce global warming and create various environmental issues. Figure no. 1 below shows the consumption of various fuels such as petroleum, coal, natural gases, hydraulic power, nuclear power, wood and alternative fuels. It creates a worry about gap between demand and supply of fuels as well as rays of light from alternative fuels. Also Figure no. 1 shows the trend towards reducing % C which creates lot of environmental issues. But there is no option till the perfect alternative is got introduced. Thus immense research is going on in the field alternatives fuels to reduce our dependency over the traditional fuels.

Figure No. 1: Consumption of various fuels in US Thorough out the world researchers are working alternative fuels to qualify energy demands and deletion of problems with traditional fuels and environmental issues. Some of the alternative sources of energy are solar energy, wind energy, tidal energy and Hydrogen energy. All these are also known as non-conventional energy sources. Out of these we are GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

going concentrate on Hydrogen energy. The Hydrogen energy is the energy generated from direct or indirect utilization of Hydrogen. There are two main options with the Hydrogen. One is fuel cell and another is direct combustion. In fuel cells reverse electrolysis process is carried out with Hydrogen and oxygen to generate electrical power like batteries. The other way to utilize Hydrogen in internal combustion engines to generate power. This option is still away due to some myths regarding Hindenburg disaster of 1937, vividly haunting images of the 1986 Challenger Space Shuttle explosion or the detonation of a Hydrogen bomb. But I assure you Hydrogen is future if handled safely by resolving some technical issues related with production, storage systems of Hydrogen. Hydrogen, first on the periodic table of the elements, is the least complex and most abundant element in the universe. Using Hydrogen as fuel can fundamentally change our relationship with the natural environment. As a nearly ideal energy carrier, Hydrogen will play a critical role in a new, decentralized energy infrastructure that can provide power to vehicles, homes, and industries. Hydrogen boasts many important advantages over other fuels: it is non-toxic, renewable, clean to use, favourable combustive properties and packs much more energy per pound. Hydrogen is also the fuel of choice for energy-efficient fuel cell and internal combustion engines. Hydrogen has a wide flammability range in comparison with all other fuels. As a result, Hydrogen can be combusted in an internal combustion (IC) engine over a wide range of fuel-air mixtures. Hydrogen has very low ignition energy. A significant advantage of this is that Hydrogen can run on a lean mixture and ensures prompt ignition. Generally, fuel economy is greater and the combustion reaction is more complete when an IC engine runs on a lean mixture. Let’s see the utilization of Hydrogen in internal combustion engines, its favourable properties overcoming over the unfavourable properties, problems due to unfavourable properties and resolving of problems and finally successful Hydrogen fuelled internal combustion engines with improved efficiency with clean steam as an exhaust. Review of experimental sets carried out to check efficiency and emission control with successful results. Problems with fossil fuel: 1. Fuel depletion

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GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

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NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

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Why Hydrogen?     

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Hydrogen, which exists as a gas under normal atmospheric conditions, is odourless, colourless, and tasteless. It is both non-toxic and safe to breathe. It is available abundantly from hydrocarbon, ammonia, water. Exhaust is emission free due to absence of carbon. Whenever fossil fuel spill out creates water pollution or earth pollution. In case of Hydrogen, it flies away as lightest element on the earth without creating any type of pollution. Trend of the fuels used by world till now is reduction in % C and enhancement in % H in fuel. It tends towards 100% H is ideal fuel. It can also be safely transported.

Combustive properties of Hydrogen: The properties of Hydrogen which contribute to its use as a combustible fuel are its: 1. 2. 3. 4. 5. 6. 7.

Wide range of flammability. Low ignition energy. Small quenching distance. High auto-ignition temperature. High flame speed at stoichiometric ratios. High diffusivity. Very low density.

1. Wide Range of Flammability Hydrogen has a wide flammability range in comparison with all other fuels. As a result, Hydrogen can be combusted in an internal combustion engine over a wide range of fuel-air mixtures. A significant advantage of this is that Hydrogen can run on a lean mixture. A lean mixture is one in which the amount of fuel is less than the theoretical, stoichiometric or chemically ideal amount needed for combustion with a given amount of air. This is why it is fairly easy to get an engine to start on Hydrogen. GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

Generally, fuel economy is greater and the combustion reaction is more complete when a vehicle is run on a lean mixture. Additionally, the final combustion temperature is generally lower, reducing the amount of pollutants, such as nitrogen oxides, emitted in the exhaust. There is a limit to how lean the engine can be run, as lean operation can significantly reduce the power output due to a reduction in the volumetric heating value of the air/fuel mixture. [2] 2. Low Ignition Energy Hydrogen has very low ignition energy. The amount of energy needed to ignite Hydrogen is about one order of magnitude less than that required for gasoline. This enables Hydrogen engines to ignite lean mixtures and ensures prompt ignition. Unfortunately, the low ignition energy means that hot gases and hot spots on the cylinder can serve as sources of ignition, creating problems of premature ignition and flashback. Preventing this is one of the challenges associated with running an engine on Hydrogen. The wide flammability range of Hydrogen means that almost any mixture can be ignited by a hot spot. [3, 7]

Figure 2. Low Ignitron energy of Hydrogen in air [3] Figure 2 above for a Hydrogen and air mix is about an order of magnitude lower than that of a petrol-air mix 0.02 mJ as compared to 0.24 mJ for petrol - and is approximately constant over the range of flammability.[3] 3. Small Quenching Distance Hydrogen has a small quenching distance, smaller than gasoline. Consequently, Hydrogen flames travel closer to the cylinder wall than other fuels before they extinguish. Thus, it is more difficult to quench a Hydrogen flame than a gasoline flame. The smaller quenching distance can also increase the tendency for backfire since the flame from a Hydrogen-air mixture more readily passes a nearly closed intake valve, than a hydrocarbonair flame. [2, 7] 4. High Auto ignition Temperature Hydrogen has a relatively high auto ignition temperature. This has important implications when a Hydrogen-air mixture is compressed. In fact, the auto ignition temperature is an important factor in determining what compression ratio an engine can use,

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

since the temperature rise during compression is related to the compression ratio. The temperature rise is shown by the equation: ( ) Where, V1/V2 = the compression ratio, γ = ratio of specific heats, T1 = absolute initial temperature, T2 = absolute final temperature. The temperature may not exceed Hydrogen’s auto ignition temperature without causing premature ignition. Thus, the absolute final temperature limits the compression ratio. The high auto-ignition temperature of Hydrogen allows larger compression ratios to be used in a Hydrogen engine than in a hydrocarbon engine. [6] This higher compression ratio is important because it is related to the thermal efficiency of the system as presented in Section 3.7. On the other hand, Hydrogen is difficult to ignite in a compression ignition or diesel configuration, because the temperatures needed for those types of ignition are relatively high. 5. High Flame Speed Hydrogen has high flame speed at stoichiometric ratios. Under these conditions, the Hydrogen flame speed is nearly an order of magnitude higher (faster) than that of gasoline. This means that Hydrogen engines can more closely approach the thermodynamically ideal engine cycle. At leaner mixtures, however, the flame velocity decreases significantly. [2, 5] 6. High Diffusivity Hydrogen has very high diffusivity. This ability to disperse in air is considerably greater than gasoline and is advantageous for two main reasons. Firstly, it facilitates the formation of a uniform mixture of fuel and air. Secondly, if a Hydrogen leak develops, the Hydrogen disperses rapidly. Thus, unsafe conditions can either be avoided or minimized. [5] 7. Low Density Hydrogen has very low density. This results in two problems when used in an internal combustion engine. Firstly, a very large volume is necessary to store enough Hydrogen to give a vehicle an adequate driving range. Secondly, the energy density of a Hydrogen-air mixture, and hence the power output, is reduced. [2]

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

Table 1: Comparison between various fuels on the basis of combustive properties. [6]

Table 1 shows the heat values of Hydrogen are higher means compact high specific energy. Highest auto ignition temperature of Hydrogen provides ability to stand with higher compression ratio engines. Higher the compression ratio higher the efficiency. Lowest ignition energy provides the ability to work with wide range of A/F ratio. That means engine can run on lean mixture to rich mixture which increases economy of the engine. The combustion range is same parameter to measure working of engines with lower to higher A/F ratio. Low ignition energy means source of pre-ignition and low density means heavy volume storage needed. These are some technical issues need to be resolved and immense research area. But they are resolved up to the mark till date. Here it is the win of favourable properties over unfavourable properties. All these parameters discussed say “Yes, Hydrogen is Future of fuels.” Hydrogen combustion: Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives off heat. The original substance is called the fuel, and the source of oxygen is called the oxidizer [9]. In Hydrogen combustion, when Hydrogen is combusted with oxygen it gives only water steam as an exhaust. It burns Hydrogen completely. Absence of carbon tends to clean, non-toxic pollutant [10]. The exhaust will be free from carbon di oxide and carbon mono oxide. The rapid combustion of Hydrogen generates a very high thermal and pressure energy which is further converted into mechanical energy. The chemical reaction takes place is 2H2 + O2 = 2H2O The combustion of Hydrogen is quite different than combustion of hydrocarbon. The first significant difference is absence of carbon. The burning velocity is very high thus very rapid combustion process is achieved. The flammability is achieved with equivalence ratio with the limits 0.1 to 7.1 which assures running of engine at lean mixture [11]. The minimum GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

energy required for ignition of Hydrogen–air mixture is 0.02 mJ only. This enables Hydrogen engine to run well on lean mixtures and ensures prompt ignition. The density of Hydrogen is 0.0838 kg/m3, which is lighter than air that it can disperse into the atmosphere easily. Hydrogen has the highest energy to weight ratio of all fuels. The flame speed of Hydrogen is 270 cm/s that may cause a very high rate of cylinder pressure rise. The diffusivity ofHydrogen is 0.63 cm2/s. As the Hydrogen self-ignition temperature is 858 K, compared to diesel of 453 K, it allows a larger compression ratio to be used for Hydrogen in internal combustion engine [9]. But it is not possible to achieve ignition of Hydrogen by compression alone. Some sources of ignition have to be created inside the combustion chamber to ensure ignition [10]. Air/Fuel Ratio and percentage volume occupied by Hydrogen in Hydrogen combustion: The theoretical or stoichiometric combustion of Hydrogen and oxygen is given as: 2H2 + O2 = 2H2O Moles of H2 for complete combustion = 2 moles Moles of O2 for complete combustion = 1 mole Because air is used as the oxidizer instead oxygen, the nitrogen in the air needs to be included in the calculation:

Number of moles of air = Moles of O2 + moles of N2 = 1 + 3.762 = 4.762 moles of air.

Weight of air = weight of O2 + weight of N2 = 32g + 105.33 g = 137.33 g Weight of H2 = 2 moles of H2 x 2 g/mole = 4 g Stoichiometric air/fuel (A/F) ratio for Hydrogen and air is: A/F based on mass

= = = 34.33:1

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

A/F based on volume: = =

= 2.4:1

The percent of the combustion chamber occupied by Hydrogen for a stoichiometric mixture:

As these calculations show, the stoichiometric or chemically correct A/F ratio for the complete combustion of Hydrogen in air is about 34:1 by mass. This means that for complete combustion, 34 pounds of air are required for every pound of Hydrogen. This is much higher than the 14.7:1 A/F ratio required for gasoline. Since Hydrogen is a gaseous fuel at ambient conditions it displaces more of the combustion chamber than a liquid fuel. Consequently less of the combustion chamber can be occupied by air. At stoichiometric conditions, Hydrogen displaces about 30% of the combustion chamber, compared to about 1 to 2% for gasoline. Figure 3 compares combustion chamber volumes and energy content for gasoline and Hydrogen fuelled engines. Because of Hydrogen’s wide range of flammability, Hydrogen engines can run on A/F ratios of anywhere from 34:1 (stoichiometric) to 180:1. The A/F ratio can also be expressed in terms of equivalence ratio, denoted by phi (Φ). Phi is equal to the stoichiometric A/F ratio divided by the actual A/F ratio. For a stoichiometric mixture, the actual A/F ratio is equal to the stoichiometric A/F ratio and thus the phi equals unity (one). For lean A/F ratios, phi will be a value less than one. For example, a phi of 0.5 means that there is only enough fuel available in the mixture to oxidize with half of the air available. Another way of saying this is that there is twice as much air available for combustion than is theoretically required.

Figure 3- Combustion Chamber Volumetric and Energy Comparison for Gasoline and Hydrogen Fuelled Engines.[14] GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

Hydrogen fuelled Diesel Engine: Hydrogen have immense specific value and zero carbon percentage, it is fuel of choice. But it has high auto-ignition temperature. It indicates very high pressure ratio is required to achieve this temperature which cannot be sustained by materials in practice. Thus Hydrogen cannot be utilized in diesel IC engines solely. So to utilize Hydrogen in diesel IC engine, it will be accompanied by diesel. The diesel will get ignited first and tends to burning of Hydrogen. It is recommended to use spark plug in diesel IC engine for igniting fuel mixture. It is done to take some advantages, first is rise in % H in mixture and second is injection of Hydrogen in diesel decrease the heterogeneity of diesel and Hydrogen diffuses with diesel and air to achieve better pre mixture. Once pre mixture got ignited initially, the diesel acts as source for ignition only and rest of the power generation is generated by the Hydrogen.[13] However trace amount of residues will be observed due to partial burning of lubricating oils. Once engine ignited, it can run over the wide range of mixtures. The engine can run on very lean mixture which improves efficiency as well as less NOx as operates at lower temperature. This lowers the fuel consumption also. But using of Hydrogen in IC engine creates pre-ignition due to low ignition energy. Along with this, storage is also one more problem. But the researchers are working on it and resolved the problems up to the mark.[14] Hydrogen fuelled SI Engine: Hydrogen can be used as a fuel directly in an internal combustion engine, almost similar to a spark-ignited (SI) gasoline engine.. Most of the past research on Hydrogen as a fuel focused on its application in SI engines. Hydrogen is an excellent candidate for use in SI engines as a fuel having some unique and highly desirable properties, such as low ignition energy, and very fast flame propagation speed, wide operational range. The Hydrogen fuel when mixed with air produces a combustible mixture which can be burned in a conventional spark ignition engine at an equivalence ratio below the lean mixture. Flammability limit of a gasoline/air mixture. The resulting ultra-lean combustion produces low flame temperatures and leads directly to lower heat transfer to the walls, higher engine efficiency and lower exhaust of NOx emission [16-6-12]. Problems and solutions: Let’s discuss the problems faced while using Hydrogen in IC engines and suggested solutions by researchers Preignition: The primary problem that has been encountered in the development of operational Hydrogen engines is premature ignition. Premature ignition is a much greater problem in Hydrogen fueled engines than in other IC engines, because of Hydrogen’s lower ignition energy, wider flammability range and shorter quenching distance. Premature ignition occurs when the fuel mixture in the combustion chamber becomes ignited before ignition by the spark plug, and results in an inefficient, rough running engine. Backfire conditions can also develop if the premature ignition occurs near the fuel intake valve and the resultant flame travels back into the induction system. GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

A number of studies have been aimed at determining the cause of pre-ignition in Hydrogen engines. Some of the results suggest those preignitions are caused by hot spots in the combustion chamber, such as on a spark plug or exhaust valve, or on carbon deposits. Other research has shown that backfire can occur when there is overlap between the openings of the intake and exhaust valves. It is also believed that the pyrolysis (chemical decomposition brought about by heat) of oil suspended in the combustion chamber or in the crevices just above the top piston ring can contribute to pre-ignition. This pyrolysed oil can enter the combustion chamber through blow-by from the crankcase (i.e. past the piston rings), through seepage past the valve guide seals and/or from the positive crankcase ventilation system (i.e. through the intake manifold). 1. Fuel Delivery Systems: Adapting or re-designing the fuel delivery system can be effective in reducing or eliminating pre-ignition. Hydrogen fuel delivery system can be broken down into three main types: central injection (or “carbureted”), port injection and direct injection. Central and port fuel delivery systems injection forms the fuel-air mixture during the intake stroke. In the case of central injection or a carburetor, the injection is at the inlet of the air intake manifold. In the case of port injection, it is injected at the inlet port. Direct cylinder injection is more technologically sophisticated and involves forming the fuel-air mixture inside the combustion cylinder after the air intake valve has closed. A. Central Injection or Carbureted SystemsThe simplest method of delivering fuel to a Hydrogen engine is by way of a carburetor or central injection system. This system has advantages for a Hydrogen engine. Firstly, central injection does not require the Hydrogen supply pressure to be as high as for other methods. Secondly, central injection or carburetors are used on gasoline engines, making it easy to convert a standard gasoline engine to Hydrogen or a gasoline/Hydrogen engine. The disadvantage of central injection is that it is more susceptible to irregular combustion due to pre-ignition and backfires. The greater amount of Hydrogen/air mixture within the intake manifold compounds the effects of pre-ignition. B. Port Injection SystemsThe port injection fuel delivery system injects fuel directly into the intake manifold at each intake port, rather than drawing fuel in at a central point. Typically, the Hydrogen is injected into the manifold after the beginning of the intake stroke. At this point conditions are much less severe and the probability for premature ignition is reduced. In port injection, the air is injected separately at the beginning of the intake stroke to dilute the hot residual gases and cool any hot spots. Since less gas (Hydrogen or air) is in the manifold at any one time, any pre-ignition is less severe. The inlet supply pressure for port injection tends to be higher than for carbureted or central injection systems, but less than for direct injection systems. The constant volume injection (CVI) system uses a mechanical cam-operated device to time the injection of the Hydrogen to each cylinder. The CVI block is shown on the far GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

right of the photo with four fuel lines exiting on left side of the block (one fuel line for each cylinder). The electronic fuel injection (EFI) system meters the Hydrogen to each cylinder. This system uses individual electronic fuel injectors (solenoid valves) for each cylinder and is plumbed to a common fuel rail located down the center of the intake manifold. Whereas the CVI system uses constant injection timing and variable fuel rail pressure, the EFI system uses variable injection timing and constant fuel rail pressure.

Figure 4: Constant volume fuel injectors.

C. Direct Injection SystemsMore sophisticated Hydrogen engines use direct injection into the combustion cylinder during the compression stroke. In direct injection, the intake valve is closed when the fuel is injected, completely avoiding premature ignition during the intake stroke. Consequently the engine cannot backfire into the intake manifold. The power output of a direct injected Hydrogen engine is 20% more than for a gasoline engine and 42% more than a Hydrogen engine using a carburetor. While direct injection solves the problem of pre-ignition in the intake manifold, it does not necessarily prevent pre-ignition within the combustion chamber. In addition, due to the reduced mixing time of the air and fuel in a direct injection engine, the air/fuel mixture can be non-homogenous. Studies have suggested this can lead to higher NOx emissions than the non-direct injection systems. Direct injection systems require a higher fuel rail pressure than the other methods.

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

2. Exhaust Gas Recirculation (EGR): As the name implies, an EGR system recirculates a portion of the exhaust gases back into the intake manifold. The introduction of exhaust gases helps to reduce the temperature of hot spots, reducing the possibility of pre-ignition. Additionally, recirculating exhaust gases reduce the peak combustion temperature, which reduces NOx emissions. Typically a 25 to 30% recirculation of exhaust gas is effective in eliminating backfire. On the other hand, the power output of the engine is reduced when using EGR. The presence of exhaust gases reduces the amount of fuel mixture that can be drawn into the combustion chamber. 3. Water Injection:

Another technique for thermally diluting the fuel mixture is the injection of water. Injecting water into the Hydrogen stream prior to mixing with air has produced better results than injecting it into the Hydrogen-air mixture within the in-take manifold. A potential problem with this type of system is that water can get mixed with the oil, so care must be taken to ensure that seals do not leak. Storage- One more technical issue needs to be resolved to use Hydrogen in IC engines. That is onboard storage of Hydrogen. Hydrogen in gaseous state at 0ºC and 1 atm. has lowest density of 0.08987 kg/m3[6] which is a great problem to use Hydrogen onboard. Due low density Hydrogen requires lot of space required to store it. For average run of 500 km of any vehicle we require 10 m3 of storage. It indicates for driving a car with Hydrogen we need truck behind it to carry fuel. If we run with smaller storage it demands charging of Hydrogen timely. It is costly to stand Hydrogen fuel stations. Along with this time taken charging of fuel is another issue. So it is not economical to use Hydrogen in gaseous state. It becomes a great research area now to resolve Hydrogen storage problem. Some solutions are given below by researchers but still need of improvements. A. Liquefied Hydrogen: Using advanced cryogenic now it is possible to liquefy Hydrogen. By liquefiction of Hydrogen at -253ºC the density is increased to 708 kg/m3 [6]. This decreases need of storage volume a great. But again the cryogenic process of liquification is costly as very high pressurized operation. The storage tank design should modify accordingly. The cylinder materials required to withstand at such a high pressure. It increases the cost. Thus material research is going down to low down the cost of storage tank. [6] B. Solid Hydrogen: Along with advancement of nanotechnology, one more solution we got for storage problem. The hydrogen is stored with various metal hydrides based on nanotechnology. By solidification of Hydrogen at -259ºC the density is increased to 858 kg/m3 [6]. On board reactions are carried out to remove hydrogen from metal hydrides and it can be utilized as a fuel [6]. The generalized chemical reaction carried out as follow ( ⁄ )

Engine Design Modification: After discussion of combustive properties, overcome of combustion favoured properties over combustion unflavoured properties, problems with using Hydrogen in IC GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

engines and solutions. It is well understood that there is need of engine design modification. Without modification engine may not run properly. 1. Spark plugs-Use cold rated spark plugs to avoid spark plug electrode temperatures exceeding the auto-ignition limit and causing backfire. Cold rated spark plugs can be used since there are hardly any spark plug deposits to burn off. Do not use spark plugs with platinum electrodes as this can be a catalyst to hydrogen oxidation.[4] 2. Ignition system- Avoid uncontrolled ignition due to residual ignition energy by properly grounding the ignition system or changing the ignition cable’s electrical resistance. Alternatively, the spark plug gap can be decreased to lower the ignition voltage; this is no problem for hydrogen engines as there will be almost no deposit formation. Spark plug gaps as small as 0.25mm has been used.[4] 3. Injection system- Provide a timed injection, either using port injection and programming the injection timing such that an initial air cooling period is created in the initial phase of the intake stroke and the end of injection is such that all hydrogen is inducted, leaving no hydrogen in the manifold when the intake valve closes; or using direct injection during the compression stroke.[4] 4. Hot spots- Avoid hot spots in the combustion chamber that could initiate pre-ignition or backfire.[4] 5. Compression ratio- The choice of the optimal compression ratio is similar to that for any fuel, it should be chosen as high as possible to increase engine efficiency, with the limit given by increased heat losses or appearance of abnormal combustion (in the case of hydrogen primarily pre-ignition).[4] Performance and Emission characteristics: After discussion over the combustive properties and feasibility of using Hydrogen in IC engine, it is time to investigate its feasibility experimentally. Due to Hydrogen’s immense potential so many experiments are carried out to check performance characteristic brake mean effective pressure, thermal efficiency, volumetric efficiency as well as emission parameters CO, CO2 and NOX. [12] Mr. Shivaprasad K., Mr. Raviteja S., Mr. Parashuram Chitragara, Mr. Kumar G. N. carried out same investigation as discussed below. Experimental set-up-

Figure No. 5: Experimental set up_Performance and Emission characteristics GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

The tests were carried out at different engine speeds. Hydrogen energy fraction adjusted with the help of regulator. The current investigation is aimed at analysing the performance and emission characteristics of hydrogen enriched high speed SI engine with ECU controlled MPI system. Let’s analyse the test results and graphs observed by Mr. Shivaprasad K., Mr. Raviteja S., Mr. Parashuram Chitragara, Mr. Kumar G. N.[12]

Figure No. 6: BMEP, ɳth, ɳvol verses speed at different Hydrogen fraction. Brake Mean Effective Pressure (BMEP)- It is the parameter which represents output power of IC engines. From the graph it is can be analyse easily that the BMEP (means output power) increases with fraction amount of Hydrogen but at 25% fraction Hydrogen the goes on decreases. It is quite obvious that due to wide range of flammability and faster propagation speed which induces prime quality pre mixture. This increases BMEP initially. Finally there is decrease in BMEP at 25% fraction Hydrogen due to insufficiency of air as increased amount of hydrogen. Brake thermal efficiency (ɳth)- Thermal efficiency of engine is a crucial parameter to economic and overall performance of engine. The graph shows the brake thermal efficiency goes on increasing with fraction amount of Hydrogen 27%, 28%, 30%, 32%, 34.5% and 32.5% respectively at 0%, 5%, 10% 15%, 20% and 25% fraction of Hydrogen. 0% fraction indicates pure gasoline which indicates lowest thermal efficiency. The increment in Hydrogen fraction increases brake thermal efficiency. If shows finally at 25 % fraction there is decrease in efficiency. The hydrogen has very low density that is volumetric energy potential is less. With rise in volume fraction Hydrogen covers all the space thus insufficient GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

space for air contributing combustion. This tends to incomplete combustion and decrease in efficiency. Volumetric Efficiency (ɳvol)- Volumetric efficiency of engine is defined as the ratio of mass of the mixture in combustion chamber to the mass of the mixture in swept volume could hold if the mixture is at ambient (free air) density. The graphs obtained volumetric efficiency verses speed at various fraction of Hydrogen shows that volumetric efficiency increases with speed and fraction of Hydrogen. Emission characteristics-

Figure No. 7: CO, HC and NOX based emission verses speed at different Hydrogen fraction.

Figure No-7 shows CO, HC based emissions are decreases as Fraction Hydrogen increases. Gasoline having higher CO, HC based emissions as compare to fraction Hydrogen fuel. As amount of hydrogen increases the carbon content decreases and CO, HC based emissions automatically decreases. But the behaviour of NOX based emissions is exactly reverse. With increase in fraction Hydrogen temperature of the mixture increases. Nitrogen has higher affinity to form NOX emissions at higher temperature. As temperature increases the NOX emissions increases. Thus NOX based emissions shows reverse behaviour and increases with increase in fraction Hydrogen in fuel. Conclusion: 

Hydrogen has great potential to replace traditional fuels and overcome problems of global warming, water pollution, CO and CO2 emission with providing superior

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

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efficiency and economy. Wide range of flammability, high auto-ignition temperature, high flame velocity, high diffusivity, high specific energy makes it perfect fuel. Due to low ignition energy, there is occurrence of pre-ignition which can be resolved by exhaust gas recirculation, water injection, cold rated platinum tip spark plugs and efficient fuel delivery system. Low density is also one more headache in using Hydrogen as less specific volumetric energy. It creates storage problem. Liquification and solidification of Hydrogen is the somewhat solution over the problem. With small modification in IC engine, the Hydrogen can be replacement for traditional fuels. Even dual fuel (with Diesel/Gasoline) option is also open to use. Hydrogen shows improved BMEP, Brake thermal efficiency and volumetric efficiency. The exhaust from Hydrogen is only steam totally pollution free from CO/CO2. Only at higher temperature there will be NOX.

Reference: 1. P. C. Souers, “Hydrogen Properties for Fusion Energy”, university of California press, 2000. 2. Gillingham K., “Hydrogen Internal Combustion Engine Vehicles: A Prudent Intermediate Step or a Step in the Wrong Direction?”, Department of Management Science & Engineering Global Climate and Energy Project, Precourt Institute for Energy Efficiency, Stanford University, Pages 1-28, 2007. 3. Overend E., “Hydrogen Combustion Engines”, The Unıversıty Of Edınburgh, School of Mechanical Engineering,Pages 1-77,1999 4. White M. C., Steeper R.R., Lutz E. A., “The Hydrogen-fueled internal combustion engine: A technical review”, International Journal of Hydrogen Energy Volume 31, Pages 1292-1305, 2006. 5. COD (College of the Desert), “Hydrogen fuel cell engines and related technologies course manual”, Module 3: “Hydrogen use in internal combustion engines”, Pages 129, 2001. 6. Gupta B. R, “Hydrogen fuel production, transport and storage”, CRC Press, ISBN 978-1-4200-4575-8, Pages 1-603.2008. 7. Wahab Abd Bın Aswad M., “Addition of Hydrogen to gasoline-fuelled 4 stroke SI engine using 1-dımensıonal analysis”, Faculty of Mechanical Engineering University Malaysia Pahang, Pages 1-68, 2009. 8. Murat Ciniviz, Huseyin Kose, “Hydrogen use in internal engines.-A review” International Journal of Automotive Engineering and Technologies Vol. 1, Issue 1, pp. 1 – 15, 2012 9. National Aeronautics and space research, www.grc.nasa.gov/WWW/k12/airplane/combst1.html date: 6Feb 2015. 10. Bose Kumar Probir, Maji Dines, “An experimental investigation on engine performance and emissions of a single cylinder diesel engine using Hydrogen as inducted fuel and diesel as injected fuel with exhaust gas recirculation”, International Journal of Hydrogen Energy, Volume 34, Pages 4847-4854, 2009,

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.

NAME: KAMBLE AMOL GULABRAO. ROLL NO. 144178001 EN-610 COURSE SEMINAR TERM PAPER-2

11. Saravanan N., Nagarajan G., “Performance and emission study in manifold Hydrogen injection with diesel as an ignition source for different start of injection”, Renewable Energy, Volume 34, Pages 328-334, 2009. 12. Shivaprasad K. V., Ravi Tejas, Parashuram Chitragara, Kumar G. N., “Experimental Investigation of the Effect of Hydrogen Addition on Combustion Performance and Emissions Characteristics of a Spark Ignition High Speed Gasoline Engine” 2nd International Conference on Innovations in Automation and Mechatronics Engineering,ICIAME 2014, Vol.2, Issue.1, Jan-Feb 2012 pp-565-571 13. Szwaja S, Grab-Rogalinski K., “Hydrogen combustion in a compression ignition diesel engine”, International Journal of Hydrogen Energy, Volume 34, Pages 4413-4421,2009 14. Saravanan N., Nagarajan G., “Performance and emission studies on port injection of Hydrogen with varied flow rates with Diesel as an ignition source.”, Applied Energy Volume 87,Pages 2218-2229, 2010 15. Wahab Abd Bın Aswad M., “Addition of Hydrogen to gasoline-fuelled 4 stroke SI engine using 1-dımensıonal analysis.” Faculty of Mechanical Engineering. University Malaysia Pahang, Pages 1-68, 2009. 16. Abdelghaffar A. W., “Spark Ignition Engine Fueled by Hydrogen: Comparative Analysis.”, European Journal of Scientific Research, Volume 44, Pages 13-28, 2010.

GUIDE: PROF. SANKARA V. TATIPARATI. ENERGY SCIENCE & ENGINEERING DEPARTMENT, IIT, BOMBAY.