Modification Of S.I Engine To HHO Engine Using HHO Generator And Its Analysis

Transcription

1 Modification Of S.I Engine To HHO Engine Using HHO Generator And Its Analysis M.Sunil Raj 1, A.Ramakrishna 2, P.Naveen kumar 3 1 M.Tech Scholar, Dept. of Mechanical Engineering, B.V.C. Engineering College, Odalarevu 2 Professor, Dept. of Mechanical Engineering, B.V.C. Engineering College, Odalarevu 3 M.Tech Scholar, Dept. of Mechanical Engineering, B.V.C. Engineering College, Odalarevu ABSTRACT With increasing need for alternate sources of energy for powering internal combustion (IC) engines, various options have been considered in the past three decades. Of these one of the popular techniques is the use of hydrogen as a primary or secondary fuel in IC engines. This paper deals with the analysis of the study conducted on a single cylinder air cooled 100cc spark ignition (SI) engine with an electrolytic HHO generator. In my thesis an attempt is made to address this issue by designing and building an HHO generator. This HHO generator uses the principle of electrolysis to split water into its two molecules, hydrogen and oxygen, in gas form. This gas will be introduced into the combustion chamber of an engine. The aim of the study is to investigate the effects of HHO gas substitution with the petrol on emissions benefits on light weight petrol engines. This low cost system can be incorporated into any single cylinder SI engines. KEYWORDS: IC engines, petrol engine, spark ignition engine, SI engine, single cylinder engine, HHO generator. I. INTRODUCTION Hydrogen being the most abundant element in the universe is a highly flammable diatomic gas having a gross calorific value of kj/kg. Though the gross calorific value of hydrogen is approximately three times of petrol and diesel, it has been rarely used in IC engines since due to certain undesired properties such as reserve ignition and highly explosive when pressurized. There were a lot of debates about the safety of using hydrogen in IC engines. It is undoubted fact that as long as certain safety measures are taken while keeping in mind its temperamental combustion characteristics, suitable retrofits can be installed for various induction techniques making it a clean burning and safe alternative fuel for SI engines. Also due to the fact that hydrogen is light, in the event of leakage, hydrogen will rise and dissipate into the atmosphere quickly. Thus it is evident that the main problem of using hydrogen as alternate fuel in IC engine is the storage. This can be solved by producing hydrogen at atmospheric conditions by means of an electrolytic process using water. Our mission is to design and create a device that will increase engine efficiency without jeopardizing its performance. Such device is an HHO Generator. This generator uses electric current (electrolysis) to produce hydrogen from water; the hydrogen will be introduced into the combustion chamber of an engine through the intake manifold. We will attempt to make it compact and affordable, in order for it to be appealing to customers. Building this generator comes with some challenges. We need to make sure that the amount of energy put into the cell to split the water molecules is less than the amount of output energy of the generator. In order to overcome this challenge we will need to make it as efficient as possible. This includes coming up with a creative design to get as much hydrogen out with the least amount of current running through the cell. More concerns include implementing very conductive wires and plates into our system. Taking these aspects into consideration will make the HHO generator a productive addition to any internal combustion engine. Page 50

2 II.CONCEPTUAL AND GENERATOR DESIGN PROPOSED HHO In electrolysis, people have tried different ways to increase the output of gas while decreasing the input of current. Some designs are more effective than others. Some people have tried to improve the conventional way, called wet system, consisting on plates or tubes submerged in S.N0 Time, in TEMPERATURE, 0 C(Electrolyte solution in the generator ) min SS 304 SS Initial water, while others have tried a design called dry cell where the water run through the plate. This design can vary in shape or size, making in it very easy to install anywhere. The wet system design consists in a more complicated manufactured process. This design is less expensive since the parts and the arrangement are more likely simple to produce. This system uses two different diameters of tubes in order to accommodate one inside the other one with different polarities, positive the inner and negative the outer. As a container, this kit uses a material capable to satisfy some important parameters. Resist higher temperatures, since the electrolysis process generates a significant amount of heat. The pressure built inside, sometimes up to 60 psi. And very important, it has to be a dielectric material in order to avoid electrolysis between the tubes and the inner wall of the container. The effectiveness of this system is higher than the dry cell system, although more current input is necessary the amount of hydrogen out is greater. Despite the cost of fabrication of this system and our limited budget we are choosing this design for our project in order to obtain a better production of hydrogen. A. SELECTION OF ELECTRODE MATERIAL: According to reference of some scientific based results electrode shape was selected as tube structure but material was selected according to my design because of production of hydrogen was purely on material. So some experiments were done on different materials like Platinum, Titanium, Nickel, Stainless Steel (304 o r 316), Carbon, Iron, Aluminium, Copper, Brass, and Graphite. Among these materials platinum, Titanium are costly but production of hydrogen was very pure and next level materials was Copper, Iron, and Stainless Steel (304 or 316) these are cheap in cost, easily available materials in any structure and production of hydrogen is almost 90% pure by electrolysis process. Among these materials Stainless Steel (304 or 316) got the better results for production of hydrogen. Again in stainless steel I was compared results by doing the experiment using electrolysis process stainless steel 316 is better than stainless steel 304. So, I was selected Stainless Steel 316 material as electrode for HHO generator. These are the test results while electrolysis process is going on and electrical energy as input. Table.1 1. Battery values: 12V-24AMPS. 2. Electrolyte as KOH: 1-2%. Bases on temperature results material was selected because more heat generation results the better hydrogen production but also causes the fire and flash point disturbance of fuel that was produced in generator so i am keeping the HHO generator in safe limits by maintaining temperature limits according to input voltage and current. With this results production of hydrogen was made based on this design. FIG.1 Copper Electrode Page 51

3 FIG.2 Stainless steel 316 and 304 Electrode Stainless steel tubes of 3mm thick and 1, 9/16 inch long stainless steel (316L Grades). The electrodes are welded with small copper wire at the end position for electrical contact. After the electrical connection the tubes are arranged in a very close manner such that the gap between the anode and cathode is 4-5mm. The gap between the electrodes is as small as possible, to increase the active surface area of the tubes and seems necessary for ultra high efficiency. The electrical connections are sealed with Teflon tape for minimizing the electrical losses. A set of electrode contains two tubes of which one tube is negatively charged and the remaining tube is positively charged. They are arranged in an alternate manner ( + ). Each electrolyzer contains four set of electrodes. And the electrodes are separated with a cup holder for reducing the heat generation. And the set of electrodes are inserted into a PVC (Pol y Vinyl Chloride) pipe of 4 gauge 6.3 diameter. This construction design was done in catia software. FIG.3 Stainless steel 304 Electrode B. ELECTRODE DESIGN: Tube Specifications: Stainless Steel Grade 316L is used where corrosion resistance and good mechanical properties are primary requirements. It is also widely used in applications where corrosion resistance is required. This cell is an electrolysis cell similar to Stan Meyer - hydrogen oxygen ( HHO ) - Energy cell. Stanley Meyer was a pioneer in electrolysis. This cell is built with 8 concentric 316L grade stainless steel seamless pipes and spacers. FIG.4 HHO Generator Design C. CONSTRUCTION: Four electrodes (Tubes) are about 2mm thick and 1, 9/16 inch long stainless steel (316L Grades). An 8mm gas vent hole is drilled for gas outlet to the cap. The electrolyte level is always about 25mm below the gas vent hole. Staggering and using small holes minimizes any efficiency loss due to current leakage between cells, but makes electrolyte refilling and level equalization significantly easier. The electrodes are welded with small copper wire at the end position for electrical contact. After the electricall connection the tubes Page 52

4 are arranged in a very close manner such that the gap between the anode and cathode is 4-5mm. The gap between the electrodes is as small as possible, to increase the active surface area of the tubes and seems necessary for ultra high efficiency. The electrical connections are sealed with Teflon tape for minimizing the electrical losses. kept mixed. The produced oxy-hydrogen gas is a stoichiometric mixture of hydrogen (2 parts vol.) and oxygen (1 part vol.) and can be combusted in vacuum. The combination of tube electrodes is very efficient, because it allows the cells to operate as close to their optimal cell voltage as possible. The electrolyzer runs fairly cool, at about 30-50C depending on the current and electrolyte. III. ELECTROLYSIS PROCESS Electrolysis of water is the decomposition of water (H 2 O) into oxygen (O 2 ) and hydrogen gas (H 2 ) due to an electric current being passed through the water. This electrolytic process is used in some industrial applications when hydrogen is needed. FIG.5 HHO Generator A set of electrode contains two tubes of which one tube is negatively charged and the remaining tube is positively charged. They are arranged in an alternate manner ( + ). Each electrolyzer contains four set of electrodes. And the electrodes are separated with a cup holder for reducing the heat generation. And the set of electrodes are inserted into a PVC (Poly Vinyl Chloride) pipe of 4 gauge 6.3 diameter. The electrodes are connected with 10 gauge wire. The best electrode material would be platinum, but platinum plates are very expensive. Platinum plated steel plates or nickel plated steel plates would also work. The most practical electrode material is stainless steel. The electrode surface conditioning is very important at minimizing the cell voltage. Bubbler is absolutely essential to prevent backfires from blowing up the electrolyzer. Bubbling the gas through a water bath is the only safe way to prevent backfires, provided that the bubbler is strong enough to contain any backfires and that the water level in the bubbler is high enough. It uses an alkaline (NaOH, KOH) electrolyte to split distilled water into hydrogen and oxygen components very efficiently. The produced hydrogen and oxygen gasses are not separated to separatee containers, but FIG.6 Electrolysis of water An electrical power source is connected to two electrodes (typically made from some inert metal such as Platinum or Stainless Steel etc.,) which are placed in water. Hydrogen will appear at the Cathode (the negatively charged electrode), and Oxygen will appear at the Anode (the positively charged electrode). The generated amount of hydrogen is twice the amount of oxygen, and both are proportional to the total electrical charge that was sent through the water. Electrolysis of pure water is very slow, and can only occur due to the Page 53

5 self-ionization of water. Pure water has an electrical conductivity about one millionth that of seawater. It is sped up dramatically by adding an electrolyte (such as a salt, an acid or a base). Historically, the first known electrolysis of water was done by William Nicholson and Anthony Carlisle in about A. Electrolysis equations: The number of hydrogen molecules produced is thus twice the number of oxygen molecules. Assuming equal temperature and pressure for both gases, the produced hydrogen gas has therefore twice the volume of the produced oxygen gas. The number of electrons pushed through the water is twice the number of generated hydrogen molecules and four times the number of generated oxygen molecules. Reduction will occur at the cathode. At this electrode hydrogen gas and hydroxide ions are formed. The electrons required for this reduction will come from the power source. 4H 2 O + 4 e - 2 H OH - Oxidation will occur at the anode, producing oxygen gas and hydrogen ions. The electrons that are produced will return to the power source: 2H 2 O O H e - Adding the two half-reactions together gives us a net reaction of: 6 H 2 O 2 H 2 + O H OH - The H + and OH - that are produced will combine to form 4 H 2 O. 6 H 2 O 2 H 2 + O H 2 O Finally we can simplify our overall equation to: 2 H 2 O (l) 2 H 2 (g) + O 2 (g) B. Hydrogen use in spark ignition (SI) engines: 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 H2 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 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 IV.THEORETICAL CALCULATIONS A. Theoretical Calculation of Hydrogen Production: In order to quantities the process of electrolysis, we have solved some equations that relate the current needed to obtain a certain volume for a gas. The process for this calculation at room temperature and at 1 atm is: 1. Write the half-reactions that take place at the anode and at the cathode. Anode (oxidation): 2H2O(I) -> O2(g) + 4H + (aq) +4e Cathode (reduction): 2H + (aq) + 2e -- -> H2(g) 2. Calculate the number of moles of electrons that were transferred. Knowing: Amperes X time = Coulombs 96,485 coulombs = 1 Faraday (F) 1 Faraday = 1 mole of electrons Example: 10(amps) 1800(seconds) = 18,000(coulomb) 18,000C (1F/96,485C) = 0.186F 0.186F (1 mole e - /1F) = mole e - 3. Calculate the moles of hydrogen and oxygen produced using the number of moles of electrons calculated and the stochiometric from the balanced half-reactions. According to the equations, 2 moles of electrons produce 2 mole of H2 and 4 moles of electrons produce 1 mole of O2 gas mole e - (2 mole H 2 / 2 mole e - ) = mole H mole e - (1 mole O 2 / 4 mole e - ) = mole O 2 4. Calculate the volume of each gas using ideal gas law (V=nRT/P). Where n: number of moles. R: Boltzmann constant = (L atm/mol K) Page 54

6 T: temperature in kelvin. Volume of Hydrogen gas: ((0.186 mole H 2 )( L atm/mole K )(298K))/1atm = 4.54L of H 2 (( mole 0 2 )( L atm/mole K )(298K))/1atm = 1.13L of O 2 These calculations have shown that for a current of 10 amps during a period of 30 minutes, the electrolysis of water yields 4.54 litres of hydrogen gas and 1.13 litres of oxygen gas. B. AIR/FUEL RATIO: The theoretical or stochiometric 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 = 1mole Because air is used as the oxidizer instead oxygen, the nitrogen in the air needs to be included in the calculation: Moles of N2 in air in air/ 21% O2 in air) = Moles of O2 * (79% N2 = 1 mole of O2 * (79% N2 in air/ 21% O2 in air) = 3.762moles N2 Number of moles of air = Moles of O2 + Moles of N2 Weight of O 2 = = moles of air = 1 mole of O 2 x 32 g/mole = 32 g Weight of N 2 = moles of N 2 x 28 g/mole = g Weight of air = weight of O 2 + weight of N Weight of H 2 = 32g g = g = 2 moles of H 2 x 2 g/mole = 4 g Stochiometric air/fuel (A/F) ratio for hydrogen and air is: A/F based on mass= mass of air/mass of fuel = g / 4 g= 34.33:1 A/F based on volume= volume (moles) of air/volume (moles) of fuel = / 2 = 2.4:1 The percent of the combustion chamber occupied by hydro-gen for a stochiometric mixture: % H 2 = volume (moles) of H 2 /total volume = volume H 2 / (volume air + volume of H 2 ) = 2 / ( ) = 29.6% As these calculations show, the stochiometric 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. V. FUEL SUPPLY ARRANGEMENT Supply of Hydrogen Gas to Engine Cylinder: The HHO gas which is generated from the HHO generator is supplied to the engine in between the air filter and carburetor, for efficient mixing of HHO gas with atmospheric air. It is supplied to the engine through the bubbler for reducing the risk of explosion. HHO gas is supplying through the PVC hose pipe of 8 mm diameter, and a nozzle is arranged at the exit of the tube for increasing the velocity of the outgoing HHO gas into the carburetor, where it is efficiently mixed with atmospheric air and is sucked in to the cylinder. Arrangement was shown in figure. Page 55

7 Hose Pipe 8 Mm Dia (2 60/- Nozzles Nos) Wire Wire 10 Gauge 250/- Sealant M-Seal, 180/- Araldite, Silicone Sealant Bubbler Water Bottle 8/- Electrode Packing Rubber 20/- Separator Or Plastic Bits Catalyst KOH (Potassium 50/- Hydroxide) pills TOTAL COST 4971/- VII. RESULTS AND DISCUSSIONS EMISSIONS TEST: FIG.7 HHO Inlet between Air-Filter and carburetor According to the properties of the HHO gas nearly 30% volume of HHO gas has to be supplied for complete combustion inside the cylinder. Since hydrogen has high flammability nature the combustion takes place very quickly compared to the general petrol or diesel engines, such that more amount of thrust (power) is generated. VI. STRUCTURAL AND PROTOTYPE COST ANALYSIS PARTS SPECIFICA-- TIONS Electrode Anode:Ss-316l Stainless (9/16 Dia, 6 Steel Height ). Grade-316L CATHODE:SS- 316L(1 Dia, 6 Height). Container Pvc Pipe 4 Gauge 6.3 Dia, 12 Height RUPEES (INDIA) /- Medium Distilled Water 18/-per litre Dummy Acirlyic Plastic 150/- Disc Of 6.3 Dia, Bottom dummy of Battery 12volts 20 Ah 3000/- Hose Pipes Pvc Pipe 8mm Dia 135/- The combustion of hydrogen with oxygen produces water as its only product: 2H 2 + O 2 = 2H 2 O The combustion of hydrogen with air however can also produce oxides of nitrogen (NOx): H 2 + O 2 + N 2 = H 2 O + N 2 + NO x The oxides of nitrogen are created due to the high temperatures generated within the combustion chamber during combustion. This high temperature causes some of the nitrogen in the air to combine with the oxygen in the air. The amount of NOx formed depends on: The air/fuel ratio The engine compression ratio The engine speed The ignition timing FUEL CO 2 (g/l) CO 2 (g/km) PETROL LPG Whether thermal dilution is utilized EMISSION DATA (STANDARD VALUES-INDIA) 1. The Carbon Dioxide Emissions In (G/Km): Page 56

8 POLLUTANT PETROL EMISSIONS LPG EMISSIO NS CO (VOLU ME %) HC (PPM) NOX (PPM) CO NO EXHAUST EMISSION LIMITS FOR PETROL ENGINE VALUES UNITS HC CO 3.54 VOLU ME % CO HC 4500 PPM 2. EMISSIONS (units: g/km) POLLUTANT PETROL EMISSIONS (mg/km) LPG (mg/km ) BENZENE ,3 BUTADIENE TOLURENE XYLENE EXH AUST EMIS SION LIMI TS CO (VOL UME %) HC (PPM) PETROL ENGINE VALUES HYDROGEN ENGINE VALUES MAXI MUM VALU E MINI MUM VALU E MAXI MUM VALU E MINI MUM VALU E FORMALDEHY DE 3. AIR-TOXIC EMISSIONS EMISSION FROM LPG ENGINE Emission Data Results of HHO (Hydrogen) Engine With Comparison to Petrol (Practical Values) In addition to oxides of nitrogen, traces of carbon monoxide and carbon dioxide can be present in the exhaust gas, due to seeped oil burning in the combustion chamber. Depending on the condition of the engine (burning of oil) and the operating strategy used (a rich versus lean air/fuel ratio), a hydrogen engine can produce from almost zero emissions (as low as a few ppm) to high NOx and significant carbon monoxide emissions. VIII. CONCLUSION Page 57

9 The investigation of the effects of HHO supplement in a single cylinder SI engine was carried out on the 100cc engine. Hydrogen enhancement was used for the comparison based on the current supplied for the production of HHO through electrolysis. The effect of engine operating conditions on the exhaust gas emissions was also investigated and the following observations were made: A smooth and stable operation of the engine has been achieved with least modifications of the vehicle hardware. An observation with both HC (ppm) and CO% emissions where the levels began to drop. NOMENCLATURE S.I - Spark ignition I.C Internal combustion HC - Hydrocarbon CO - Carbon monoxide CO2 - Carbon dioxide NOx - Oxides of nitrogen SOx - Oxides of sulphur [8] Negurescu, N., Researches related to the SI hydrogen fuelled engines, PhD Thesis U.P.B., p. 67,1980 (In Romanian) [9] Negurescu N, Pana C, Cernat A (2012). Aspects of using hydrogen in SI engine, U.P.B. Sci. Bull. Series D, ISSN :1. M.sunilraj is pursuing M.Tech with the specialization in Thermal Engineering at BVC Engineering College Odalarevu. He received the B.Tech degree ( ) in Mechanical Engineering at Pragati Engineering College,Surampalem. A.Ramakrishna, B.Tech,M.E,MISTE, (P.hd), working as Professor & Head, Dept of Mech.Engg BVC Engineering College, Odalarevu. REFERENCES [1] L.M. Das, Hydrogen engine: research and development (R&D) programmes in Indian Institute of Technology Delhi, New Delhi, India. [2] Erjiang Hu Zuohua Huang, Bing Liu, Jianjun Zheng, Xiaolei Gu, Bin Huang, Experimental investigation on performance and emissions of a spark ignition engine fuelled with natural gashydrogen blends combined with EGR, International Journal Of Hydrogen Energy, Vol. 88 (1), pp , [3] Teruo Suzuki and Yoshihito Sakurai, Effect of hydrogen rich gas and gasoline mixture on ignition engine, [4] Enrico Conte and Konstantin Boulouchos, Influence of hydrogen rich gas addition on combustion, Pollutant formation and efficiency of an IC-SI engine, SAE Transactions, Vol. 113, pp , [5] John B. Heywood, Internal Combustion Engines, McGraw Hill Inc., [6] Constantin Pana, Niculae Negurescu, Marcel Ginu Popa, Alexandru Cernat and Dorin Soare, An investigation of the hydrogen addition effects to gasoline fuelled spark ignition engine, SAE Transactions, Vol. 116, pp , [7]Verhelst, S., Verstraeten, ST., Sierens, R., Combustion Strategies and NOx Emissions for Hydrogen Fueled IC Engines, FISITA World Automotive Congress, 2006, YOKOHAMA, paper F Page 58