Literature Review

Hydrogen combustion engine is an engine designed in a way where by cremation occurs after oxidation is done on the engine.  This leads to the production of heat and gases which put up a lot of pressure on the engine leading to consumption of more fuel.  Hydrogen combustion engine is designed in a way that will facilitate less use of fuel energy.  Hydrogen gas possessing a high affinity for burning facilitates the continued production of energy.  Hydrogen enhances the production of more heat energy which as a result improves on the speed of the locomotive in subject (Zhou, Cheung and Leung 2014  p.10).

Hydrogen combustion kit uses fossils fuels which are a major production of carbon dioxide.  These gases result into an effect to the environment such as clotting of stomata which leads to drying of plants, it has leads to global warming which is a major disaster which leads to draughts.  The hydrogen kit is therefore designed to reduce on these emissions so as to enhance a better living and conserve the environment (Hamd and Askalany 2015). This is made possible by replacing the use of fossils fuels with hydrogen energy which is a clean source of energy.  Hydrogen is produced from different sources such as from natural gases or through the process of hydrolysis.  This leaves no change to the production of harmful emissions which may have a negative impact on the environment and to the ozone layer (Van der Laak, Raven  and Verbong, 2007 p.3215).

Hydrogen combustion engine contains a particulate filter which helps in the removal of unwanted substances from air before it enters the engine.  These particles may include dust, pollen and other tiny metallic particles which may be carried by air.  As a result the filter enhances the good performance of the engine and also helps in the prevention of the engine destruction (Zhang 2016).

How Hydrogen Enhanced Combustion Engine Works

According to Zhang, Ji and Wang (2015 p.4707) Hydrogen has a high burning affinity and produces more energy compared to other fuel products.  This makes it more efficient for use since it does not produce harmful gases.  In the engine combustion occurs once oxidation takes place in the combustion chamber which completes the fluid flow circuit.  Once the circuit is completed locomotion occurs as a result of chemical energy being transformed to mechanical energy.

Figure showing the Hydrogen Enhanced Combustion Engine (Köse and Ciniviz 2013)

How Hydrogen Enhanced Combustion Engine Works

speeds up the combustion process as hydrogen displaces a greater percentage of the gases available.  These increase the chance of more air to be absorbed in to the combustion chamber which as a result enhances the combustion process.

Hydrogen enhanced engine is also fitted with catalytic converter which helps in reducing pollution on the environment as a result of exhaust gases.  This makes the engine more effective as it takes care of all aspects including pollution which has a major negative impact on the ozone layer and other forms of pollution (Köse and Ciniviz 2013). Additionally, the hydrogen engine is also fitted with a cylinder head exhaust which allows for effective exhaust of waste gases out of the engine.  It possesses a great advantage as it reduces congestion of waste gases in the engine.  This makes the performance of the engine smooth and there is reduced risk of damage.

The cost of installation and maintenance of the engine is lower compared to other fossils fuels engines.  This becomes an added advantage to hydrogen combustion engines.  This creates more interest to clients to adopt vehicles which use such engines promotion the sales (Munshi et al. 2012).  Additionally, available technologies are able to be used in the repair and development of these engines.  As a result there is no much struggle in the maintenance of the engine.

Moreover, hydrogen combustion engine has low emissions.  This becomes an advantage since the output is water which comes from the reaction of hydrogen and oxygen and thus not harmful to the environment.  2H₂ + O₂ → 2H₂O.

Additionally, enhanced hydrogen combustion engine embraces a better design compared to other fossils fuels engines.  It contains stronger connecting tools within the engine network, hardened valves and valve seats, an ignition coil which accommodates a higher voltage, fuel injectors that are specifically designed for gases rather than liquid which is common to the engines as well as high temperature engine oil. Depending on air injection into the hydrogen engine, the output tends to be 15% higher in the energy production when compared to gasoline engine and as a result making the hydrogen engine more effective and efficient.

Hydrogen engines are designed in a way that they are larger in size compared to gasoline engines.  This becomes an added advantage since it produces more energy compared to the other engines.  It is designed to accommodate double of the normal air combustion in other engines.  These increase the chance for full combustion of the gases and hence more energy.  This size is ideal especially for large vehicles such as trucks.  Trucks and buses need more energy to be able to maintain the required speed of operation.  The hydrogen combustion engine can therefore facilitate this required energy,

Benefit of Hydrogen Combustion Engine

Hydrogen having a high combustion affinity within the engine outdoes other fuels.  Even with the availability of other resources in the engine, hydrogen takes a long combustion period and thus continuity in the production of energy which facilitates the running of machine or the locomotive in subject.

The hydrogen engine is highly adaptable and as a result change may be implemented and introduce fuels in the right ratios and implement a few changes and it works well.  This feature makes it possible for many users to adopt the engine since it does not have a possibility of total breakdown.  The beneficial feature about this engine is that it can use other fuels for the production of energy without changes in the model being done.

Additionally, hydrogen combustion engine when used in a company to run machines can be of added advantage.  As a result of its high energy production, it can be used in the rotation of heavy turbines or even used in heating up of metals.  The vapor produced as a by-product of the combustion process can be collected using a condenser and become beneficial to the company as it can be used in other operations such as cooling of machines or washing of substances.

CARBURETOR

Carburetor engines are used in aircrafts during inverted flights.  It is used to prevent fuel combustion. As a result hydrogen combustion engines can be used as an enhanced carburetor since there is no fuel combustion on the hydrogen engines.  

Figure showing the  illustrations for the denoted  Carburetor (Köse and Ciniviz 2013)

Hydrogen having low density is suitable to be used in the carburetor in aircrafts.  This engine operates well as the craft needs a lot of energy so as to maintain its movement.  Hydrogen combustion engine becomes of added advantage.

Challenges of the Enhanced Hydrogen Combustion Engine

The increased production of fossils fuels has been a great challenge to the enhanced hydrogen engine.  This is as a result of ignorance by the public on the advantages of using hydrogen engine.  The comfort of having cheap and readily available fuels for the fuels engine has contributed to the great challenge of adoption hydrogen energy.  To cub this challenge, the company producing hydrogen enhanced combustion engines should create awareness to the public through the use of various techniques (Karvonen 2016).  

Though public awareness, the effects of the by-products of fuel to the environment would have a major impact in the capturing of the public attention.  The benefits of using the hydrogen engine therefore should be well highlighted so as to give room for easy understanding and promote convincing of the targeted market of the engines. Incomplete combustion of the hydrogen gases lead to the production of toxic gases that are emitted to the atmosphere.  These emissions have a negative impact to the environment by having a negative impact to the ozone layer.  These gases contribute with a great percentage the formation of acid rain which affects plants, aquatic animals as well as having an impact on structure roofing’s.

However, strong competition from international bodies to build clean engines with less harmful emissions has been a great challenge in the construction of the hydrogen enhanced combustion engine.  Some of the international bodies have a great influence on their products having acquired customer loyalty and as a result their products become more marketable.  Technological obsolescence has also become a great challenge in the improvement and enhancement of hydrogen engines.  These changes have made it impossible to access some of the procedures of maintaining the hydrogen engines and therefore maintenance becomes a challenge (Ghazal 2013).  This can be dealt with by enhancing regular updating of software’s and proper choice of software’s that will be compatible with the existing ones.  Through this, it will be much easier to manage the development of the hydrogen engines (Karvonen 2016). 

According to Greenwood and Johnson (2014), resources are a major drawback in many investments.  Insufficient funds to cater for the acquisition and maintenance of the hydrogen engines are a challenge that pulls back the development of enhanced combustion engine.  Resources such as human power are required in the effective running of the design of these engines. This challenge can be manipulated by identifying a reliable source of income which will enhance the smooth running of the development activities.  

Additionally, lack of the required technical skills for the construction of the hydrogen enhanced combustion engine can be a major problem in the development.  For an effective technical knowledge is required to improve on the output and maintain quality.   The engine construction company can implement training opportunities for all the recruited staff to enhance the quality of output and clear the doubt of inconsistency.  

Moreover, hydrogen combustion engine produces waste heat whereby it produces heat three times more compared to the other regular engines (Karvonen 2016). This can be a great challenge since it may lead to unwanted wastage and as a result become an expensive model of an engine.  For this heat to me managed, a condenser is required to be implemented in the engine to cool the water vapor being heated by the exhaust gases in the combustion chamber.  This method is not cost effective and thus a challenge.

The greatest challenge is that when hydrogen explodes it brings about tremendous effects.  Having high affinity for combustion, hydrogen may lead to loss of lives which makes many people not to accommodate this type of engine even though it possesses many advantages.

Opportunities

Hydrogen combustion engine can be combined with a turbocharger to enhance an effective output.  Turbocharger uses the exhaust gas compressor to get rid of the waste as produced and as a result improving the function ability of an engine. Turbochargers increase the power of an engine by 40% and thus making small engines to become equivalent to large engines (Becky and Johnson 2018).  This poses a great competition to the other engine producing companies.  The effective performance and a powerful engine will lead to customer satisfaction and as a result improve on sales as well as gaining customer loyalty.

Turbocharger enhances the cooling of the gases produced after combustion by passing them through the charge air cooler which reduce the temperatures and this once they are released from the engine they do not bring about a negative impact on the environment (Zhang and Wang 2015). The cooling also enhances the maintenance of the engine and thus reduces the high risk of damage.

There has been a debate that focuses on the abandoning of fossils fuels to be used as a source of energy in aircrafts.  This becomes a great opportunity for hydrogen to be absorbed as the new method of energy source.  It is advantageous since no change in the mode of the craft is required.  Simple modifications of the available engines are done to enhance the smooth running of the crafts engine. Ghazal (2013) reported that the adoption of hydrogen as a source of energy also reduces on the intensity of air pollution caused by the waste products of fossils fuels when used in the production of energy.  Fossils fuels produce carbon monoxide which has a great negative impact on the ozone layer.  There are many more waste gases produced from the combustion of fossils fuels that are harmful to both human and aquatic life.  Hydrogen is a source of clean energy and is an effective source.

The possible depletion of fossil fuels is a great opportunity for the embrace of the hydrogen combustion engines to be used in the operations of motor vehicles.  As the levels of fossils fuel go down, the cost of using fossil fuel as a source of energy will rise.  This will give room to the shift to hydrogen combustion engines to be used.

Figure showing Turbocharger

The small size of the enhanced hydrogen combustion increases the ease of maintenance and it is easy to repair in the case of breakdown.   Since the engine does not use fossils fuels its durability is enhanced and as a result gives a good service to the users. Additionally, creating a customer feedback platform is a major aspect that can promote the effective implementation of the hydrogen enhanced combustion engine.  This platform enhances the communication between the customers and the manufactures (Zurbriggen et al.  2014). The customer consideration and specifications can be tailored to the engines and as a result a high quality product is produced.

However, implementation of new hydrogen engine models can be done in phases hand in hand with the older models whereby pre-testing is done to determine the workability of the engine.  After they become fully stable, the new design fully implemented and the older models be upgraded.  These phases enhance the comfortable improvement of models and avoid the unnecessary breakdown of the engines.

Continued research should be conducted aimed at improving the hydrogen enhanced combustion engine.  This research will aid in the modeling of the engine in a way that give better results and is cost effective.  Research can be conducted using the available technologies and  through the combination of other older models of engines with the hydrogen combustion engine to have a better product.

Hydrogen Fuel Enrichment

Hydrogen can be used in engines to enhance their performance in terms of energy production.  Hydrogen mixed with other biofuels produces more energy that can be used for a longer period.  Additionally, the combination of hydrogen with other fuels in the engine reduces the amount of exhaust gases being produced to the environment. This can be used as a methodology for controlling environmental pollution.  Hydrogen in the engine can be obtained through electrolysis method and get stored as useful energy.

Hamdy et al. (2015) noted that Hydrogen can be used in gasoline engines to improve on the performance of the engine.  Gasoline has a low flammability and as a result there is reduced energy production which has a negative effect to the normal functioning of the engine.  The introduction of hydrogen in the combustion chamber boosts energy production and the continued combustion of gasoline.  This improves the general functioning of the gasoline engine.

History

In the beginning when the engines were being tested, all the experiments were designed for gases to be burned. There were several preferred gases including natural and propane. However, hydrogen gas was not a priority even thou there were investigations on incorporating hydrogen in the design experiments of engines. According to Robinson (2011), the first invention was from Rivaz (1807); a Swiss scientist who used a mixture of hydrogen and oxygen to design an internal combustion engine with an electric ignition. He later designed a car specifically for this engine which became the first internal combustible automobile. When he was convinced that his idea and design were workable, Rivaz obtained a patent from France for his invention. His sketch invention from the patent is shown below:

Figure showing sketch for Rivaz

He used the idea of using hydrogen combined with oxygen to generate power that could be used to move machinery. The hydrogen burns and creates a vacuum after explosion. The pressure from the atmosphere is responsible for moving the car. However, this was one of the primitive hydrogen fueled engines.

In 1974, Stebar and Parks did an investigation on supplementing hydrogen through extension of the lead operating limits of gasoline engines for the purposes of controlling NOx emissions (MILLER 2015). The experiment results indicated that addition of small amounts to the fuel resulted to limited emissions of NOx and CO. this was only possible for fuels containing Hydro-isooctane mixtures that were leaner than 0.55 equivalent ratios. However, the hydrocarbon (HC) emissions markedly increased at the given conditions. Therefore, they concluded and recommended that for the hydrogen supplemented fuel approach to succeed would require the development of means to control emissions of hydrocarbons. Additionally, a suitable hydrogen source on board the vehicle had to be established.

Varde and Frame performed another experiment to study how diesel particulates could be reduced in the exhaust of a diesel engine in 1983. The study involved the aspirating small quantities of hydrogen in gaseous form in the engine intake (Karvonen et al. 2016 p.3735).

A four stroke single cylinder diesel engine was used which had a compression ratio of 17.4:1. It was found out that the flow rate of hydrogen was equivalent to approximately 10% of the total energy. Additionally, the smoke emission had substantially reduced at part loads. However, the smoke levels reductions were limited at full rated loads. This was related to the lower amounts of air which was in excess I the cylinder. The most intriguing part is that they also found out that the thermal efficiency of the engine depended on the hydrogen energy portion. This was as a result of performing two tests whereby the hydrogen portions were varied in the diesel mixture. In the first experiment, the hydrogen flow was maintained constant while to increase the output of the engine the diesel kept on increasing. In the second set, the engine kept running at 40rps but a variation in the hydrogen flow rate was kept. The results indicate that the efficiency increased with as the energy portion of hydrogen was raised. At the same time, the lowest hydrogen fueling rate produced decreases in the efficiency or remained constant relative to the operation baseline (when no hydrogen was supplied to the engine).

Engine combustion under oxygen enriched air

An engine dynamometer was designed to determine oxygen enriched air impacts on exhaust emissions. The designer and founder of the dynamometer found that the hydrocarbons were reduced to substantia amounts compared with operating engines running on lean-air mixture. However, carbon monoxide emission was similar while nitrogen emissions significantly increased. With oxygen enrichment, octane requirements were high and also increased levels of fuel consumption. Therefore, the emissions and the characteristics of performance were due to the higher peak temperatures that resulted from high oxygen concentrations. Maxwell (2013) reported  in 1993 that the impact of oxygen enriched air was evaluated  the performance of engines and the exhaust emissions of a four stroke single cylinder engine. The evaluation was done on both gasoline and natural gas (Nguyen et al. 2018 p.17520-17530

 They used different variations of the oxygen content in the intake air between 20.9% (ambient air) and 25%. The indication in the test results is that the use of oxygen enriched air had a significant impact on the power output as well as improvements in fuel conversion efficiency.  Additionally, there was also lower specific fuel consumption, higher exhaust gas temperature and a significant reduction in carbon monoxide and hydrocarbon emissions as long as the engine was either fueled with gasoline or natural gas (Greenwood et al.  2014 p.12983).

Research Question

The research question for this project is grounded on

How to improve the overall efficiency of the combined hydrogen combustion engines?

Objective  

The overall objective is to evaluate the efficiency and improve its performance in line with the combined hydrogen combustion engines.

Sub-goal

To assess for the efficiency via the application of the simulation technique

There are factors influencing the homogeneous charge spark ignition thermal efficiency of an SI engine that combines fuel with hydrogen. According to Reif (2015), the main focus is on the degree of degree of cooling loss and constant volume. The engine that was used was a four stroke with four cylinders. It was an improvised gasoline engine which was specifically created for passengers cars. The engines bore 85 mm, stroke 88 mm, and the compression ratio of 8.5. With these features the engine was perfect for the tests. Hydrogen or methane was supplied into the manifold of the engine. The supply was continuous and a flow rate meter was used to measure the flow rate of the fuel gas (Deb et al. 2015 p.8586).

The engine speed was kept 1500 rpm and the volumetric efficiency at 50%. The percentage also includes the fuel gas so that the flashback phenomenon can be avoided. There is the required amount of pressure required for the tests to be accurate. The in-cylinder pressure records were taken using piezoelectric type pressure transducer (AVL, GM12D). The data of the pressure over 200 cycles was used to calculate the thermal efficiency, heat release rate and the degree of constant volume (Chintala, V Subramanian and K 2015 p.183).

The temperature was instantaneous as the engine was running and generating heat.  A thin film-type thermocouple (Medtherm, TCS-103E, chromel constantan type) was used to collect the temperature results. An exhaust gas analyzer (Horiba, MEXA 9100) was used to analyses the exhaust gases and sort them according to their amounts and characteristics. The behavior of these gases is crucial for the combustion efficiency calculation. The burning gas also causes cooling losses which need to be significantly analyses (Ji et al.  2016 p.274).

The process is facilitated by analyzing the cylinder pressure diagram and the composition of the exhaust gases. This cooling loss analysis is done from the burning gas in a homogenous SI engine to its cylinders. For the analysis of cooling loss to be effective, a comparison between the combustion of methane and hydrogen was done. The comparison revealed that the cooling loss in the combustion of hydrogen was higher than that of methane combustion. This was due to the faster burning velocity and the quenching distance for the combustion of hydrogen (Ma, Zhong and Zhang 2018 p.7591).

According to Ghazal (2013) when measuring the pressure of the cylinder and the instantaneous pressure, they varied the ignition timing for both hydrogen and methane combustion. The results indicated that the combustion of hydrogen was for a shorter period compared to methane since it had higher burning velocity. It was further observed that the combustion chamber walls’ temperatures tended to increase with an advance of burning both fuels. The cooling loss also influenced the apparent rate of heat release in hydrogen combustion. This is attributable to the higher cooling loss of hydrogen combustion to the thin temperature boundary layer thickness on te chamber of combustion. The quenching distance is short enabling heat to travel at short distance before reaching the surface of the combustible chamber. Additionally, hydrogen’s high burning velocity during combustion causes convection that is intense between the burning gas and the walls of the camber resulting to heat transfer enhancement. For both fuels, it was observed that the cooling loss ratio was tending to increase with advance in ignition timing during combustion. In hydrogen combustion, it was significantly higher than methane combustion at the same ignition timing (Wang et al.  2012 p.58).

With the retardation of the ignition timing, there was a decrease in the cooling loss for bot methane and hydrogen combustion. This was confirmed from taking instantaneous measurements of heat flux at a represented location in the cylinder head. In hydrogen combustion, a lower thermal efficiency was obtained than that of methane combustion at throttled conditions. These results were due to the higher cooling loss ratio and hydrogen’s higher levels of constant volume cooling during its combustion. Therefore, the conclusion about improving the thermal efficiency of hydrogen-fueled engines is to essentially reducing the cooling losses (Nguyen et al. 2018 p.17520).

The application often preferred and considered for the utilization and the appraisal of this experiment is the simulation context.

Gant chart has been used to show and illustrate clearly the schedule of activities of the proposed project research.

MONTHS	1STMONTH NOV,2018	2NDMONTH DEC,2018	3RDMONHT JAN,2019	4THMONTH FEB,2019	5THMONTH MAR,2019	APRIL, MAY, JUNE,2019
Project initiation
Project system analysis
Project system design
Project implementation
Documentation and reporting

Hydrogen combustion engine came as a result of modification of the old model of gasoline engine.  This development was focused on lowering the cost of maintaining the engine as well as targeting on low consumption of energy. The hydrogen combustion engine worked perfectly in meeting the specifications since it produced a high voltage energy that could operate a car for a long period of time.  Hydrogen enhanced combustion engine also has low emissions since it was designed to purify its exhaust before they are released into the environment. The first hydrogen combustion engine worked with the combination of hydrogen and oxygen to produce energy that facilitated car movement.  Due to the high reaction between hydrogen and oxygen to produce water brought a need for the advanced development of hydrogen engine for function with hydrogen as the only component.

In the development period Mazda incorporated wankel engines that used pure hydrogen for combustion.  This incorporation worked well since the engine did not need retooling in the case of a shift from the source of energy.  Only a few changes would be implemented and the engine would work perfectly with any other fuel (Beck, 2018). BMW also tested the hydrogen powered engine and it really met the expectations by having a high combustion rate which lead to an increase in the production of energy.  High energy power facilitated the fast movement of the car at an approximate speed of 301km/h.  The hydrogen combustion engine only produced water as the only by-product which was a great excitement to the BMW Company (Beck, Uyehara and Johnson 2018 p.478).

Conclusions

There were several preferred gases including natural and propane in the history of engine invention. However, hydrogen gas was not a priority even thou there were investigations on incorporating hydrogen in the design experiments of engines. The first invention was from Rivaz (1807); a Swiss scientist who used a mixture of hydrogen and oxygen to design an internal combustion engine with an electric ignition. He later designed a car specifically for this engine which became the first internal combustible automobile. When he was convinced that his idea and design were workable, Rivaz obtained a patent from France for his invention. His sketch invention from the patent is shown below: he used the idea of using hydrogen combined with oxygen to generate power that could be used to move machinery. In the recent years, there have been enhancements in the overall engine outlook to come up with Hydrogen enhanced combustion engine.

 Hydrogen enhanced combustion engine is an appropriate motor engine which is designed to have hydrogen as the major source of energy.  It combines different fuels and through the induction of hydrogen more energy is produced to facilitate movement.  The engine is designed in a way that accommodates changes as well as use of different sources of fuels.  Through its well defined features, the engine reduces on emissions from internal combustion.  The little emissions therefore are filtered and cooled before they are released into the environment.  The engine is environmental friendly since it has contributed into a major reduction of environmental pollution.  Despite the challenges in the performance of the engine, it is more beneficial compared to other types of engines.

References

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Ghazal, O.H., 2013. Performance and combustion characteristic of CI engine fueled with hydrogen enriched diesel. international journal of hydrogen energy, 38(35), pp.15469-15476.

Greenwood, J.B., Erickson, P.A., Hwang, J. and Jordan, E.A., 2014. Experimental results of hydrogen enrichment of ethanol in an ultra-lean internal combustion engine. international journal of hydrogen energy, 39(24), pp.12980-12990.

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Nguyen, V.N., Deja, R., Peters, R., Blum, L. and Stolten, D., 2018. Study of the catalytic combustion of lean hydrogen-air mixtures in a monolith reactor. International Journal of Hydrogen Energy, 43(36), pp.17520-17530.

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