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The present work discusses a novel oxy-fuel combustion cycle utilized in compression ignition internal combustion engine. The most prominent feature of this cycle is that the air intake is replaced by oxygen; therefore nitric oxide (NOX) emission is eliminated. ...As water injection is already utilized in gasoline engine to control knocking, the utilization of water injection in optimizing oxy-fuel combustion process has been tested in this study. To understand the relationship between water injection strategy and cycle efficiency, computational fluid dynamics (CFD) simulations were carried out. ...The simulation results show that the injected water absorbs combustion heat to evaporate; therefore increased amount of working fluid leads to higher cycle efficiency. As water injection quantity increases, the water consumes too much heat and thus deteriorates combustion leading to lower cycle efficiency.

A novel combustion cycle which operates in 2-stroke operation and utilizes a novel exhaust valve timing and lift strategy is proposed to potentially replace the existing Otto and Diesel cycles. ...Air is replaced with oxygen to maximize the combustion efficiency and to enable broader range of fuels to be used. Water is injected into the combustion chamber to enhance the combustion heat absorption, gas expansion and to function as an energy carrier. ...Water is injected into the combustion chamber to enhance the combustion heat absorption, gas expansion and to function as an energy carrier.

The results show high differences comparing the high-pressure fuel/water mixture injection with both low-pressure injections. Low-pressure injection leads to large water droplets, which evaporate slowly and show high wall contact. ...The mixture formation with water is of special importance to achieve sufficient cooling and is, therefore, visualized by means of optical measuring technology. A novel laser-optic measuring technique for the detection of liquid water in the combustion chamber is developed on a theoretical basis and implemented in practice on a single-cylinder optical engine. ...Three different water injection concepts are optically measured: a low-pressure injection in the plenum chamber, a low-pressure injection in the intake pipe, and a high-pressure injection of a premixed fuel/water mixture via the central injector.

Water Injection (WI) has become a key technology for increasing combustion efficiency in modern GDI turbocharged engines. ...The controller is based on a novel approach that involves an analytic combustion model to define the spark advance (SA) required to reach a combustion phase target, considering injected water mass effects. ...The controller is based on a novel approach that involves an analytic combustion model to define the spark advance (SA) required to reach a combustion phase target, considering injected water mass effects. The calibration and experimental validation of the proposed controller is shown in detail in the paper.

The results indicate that both indicated work and thermal efficiency increase significantly due to water injection process. The increase of water injection temperature results in higher peak in-cylinder pressure and improves MEP. ...The present work discusses a novel oxyfuel combustion method named internal combustion rankine cycle (ICRC) used in reciprocating engines. ...This study investigates the effect of water injection temperature on the combustion and emission characteristics of an ICRC engine based on self-designed test bench.

The effects of in-cylinder water injection on a direct injection (DI) Diesel engine were studied using a computational fluid dynamics (CFD) program based on the Kiva-3v code. ...Using stratified fuel-water injection increases soot at 86% loads due in part to late injection. Because NOx decreased at all loads, the injection timing can be advanced to minimize fuel consumption and soot. ...It was found that liquid penetration increased approximately 35% with 23% of the fuel volume replaced by water, due mostly to the increase in latent heat of vaporization. Engine calculations were compared to experimental results and showed very good agreement with pressure, ignition delay and fuel consumption.

Two novel diesel injection systems have been tested in prototype form. Both are intended to overcome particular deficiencies of conventional equipment which are especially pronounced in small high-speed engines. ...These objectives were achieved by utilising the phenomenon usually called ‘water hammer’. Sufficiently high injection pressures were generated by rapidly halting a moving column of fuel. ...A continuously-operating pump thus generated injection pressures ten times higher than its delivery pressure. Injection data are given for a range of conditions.

Many recent studies have advocated Water Injection (WI) as an approach to replace or supplement existing knock mitigation techniques. ...Furthermore, water vapor acts as diluent in the combustion process. In this paper, the development of a novel closed-loop, model-based WI controller is discussed and critically analyzed. ...The innovative contribution of this paper is to propose a control strategy based on an analytical combustion model that describes the relationship between the combustion phase and the Spark Advance (SA), considering also the effects of the injected water mass.

The purpose of this study was to examine whether it is possible to control the ignition timing and slow down the rate of combustion with the use of water injection. The effects of different water flows, air/fuel ratios and inlet pressures were studied for three different fuels, iso-octane, ethanol and natural gas. ...The NOx emissions, which are very low for HCCI, decreased even more when water injection was applied. The amount of water used was of the magnitude of the fuel flow....The use of water injection in a Homogeneous Charge Compression Ignition (HCCI) engine was experimentally investigated.

On the basis of our experiments on a diesel truck engine with an in-line injection system, the following cases are considered: fuel/water emulsion injection into the combustion chamber; multi-point water injection into the air in the intake manifold; mono-point water injection before turbocharger as well as mono-point water injection after the turbocharger. ...On the basis of our experiments on a diesel truck engine with an in-line injection system, the following cases are considered: fuel/water emulsion injection into the combustion chamber; multi-point water injection into the air in the intake manifold; mono-point water injection before turbocharger as well as mono-point water injection after the turbocharger. For the fuel/water emulsion injection approach, the injection characteristics as well as the fuel spray characteristics are analyzed using the numerical simulation. ...On the basis of our experiments on a diesel truck engine with an in-line injection system, the following cases are considered: fuel/water emulsion injection into the combustion chamber; multi-point water injection into the air in the intake manifold; mono-point water injection before turbocharger as well as mono-point water injection after the turbocharger.

A novel combustion cycle involving oxygen and water is proposed as a potential replacement to the existing Otto and Diesel cycles. ...The cycle involves a compression ignition 2-stroke engine equipped with poppet exhaust valves and 2 high pressure gas injectors. Novel exhaust valve timing and lift strategy is applied to control the cylinder temperature for optimal fuel auto-ignition. ...High purity oxygen is used to replace air. Water having high specific heat capacity and gas constant is used as a working medium. In theory, relatively higher engine output from a comparable size of engine displacement can be expected as lesser heat is rejected to the environment.

It was possible to expand the initial engine load from 2.0 bar without water injection to 6.0 bar IMEP with water injection. In addition, the ethanol HCCI combustion achieved high indicated efficiencies, ranging from 34 to 39%, while maintaining good combustion stability and low emissions characteristics. ...The results showed that the water injection technique was effective in controlling the charge reactivity and consequently the combustion phasing while enabling higher engine load. The water injection reduced combustion speed and heat release rates, which led to higher combustion duration, better combustion phasing control, and a reduction of ringing intensity. ...In this context, this paper explores the use of water injection technique to control the combustion phasing and expand the load of an ethanol HCCI engine.

Besides Miller cycle application, cooled exhaust gas recirculation and variable compression ratio, the injection of water has recently gained increased attention as a promising technology for significant CO2 reduction. ...This paper gives deep insight into the fuel consumption reduction potential of direct water injection. Single cylinder investigations were performed in order to investigate the influence of water injection in the entire engine map. ...Single cylinder investigations were performed in order to investigate the influence of water injection in the entire engine map. In addition, different engine configurations were tested to evaluate the influence of the altering compression ratios and Miller timings on the fuel consumption reduction potential with water injection.

Another option identified in the last decade (following trials of similar technology in aircraft combustion engines) is water injection, which suppresses knocking largely by reducing local in-cylinder mixture temperatures due to its latent heat of vaporization. ...Thus, in this study, a 4-stroke, 1.5 liter, 3-cylinder turbocharged engine with direct fuel injection and port water injection was operated on 91, 95 and 98 RON gasoline fuel to assess effects of water injection on knock mitigation, combustion phasing, required air:fuel ratios and exhaust gas temperature control. ...Thus, in this study, a 4-stroke, 1.5 liter, 3-cylinder turbocharged engine with direct fuel injection and port water injection was operated on 91, 95 and 98 RON gasoline fuel to assess effects of water injection on knock mitigation, combustion phasing, required air:fuel ratios and exhaust gas temperature control.

Specifically, the effects on engine performance of the injection of water into the intake air charge were explored. The hydrogen fuel was injected into the cylinder directly. ...The results were compared with expectations for a conventionally operated hydrogen engine where load was controlled through changes in equivalence ratio. With water injection into the intake air charge, the NOx emissions were reduced by 87% with a 2% penalty in fuel consumption. ...Hydrogen fueled internal combustion engines have potential for high thermal efficiencies; however, high efficiency conditions can produce high nitrogen oxide emissions (NOx) that are challenging to treat using conventional 3-way catalysts.

In this study, we applied this system to PREDIC using a heavy-duty single cylinder engine with direct water injection, and evaluated the combustion controllability by water latent heat and thermal efficiency improvement by water vapor atmosphere for an adiabatic effect. ...Premixed Lean Diesel Combustion (PREDIC) has very low NOx combustion because of early injection timing, for example, at -120 degrees ATDC; however, it has some problems. ...In this study, we applied this system to PREDIC using a heavy-duty single cylinder engine with direct water injection, and evaluated the combustion controllability by water latent heat and thermal efficiency improvement by water vapor atmosphere for an adiabatic effect. As a result, we find that adequate water injection with the impingemnt spray of a split injection pattern can retard fuel injection timing by keeping low NOx and low HC emission levels, whose timing is more retarded than that of PREDIC.

Improving efficiency and reducing emissions are currently two hot topics in the internal combustion engine industry. Direct water injection technology (DWI) can effectively reduce the cylinder temperature, which is due to the absorption of the heat by the injecting liquid water. ...And then the effect of DWI strategy with different injecting water mass on the combustion and emissions characteristics are analyzed. Physically, injected water not only absorbs heat but also provides heat insulation. ...NO emission will significantly reduce under the water mass is 5mg and the injection timing is -150°CA ATDC. The ITE decreases by 3.3% while the NO emission decreases by about 80%.

The measured reductions are also compared with those in another DI Diesel utilizing split injections; water injection at greater than 30% water to fuel ratio by mass via the hybrid injector is found to be the more effective technique to lower NOx emissions. ...Here the effects of a new Mitsubishi water injection system for a direct injection (DI) Diesel engine on exhaust emissions are examined. ...Inert injection is an often-used technique to reduce NOx emissions from engines. Here the effects of a new Mitsubishi water injection system for a direct injection (DI) Diesel engine on exhaust emissions are examined.

Under knock limited spark advance (KLSA) condition, we find that the application of port water injection could effectively advance the combustion phasing and reduce exhaust gas temperature, which makes it possible to eliminate fuel enrichment and further enhances the fuel economy improvement at the maximum power point. ...Therefore, to address the issues discussed above, the port water injection (PWI) techniques on a 1.2-L turbocharged, three-cylinder, SIDI engine were investigated. ...For the exhaust emissions, due to the increasing heat capacity of the mixture and the elimination of fuel enrichment, port water injection techniques cause an 85.3% reduction in particle number concentration. However, it shows that for a given λ, an increase in the water/fuel ratio would cause higher THC emissions, which is contributed to the occurrence of more quenching caused by higher peak combustion pressure.

The paper reports on investigations carried out on a modern single cylinder high speed direct injection diesel engine (0.5 liter displ.) by means of a novel combustion photography technique. ...The novelty consists in using especially designed windows and endoscopes providing optical access into the combustion chamber. Due to the minuteness of the optical components they can be mounted in the cylinder head in a similar way as is common practice with cylinder pressure transducers. ...Due to the minuteness of the optical components they can be mounted in the cylinder head in a similar way as is common practice with cylinder pressure transducers. Thus, combustion may be watched "with the eye on the cylinder head fire deck". Illumination of fuel sprays is provided by a flash bulb positioned behind a second window.