Browse Topic: Rotary engines

Items (240)
In the present problem, we have studied mechanical & aero dynamic induced noise. Mechanical noise refers to noise generated by the vibrating surface of the engine structure, engine components and engine accessories after excitation by reciprocating or rotary components. Aero dynamic noises are due to air intake and exhaust of the gases. In the present study, the identification of the engine sources such as Engine Structural Noise, Fuel Pump Noise, Oil Pan Noise, Air Suction Noise and Exhaust Noise has been performed. These four noise sources like Fuel pump, oil pan, Suction noise and Exhaust noise were isolated through wooden/plastic/steel ducts by acoustical duct method for a 80.85 kW diesel engine coupled with a hydraulic dynamo meter at different speeds and load conditions. The results were compared with the overall/structural Sound Pressure Level (SPL). The SPL of engine sources like oil Pan, fuel pump & Air intake are also plotted to show the ranking of all sources and also
Goel, ArunkumarMeena, Avadhesh Kumar
ABSTRACT Today automotive gasoline combustion engine’s are relatively inefficient. Diesel engines are more efficient, but are large and heavy, and are typically not used for hybrid electric applications. This paper presents an optimized thermodynamic cycle dubbed the High Efficiency Hybrid Cycle, with 75% thermodynamic efficiency potential, as well as a new rotary ‘X’ type engine architecture that embodies this cycle efficiently and compactly, while addressing the challenges of prior Wankel-type rotary engines, including sealing, lubrication, durability, and emissions. Preliminary results of development of a Compression Ignited 30 kW X engine targeting 45% (peak) brake thermal efficiency are presented. This engine aims to fit in a 10” box, with a weight of less than 40 lb, and could efficiently charge a battery to extend the range of an electric vehicle
Shkolnik, AlexanderShkolnik, NikolayScarcella, JeffNickerson, MarkKopache, AlexanderBecker, KyleBergin, MichaelSpitulnik, AdamEquiluz, RodrigoFagan, RyanAhmed, SaadDonnelly, SeanCosta, Tiago
ABSTRACT Military Ground Vehicle electric power demands continue to grow as new mission equipment is added. Using an Auxiliary Power Unit (APU) consumes less fuel than restarting the main engine frequently to charge batteries. To meet the rising demand for powerful, L-3 Combat Propulsion Systems is developing a family of heavy-fuel rotary engines. Rotary engines offer superior power density making them a good choice for applications that require high power in a limited space. Heavy fuel capability simplifies logistical challenges in the field. However, rotary engines have unique cooling challenges. Unlike a piston engine, the intake, compression, expansion, and exhaust events all take place at their respective fixed positions around the circumference of the rotor housing, leading to large temperature differences around the housing. The cooling system must be carefully developed to minimize these temperature differences in an effort to control thermal deformation, minimize thermal
Lee, KevinOehlerking, DaleRoodvoets, Levi
ABSTRACT This paper discusses the design and performance results of a modular designed spark ignited rotary engine Auxiliary Power Unit (APU) fueled by JP-8. This APU is intended for use onboard tactical and combat vehicles applications where packaging space and weight are at a premium. The platform is flexible and scalable to allow for application to the full portfolio of tactical and combat systems. Such an APU would enable the Army to realize significant cost savings in terms of fuel and fuel support, as well as enable enhanced operation modes of existing vehicles by enabling Silent Watch capability
Stein, JoshuaTroia, JosephTruemner, RussellHunter, Gary
At present, the problem of global warming is becoming more and more serious, and the transformation of energy structure is very important. The rotary engine has the advantages of small size, high power-to-weight ratio, and high fuel adaptability, which makes it promising for application in the fields of new energy vehicle range extender and unmanned aerial vehicle. To this end, this paper proposes the idea of hydrogen/ammonia dual-fuel combination applied to rotary engine, using the experimentally verified three-dimensional simulation model of rotary engine, to study the process of hydrogen/ammonia rotary engine in-cylinder mixture formation under the direct-injection dilute combustion mode, and to analyze the impact of different dual-fuel injection strategies on the performance of rotary engine, and finds that delaying the moment of injection leads to the ammonia concentration in the middle and front of the combustion chamber; when the ammonia nozzle is located in the intake port, the
Chen, WeiYang, XuYu, ShiwuLiu, XuHe, WeibiaoZuo, Qingsong
Amongst all the hybrid-vehicles technologies and layouts, range-extended electric vehicles are the ones with the real prospect to reduce the emissions produced by the thermal machine when in driving conditions, while assuring an adequate range for the common user. The BMW i3 represents one of the most successful series hybrid electric vehicles, having been on the market since 2013. Given the complexities of a hybrid layout employing both thermal and electrical machines, the range extender must have compactness and lightweight characteristics in addition to a suitable power output for the vehicle. Usually, standard 4- stroke small-displacement engines are employed for this application, with the BMW i3 employing a 2- cylinder range extender. More interestingly, a Wankel rotary engine can provide the same amount of mechanical power by reducing the weight and the volume of nearly a third to the equivalent 4-stroke engine. In this study a numerical assessment of the Advanced Innovative
Vorraro, GiovanniTurner, James W.G.
The Wankel rotary engine has been an attractive alternative for transportation due to its unique features of lightweight construction, small size, high power density, and adaptability to various fuels. This paper aims to investigate the performance of air-fuel mixing in a hydrogen-fuelled Wankel rotary engine using different fuelling strategies. To achieve this, 3D computational fluid dynamics (CFD) simulations were conducted using CONVERGE software on a prototype engine with a displacement of 225 cc, manufactured by Advanced Innovative Engineering UK. Initially, the simulations were validated by comparing the results with experimental data obtained from the engine fuelled with conventional gasoline under both motored and fired conditions. After validating the model, simulations were conducted on the premixed hydrogen engine combustion, followed by more detailed simulations of port fuel injection (PFI) and direct injection (DI) of hydrogen in the engine. The results indicate that
Moreno Cabezas, KevinVorraro, GiovanniLiu, XinleiMenaca, RafaelIm, Hong G.Turner, James W.G.
The Wankel engine is an eccentric rotary internal combustion engine known for its simplicity, compactness, reliability, and efficiency. However, issues related to sealing, efficiency, and emissions have hindered its widespread use. Recent advancements in sealing technology, novel designs, material coatings, and alternative fuels have addressed some of these problems, leading to improvements in Wankel engine performance. This study examines these advancements in Wankel engine technology and proposes three potential applications for future automotive use. The first application involves utilizing a Wankel engine with a continuously variable transmission to replace the powertrain in conventional vehicles. The second application suggests replacing the engine in a series-parallel electric-hybrid architecture with a Wankel engine. Lastly, the third application explores using a Wankel engine as a range extender for electric vehicles. To evaluate the benefits in terms of fuel consumption for
Mittal, VikramShah, RajeshPrzyborowski, Alexandra
Mazda, the automaker with the longest and richest history of using the Wankel rotary engine announced that it resumed mass production of rotary engines for a new variant of the MX-30 compact crossover. Mazda provided little detail about the engine itself, which serves as a generator for the MX-30 e-SKYACTIV R-EV, a plug-in hybrid (PHEV) variant of the MX-30 crossover. Mazda hasn't used the unique powerplant for a production vehicle for more than a decade. The MX-30 e-SKYACTIV R-EV employs the rotary engine in a series-hybrid layout to generate electricity to replenish the vehicle's 17.8-kWh lithium-ion battery, which when fully charged, can provide up to 85 km (31 miles) of driving range on Europe's Worldwide Light Vehicle Test Procedure (WLTP) cycle. Gasoline from a 50-L (13.2-gal.) fuel tank supplies the rotary when its operation is required to provide electricity for extended-range driving. In a release, Mazda explained it “positioned it [the rotary engine] on the same axle as a
Visnic, Bill
TOC
Tobolski, Sue
Unmanned, autonomous aerial vehicle applications are an indispensable part of modern aviation. The propulsion of such aerial vehicles is often realized by Wankel rotary engine. They are particularly suitable for this application due to their high power-to-weight ratio and smooth operation. As a result of their properties and geometric characteristics, Wankel rotary engines are usually operated with highly volatile fuels like aviation gasoline (AvGas). In comparison, the existing aviation refueling infrastructure is oriented toward the most common aviation fuel, kerosene. This and other reasons, such as significantly lower prices and easier fire protection regulations, lead to the desire to be able to operate these propulsion units with kerosene. Opposed to reciprocating engines, the low compression ratio of rotary engines prevents the implementation of compression ignition (CI) combustion processes. In previous studies, the effects of an air-assisted injection system on operation with
Gotthard, ThomasHofmann, PeterZahradnik, Felix
The present work extends the performance analysis of a rotary Wankel engine for range extender applications already introduced in the companion papers of this series. Specifically, in this work, an overall balance was carried out on mechanical and thermal parameters inferred from the indicated pressure cycles and those measured by the dynamometer and the data acquisition system during steady-state engine testing, highlighting the energy fluxes within the machine. The evaluation of the in-chamber heat transfer coefficient, by means of an adapted Woschni model, and the related heat rejected to the coolant represent the additional and necessary analysis to complete the experimental assessment already presented in the previous papers. The tested engine is the Advanced Innovative Engineering 225CS and the experimental testing was conducted using a combustion analyser specifically developed for rotary machines. The results reported in this work are representative of the performance of
Vorraro, GiovanniTurner, James
Internal combustion engines are generally reciprocating or, to a less extent, Wankel rotary engine types. Reciprocating engines are bulky, heavy and complex, mainly due to the need for intake and exhaust valves and their associated cam-train, and their complicated crankshaft. Wankel rotary engines overcome these deficiencies but have other undesirable features. An alternative to the Wankel engine is the Szorenyi Three Chamber Rotary Engine concept created by the Rotary Engine Development Agency (REDA). This paper analyses the design features of the two rotary engine types and directly compares the merits of the designs. The paper analyses the Wankel engine’s geometry which causes an excessive eccentric shaft deflection due to the centrifugal force of the rotor that is eccentric to the engine centreline and which results in limiting the engine rotor to low revs; a combustion chamber shape that causes a high-speed transfer of the combusting gases (the ‘squish’ effect) which results in
King, Peter
Today unmanned aerial vehicle applications are powered by Wankel rotary engines due to their high power-to-weight ratio and smooth operation. Most of modern propulsion units for unmanned aerial vehicles are designed to run on high volatile fuels such as aviation gasoline (AvGas). However, the refueling infrastructure in aviation is geared toward the most used aviation fuel, kerosene. This and other reasons, such as significantly lower price and easier fire protection regulations, lead to the desire to be able to operate these propulsion units with kerosene. Opposed to reciprocating engines, the low compression ratio of rotary engines prevents the implementation of compression ignition combustion processes. Therefore, the purpose of this paper is to discuss the operation of a spark-ignited rotary engine on different fuels. In detail, different qualities of kerosene as well as gasoline/kerosene blends are compared together. In this respect, a thermodynamic analysis of the individual
Gotthard, ThomasBeyfuss, BastianHofmann, Peter
A closed-cycle computational model of a non-Wankel rotary engine was thoroughly investigated to achieve optimal efficiencies, in a multitude of loading conditions relevant to automotive and aeronautical applications. Computational fluid dynamics (CFD) modeling was conducted in CONVERGE CFD, targeting the operation of a single pre-chamber and downstream main chamber engine system, roughly from 100 crank angle degrees (CAD) before top dead center (bTDC) to 100 CAD after top dead center (aTDC). In the developed framework, optimization studies involved main decision variables, including the engine’s compression ratio (CR), the injector’s position within the pre-chamber, the injector’s nozzle hole count and nozzle hole diameters. Traditional and split-injection strategies for the introduction of diesel fuel into the pre-chamber were evaluated by varying spray-related parameters including total injected mass, injection pressure, start of injection(s), and injection duration(s). The main
Nikiforakis, IoannisGuleria, GauravKoraiem, MahmoudAssanis, DimitrisCollie, CurtisCosta, TiagoKute, PiyushShkolnik, Alec
The present work represents the continuation of the introductory study presented in part I [11] where the experimental plan, the measurement system and the tools developed for the testing of a modern Wankel engine were illustrated. In this paper the motored data coming from the subsequent stage of the testing are presented. The AIE 225CS Wankel rotary engine produced by Advanced Innovative Engineering UK, installed in the test cell of the University of Bath and equipped with pressure transducers selected for the particular application, has been preliminarily tested under motored conditions in order to validate the data acquisition software on the real application and the correct determination of the Top Dead Centre (TDC) location which is of foremost importance in the computation of parameters such as the indicated work and the combustion heat release when the engine is tested later under fired conditions. In this testing phase much importance has been given also to the measurement of
Vorraro, GiovanniTurner, James W.G.Brace, Chris
This work represents a further contribution to reporting experimental activities carried out on a modern Wankel rotary engine. Specifically, in this study, the firing performance of the Advanced Innovative Engineering 225CS engine is analysed. Preliminary presentations of the experimental and measurement setup and a motoring analysis were extensively covered in Part I and II of this suite of papers while the current work presents the combustion analysis of the firing indicated pressure cycles collected through the bespoke combustion analyser software developed within the project. With the Wankel rotary engine gaining popularity again due to its potential as a range extender for battery electric vehicles, the aim of this work was mainly to analyse the fuel consumption together with the overall efficiency and the emissions at different engine speeds and loads as per classic steady-state engine testing. The characteristic curves of power and torque thus derived from the experimental
Vorraro, GiovanniTurner, James W.G.Akehurst, Sam
The present work investigates a means of controlling engine hydrocarbon startup and shutdown emissions in a Wankel engine which uses a novel rotor cooling method. Mechanically the engine employs a self-pressurizing air-cooled rotor system (SPARCS) configured to provide improved cooling versus a simple air-cooled rotor arrangement. The novelty of the SPARCS system is that it uses the fact that blowby past the sealing grid is inevitable in a Wankel engine as a means of increasing the density of the medium used for cooling the rotor. Unfortunately, the design also means that when the engine is shutdown, due to the overpressure within the engine core and the fact that fuel vapour and lubricating oil are to be found within it, unburned hydrocarbons can leak into the combustion chambers, and thence to the atmosphere via either or both of the intake and exhaust ports. As well as shutdown it also affects the startup process, where higher hydrocarbon emissions are caused due to the forced
Turner, JamesIslam, RezaVorraro, GiovanniTurner, MatthewAkehurst, SamBailey, NathanAddy, Shaun
Wankel rotary engines (REs) are often used for unmanned aerial vehicle (UAV) applications due to their excellent power-to-weight ratio and their smooth operation. Existing RE propulsion units are mainly designed to run on high-volatility fuels like aviation gasoline or regular gasoline. However, specific applications require a jet fuel or even multi-fuel capability. Due to their geometry, the low compression ratio (CR) of REs prevents the implementation of compression ignition (CI) combustion processes. While publications of modified spark-ignition engines that are able to run on low-volatile fuels are already few in number, publications of heavy-fuel spark-ignited (SI) REs can hardly be found at all. The purpose of this paper is as follows: The operation of a SI RE operated on kerosene is discussed. Accordingly, a thermodynamic analysis is carried out at warmed-up operation with kerosene. It is shown that sufficient performance and power output can be achieved on kerosene for full
Beyfuss, BastianFlicker, LukasGotthard, ThomasHofmann, PeterZahradnik, FelixKrenn, ChristianLubich, Georg
In a previous study it was shown that a production vehicle employing a Wankel rotary engine, the Mazda RX-8, was easily capable of meeting much more modern hydrocarbon emissions than it had been certified for. It was contended that this was mainly due to its provision of zero port overlap through its adoption of side intake and exhaust ports. In that earlier work a preliminary investigation was conducted to gauge the impact of adopting a zero overlap approach in a peripherally-ported Wankel engine, with a significant reduction in performance and fuel economy being found. The present work builds on those initial studies by taking the engine from the vehicle and testing it on an engine dynamometer. The results show that the best fuel consumption of the engine is entirely in line with that of several proposed dedicated range extender engines, supporting the contention that the Wankel engine is an excellent candidate for that role. Also, continued 1-D modelling of the zero overlap
Turner, JamesTurner, MatthewIslam, RezaShen, XuankunCostall, Aaron
The growing need for a sustainable worldwide mobility is leading towards a paradigm shift in the automotive industry. The increasingly restrictive regulations on vehicle emissions are indeed driving all of the world-leading road vehicles manufacturers to redesign the concept of transportation by developing new propulsion solutions. To this aim, a gradual electrification strategy is being adopted, and several hybrid electric solutions, such as extended-range electric vehicles with reciprocating engines or fuel cells, already represent a valid alternative to conventional vehicles powered by fossil fuels. Despite their appealing features, these hybrid propulsion systems present some drawbacks, mainly related to their complex architecture, causing high overall dimensions, weight and costs, which pose some limitation in their use for small-size vehicles. In this context, the Wankel engine may bring significant advantages, since it is characterized by an extremely compact and light design
Di Ilio, GiovanniBella, GinoJannelli, Elio
The Wankel rotary engine historically found limited success in automotive applications due in part to poor combustion efficiency and challenges around emissions. This is despite its significant advantages in terms of power density, compactness, vibrationless operation, and reduced parts count in relation to the 4-stroke reciprocating engine, which is now-dominant in the automotive market. A large part of the reason for the poor fuel economy and high hydrocarbon emissions of the Wankel engine is that there is a very significant amount of overlap when the ports are opened and/or closed by the rotor apices (so-called peripheral ports). This paper investigates the benefits of zero overlap from a production engine with this characteristic and the effect of configuring a peripherally-ported Wankel engine in such a manner. As discussed in the paper, arranging this condition for peripherally-ported engines unfortunately reduces the trapped compression and/or expansion ratios significantly
Turner, JamesTurner, MatthewVorraro, GiovanniThomas, Toby
The current quest to reduce CO2 emissions combined to new technologies has sparked an interest in revisiting radically different engine configuration concepts, such as adiabatic and split-cycle engines. To achieve the full potential of both concepts, the combustion chamber must be sealed without lubricating oil. A promising approach that has yet remained elusive, is to lubricate the piston-liner interface with gases. This paper explores the concept of using non-contacting finger seals to seal piston engines combustion chambers. The finger seals, made of a gas-lubricated pad at the end of a flexible beam, are fixed on a rotating piston that uses the centrifugal force to close the piston-liner gap. A physics-based fluid-structure model is developed to predict finger displacements and sealing performances. The model shows that the radial displacement of the fingers naturally creates a convergent profile with the liner that generates sufficient aerodynamic pressure to maintain a micrometer
Boudreau, PascalPicard, Mathieu
The paper first includes the main objective and boundary conditions for design and simulation of a multi fuel gas mixture system of a Wankel rotary engine. New regenerative fuels are more and more important for use in automotive propulsion and stationary applications of combustion engines. Due to the special design and operation of rotary engines there are opportunities for running these engines in future electric and hybrid applications with new designed liquids and gaseous fuels based on regenerative energy sources. Nevertheless, rotary engines have advantages in avoidance of preignition and detonation especially when using gaseous fuels with a higher percentage of hydrogen. The focus is on basic research and analyses of main physical and thermodynamic properties of separate lean burn gases (lower calorific value, mixed calorific value, AFR) and their effects on fuel mixing and engine performance. Furthermore, the scope of the investigation is on the development of simulation models
Dost, TobiasGetzlaff, Joern
The use of Wankel rotary engines as a range extender has been recognised as an appealing method to enhance the performance of Hybrid Electric Vehicles (HEV). They are effective alternatives to conventional reciprocating piston engines due to their considerable merits such as lightness, compactness, and higher power-to-weight ratio. However, further improvements on Wankel engines in terms of fuel economy and emissions are still needed. The objective of this work is to investigate the engine modelling methodology that is particularly suitable for the theoretical studies on Wankel engine dynamics and new control development. In this paper, control-oriented models are developed for a 225CS Wankel rotary engine produced by Advanced Innovative Engineering (AIE) UK Ltd. Through a synthesis approach that involves State Space (SS) principles and the artificial Neural Networks (NN), the Wankel engine models are derived by leveraging both first-principle knowledge and engine test data. We first
Chen, Anthony SimingVorraro, GiovanniTurner, MatthewIslam, RezaHerrmann, GuidoBurgess, StuartBrace, ChrisTurner, JamesBailey, Nathan
Currently automotive engines are reciprocating or Wankel rotary engine types. Reciprocating engines are bulky, heavy and complex, mainly due to the intake and exhaust valves and their associated cam-train. Wankel engines have a low rotor rev limit, and have inefficient sealing of the apex seals leading to poor economy and undesirable emission gases. The Rotary Engine Development Agency (REDA) has designed a new three-chamber rotary internal combustion engine concept using an adaptation of the patented Szorenyi Curve. The new design is an evolution of the design which was the subject of SAE Technical Paper 2017-01-2413 and SAE publication ‘So You Want to Design Engines: UAV Propulsion Systems’. This paper describes the features of the new three-chamber engine concept and includes an analysis of the major shortcomings of the Wankel engine. The Wankel engine’s geometry results in excessive crankshaft deflection at high engine revs due to the centrifugal force of the rotor which is
King, Peter
The intent of the specification is to present a functional set of requirements which define the user and hardware interfaces while providing sufficient capability to meet the misfire patterns for compliance demonstration and engineering development. Throughout this requirement, any reference to “ignition or injector control signal” is used interchangeably to infer that the effected spark ignition engine’s ignition control signal or the compression ignition engine’s injector control signal is interrupted, timing phased, or directly passed by the misfire generator. For spark ignition engines, the misfire generator behaves as a spark-defeat device which induces misfires by inhibiting normal ignition coil discharge. It does so by monitoring the vehicle’s ignition timing signals and suspends ignition coil saturation for selected cylinder firing events. The misfire generator will thereby induce engine misfire in spark ignited gasoline internal combustion engines; including rotary engines
Vehicle E E System Diagnostic Standards Committee
The present work presents the concept of a new rotary engine, and provides first investigations for its implementation in the energy sector. The main focus of this work is to provide a theoretical description of the engine and its differences from the state-of-the-art technologies. Its innovative principle consists of concentric operation, with two pistons of different rotation radius and the addition of a third intermediate chamber between the compression and combustion chamber. A description of the engine’s physical model is provided, followed by an analysis of the selected specific geometrical features. Additionally, a thermodynamic analysis clarifies the operational advantage compared to the existing cycles and, finally, a numerical investigation on the engine’s bulk performance is provided to quantify the anticipated results of the theoretical analysis. The theoretical description concludes that the new rotary engine is characterized by simple design with the minimum possible
Savvakis, SavvasGkoutzamanis, VasilisSamaras, Zissis
A four-chamber Otto cycle rotary engine, the Szorenyi Rotary Engine, has been invented and developed by the Rotary Engine Development Agency (REDA) in Melbourne, Australia. The engine concept has been awarded a U.S. Patent (Number 6,718,938 B2). A prototype engine has been constructed and a successful proof-of-concept engine test was achieved in 2008. The stator of the Szorenyi engine is a similar shape to a Wankel engine. However, the geometric shape of the engine rotor is a rhombus, which deforms as it rotates inside the contour of the mathematically defined stator. This geometry translates to a rotary engine with four combustion chambers. Each revolution of the crankshaft produces one revolution of the rotor; a complete engine cycle in each of the four chambers; and therefore four power strokes. In contrast, the Wankel engine produces one power stroke per crankshaft revolution. Additionally, the Wankel engine is rev limited due to the excessive crankshaft bending resulting from the
King, Peter
VRDE has developed Wankel type rotary engine to achieve high power output & fuel efficiency for indigenization programme of UAVs. This engine is meeting all performance parameters needed for intended aerial vehicle. This paper describes the testing methodology followed by development engineers to prove the endurance and reliability of UAV engine for airworthiness certification. This paper gives the brief about testing carried out on the Wankel engine, failures faced during endurance testing and their rectification to enhance the life of the engine to achieve hundred test cycle mark. This paper also briefs about the test set up, endurance test cycles simulating the practical operating conditions
Yewale, Ganesh LiladharTapkire, AbhishekRadhakrishna, DShejwal, PopatSingh, KaushalPanchal, Gaurav
Energy independence and reduction in pollutant emissions are a center of interest for several researchers and car manufacturers. Renewable fuels have gained in popularity because of their sustainability and, in some cases, lower amounts of greenhouse gases. Moreover, energy diversification is also required by all countries. One possible solution is the use of biofuels such as ethanol, methanol, etc. These biofuels have been shown as good candidates as alternative fuels for vehicles because they are liquid and they have several physical and combustion properties similar to gasoline. Alcohols have also a higher octane number and oxygen content than gasoline. This allows the alcohol engines to have much higher compression ratios (CRs), and thus, better BTE (brake thermal efficiency). Brazilian car manufacturing industry has developed flexible-fuel vehicles, introduced in 2003, which became a commercial success. Flex fuel internal combustion engines (ICEs) can run on any proportion of
Guarato, Alexandre Z.Ticona, Epifanio M.Braga, Sergio L.
The demand for lighter, smaller, more efficient, and more powerful engines calls for a rethinking of the traditional internal combustion engine (ICE). This paper describes development progress of LiquidPiston's small rotary engine, the XMv3, which operates on a Spark-Ignited (SI) variant of its patented High Efficiency Hybrid Cycle (HEHC). This thermodynamic cycle, which combines high compression ratio (CR), constant-volume combustion, and overexpansion, has a theoretical efficiency of up to 75 percent using air-standard assumptions and first-law analysis. XMv3 displaces 70cc (23cc per each of three working chambers) and is gasoline fueled. The engine is simple, having only two primary moving parts, which are balanced to prevent vibration. The ‘X’ engine geometry utilized by XMv3 can be considered an inverted ‘Wankel’, retaining the traditional Wankel' rotary advantages of high power density and smooth operation, while also overcoming some of Wankel's inherent performance limitations
Littera, DanieleNickerson, MarkKopache, AlexanderMachamada, G.Sun, ChuankaiSchramm, A.Medeiros, N.Becker, K.Shkolnik, NikolayShkolnik, A.
Combustion behavior in Rotary Engine (RE) is quite different from that in conventional reciprocating engines. Therefore, it is important to observe the combustion in RE. In the previous studies, an optical RE was developed, which enabled the observation of the flame propagation in the rotor rotating direction (side view). In the present study, modification was made to the optical RE so that the observation of the flame propagation in the rotor width direction (bottom view) became possible. By using two high-speed cameras, the combustion in RE was observed by bottom view and side view simultaneously. Consequently, it was found that the flame propagation in the rotor width direction is also important for better engine performance as well as that in the rotor rotating direction
Karatsu, YuichiMinota, ShunkiHashimoto, HidekiMoriue, OsamuMurase, EiichiYun, Jyong-HoKagawa, Ryoji
The Wankel rotary engine is more compact than conventional piston engines, but its oil and fuel consumption must be reduced to satisfy emission standards and customer expectations. A key step toward this goal is to develop a better understanding of the apex seal lubrication to reduce oil injection while reducing friction and maintaining adequate wear. This paper presents an apex seal dynamics model capable of estimating relative wear and predicting friction, by modeling the gas and oil flows at the seal interfaces with the rotor housing and groove flanks. Model predictions show that a thin oil film can reduce wear and friction, but to a limited extent as the apex seal running face profile is sharp due to the engine kinematics. The seal-housing interface remains between the boundary and mixed lubrication regimes, which leads to large asperity contact pressure and therefore significant wear of the running face, and an effective friction coefficient that varies between 0.03 to 0.11
Picard, MathieuTian, TianNishino, Takayuki
This paper describes the development of a comprehensive simulation environment for investigations of gas-dynamic processes and combustion phenomena in rotary engines, conducted by the Austrian Institute for Powertrains and Automotive Technology of the Vienna University of Technology. In this connection, proven, commercially available engine cycle calculation Software-Tools have been used. For this, a rotary engine test bench has been established. As analysis tools, in addition to the traditional acquisition of the emitted engine torque, various pressures and temperatures, the recording of the pressure profile (combustion analysis measurement system) in the combustion chamber, as well as in the intake and exhaust ports, were used. The data of the test bench were used to develop and validate the methodology for the simulation tools. The focus in this paper is the development of a CFD (computational fluid dynamics) model with the software Converge from Convergent Science, Inc. In close
Spreitzer, JohannZahradnik, FelixGeringer, Bernhard
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