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Viewing 1 to 30 of 102051
Technical Paper
2015-01-01
Susan Sawyer-Beaulieu, Edwin K.L. Tam
Life-cycle assessments (LCAs) conducted, to date, of the end-of-life phase of vehicles rely significantly on assumed values and extrapolations within models. The end phase of vehicles, however, has become all the more important as a consequence of increasing regulatory requirements on materials recovery, tightening disposal restrictions, and the rapid introduction of new materials and electronics, all potentially impacting a vehicle’s efficacy for achieving greater levels of sustainability. This article presents and discusses selected research results of a comprehensive gate-to-gate life-cycle-inventory (LCI) of end-of-life vehicle (ELV) dismantling and shredding processes, constructed through a comprehensive and detailed case study, and argues that managing and implementing creative dismantling practices can improve significantly the recovery of both reusable and recyclable materials from end-of-life vehicles. Although the amount of parts and materials recovered and directed for reuse, remanufacturing or recycling may be as much as 11.6% by weight of the ELVs entering a dismantling process [1], greater rates of reuse and/or recycling may be achieved by the strategic management of the ELVs entering the dismantling process according to age.
Technical Paper
2014-11-11
Alexander K. Rowton, Joseph K. Ausserer, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
As internal combustion engines (ICEs) decrease in displacement, their cylinder surface area to swept volume ratio increases. Examining power output of ICEs with respect to cylinder surface area to swept volume ratio shows that there is a dramatic change in power scaling trends at approximately 1.5 cm-1. At this size, thermal quenching becomes the dominant thermal loss mechanism and performance and efficiency characteristics suffer. Furthermore, small ICEs (>1 cm-1) have limited technical performance data compared to ICEs in larger size classes. Therefore, it is critical to establish accurate performance figures for a family of geometrically similar engines in the size class of approximately 1.5 cm-1 in order to better predict and model the thermal losses as well as other phenomena that contribute to lower efficiencies in small ICEs. The engines considered in this scaling study were manufactured by 3W Modellmotoren, GmbH. In particular, they are the 3W-28i, 3W-55i, and 3W-85Xi which have a cylinder surface area to swept volume ratio of 1.81 cm-1, 1.46 cm-1, and 1.28 cm-1 respectively.
Technical Paper
2014-11-11
Joseph K. Ausserer, Alexander K. Rowton, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
In this work, in-cylinder pressure was measured in a 55 cc single cylinder, 4.4 kW, two stroke, spark ignition engine. Engines of this size are common in handheld power tools, hobbyist aircraft, and more recently, commercially developed remotely piloted aircraft operated by the government and military. Literature data on adapting performance measurements developed for larger engines to engines of this size is sparse. This work focuses on evaluating two different methods for measuring in-cylinder pressure, a critical parameter for combustion analysis, matching power plants to airframes, and engine optimization. In-cylinder pressure measurements were taken using two different pressure transducers to determine if the performance differences between the two transducers are discernible in a small, spark ignition engine. A Kistler brand measuring spark plug was compared to a Kistler brand flush mount high temperature pressure sensor. Both sensors employ a piezo-electric pressure sensing element and were designed to measure indicated mean effective pressure and to detect knock at high temperature engine conditions.
Technical Paper
2014-11-11
Alessandro Franceschini, Emanuele Pellegrini, Raffaele Squarcini
Nowadays the challenge in design auxiliary device for automotive small engine is focused on the packaging reduction and on the increase of the performances. This requirements are in contrast to each other and in order to fulfil the project specifications, new and more refined design tools and procedures need to be developed. This paper presents a calculation loop developed by Pierburg Pump Technology Italy S.p.a. (PPT). It supports the design of a variable displacement oil pump component for engine applications. The work is focused on the fatigue life evaluation of a joint, which transmits the drive torque from the engine to the oil pump. The aim of the procedure is to calculate the onset of the surface fatigue phenomenon in the hexagonal joint which drives the oil pump, taking into account the axes misalignment and the flat to flat clearance. The study has involved several matters, experimental measures, CFD, MBA and FEM analyses. A calculation procedure has been set up in order to consider all the necessary loads applied on the joint.
Technical Paper
2014-11-11
Claudio Annicchiarico, Renzo Capitani
In a Formula SAE, as for almost all racecars, suppressing or limiting the differential action of the differential mechanism is the technique mostly adopted to improve the traction exiting the high lateral acceleration corners. The devices carrying out this function are usually called LSD, “Limited Slip Differentials”, which unbalance the traction force distribution, generating as a secondary effect a yaw torque acting on the vehicle. If the differential action is electronically controlled, this yaw torque can be used as a torque vectoring technique to affect the attitude of car. The yaw torque introduced by an electronically controlled LSD (also called SAD, “Semi-Active Differential”) could suddenly change from oversteering (i.e. pro-yaw) to understeering (i.e. anti-yaw), depending on the riding conditions. Therefore, controlling the vehicle attitude with a SAD could be quite tricky, and its effectiveness could be low if compared to the common torque vectoring systems, which usually act on the brake system of the car.
Technical Paper
2014-11-11
Giovanni Vichi, Luca Romani, Giovanni Ferrara, Luca Carmignani, Francesco Maiani
In the last years, the engineering in the automotive industry has been revolutionized by the continuous research in the reduction of consumption and pollutant emissions. On this topic there is the maximum attention both by the legislative bodies and by the costumers. The more and more severe limitations in pollutant and CO2 emissions imposed by international standards on the engine manufacturers and the increasing price of the fuel force the automotive research to more efficient and ecological engines. The standard approach for the definition of the engine parameters at the beginning of the design process is based on wide open throttle condition although, both in homologation cycles and in the real utilization, engines work mainly in partial load where the efficiency dramatically decreases. This aspect has recently become strongly relevant also for two-wheels vehicles especially for urban purpose. Within this context the authors developed an integrated numerical model, in MatLab Simulink ambient, in order to couple the engine simulation, performed by means of a 1D computer-aided engineering code, with the whole vehicle dynamic behaviour.
Technical Paper
2014-11-11
Rama Subbu, Baskar Anthony Samy, Piyush Mani Sharma, Prasanna Mahendiran
Ride comfort, driving stability and drivability are vital factors in terms of vehicle performance and the customer satisfaction. Crankshaft balancing is the source for the vibration that reduces the vehicle performance and it need to be controlled to some extent such that the vehicle performance will be improved. The IC engine is made up of reciprocating and rotating parts and they produce unbalanced forces during their operation and produce the vibratory output at the vehicle supporting members. The vibration reduction will be possible by minimizing unbalanced forces and by optimizing the crankshaft at the two wheeled vehicle engine design. Many researches were made to find the causes for the vibration and to reduce the vibrations at the engine supports. But still there is a research gap on the testing and simulation of engine components (crankshaft, connecting rod and piston assembly) and the correlation between the testing and simulation. In this work, an attempt is made to represent the engine vibrations and its isolations and to provide a gate way for the future work on it.
Technical Paper
2014-11-11
Daniela Siano, Fabio Bozza, Danilo D'Agostino, Maria Antonietta Panza
In the present work, an Auto Regressive (AR) model and a Discrete Wavelet Transform (DWT) are applied on vibrational signals, acquired by an accelerometer placed on the cylinder block of an internal combustion engine, for knock detection purposes. To this aim, vibrational signals are acquired on a four cylinder Spark Ignition engine for different engine speeds and spark advances. The same analysis is executed by also using the traditional MAPO (Maximum Amplitude of Pressure Oscillations) index, applied on the in-cylinder pressure waveforms. The results of the three methods are compared and in depth discussed to the aim of highlighting the pros and cons of each methodology. In particular, the problem of fixing a constant threshold level for each running condition is afforded and solved. The examples presented show the capability of the vibration based detection algorithms in accurately monitor the presence of heavy or soft knock phenomena, and to determine its intensity. Therefore, the possibility of implementation in modern on-board control units is foreseen, as well.
Technical Paper
2014-11-11
Koorosh Khanjani, Jiamei Deng, Andrzej Ordys
Controlling Variable Coolant Temperature in Internal Combustion Engines and Its Effects on Fuel Consumption Koorosh Khanjani ; Roehampton Vale Campus, Kingston University, Friars Avenue, London SW15 3DW; K1155703@kingston.ac.uk; Tel: +44 (0)208 417 4730; Jiamei Deng ; Roehampton Vale Campus, Kingston University, Friars Avenue, London SW15 3DW; J.Deng@kingston.ac.uk; Tel: +44 (0)208 417 4712; Andrzej Ordys ; Roehampton Vale Campus, Kingston University, Friars Avenue, London SW15 3DW; A.Ordys@kingston.ac.uk; +44 (0) 208 417 4846; Abstract: Increasing the efficiency and durability of internal combustion engines is one of the major concerns of engineers in development of modern road vehicles. Emission legislations are becoming stricter each year forcing manufacturers to deploy sophisticated engine control strategies to transfer more of the fuel chemical energy into power output. Internal combustion engines have now been equipped with electronic engine management control units which consist of precise measurements and performance by means of various sensors and actuators.
Technical Paper
2014-11-11
Ken Fosaaen
Global concerns over pollution have led to increasingly strict emissions legislation targeting small engines, which currently pollute at a much greater level than modern multi-cylinder automotive engines. Closed-loop control may be required to meet many future legislation requirements; however, such systems can be impractical due to high added component costs. A necessary component for closed-loop engine control is an oxygen sensor. Existing automotive oxygen sensors are too large, require too much power, and far too expensive to be suitable for the vast majority of the global small engine applications; therefore, some manufacturers have developed smaller and/or unheated versions based on their existing sensors to meet this emerging need. The ability to miniaturize resistive based sensors well below that of traditional Nernst (zirconia based) oxygen sensors affords the opportunity to meet future emissions standards with less of an impact on cost. The performance of a novel low-cost, low-power, narrow-band resistive-based oxygen sensor was compared with the stock oxygen sensor and several other commercially available oxygen sensors on a 2014 Honda Grom 125E motorcycle.
Technical Paper
2014-11-11
Horizon Walker Gitano, Ray Chim, Jian Loh
Recent concern over air quality has lead to increasingly stringent emissions regulations on ever smaller displacement engines, resulting in the application of Electronic Fuel Injection to the 100cc-200cc class 2-wheelers in many countries. In the pursuit of ever smaller and less expensive EFI systems, a number of unique technologies are being explored, including resistive type oxygen sensors. In this paper we investigate the application of a small resistive oxygen sensor to a small motorcycle EFI system. Measurements of the exhaust system temperatures, and Air/Fuel Ratio ranges are carried out, and compared to the sensors response over this range to create an estimate of the sensors in-use performance. Actual sensor and temperature measurements are then compared to both a standard zirconia switching type oxygen sensor, and a wide-band oxygen sensor. Results are analyzed and indicate that the resistive type oxygen sensor should be capable of allowing the EFI controller to successfully control the vehicles AFR in all operating modes with a faster “light off” time, and lower overall current draw when compared to the standard heated zirconia sensor.
Technical Paper
2014-11-11
Kenta Sugimoto
Cost reduction is an important development goal for small motorcycles (1). As a way to reduce costs, we have developed an electronically controlled fuel injection (hereafter FI) system without a throttle position sensor (hereafter TPS). Ordinarily, the high throttle range is controlled and computed by TPS, and the low throttle range by manifold pressure sensor (hereafter MPS). The intake airflow is estimated with consistent high precision regardless of the engine load, and the basic fuel injection is executed accordingly. Also, transient correction monitors the size of TPS changes, to inject fuel immediately when a TPS change equal to or greater than a threshold value is detected. In our development, we replaced these functions with control by MPS. For calculation of basic fuel injection quantity by MPS, we carried on the conventional method. However, MPS transient correction control had some aspects with poor tracking. Thus, we constructed a new form of transient correction control, securing the following points. - To estimate changed intake airflow, we calculated the size of MPS value changes between the previous cycle and the current cycle in the crank intake stroke, securing precision. - We distributed the locations for transient correction into three before the completion of the intake stroke, making it possible to supply the calculated transient correction values to the current intake stroke regardless of the throttle input or engine state. - We subtracted the manifold pressure change due to engine speed fluctuation from the MPS change calculated at the transient correction execution positions, preventing unintended injection while lowering the threshold value for transient correction.
Technical Paper
2014-11-11
Kazuyoshi Shimatani
Various sensors including throttle position sensors (TPS), manifold pressure sensors (MPS), crank angle sensors, engine temperature sensors, and oxygen sensors are mounted in electronically controlled fuel injection (FI) systems to accurately regulate the air-fuel ratio according to the operating state and operating environment. Among these vehicle-mounted sensors, TPS has functions for detecting a fully-closed throttle and estimating intake air volume by the amount of throttle opening. Currently, we have conducted a study on transferring TPS functions into the MPS (manifold pressure sensor) in order to eliminate the TPS. Here we report on detecting a fully-closed throttle for achieving fuel cut control (FCC) and idle speed control (ISC) in fuel injection systems. We contrived a means for fully-closed throttle detection during ISC and controlling changes in the bypass opening during FCC in order to accurately judge each fully-closed throttle state via the manifold pressure. A factor in causing fluctuations in manifold pressure in a fully-closed throttle state are changes in the engine RPM (also referred to as engine speed) and changes in the degree of opening of the bypass (hereafter simply bypass opening).
Technical Paper
2014-11-11
Yuta Kugimachi, Yusuke Nakamura, Norimasa Iida
Homogeneous Charge Compression Ignition (HCCI) engine has several advantages of high thermal efficiency and low emission over the conventional Spark Ignition (SI) engine and Compression Ignition (CI) engine. Although one way to achieve higher loads without knocking in HCCI engine is the combustion phasing retard, it is difficult to control a combustion-phasing since there is no external combustion trigger for controlling ignition like spark ignition and diesel fuel injection. Futhermore, recent researches show that too much combustion-phasing retard leads to unacceptable cycle-to-cycle variation of Pressure Rise Rate (PRR) and Indicated Mean Effective Pressure (IMEP). Therefore, it is necessary to construct a HCCI combustion control system to control a combustion-phasing at constant phasing in the expansion stroke accurately to get the high load without knocking. This study investigates the HCCI combustion control system and the algorithm as a means of extending the limit of IMEP of HCCI combustion at high load for realize HCCI engine fuelled with Dimethyl Ether (DME).
Technical Paper
2014-11-11
Bo-Chiuan Chen, Yuh-Yih Wu, Wen-Han Tsai, Hsien-Chi Tsai, Huang-Min Lin, Yao-Chung Liang
Fuel film dynamics in the intake manifold are considered to develop air fuel ratio (AFR) control strategy with on-line system identification for a V2 engine in this paper. A1000 cc four-stroke two-cylinder, water-cooled port injection SI engine is used as the target engine to develop the engine model in Matlab/Simulink. The model which consists of charging, fueling, combustion, friction, and engine rotational dynamics is used to verify the proposed AFR control. Since the fuel film dynamics changes with different engine operating conditions, the fuel film parameters are often listed as look-up tables for fuel film dynamics calculation in the conventional AFR control. However, those parameters might be inaccurate during transient engine operation. Different intake port temperature will affect the accuracy of those fuel film parameters as well. In order to solve this problem, recursive least square (RLS) is used to identify those parameters on-line. Kalman filter is utilized to estimate the AFR using a narrow-band oxygen sensor.
Technical Paper
2014-11-11
Stefano Frigo, Roberto Gentili, Franco De Angelis
Storing hydrogen is one of the major issues concerning its utilization on board vehicles. A promising solution is storing hydrogen in the form of ammonia that contains almost 18% hydrogen by mass and is liquid at roughly 9 bar at environmental temperature. As a matter of fact, liquid ammonia contains 1.7 times as much hydrogen as liquid hydrogen itself, thus involving relatively small volumes and light and low-cost tanks. It is well known that ammonia can be burned directly in I.C. engines, however a combustion promoter is necessary to support and speed up combustion especially in the case of high-speed S.I. engines. The best promoter is hydrogen, due to is opposed and complementary characteristics to those of ammonia. Hydrogen has high combustion velocity, low ignition energy and wide flammability range, whereas ammonia has low flame speed, narrow flammability range, high ignition energy and high self-ignition temperature. Another important point is the possibility to obtain hydrogen on board from ammonia, by means of a catalytic reactor.
Technical Paper
2014-11-11
Eiji Kinoshita, Akira Itakura, Takeshi Otaka, Kenta Koide, Yasufumi Yoshimoto, Thet Myo
Biodiesel is a renewable, biodegradable, and nontoxic alternative diesel fuel with a potential to reduce the life cycle CO2 emission. Biodiesel contains oxygen, therefore the smoke emissions is lower than that of the conventional diesel fuel. Several technical papers express that among the various kinds of biodiesel, coconut oil methyl ester (CME) has lower HC, CO, NOx and smoke emissions compared to other biodiesels, such as rapeseed oil methyl ester and soybean oil methyl ester because CME contains medium chain saturated FAME (methyl caprylate, methyl caprate) with lower boiling point and kinematic viscosity, compared to long chain saturated FAME (methyl laurate, methyl palmitate et al.) and the oxygen content of CME is about 4 mass% higher than that of other biodiesels. Generally biodiesel is made from vegetable oil and methanol by transesterification. However, biodiesel can be made by using other alcohols, such as ethanol and butanol which are bio-alcohols. Biodiesel made from bio-alcohol has higher lifecycle CO2 reduction compared with that from methanol.
Technical Paper
2014-11-11
Akihiko Azetsu, Hiroomi Hagio
The objective of this study is to understand the fundamental spray combustion characteristics of fatty acid methyl ester, FAME, mixed with diesel oil, called bio diesel fuel hereafter. To examine the phenomena in detail, diesel spray flame formed in a constant volume high pressure vessel was visualized and the flame temperature and the soot concentration were analyzed by two color method of luminous flame. The composition of combustion gas was measured by a Gas analyzer to quantify the concentration of NOx and CO. The ambient high-pressure and high-temperature conditions inside the constant volume vessel were achieved by the combustion of hydrogen in an enriched oxygen and air mixture. The composition of the mixture was such that the oxygen concentration after hydrogen combustion was approximately 21% by volume. Following hydrogen combustion, fuel was injected into the vessel at the time when the ambient pressure reached the expected value, and the spray combustion was then examined. The fuel injection system used in the present study is an electronically controlled accumulator type fuel injection system developed by the authors.
Technical Paper
2014-11-11
Yasufumi Yoshimoto, Eiji Kinoshita, Kazuyo Fushimi, Masayuki Yamada
Biodiesel (BDF), a transesterified fuel made from vegetable oils, is a renewable energy resource and offers potential reductions in carbon dioxide emissions, and a number of studies have been conducted in diesel engines with BDFs as diesel fuel substitutes. With environmental protection in mind, it may be expected that compared with ordinary diesel operation BDFs will result in PM reductions at high load operation as well as lower HC and CO emissions because of the oxygenated fuel characteristics. The properties of BDF are close to those of gas oil and practical applications in automobiles are increasing globally. As vegetable oil contains different kinds of fatty acids, they will contain different components of the fatty acid methyl esters (FAME) formed in the transesterification. The aim of the present study is to clarify how the kinds of FAME influence smoke emissions and soot formation characteristics. The study employed two experimental determinations: diesel engine combustion and suspended single droplet combustion, and used eight kinds of FAME and diesel fuel blends with 20:80 and 80:20 mass ratios.
Technical Paper
2014-11-11
Takeshi Otaka, Kazuyo Fushimi, Eiji Kinoshita, Yasufumi Yoshimoto
Biofuel, such as biodiesel and bio-alcohol, is a renewable, biodegradable and nontoxic alternative fuel with the potential to reduce CO2 emissions. Biodiesel produced from vegetable oils and animal fats is utilized as an alternative diesel fuel. On the other hand, bio-ethanol produced by fermentation from various organic substances, such as agricultural crops and garbage, is utilized as an alternative fuel for SI engine. Bio-butanol also can be made by fermentation, but it is different fermentation, Acetone-Ethanol-Butanol (ABE) fermentation. It is possible to use alcohol for diesel engines with higher thermal efficiency if alcohol is blended with high cetane number fuels, such as conventional diesel fuel and biodiesel. Butanol has higher net calorific value and cetane number compared with ethanol. Therefore, butanol may be better alternative diesel fuel or diesel fuel additive than ethanol. Also, biodiesel has higher kinematic viscosity and boiling point compared with conventional diesel fuel.
Technical Paper
2014-11-11
Jeffrey Blair, Glenn Bower
Operation of snowmobiles in national parks is restricted to vehicles meeting the Best Available Technology standard for exhaust and noise emissions as established by the National Parks Service. An engine exceeding these standards while operating on a blend of gasoline and bio-isobutanol has been developed based on a production 4 stroke snowmobile engine. Miller cycle operation was achieved via late intake valve closing and turbocharging. The production Rotax ACE 600cc 2 cylinder engine was modeled using Ricardo Wave. After this model was validated with physical testing, different valve lift profiles were evaluated for brake specific fuel consumption and brake power. The results from this analysis were used to determine the cam profile for Miller cycle operation. This was done to reduce part load pumping losses and increase engine efficiency while maintaining production power density. A catalytic converter was added to reduce exhaust gas emissions, as measured by the EPA 40 CFR Part 1051 5-mode emissions test cycle.
Technical Paper
2014-11-11
Ken Naitoh, Daiki Ikoma, Hiroki Sagara, Taro Tamura, Taiki Hashimoto, Yoshiyuki Nojima, Masato Tanaka, Kentaro Kojima, Kenya Hasegawa, Takuya Nakai, Shouhei Nonaka, Tomoaki Kubota
In our previous reports based on computational experiments and fluid dynamic theory, we proposed a new compressive combustion principle for an inexpensive, lightweight, and relatively quiet engine reactor that has the potential to achieve thermal efficiency over 50% even for small combustion chambers having less than 100 cc. This level of efficiency can be achieved with colliding supermulti-jets that create complete air insulation to encase burned gas around the chamber center. The P-V diagram for this engine concept is between the Otto and Lenoir cycles. We originally developed two small prototype engine systems for gasoline. First one having one rotary valve for pulsating the intake flow and also sixteen nozzles of jets colliding is for examining combustion occurrence. As this prototype has no pistons, the bore size can be varied easily between about 50mm and 15mm. Experimental data basically indicates combustion occurrence. Next, we developed the second one having a strongly-asymmetric double piston system with the supermulti-jets colliding, although there are no poppet valves.
Technical Paper
2014-11-11
Ken Naitoh, Takuma Okamoto, Tomoaki Kubota, Kan Yamagishi, Yoshiyuki Nojima, Taro Tamura
In our previous reports, we found an inexpensive, lightweight, and relatively quiet engine reactor that has the potential to achieve thermal efficiency over 50% for small engines may be achieved with colliding supermulti-jets that create air insulation to encase burned gas around the chamber center, avoiding contact with the chamber walls and piston surfaces. One of interesting features is that, although traditional homogeneous compression due to piston becomes weak at stoichiometric condition, the colliding of pulse jets can maintain high compression ratio for various air-fuel ratios. Here, a small prototype engine having colliding supermulti-jets pulsed and strongly-asymmetric double-piston system is examined by using compuattional experiments. Pulse can be generated by the double piston system of a short stroke of about 40mm. An original governing equation extended from the stochastic Navier-Stokes equation lying between the Boltzmann and Langevin equations is proposed and the numerical methodology based on the multi-level formulation proposed previously by us is included, which can also capture cyclic variations of combustion in traditional direct-injection gasoline engine and transition to turbulence in intake pipes.
Technical Paper
2014-11-11
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco, Marcello Fiaccavento, Francesco Giari, Antonio Marchetti
This paper deals with the investigation of anomalous phenomena during the cranking phase of a spark ignition small engine, in particular backfire. The growing interest of this abnormal combustion is due to the use of fuels with different chemical-physical properties with respect to gasoline, that can affect especially the cranking phase of the engine. In this work the influence of the composition of the fuel on backfire was studied. In particular the investigation was focused on the presence of ethanol in the fuel. The experimental activity was carried out in an optically accessible engine derived from a 4-stroke spark ignition engine for two-wheel application. The test bench was instrumented and adapted in order to simulate the engine conditions similar to the ones that lead to the anomalous auto-ignition in the intake duct during the reverse rotation of the engine. Two different test procedures have been developed with the aim of promoting the auto-ignition at the intake. All the major engine parameters were measured, such as the in-cylinder pressure, the pressure at the exhaust and at the intake; in order to characterize the engine condition and to monitor the auto-ignition.
Technical Paper
2014-11-11
Alexander Shkolnik, Daniele Littera, Mark Nickerson, Nikolay Shkolnik, Kukwon Cho
In this paper, we will present the development of a small (<50cc) rotary diesel internal combustion engine based on the High Efficiency Hybrid Cycle (HEHC). The cycle, which combines compression ignition (high compression ratio), constant-volume (isochoric) combustion, and over-expansion, has a theoretical efficiency of 75% using air-standard assumptions and first-law analysis. A new engine architecture dubbed the 'X' engine was developed to embody this thermodynamic cycle, and simulations show potential brake efficiency exceeding 50%. As this engine does not have poppet valves, and the gas is fully expanded before the exhaust stroke starts, the engine has potential to be very quiet compared to alternative 2-stroke and 4-stroke piston engines. Similar to the Wankel-type rotary engine, the 'X' engine has only two primary moving parts - a shaft, and a rotor, and both engine types will be compact and offer low-vibration operation. Unlike the Wankel, however, the X engine is uniquely configured to adopt the HEHC cycle and its associated efficiency and low-noise benefits.
Technical Paper
2014-11-11
Atsushi Maruyama, Gaku Naoe
For a small general purpose engine, the authors have studied about the mechanical noise originating from combustion, which is called “combustion noise”. The Purpose of this study is to clarify the generating mechanism of combustion noise, and the relation between combustion noise and the components design unique to small general purpose engines. In development of internal-combustion engines, the improvement in fuel economy performance is one of the most important issues. For this purpose, various methods to improve combustion efficiency are suggested. However, most of those methods involve the increase in cylinder pressure or rapid combustion, which causes the increase in combustion noise. Therefore, technological development for reducing the combustion noise is also an issue. Although a number of previous papers about combustion noise focused on the engines used for motorcycle or automobile, few papers focused on small general purpose engines. By contrast, this study focuses on the small general purpose engine.
Technical Paper
2014-11-11
Patrick Pertl, Philipp Zojer, Michael Lang, Oliver Schoegl, Alexander Trattner, Stephan Schmidt, Roland Kirchberger, Nagesh Mavinahally, Vinayaka Mavinahalli
The automotive industry has made great efforts in reducing fuel consumption recently. The efficiency of modern spark ignition (SI) engines has been increased by improving the combustion process and reducing engine losses such as friction, gas exchange and wall heat losses. Nevertheless, further efficiency improvement is indispensable for the reduction of CO2 emissions and the smart usage of available energy. In the previous years the Atkinson cycle realized over the crank train is attracting considerable interest of several OEMs due to the high theoretical efficiency potential. In this publication a crank train-based Atkinson cycle engine is investigated. The researched engine, a 4-stroke 2 cylinder V-engine, basically consists of a special crank train linkage system and a novel mono shaft valve train concept. The idea of a mono shaft valve train mechanism is to realize the valve actuation without the need for separate cam shafts and gears, but via a cam disk rotating crank shaft speed, thus enabling the integration of the cam disk in the crank shaft.
Technical Paper
2014-11-11
Denis Neher, Maurice Kettner, Fino Scholl, Markus Klaissle, Danny Schwarz, Blanca Gimenez
Electrical power and efficiency are decisive factors to minimise payoff time of cogeneration units and thus increase their profitability. The expected tightening of emission standards by the European Union in 2018, however, demands new approaches in engine development to maintain operation of stationary reciprocating gas engines profitable. In the case of small scale cogeneration engines, low-NOx operation and high engine efficiency are frequently achieved through lean burn operation. While further mixture dilution enables future emission standards to be met, it results in poor combustion phasing, reducing engine efficiency as well as engine power. In this work, 1D-CFD and DOE were used as development tools in order to investigate an engine concept that improves the trade-off between engine efficiency, NOx emissions and engine power. The concept combines well-established individual measures such as lean burn operation, overexpanded cycle and a power-optimised intake system. Overexpansion can be realised by advanced or retarded inlet valve closing timing, which is also known as Miller or Atkinson cycle, respectively.
Technical Paper
2014-11-11
Vipin Sukumaran T., Sumith Joseph, Kamal kant, Vipin P, Mohan D Umate
In recent past, the two stroke vehicle manufacturers are continuously motivated to develop extreme low emission vehicle for meeting the requirements of emissions regulations. To achieve this emission compliance, manufacturers have developed engines with better induction system, improved ignition timings, increased compression ratio (C.R) and larger after-treatment devices. As an effect of above changes, engine operating temperatures are quite high which reduces the block-piston life. Even though, typical two stroke engines are forced cooled engines, there is a lot of potential for optimizing block cooling to reduce maximum liner temperature and block gradient for enhancing block-piston durability. This paper presents an experimental study of various measures to reduce liner temperature for a two stroke, single cylinder 70 c.c. engine used for two wheeler application. By studying the cooling air flow around the block and block to interface parts heat transfer, the following parts were redesigned to reduce maximum liner temperature – exhaust gasket, base gasket, cooling fan profile and cooling cowl.
Technical Paper
2014-11-11
Brian Mason, Keith Lawes
For handheld power tools, a four-stroke engine allows compliance with exhaust emissions regulations although four-stroke engines available tend to have unfavourable power to weight. The requirement for a low cost diecast block compromises valve sizes and port flow. While dynamic valve train limitations restrict maximum engine speeds. The use of a rotary valve as opposed to poppet valves avoids these issues and results in an engine with competitive performance. The engine block can be diecast and the engine can operate up to 14,000 rpm without valve related issues. This paper describes the evolution of a rotary valve concept and its application to two 35cc handheld development engines. The HRCV35 is based on a belt driven rotary valve horizontally mounted parallel to the crankshaft axis. The VRCV35 is based on a gear driven rotary valve vertically mounted on the cylinder axis. In both configurations, the rotary valve exposes inlet and exhaust ports providing unrestricted flow. The valve generates turbulence for easy starting and can operate on low volatility fuels such as aviation kerosene or JP8.
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