bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Performance Prediction using Experimental Combustion Model for Controlled-Auto-Ignition Natural Gas Engines
Authors: Kiura Toshiro , Kogo Hibiki
Published: November 2023

This study was undertaken to develop a method of numerical performance prediction for application to the development of controlled-auto-ignition (CAI) natural gas engines. By using a combustion model based on analyzed combustion data and introducing this to a commercial one-dimensional gas dynamic simulator, we attempted to establish a means of attaining a highly accurate performance prediction while reducing the calculation load. The combustion model was separately calibrated for two models, namely, the auto-ignition timing of the combustion and the mass fraction burned. As a result, the combustion modeling was able to successfully predict the accuracy of the auto-ignition timing difference at 0.03 degree of crank angle on average, and 0.95 degree in the 2σ region. Furthermore, the functions of the mass fraction burned were expressed using closely correlated in-cylinder parameters. To investigate the application of this numerical performance prediction method, a parametric study to maximize the thermal efficiency of CAI natural gas engines was conducted. Different engine configurations with stroke /bore ratios of 1.0 to 2.5 and intake/exhaust valve diameter ratios of 0.8 to 1.4 were examined, with the maximum net indicated thermal efficiency being 45% for a stroke/bore ratio of about 2.0.and an intake/exhaust valve diameter ratio of 1.0. Using this approach, it is possible to predict the performance by specifying the configuration, while reducing the calculation load involved in a parameter study of CAI engines with a wide range of specifications. Moreover, the measured data can be stored as combustion data for incorporation into the model used for simulation. Also, this simplified experiment-based combustion model could be implemented in the engine electric control unit to ensure the stable running of a CAI natural gas engine.
Application of a New-Concept Gasoline Pump Injector (GPI) on a Motorcycle Engine
Authors: Balasubramanian N. , Keerthi G. R. , Nithin J. T. , Jayabalan S. , Anand T. N. C.
Published: November 2023

This paper presents the results of tests using a prototype pump-integrated port fuel injector that is designed for small gasoline engines. The unique construction of the injector eliminates the need for a separate feed pump. The device is intended as a solution to meet the upcoming emission norms similar to Euro 6 standards, to be implemented in Asian countries. In particular, the Indian two-wheeler market which produces around 20 million vehicles annually [1], migrates to Bharat Stage VI (BS VI) emission standards in the year 2020. This market is largely cost-driven and currently most of the motorcycles use carburettors as fuelling systems. It is expected that the adoption of port fuel injection would be inevitable to meet the BS VI emission norms. To minimize the increase in cost due to such a change, a new injector is developed, which integrates the fuel pump within the injector, making the system simple and compact, while calling for no change in the fuel tank. Usage of a solenoid actuator in the injector design, enables closed-loop fuel quantity control. In the injector, fuel is pressurized in a pumping chamber, and the pressurized fuel is then injected through orifices to produce a spray in the intake port of the engine. This injector was tested on a 200 cc motorcycle engine, using a steady state dynamometer. The performance and emission results were encouraging and the same are reported in this paper.
Delivering Fuel Economy with Motorcycle Oil Additive Technology
Authors: Lim Pei Yi , Inagaki Youhei
Published: November 2023

Sustainability trends and reduced fuel consumption as a value proposition to end users have led to an ever-increasing focus on fuel efficiency in the personal mobility segment. This is evident in the development of smaller and lighter engine hardware with optimized combustion systems as well as the lowering of engine oil viscosity grades and formulation of additives with improved friction properties. Due to the unique challenges of lubricating motorcycle engines, the development of fuel efficient motorcycle engine oil presents several technical dilemmas. The reduction of oil viscosity gives rise to durability concerns particularly in such high temperature and high speed operating conditions, while the formulation of additives with lower friction properties may affect clutch friction that is necessary for a manual motorcycle. Hence, this study was embarked on to develop a 4T motorcycle engine oil formulation that can achieve fuel economy credits without compromising clutch friction and durability.

The development began with a fundamental understanding of the surface and viscometric effects from each major component of the formulation (including within the additive system, the base stocks and the formulation viscometrics) and across each lubrication regime (i.e. from the boundary to hydrodynamic regime). This was followed by the optimization of these components to maximize fuel economy credits. Finally, a prototype was developed through a balanced combination of these components to provide a well-rounded friction reduction across the entire lubrication regime, as benchmarked against an SAE 10W-30 OEM Genuine Oil. The preliminary friction screening tools used in this study were bench tests (i.e. SRV, HFRR and MTM) run under carefully selected test conditions, with the fuel economy data subsequently validated through a chassis dynamometer test based on the World Motorcycle Test Cycle in an actual motorcycle. In addition, to assess the hypothesis that engine friction can be reduced without compromising clutch friction and durability, the prototype was put through the JASO T903:2016 and modified FZG gear pitting tests. The results of this extensive fundamental understanding and performance evaluation activity will be presented in detail in this paper.
Study of Ion Current Based Misfire Detection in Motorcycle Applications
Authors: Grimaldi Alberto , Mucciarella Lorenzo , Virgilii Francesco
Published: November 2023

Concerning internal combustion engines (ICEs), the analysis and evaluation of combustion quality and pollutant agents has drawn the attention of public opinion and worldwide authorities. Moreover, combustion quality in ICEs affects the drivability of motorbikes/cars, a most important quality for the customers’ point of view. The possibility to monitor engine behavior is a target that every car/motorcycle OEM is seeking, so as to comply with legislated pollutant limits. As the EURO V OBD Stage II regulations state, starting from the year 2020 all the emission related components will need to be monitored. In particular, the legislator requests to monitor the frequency of misfires, due to possible damage to the catalytic converter; in fact, the malfunction of this component can dramatically affect exhaust gas pollutant emissions. This article introduces a method for combustion quality and misfire monitoring, aimed at motorcycle engine applications, based on ion current flowing in an electronic circuit in which the sensing element is the common spark plug. It is well known that motorcycle engine characteristics, such as increased speed, low inertia and chain transmission, represent limits and challenges for conventional misfire monitoring methods based on readings from the crankshaft speed sensor. The scope of the paper is to demonstrate that the use of ion current sensing for combustion analysis is suitable and reliable for motorcycle applications. The study is developed using a production Eldor electronic control unit (ECU), with an integrated ion acquisition circuit and installed on a production series sport motorcycle, compliant with the Euro 4 emissions legislation. Moreover, the ECU software (SW) is modified to stimulate misfiring caused by both ignition and injection failures. A phase of system calibration was needed in order to identify the proper misfire detection thresholds, as a function of engine speed/load. After calibration, the overall test has been carried out by means of a chassis dynamometer test bench, with the vehicle following a WLTC emission cycle. The analysis of results shows that ion current based misfire monitoring is worthwhile and can be used as a feedback for cycle-by-cycle improvement of combustion in small engines for motorcycle applications.
The Tire Characteristic Effect on Motorcycle Maneuverability Using a Riding Simulator
Authors: Miki Masayuki , Kimura Tetsuya
Published: November 2023

The stability factor is widely used for four-wheel vehicles as an index representing the turning performance of a vehicle. Stability factor for two-wheel vehicles has been proposed as an indicator of cornering performance from the same way of thinking. In line traceability evaluation as a sensory evaluation item of motorcycles, the expressions of understeer and oversteer are sometimes used, but the relation with stability factor for two-wheel vehicles has not been investigated. In this paper, a test in which the slip angle characteristics of the front and rear tires were varied using a riding simulator was conducted, and the correlation between the stability factor and the rider evaluation was investigated to derive an index showing the line traceability.
Numerical Modeling of Heat Dissipation inside the Continuously Variable Transmission of a 400cc Scooter
Authors: Hui-Hui Huang , Chien-Hsiung Tsai , Wei-Ta He
Published: November 2023

In this study, the temperature of solid/fluid inside a continuously variable transmission (CVT) of a 400 cc scooter is investigated numerically utilizing ANSYS FLUENT. The moving reference frame (MRF) technique with conjugate heat transfer between gases and solid rotation/translation are implemented to carry out the simulation. The emphasis of the present study is put on the effects of CVT housing configuration, belt’s thermal conductivity, and the heat dissipated from the crankcase on the thermal-flow-field of CVT.

The numerical results show that the temperature of the drive/driven pulleys are concurred with those of experimental results. It is found that the proposed design of partition plate inside the CVT housing can direct the flow into belt and prevent the fluid around driven and drive pulley from mixing, and can further decrease the temperatures of the belt and pulley. The increase of thermal conductivity of belt will increase the average temperature of belt but minimize the temperature difference on it. In addition, the temperature of driven pulley will decrease when belt transition from high ratio to low ratio due to the increase of its rotational speed. The heat dissipation from the crankcase to CVT housing is also explored that the ribs in the housing adjacent to the crankcase served as the fin to enhance the heat transfer from engine to CVT housing. In comparison with the methods proposed by other researchers, this method is found to be the most detailed model.
Data Analysis of Off-Road Motorcycles in an Enduro Race
Authors: Shinagawa Akinori , Nozawa Hisayuki , Uchiyama Yutaro
Published: November 2023

Two-wheeled off-road vehicles are mainly ridden on slippery dirt roads that include steep slopes and rough, uneven surfaces. An analysis method for the driving state and the vehicle movement limits that would be suitable for analyzing the movement of such two-wheeled off-road vehicles under these conditions was examined. These movement limits were then formulated by taking into consideration the coefficient of friction and the road surface gradient in accordance with the basic laws of physics and also by focusing on the vehicle movement in the longitudinal direction. Measurements were also taken during actual off-road riding by top-class Japanese off-road motorcycle riders. It was confirmed that this measurement data was distributed within the range of the assumed vehicle movement limits. Consequently, it was confirmed that it is possible to use such measurements to accurately grasp the vehicle movement limits and the associated driving state for two-wheeled off-road vehicles.
Active Sound Quality Control Based on Subjective Preference
Authors: Ishimitsu Shunsuke , Sagawa Takuma , Ito Tomoaki , Shibatani Naoaki , Takagi Toshihisa , Yoshida Kazuki , Suzuki Kenta , Chino Takanori
Published: November 2023

Recent years, ANC (Active Noise Control) technology has been paying attention. However, rather than the noise measures, the noise gives us the impression even running sound for motorcycles. That is, the control method of the engine sound is shifted from the noise reduction to sound design in each manufactures. Therefore, we proposed a method to design the engine sound using Active Sound Quality Control (ASQC) based on the ANC. Specifically, we proposed the algorithm amplifying and reducing the engine specific order components. From the simulation results, the engine specific order components can be amplified and reduced like an equalizer with the proposed algorithm. And, auditory impressions of engine sound controlled by ASQC were investigated using psychoacoustic measurements. 13 stimuli were obtained by applying ASQC for several order components to amplify or reduce their levels. Following stimuli were presented to 10 healthy volunteers with control for first-, second- and both first- and second-, order components to decrease or increase, respectively. The scale values of preference for each stimulus were obtained by Scheffe's paired comparison tests. When the reduction-level increased, the preference was decreased or increased from the reference sound. Also when the amplification-level increased, the preference was decreased from the reference sound. As the reason, it seems that reference sound pressure is felt to be sufficiently large. These results indicated that the control corresponding to the individual is important for improvements in auditory impressions.
A Comprehensive CFD Method for Thermal Performance Evaluation of a Scooter Type Motorcycle and Its Application
Authors: Kumar Gundavarapu V S , Suresh M , Garg Manish
Published: November 2023

Thermal management is of vital importance in the development of a scooter type motorcycle (two-wheeler). Traditionally the thermal management development of a two-wheeler is done through experimental methods, or using sub-system level CFD models. In current work, a comprehensive, complete vehicle, three-dimensional CFD model has been developed to assess thermal performance of the scooter and its sub-systems. The model can predict thermal performance in different operating conditions, such as, wide open throttle, idling and key-off. A typical thermal interaction in engine happens through metal contact conduction, air cooling and oil flow path in the engine. The model can capture the sub system interaction, such as, an interaction between the cooling system and engine cabin. Modeling oil is computationally expensive, as it involves complex physics modeling such as multiphase flow. An energy balance based new sub-model is added to the CFD model which can predict the engine oil temperature without modeling the oil flow inside the oil sump. A good correlation for this new sub-model has been achieved between CFD model and on-road experimental values. The air and solid temperatures at different locations of engine and vehicle from CFD model has been validated with the on-road measurement. The time to build and evaluate a design is being reduced to one fifth with this new method, and incorporating any design change in the model and its evaluation through CFD is reduced to one tenth. Finally, a case-study has been presented to demonstrate how the model has been used in product development process by capturing various failure modes early in the product development process and resolution of these failure modes using model and test.
Results, Assessment and Legislative Relevance of RDE and Fuel Consumption Measurements of Two-Wheeler-Applications
Authors: Hiesmayr Johannes , Schmidt Stephan , Hausberger Stefan , Kirchberger Roland , Zinner Christian , Filips Patrick , Wanker Roland , Friedl Hubert
Published: November 2023

The reduction of environmentally harmful gases and the ambitions to reduce the exploitation of fossil resources lead to stricter legislation for all mobile sources. Legislative development significantly affected improvements in emissions and fuel consumptions over the last years, mainly measured under laboratory conditions. But real world operating scenarios have a major influence on emissions and it is already well known that these values considerably differ from officially published figures [1]. There are regulated emissions by the European Commission by means of real driving scenarios for passenger cars. A methodology to measure real drive emissions RDE is therefore well approved for automotive applications but was not adapted for two-wheeler-applications yet [2].

Hence measurements have been performed on-road and on chassis dynamometer for motorcycles with the state of the art RDE measurement equipment to be prepared for possible future legislation. The collected data led to insights into driving dynamic of motorcycles. Therefore, synthetic RDE test cycles on test rig and dynamic trip indicators are discussed to gain a better understanding of the determining influencing factors for RDE and to compare and assess the data with automotive applications.

Furthermore, results of on-road and test bench emission measurements are demonstrated for bridging the gap between the relevance of different measurement methodologies, including their assessment, and a possible RDE legislation process for motorcycles. The aim is to give an idea of how to represent real word driving of two-wheeler-applications with state of the art measurement technologies and, additionally, to reflect on possible adaptions.
Practicability and Influencing Factors of a Lean Burn Mode for Two-Stroke Engines in Hand-Held Powertools
Authors: Piecha Pascal , Ninaus Christoph , Schmidt Stephan , Kirchberger Roland , Schumann Florian , Gegg Tim
Published: November 2023

For many applications, such as scooters, hand-held power tools and many off-road vehicles, two-stroke engines are used as a preferred propulsion unit. These engines convince by a good power to weight ratio, a high durability and low maintenance technology and are therefore the first choice in this field of application. In general, already much development effort has been expended to improve those systems. However, an increasing environmental awareness, the protection of health and the shortage of fossil resources are the driving factors to further enhance the internal combustion process of those adapted two-stroke engines. The current focus here is on the reduction of emissions and fuel consumption with an at least constant power output.

An approach to address an improvement of engine efficiency can be covered by applying a lean combustion burn mode. In almost all combustion technology sectors, including furnaces, gas turbines and many internal combustion engines, a lean combustion is utilized. Possible advantages of a combustion process under lean conditions are low pollutant emissions and high efficiencies, because flame temperatures are typically low. Nevertheless, most air-cooled two-stroke engines still operate at wide open throttle with a rich air to fuel ratio. This is due to reliability, durability reasons and the ease of use. For that reason, it is mandatory to determine the key factors for the practicability of a lean burn mode for two-stroke engines. In this context, a new approach to implement a lean combustion is discussed and different influencing factors, which have an impact on lean combustion process, are investigated and analyzed. A thermodynamic loss analysis is performed to highlight the differences. Moreover, further research demands to realize a lean combustion in a series production engine are pointed out.
Development of Motorcycle Engine Starting System Simulation Considering Air-Fuel Ratio Control
Authors: Itou Yoshihito , Itou Daiki , Iida Minoru
Published: November 2023

Recently the response of the engine speed at starting has more importance than ever for quick start satisfying rider’s needs, as well as exhaust emissions. We have developed a simulation for studying engine and starter specifications, engine control algorithm and other engine control parameters. This system can be utilized to realize appropriate starting time by considering air-fuel ratio under various conditions.

This paper addresses what are taken account of in our method. Examples applying this to a conventional motorcycle engine are shown.
Optimization of Intake Port for Improvement of Fuel Consumption and Torque
Authors: Sakurai Yota , Nakao Yoshinori , Hisano Astushi , Saitou Masahito , Tanaka Kunihiro
Published: November 2023

In this study on the motorcycle engine, we investigated the geometry of the newly developed intake port with an objective of improving the fuel consumption and the torque in practical range. Herein we present the results obtained. We believe that an effective measure for achieving the stated objective is to improve the combustion speed and combustion stability. To realize that, it is necessary to increase the turbulence during combustion and improve the homogeneity of air-fuel mixture. To investigate the feasible shape of the port, the CFD simulation (including fuel spray analysis) was performed and a geometry that improved the turbulent kinetic energy and mixture homogeneity at the time of ignition was selected.

For confirming the combustion improvement effect achieved by tumble strengthening, an engine test was conducted with the same amount of intake air as that used in. Analysis of the heat release rate calculated from the pressure in the cylinder revealed that an improvement in the burning rate and combustion was achieved by adopting the newly developed intake port shape. As a result of the above approach, by improving the turbulent kinetic energy and the homogeneity of the air-fuel mixture, the fuel efficiency has been improved and the torque also improved in the practical range.
Effects of Port Injection Specifications on Emission Behavior of THC and Engine Maximum Power
Authors: Nakao Yoshinori , Hisano Atsushi , Saitou Masahito , Suzuki Kozo , Sobakiri Katsumi
Published: November 2023

In this paper, it is also elucidated that the influence of the downstream injection, which caused different fuel behavior in contrast with upstream injection, on the THC after warm-up and at the maximum power, as well as its mechanism. The mechanism is clarified by use of the intake port visualization system. First, at each injection position, the effect of injection timing on THC emission after warm-up was evaluated. In the downstream injection, THC emission increases during the injection timing, in which the fuel spray directly flows in-cylinder during the intake process (hereinafter defined as the intake valve opening injection timing), and the amount of THC emission is reduced at the other injection timing (hereinafter defined as the intake valve closing injection timing). Based on the results of visualizing the intake port, injected fuel phase near the intake valve is spray in the downstream injection. Furthermore, the high temperature intake valve immediately caused the fuel spray to evaporate at the intake valve closing injection timing and then flown in-cylinder. Next, the influences of the injection pressure and the injection timing on the maximum power are evaluated at each injection position. In the downstream injection, the intake air mass flow and the maximum power at the intake valve opening injection timing are increased. Furthermore, the tendency in downstream injection becomes more prominent in high injection pressure. In the downstream injection, intake air mass flow and the maximum power increased due to the fuel cooling effect by the direct spray flow in-cylinder.
Study on a Cyclone Air Cleaner with Discharge Function under the Intake Pulsation of a General Purpose Engine
Authors: Takahashi Hiroto , Shinohara Toshiki
Published: November 2023

Many general purpose engines, such as the ones used in construction machines, operate in environments with excessive amounts of airborne dust, and are thereby equipped with a cyclone air cleaner so that they can remove as much dust from contaminated air streams in the engine. However, the compact general purpose engine is mainly a single-cylinder type, and the intake flow pulsates. Since the centrifugal action of the cyclone air cleaner under the intake pulsation changes according to the pulsation, it is difficult to enhance the dust separation performance. In this study, we aimed to determine a cyclone air cleaner factor with high purification performance even under the intake pulsation conditions of a general purpose engine. We have designed an ideal geometry for the cyclone air cleaner, which centrifugally separates dust during inhaling and discharges the centrifuged dust using positive pressure due to pulsation. A numerical calculation of the flow under the intake pulsation of this cyclone air cleaner was carried out, and the separation and discharge functions were analyzed. Accordingly, it was confirmed that although the swirling speed inside the cyclone air cleaner depended on pulsation, it demonstrated purification performance even under an intake pulsation by the dust discharge function. We have also found a method to operate the discharge function at the instant when the separation function is the strongest.
The Effect of In-Cylinder Flow and Mixture Distributions on Combustion Characteristics in a HCCI Engine
Authors: Watanabe Shogo , Kuboyama Tatsuya , Moriyoshi Yasuo , Yoshimura Kei
Published: November 2023

It has been widely known that thermal and fuel stratifications of in-cylinder mixture are effective to reduce in-cylinder pressure rise rate during high load HCCI operations. In order to optimize a combustion chamber design and combustion control strategy for HCCI engines with wide operational range, it is important to know quantitatively the influence of the temperature and fuel concentration distributions on ignition and heat release characteristics. At the same time, it is important to know the influence of in-cylinder flow and turbulence on the temperature and fuel concentration distributions. In this study, a numerical simulation of HCCI combustion were conducted to investigate the effects of the in-cylinder flow and turbulence, and the distributions of temperature on ignition and combustion characteristics in HCCI combustion. As a result, the initial temperature distribution of the cylinder air-fuel mixture was found to be effective for slowing the combustion because the large distribution of the scale is not easily influenced by the mixing due to the flow. In addition, it was found that the combustion slows down when the temperature gradient is wide in the combustion region.
Fuel Economy Development for a CVT Powertrain on Roller-Chassis Dynamometer and Transfer to Dynamic Engine Testbed
Authors: Hubmann Christian , Mayrhofer Harald , Friedl Hubert , Hochmann Gerald
Published: November 2023

The motorcycle and small engine industry is entering a chapter where emission legislation (EU5, BS6) is adapted to the automotive industries and especially CO2 emission is coming more and more into the focus of the OEMs, the legislative authorities and finally the end-user. Technologies like variable valve actuation, direct gasoline injection and turbo charging are state of the art in the automotive industry and have brought the efficiency of the internal combustion engine onto the next level. Nevertheless the small engine manufacturers are seeking for solutions which are cost efficient as well as simple and easy to apply. Even powertrain complexity is increasing the development efforts have to be kept moderate. Therefore, there is strong request for modern instrumentation and Testbeds which support an efficient and effective development process.

This paper describes the development on an 110cc scooter engine with the main focus on fuel consumption reduction during the hardware development on the engine Testbed as well as chassis dyno . Furthermore, it has been investigated how the efficiency, robustness and reproducibility of the development process and its test environments can be increased by using an advanced dynamic engine Testbed. This innovative Testbed is combined with a belt drive transmission which allows to operate as stationary single cylinder engine, as well as in power pack- (i.e. internal combustion engine including transmission) configuration under steady-state or dynamic operating mode.
Design and Performance of Acoustic Metamaterial Structure for Inlet Duct Noise Attenuation
Authors: Lavrentjev Jüri , Rämmal Hans
Published: November 2023

To control noise emission from internal combustion inlet, designers often choose small chamber type silencers at the inlet. In order to improve the inlet acoustic efficiency, inlet ducts with improved acoustic attenuation can be used. One potentially applicable material is acoustic metamaterial rapidly gaining popularity in different fields of engineering application. Small engine inlet duct, designed by using acoustic metamaterial structure comprising an array of resonators inside the wall of a rigid duct is investigated in this study. Experimental investigation of different designs is performed to characterize the acoustic behavior in terms of transmission loss (TL). By connecting multiple resonators of different size and location it is shown that a broadband TL can be achieved. The resulted attenuation band can be tuned by varying the resonator physical characteristics, showing promising potentials such of the material in the described application.
Parallel Active Control of Acceleration Noise
Authors: Aramaki Yoshihiro , Ishimitsu Shunsuke , Murai Kenta , Yoshida Kazuki , Takaki Toshihisa , Chino Takanori , Suzuki Kenta
Published: November 2023

The number of people experiencing psychological discomfort due to the increasing amount of noise emanating from motor vehicles has been on the rise. Legal regulations define the permissible level of vehicle noise in a given area. Active noise control (ANC) is a noise cancellation method that reduces low-frequency sounds, such as engine noise, effectively. Furthermore, this method is suitable for controlling engine noise because the equipment necessary to perform it is small and does not require a large space for installation. Advances in digital processing technology have increased the scope of ANC’s applications, and it is no longer restricted to use in motor vehicles.

The purpose of this study is to demonstrate the effectiveness of the proposed method in reducing the motor vehicle engine noise produced during acceleration. In this study, we attempt to control the engine sounds from a vehicle with a four-cylinder four-stroke engine. In previous studies [7], we proposed using and performed experiments on a reference signal for both the fundamental frequency and its harmonic, calculated from the engine pulse and focused on harmonic structures of engine sound. However, tracking the variations in the fundamental frequency resulting from the fluctuation of the engine’s rotation during acceleration presented quite a challenge. Therefore, in the present study, a sinusoidal waves, consisting of numerous frequencies, are employed as reference signals. Each reference signal is inputted to its respective adaptive filter. In this manner, we attempt to expand the reduction range by utilizing multiple adaptive filters.

As a result, we achieve noise reductions of at least 8 dB for acceleration and at least 20 dB for constant-speed driving.
A Study of Ignition and Combustion in an SI Engine Using Multistage Pulse Discharge Ignition
Authors: Furusyo Takuma , Takeda Kotaro , Yoshida Yuki , Rin Chibin , Iijima Akira , Shoji Hideo , Tamida Taichiro , Hashimoto Takashi
Published: November 2023

Lean-burn technology is regarded as one effective way to increase the efficiency of internal combustion engines. However, stable ignition is difficult to ensure with a lean mixture. It is expected that this issue can be resolved by improving ignition performance as a result of increasing the amount of energy discharged into the gaseous mixture at the time of ignition. There are limits, however, to how high ignition energy can be increased from the standpoints of spark plug durability, energy consumption and other considerations. Therefore, the authors have focused on a multistage pulse discharge (MSPD) ignition system that performs low-energy ignition multiple times. In this study, a comparison was made of ignition performance between MSPD ignition and conventional spark ignition (SI). A high-speed camera was used to obtain visualized images of ignition in the cylinder and a pressure sensor was used to measure pressure histories in the combustion chamber. The results revealed that MSPD ignition formed a stronger flame kernel than conventional SI under conditions inconducive to flame kernel formation. This was found to be effective in promoting stable combustion.
Thermodynamic Loss Analysis of a High Power Motorcycle Engine with Focus on Alcohol Blended Fuels
Authors: Jandl Stephan , Pertl Patrick , Schacht Hans-Juergen , Schmidt Stephan , Leiber Stefan
Published: November 2023

The development of future internal combustion engines and fuels is influenced by decreasing energy resources, restriction of emission legislation and increasing environmental awareness of humanity itself. Alternative renewable fuels have, in dependency on their physical and chemical properties, on the production process and on the raw material, the potential to contribute a better well-to-wheel-CO2-emission-balance in automotive and nonautomotive applications. The focus of this research is the usage of alcohol fuels, like ethanol and 2-butanol, in motorcycle high power engines. The different propulsion systems and operation scenarios of motorcycle applications in comparison to automobile applications raise the need for specific research in this area. In comparison to conventional gasoline physical and chemical properties of alcohol fuels are changing, which has a direct impact on mixture formation, combustion process, exhaust gas and exhaust gas after treatment of motorcycle applications. The combustion process is directly influenced by the mixture formation and the chemical composition of the liquid fuel and determines the boundary conditions for the exhaust gas after treatment. On this account, this study concentrates on the thermodynamic loss analysis of the combustion process of a motorcycle high power MPFI SI engine with special focus on different bio-fuel gasoline mixtures. The chemical fuel composition has a direct influence on the combustion process, wall heat transfer, scavenging losses and the enthalpy of the exhaust mass flow. The thermodynamic loss analysis provides a detailed quantification of different engine efficiency losses. The complex thermodynamic interactions cause a mutual influence of the individual losses. For this reason, the individual losses cannot be calculated separately and, thus, a defined calculation order is important. Based on the results of this thermodynamic loss analysis, the potentials of different bio-fuel gasoline blends can be shown. On this account the development of future flex fuel internal combustion engines should underline the needs of gasoline and bio-fuels.
Numerical Investigations of the Auto-Ignition Ranges of a Natural Gas Fueled HCCI Engine
Authors: Judith Jörn , Neher Denis , Kettner Maurice , Klaissle Markus , Kozarac Darko
Published: November 2023

Homogeneous charge compression ignition (HCCI) in natural gas fueled engines is thought to achieve high efficiency and low NOx emissions. While automotive applications require various load and speed regions, the operation range of stationary cogeneration engines is narrower. Hence, HCCI operation is easier to reach and more applicable to comply with future emission standards.

This study presents computationally investigations of the auto-ignition ranges of a stationary natural gas HCCI engine. Starting from a detailed 1D engine cycle simulation model, a reduced engine model was developed and coupled to chemical kinetics using AVL Boost. Compression ratio, air-fuel ratio, internal EGR rate (iEGR) and intake temperature were varied for three different speeds, namely 1200, 1700 and 2200 rpm. Each examination includes a full factorial design study of 375 configurations.

In the first step, the combustion was calculated using the GRI-mechanism 3.0 and a single zone combustion model. The data generated was analyzed and single effects of the design parameters on auto-ignition characteristics were derived. In the second step, quadratic regression models were built and sensitivity analysis was performed. Compression ratio and intake temperature show the largest impact on auto-ignition timing (AIT) and auto-ignition temperature, whereas iEGR and air-fuel ratio mainly influence indicated mean effective pressure (IMEP). The design space indicates narrower auto-ignition range at lower engine speed due to decreasing volumetric efficiency and increasing heat losses.
Reliability Study of Micro-Perforated Elements in Small Engine Silencer Application
Authors: Rämmal Hans , Lavrentjev Jüri
Published: November 2023

Since the introduction of microperforated (MP) sound absorption elements more than 40 years ago many variations of noise control devices from room acoustics to induct applications have been manufactured based on this technology.

It has been demonstrated that micro-perforated elements can provide adequate IC-engine gas exchange noise attenuation. Several exhaust and inlet system silencers incorporating micro-perforated elements have been presented during the past 15 years for engine applications, encouraging the replacement of the typical fibrous materials and aiming several advantages including cleaner environment.

The acoustical characteristics of the MP elements, have been studied thoroughly by several authors and good analytical models exist to predict the attenuation performance of those elements. However, almost no published information can be found regarding the reliability of the MP elements utilized in harsh engine exhaust system environment.

In this paper the reliability of stainless still MP element designed for small engine exhaust systems is critically studied, with the focus on the durability of the acoustical performance.
A Study of Combustion in an HCCI Engine Using Non-Equilibrium Plasma Discharge Assist
Authors: Hoshino Hyota , Sato Tatsuya , Takano Shuntaro , Motoki Yuya , Tanaka Hiroto , Higuchi Yuya , Iijima Akira , Asai Tomohiko , Tanabe Mitsuaki , Ashizawa Yoshito , Sekiguchi Junichi , Shoji Hideo
Published: November 2023

This study focused on a non-equilibrium plasma discharge as a means of assisting HCCI combustion.Experiments were conducted with a four-stroke single-cylinder engine fitted with a spark electrode in the top of the combustion chamber for continuously generating non-equilibrium plasma from the intake stroke to the exhaust stroke.

The results showed that applying non-equilibrium plasma to the HCCI test engine advanced the main combustion period that otherwise tended to be delayed as the engine speed was increased. In addition, it was found that the combined use of exhaust gas recirculation and non-equilibrium plasma prevented a transition to partial combustion while suppressing cylinder pressure oscillations at high loads.
Impact of Biodiesel on Small CI Engine Combustion Behavior and Particle Emission Characteristic
Authors: Karin Preechar , Watanawongskorn Park , Saenkhumvong Jiramed Boonsakda Eakkawut , Rungsritanapaisan Sippakorn , Srivarocha Settavit , Charoenphonphanich Chinda , Chollacoop Nuwong , Hanamura Katsunori
Published: November 2023

Diesel engines are high thermal efficiency because of high compression ratio but produce high concentration of particulate matter (PM) because of direct injection fuel diffusion combustion. PM must be removed from the exhaust gas to protect human health. This research describes biodiesel engine performance, efficiency and combustion behavior using combustion pressure analyzer. It was clearly observed that PM emitted from CI engines can be reduced by using renewable bio-oxygenated fuels. The morphology and nanostructure of fossil fuel and biofuel PMs were investigated by using a Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The morphology of biodiesel and diesel doesn’t have much different in the viewpoint of particulate matter trapping using DPF micro surface pores. The agglomerated ultrafine particles and primary nanoparticles sizes of diesel and biodiesel engine’s PM are approximately 50-500 nm and 20-50 nm, respectively. The primary particle of biodiesel engine’s PM is smaller than that of fossil diesel. The average of diesel and biodiesel PM’s carbon platelets is in the range of 0.2-5.2 nm.
Dynamic Modeling of a Diesel Oxidation Catalyst and Diesel Particulate Filter Aftertreatment System for Regeneration Control Development
Authors: Chiang C. J. , Kuo T. F. , Halim Anton , Cheng S. C. , Ku Y.Y.
Published: November 2023

The main function of diesel particulate filter (DPF) is to remove the particulate matter (PM) from diesel engine emission. However, the accumulated PM restricts the exhaust flow through the DPF and increases the back pressure which may negatively impact fuel consumption. Therefore, the particulate filter needs to be regenerated by burning off the accumulated particulate, which is achieved either by passively use of a catalyst or by actively introducing high heat into the exhaust system.

In the exhaust after treatment system considered in this paper, a diesel oxidation catalyst (DOC) is installed upstream of the DPF to facilitate the regeneration process. In order to combust the captured particulate in the DPF, a small amount of fuel can be injected into the exhaust, upstream of the DOC, when necessary. In an effort to develop a model-based control strategy which completes the regeneration while satisfies the constraints such as fuel consumption, temperature and regeneration period, a physics-based dynamic model of the DOC-DPF exhaust after treatment system is proposed. Parameters in the model including the heat transfer coefficient, reaction constants in the DOC and DPF, and the permeability of the filter and soot are identified based on the experimental measurements. The DOC-DPF model is then validated both at steady state and during transient against experimental data measured at various engine operating conditions, PM loads and fuel injection rates.
Model-based Analysis of the Oscillatory NO x in Urea Selective Catalytic Reduction Systems
Authors: Chou C. C. , Kuo T. F. , Tsai T. H. , Su Y. H. , Lu J. H. , Ku Y. Y.
Published: November 2023

The urea-water-solution based selective catalyst reduction (SCR) system is one of the effective devices for reduction of NOx from diesel engines. In an effort to understand the various levels of oscillation observed in the NOx measurement downstream of a SCR in which the urea dosage is controlled by a crankshaft-link pump, a zero-dimensional dynamic SCR model is developed in this paper based on conservation of mass. The model contains three states including the concentrations of NOx and ammonia in the SCR and the surface coverage rate of the catalyst. The temperature-dependent reactions considered in the model include the adsorption, desorption and oxidation of ammonia and the NOx reduction with the reaction constants provided by the catalyst company. The dynamic SCR model is validated both at steady state and during transient under various engine operating conditions and urea dosing rates. A periodic modulation of the urea dosing rate is adopted to simulate the periodic urea supply resulted from the reciprocating motion of the crankshaft-link pump. The simulation results exhibit similar oscillatory behaviors in the NOx concentration as observed in the experimental measurement, which is further analyzed and explained based on the nonlinear characteristics between the downstream NOx and the ammonia dosage. Based on the interpretation of the oscillatory NOx signal, an algorithm for identification of the cross-sensitivity of the smart NOx sensor to ammonia is proposed.
The Effect of Fuel Composition on Ignition Delay and Knocking in Lean Burn SI Engine
Authors: Goto Yasunobu , Jung Dongwon , Ueda Toshihisa , Iida Norimasa
Published: November 2023

Super lean burn technology is conceived as one of methods for improving the thermal efficiency of SI engines[1][2]. For lean burn, reduction of heat loss and the due to decrease in flame temperature can be expected. However, as the premixed gas dilutes, the combustion speed decreases, so the combustion fluctuation between cycles increases. Also, to improve the thermal efficiency, the ignition timing is advanced to advance the combustion phase. However, when the combustion phase is excessively advanced, knocking occurs, which hinders the improvement of thermal efficiency. Knocking is a phenomenon in which unburned gas in a combustion chamber compressed by a piston and combustion gas suffer compression auto-ignition. It is necessary to avoid knocking because the amplitude of the large pressure wave may cause noise and damage to the engine. Also, knocking is not a steady phenomenon but a phenomenon that fluctuates from cycle to cycle. Many studies have already been made on the knocking characteristics that occurred during stoichiometric combustion[3], but there have been no reports on knocking characteristics in super lean burn near the excess air ratio of 2.0. In order to establish super lean burn technology it is essential to grasp the knocking characteristics of super lean burn. In this research, we aim to clarify the factors that fuel composition affects auto-ignition of unburned gas using SIP common 5 component surrogate fuel.
Instantaneous Surface Temperature Measurement in Internal Combustion Engine Using Newly Developed Coaxial Type Thin-Film Temperature Sensor
Authors: Ishii Daijiro , Saito Hiromi , Mihara Yuji , Takagi Yasuo
Published: November 2023

In order to establish standard method to evaluate cooling loss in combustion chamber of internal combustion engines based on measurement of instantaneous heat flux / wall temperature with higher response and accuracy than previously reported coaxial type thin-film temperature sensor by applying thin film fabrication technology based on PVD method (Physical Vapor Deposition method) which improved to realize higher responsiveness than the conventional sensor was developed by the authors, and it was confirmed that the sensor has sufficient durability in conditions in which the hydrogen jet and flame directly contacts surface of the sensor by thin-film material change. The influence of the improvement on the measurement accuracy was verified by numerical analysis including thermoproperty evaluation. In this report, the configuration of measurement system that can measure minute voltage from the sensor with low noise and high response is reported. Furthermore, in addition to the thermoelectromotive force calibration, an instantaneous responsiveness evaluation device (laser calibration device) that can evaluate the responsiveness of instantaneous heat flux of the sensor was developed and evaluated.