bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD Simulation and Experimental Validation of a Throttle Body Design without Bypass for Fuel Injected Motorcycles
Authors: Ramachandra Pradeep , Nagalapura Mohankumar
Published: November 2023

Increased penetration of gasoline EFI (Electronic Fuel Injection) in the Indian two wheeler commuter segment, demands simplified, but robust solutions. Freedom for the end user to adjust the idle speed with carbureted engines is considered as reference behavior. Control of idle air flow in the traditional throttle body designs is through a bypass path with either an idle speed actuator or a mechanical screw. Due to the quality of air and vented blow-by in the air path, field issues observed on most throttle body designs include a) carbon deposition influencing the air flow characteristics b) consequent effects included instability of idle speed, jamming of throttle valve or clogging of idle air control valve. One of the design measures suggested [1] was to introduce an idle screw on the throttle flap to retain the user experience based on the incumbent carburettor and address the carbon deposition based on the knowledge of ETB (Electronic Throttle Body).

The primary objective of this investigation was to validate this assumption through CFD (Computational Fluid Dynamics) analysis backed by vehicle trials. In CFD, carbon deposition can be characterized as a function of velocity and pressure. This phenomenon was used to simulate air flow in the throttle body with and without bypass path and compared against the experimental results. Further, these configurations were subjected to real world driving conditions to evaluate the effect on carbon deposition phenomenon.

The simulation showed a channeled air flow with the maximum velocity of 353m/s (which is greater than sonic velocity) for throttle body without bypass path. The simulation and experimental results for air mass flow had close agreement with <8% deviation over the entire range of throttle opening. The results from vehicle trials indicated reduced rate of carbon deposition when observed at frequent intervals during the trials. Learning from the iterative steps, vehicle validation results and combination of smart software algorithm enabled a robust throttle body design.
Free Piston Combustion Engine Design Analysis and Challenges
Authors: Washko Frank M. , Winchell Rodeo A.
Published: November 2023

There has been a recent resurgence in interest in “free piston” engine designs, particularly for small engine applications. This has been driven primarily by the demand for higher efficiency, flex-fuel capability, and also electrical demand in hybrid-electric applications. In free piston engines, expansion gasses are used to send energy directly to electrical or hydraulic power systems, rather than through a crankshaft. In many instances, the designs use opposed pistons to contribute the momentum of one piston to the upwards stroke of the opposing piston. This paper will review the details and benefits of the early free piston designs and some current designs, including our own hydraulic hybrid engine designs. The paper will then turn to a future free piston engine application that is in development.
“Investigation of High Achievable Pollutant Reduction on a “State of the Art” Indian 2 Wheelers - Technology Road Map to a Cleaner Air”
Authors: Jayat Francois , Seifert Sven
Published: November 2023

Affordable, efficient and durable catalytic converters for the two and three wheeler industry in developing countries are required to reduce vehicle emissions and to participate in a cleaner and healthier environment. As a contribution Continental Emitec started a comprehensive testing program with a state of the art 180 cc Bharat Stage (BS) III Indian motorcycle. The program consists of testing the state of the art of Metallic substrates with structured foils with various catalyst sizes and positions (original or close coupled). The publication presents a short literature survey and the results of the investigation with a big catalyst volume mounted in underfloor position as well as in close coupled position, gained over the World-wide harmonized Motorcycle Test Cycle, considering the two possible vehicle classifications of this motorcycle, Sub-Class 2.1 and Sub-Class 2.2. This catalyst is based on metal turbulent structured catalyst substrate with longitudinal foil structures (LS-Design™). The results are showing that all pollutant emissions could be reduced to very low levels if an appropriated technology road map is applied.
Investigation of In-Cylinder Heat Flux in a Single Cylinder, 4 Stroke, Air Cooled, Spark Ignition Engine for Motorcycle Application
Authors: Rajagopalan V.R , Anand S , Nagendra Kumar D , Karunaharan V , Lakshminarasimhan V
Published: November 2023

Heat flux measurements can provide much needed insight into the energy flow inside an IC engine, which is the key to optimizing its performance. This paper focuses on understanding the nature of heat flux curve and how it varies with varying load conditions, engine speed, Air fuel ratio and ignition timing in a single cylinder, 4 stroke, carbureted, air cooled, spark ignition engine for motorcycle application. In-cylinder heat flux was monitored along with wall temperature and cylinder pressure for motored operation as well as fired conditions. The difference between the motoring mode and fired mode was analyzed to separate out the effects of combustion. In general, the magnitude of maximum heat flux was found to increase with engine rpm and load when all other engine parameters remained constant. The heat flux was found to increase when a mixture setting closer to the stoichiometric value was used. While studying the effect of ignition timing, it was observed that the peak cylinder pressure and cylinder head wall temperatures increased as the ignition timing was advanced. However, there exists a particular value of ignition timing for which the heat flux peaked for any set of operating conditions and advancing the timing any further resulted in a decrease in the magnitude of peak heat flux regardless of the fact that the cylinder pressure continued to rise well beyond this point.
Development of Two Types of Industrial SI Engines, to Meet Diverseness of Regional Demands and Emissions Requirements
Authors: Kawasaki Takeshi , Yamada Yuichiro , Tsujioka Toshihiro , Shiraishi Kentaro , Kishi Shinji
Published: November 2023

Due to the changes in the environment surrounding the industrial engine market, such as strengthening of exhaust emissions regulations of diesel engines and production increase of shale gas, the needs of the gasoline, LPG or natural gas fueled engines are growing.

In the North American market, exhaust emissions regulations of industrial SI engines are getting strict. On the other hand, European market and developing countrys' market have no exhaust emissions regulations for SI engines. Therefore it is necessary to develop the engines which meet the needs of each region. Based on the existing diesel engine, we developed the two types of SI engine WG2503 (displacement 2.491L) simultaneously. In this paper, approaches and technologies used for the development of these models are explained.

To secure the high torque characteristics, its combustion chamber configuration was optimized. Ignition timing was optimized according to the fuel types. By these approaches, the frequency of knocking was reduced and high torque characteristics at medium and low speed range was realized. Because industrial engines are installed on the various applications, engines must be compact and installed easily. To meet these requirements, we have developed the compact inlet manifold and the compact exhaust manifold. This also secured installation compatibility with the original diesel engine model.

Long maintenance intervals are also required for industrial engines. Prolongation of oil change intervals is one of the most important items of the maintenance intervals. We have challenged to reduce oil carry-over by changing the structure of the head cover.
Layout and Development of a 300 cm
3
High Performance 2S-LPDI Engine
Authors: Winkler Franz , Oswald Roland , Schögl Oliver , Abis Andrea , Krimplstatter Stefan , Kirchberger Roland
Published: November 2023

In consideration of the fact that in extreme Enduro competitions two-stroke motorcycles are still dominating, the Institute of Internal Combustion Engines and Thermodynamics, Graz University of Technology, with a long tradition in two-stroke technology, has developed a new 300 cm3 two-stroke motorcycle engine.

The 2-stroke LPDI (Low Pressure Direct Injection) technology was originally developed for the 50 cm3 Scooter and moped market in Europe. In 50 cm3 applications the LPDI technology fulfils the EURO 4 emission standard (2017) [1]. In a next step the LPDI technology was applied to a 250 cm3 Enduro engine demonstrator vehicle. Based on the results of the demonstrator, a complete new high performance 300 cm3 engine was developed. The development of this new engine will be described in this publication.

Some interesting aspects of the layout with 3D-CFD methods and also 1D-CFD simulation to optimize the exhaust system by DoE methods are discussed in the paper.

For the first prototype (prototype 1) some carry over parts had to be used - crankshaft, connecting rod, clutch, gearbox - whereby these parts were redesigned for the next project step (prototype 2) in order to optimize the engine weight. The design of the engine will focus on special features like the balance shaft and the optimization steps between prototype 1 and prototype 2. Some improvements identified during the prototype 1 durability test will also be described.

The most interesting aspect of the engine test bench development is the performance development which is strongly linked to the 1D-CFD simulation.

Finally, the engine calibration and EMS (engine management system) will be described in this paper. In this case, the span between idle and maximum power as well as the transient calibration were the challenge during the development. Quick and smooth response on throttle opening is essential for the characteristic of these engines.
Patented Software Solution to Prevent Rotation of the Tool Upon Machine Start at Idle
Authors: Lajda Marek , Hook Sebastian , Reimgen Nikolai
Published: November 2023

During the start-up phase of machines it can happen that tools are inadvertently rotating, which is caused by the half-throttle setting. Due to the starting throttle locking mechanism, the engine's rotational speed is above the engagement speed of the tool (for example the chain of a chain saw).

This article describes the software algorithms developed by PRUFREX that are able to prevent rotation of the tool upon machine start at idle. The patented software solution is able to differentiate between start behavior with and without a starting throttle locking mechanism based on the machine's speed and time information and, as a result, can identify or estimate the position of the throttle valve. The effect of the algorithms is the switch-over between different ignition curves that are stored in the microcontroller-operated ignition modules. This includes a provision in the start ignition curve that prevents the tool from rotating. Toggling between different ignition curves is already part of today's technology. The underlying patent defines the conditions for switch-over that is solely controlled by software.

The article explains the various machine states and their identification in detail. The possible program sequence is featured.
Measurement and 3D Simulation for Analysis of Emission Improvement in Oil-Cooled Engine
Authors: Tanaka Koichi , Arase Kunio , Kitayama Amane , Shimizu Toru , Shimura Akihisa
Published: November 2023

The aim of this study is to analyze the emission improvement in the oil-cooled engine by use of internal cylinder gas pressure measurement and 3D simulation of thermal flow and combustion.

In the previous study, two test engines were designed to evaluate the benefits of the oil-cooled engine. One was an oil-cooled, and the other was a water-cooled engine. Both engines were single cylinder engines with SOHC valve-train systems. The hardware specifications of both engines were exactly the same except for their cooling systems in order to clarify how the difference in engine cooling system affects their cooling performance, warm-up performance and emission performance. Consequently, the oil-cooled engine showed a rise in temperature by about 80 K in the combustion chamber, resulting in a slight decrease in cooling performance, a 20% shorter warm-up time of the engine, while total hydrocarbons(THC) levels were lowered by 50% at maximum and nitrogen oxides(NOx) levels were almost equivalent to that of water-cooled engine in full-load operation.

In this study, in-cylinder gas pressure measurement and 3D simulation of two test engines were conducted in full-load operation for clarifying the benefits of oil-cooling system with reproducing engine temperature and fuel evaporation. Thermal flow simulation was conducted to determine the temperature of combustion chamber surface and heat flux condition. Three-dimensional combustion simulation was conducted to evaluate how the difference in temperature of the combustion chamber affected the THC and NOx levels in emission. Both simulation conditions were based on previous experiment results.

As the result of combustion pressure measurement, the difference in pressure values among the two engines were minimal indicating that the temperature of combustion gas is dominant in producing NOx rather than the temperature of combustion chamber. The result of steady state thermal flow simulation indicates that latent heat amount of fuel evaporation in the intake port and the cylinder of the oil-cooled engine were greater than that of the water-cooled engine. Finally, the result of three-dimensional combustion simulation based on thermal flow simulation indicates a higher combustion chamber temperature in the oil-cooled engine is more effective to reduce THC levels compared to water-cooled engine.
Numerical Transient Thermo-Mechanical Analysis of Cylinder Head and Valve within a 400cc Engine
Authors: Tsai Chien-Hsiung , Huang Hui-Hui , Chang Wei-Chun
Published: November 2023

In this paper, the temperature of coupling system including cylinder, head, inlet/exhaust valve, and the cooling jacket of a 400cc engine is investigated by computational fluid dynamic (CFD) method. Firstly, the total pressure loss of water jacket, radiator, and thermostat is calculated first, and then the mass flow rate inside the cooling system can be determined by fitting the water pump’s performance curve (P-Q curve). The thermal boundary conditions for analysis of conjugate heat transfer of cooling system, such as combusting gas temperature and heat transfer coefficient are utilizing the results of 1-D engine simulation software (Ricardo WAVE). The current approach is that the heat transfer coefficients of valve while opening are calculated by considering the intake and exhaust stroke using FLUENT to overcome the difficulty of these values that are not modeled in such 1-D software. Finally, the finite element method (FEM) is used for the valve stress calculation.

The results indicate that the temperature, pressure loss and the flow rate of coolant exhausted from the cooling jacket are concurred with those of experimental results. In addition, the distributions of convective heat transfer coefficients of valves are found to have different behavior for five sections of valve defined in this study. Therefore, this method is expected to predict the transient temperature distribution of valve seats and valves with a high degree of accuracy. The results show that maximum valve stress can be found in the seat face of the intake/exhaust valves because of the thermal gradient.
Characteristics of Flat-Wall Impinging Spray Flame and Its Heat Transfer under Small Diesel Engine-Like Condition
Authors: Mahmud Rizal , Kim Seong Bum , Kurisu Toru , Nishida Keiya , Ogata Yoichi , Kanzaki Jun , Tadokoro Tadashi
Published: November 2023

Heat loss is more critical for the thermal efficiency improvement in small size diesel engines than large-size diesel engines. More than half of total heat energy in the internal-combustion engine is lost by cooling through the cylinder walls to the atmosphere and the exhaust gas. Therefore, the new combustion concept is needed to reduce losses in the cylinder wall. In a Direct Injection (DI) diesel engine, the spray behavior, including spray-wall impingement has an important role in the combustion development to reduce heat loss. The aim of this study is to understand the mechanism of the heat transfer from the spray and flame to the impinging wall. Experiments were performed in a constant volume vessel (CVV) at high pressures and high temperatures. Fuel was injected using a single-hole injector with a 0.133 mm diameter nozzle. Under these conditions, spray evaporates, then burns near the wall. Spray/flame behavior was investigated with a high-speed video camera. At the same time, the surface heat flux of the impingement wall was studied by three thin film thermocouple heat flux sensors. The results showed that local heat flux becomes a maximum at some spray impingement distances to the wall.
Analysis of SI and HCCI Combustion in a Two-Stroke Opposed-Piston Free-Piston Engine
Authors: Schneider Stephan , Friedrich Horst , Chiodi Marco , Bargende Michael
Published: November 2023

The German Aerospace Center (DLR) is developing a free-piston engine as an innovative internal combustion engine for the generation of electrical power. The arrangement of the Free Piston Linear Generator (FPLG) in opposed-piston design consists of two piston units oscillating freely, thereby alternately compressing the common combustion chamber in the center of the unit and gas springs on either side. Linear alternators convert the kinetic energy of the moving pistons into electric energy. Since the pistons are not mechanically coupled to a crank train, the bottom and top dead centers of the piston movement can be varied during operation e.g. to adjust the compression ratio. Utilizing these degrees of freedom, the present paper deals with the analysis of different combustion processes in a port scavenged opposed-piston combustion chamber prototype. This contains the experimental investigation of spark ignition (SI) as well as the transition to homogeneous charge compression ignition (HCCI). Based on test bench results, a 3D-CFD model, which has been used to develop the first prototype, is calibrated by actual measurements. The simulation results enable a deeper analysis of scavenging and in-cylinder processes exceeding the measurement possibilities on a test bench.
Development of New Compact Hybrid System
Authors: Itoh Satoshi , Yamamoto Michiyasu
Published: November 2023

One of the fuel efficiency improvement policy of Small vehicle included Regenerative Braking System (JSAE 20139006 / SAE 2013-32-9006), but developed New Compact Hybrid System to realize further fuel efficiency improvement. The previous system has losses for the engine friction when deceleration energy is collected, but the new system realizes effective regeneration with separating the engine. The new system collect deceleration energy in decelerating time and coasting as well as the previous system, but the fuel consumption with the engine is minimized by running EV with the collected energy and realize further fuel efficiency improvement. In addition, the assist is also performed with collected energy, so both good efficiency and good accelerating performance are realized.

This system adopts Auto Gear Shift® system (following, AGS) which is based on a manual transmission. This AGS is one of the systems which is light-weight, compact, and transfer efficiency is good, and is most suitable for the fuel efficiency improvement of small vehicle. But there is a problem of driving torque outran at the time of gear shifting, and acceleration fluctuation occurs. About this problem, using collected deceleration energy, supplemented torque realize smooth transmission feel.

When a hybrid system is put on small vehicle, the vehicle behavior is subject to increase of weight, but, as for this hybrid system, it is suitable for small vehicle because of its minimizing weight.

This paper focuses on our concept and basic performance of the new compact hybrid system.
Development of Titanium Fuel Tank Applied for Mass Production Motocrossers
Authors: Hirano Kohei , Chihara Yuki
Published: November 2023

The new titanium fuel tank has been developed to reduce weight of the fuel tank of production motocrossers. While the titanium permits deep drawing to shape a tank by presswork, the processing of titanium material is difficult, hence no past application of the material for a motorcycle fuel tank. This project was aimed at development of new techniques for mass production of titanium fuel tanks, and succeeded in mass production of titanium fuel tanks having an adequate durability to apply to a motocrosser that can receive a strong impact while driving. As a result, approximately 40% of weight reduction from the plastic fuel tank having the same fuel capacity was realized.
Investigation and Model-Based Compensation of the Pitch Dynamic Impact on Longitudinal Acceleration Measurement on Motorcycles
Authors: Winkler Alexander , Grabmair Gernot
Published: November 2023

In this study we focus on systematic disturbances caused by the motorcycle pitch dynamic when measuring longitudinal acceleration on motorcycles using low-cost acceleration sensors. Major systematic influences in the sensor measurement like gravitational acceleration, suspension dynamics and the road slope are addressed. During acceleration phases the motorcycle pitch angle changes according to the suspension setting. As a result the longitudinal sensing axis of the accelerometer includes parts of the gravitational acceleration and lags parts of the longitudinal acceleration. Gravitational acceleration has also significant influence on inclined roads. To obtain correct values of the effective longitudinal acceleration, the disturbances in the measured signal are analyzed and in further consequence compensated. For this purpose a linearized in-plane-dynamics model of the motorcycle is derived from a comprehensive multibody simulation. The mathematical description of the motorcycle behavior includes the systematic influences and serves as a basis for the model-based compensation. A state observer for pitch angle estimation and road slope reconstruction is designed. As a result the measured acceleration can be corrected with the estimated quantities. In the course of ongoing development of motorcycle dynamics control and advancement of drivetrains, e.g. hybridization, independent and economically measureable reference signals are required to achieve desired vehicle behavior with closed-loop control. Acceleration measurement on two-wheelers can be achieved at low hardware cost and is a promising quantity for innovative control designs.
ISO 26262 C Class Evaluation Method for Motorcycles by Expert Riders Incorporating Technical Knowledge Obtained from Actual Riding Tests
Authors: Kawakoshi Maki , Kobayashi Takashi , Hasegawa Makoto
Published: November 2023

In applying the ISO 26262 controllability classification for motorcycles in actual riding tests, a subjective evaluation by expert riders is considered to be the appropriate approach from the viewpoint of safety. We studied the construction of an expert-rider-based C class evaluation method for motorcycles and developed some evaluation test cases reproducing various hazardous events. We determined that it was necessary to accumulate more evaluation cases for further representative scenarios and that, to avoid variations in such evaluations, a method in which different expert riders can carry out testing following a common understanding had to be devised.

Considering these problems for practical application, this study aimed at establishing an actual riding test method for C class evaluation by expert riders and to develop a deeper understanding of test procedures and management. To this purpose, representative hazards related to electrical/electronic (E/E) system failures particular to motorcycle control characteristics were extracted by referring to the hazard cases of passenger cars and ISO/DIS 26262. C class evaluation tests were conducted on some extracted hazards to obtain comparable class ratings. On the basis of the riders’ comments and discussion, it was confirmed that interpreting a baseline for the C0 rating in each assumed scenario is useful in developing a common rider understanding during subjective evaluations. We organized the resulting technical knowledge set and added it to the existing classification method, creating a C class expert-rider-based evaluation method for motorcycles that can feasibly be used in practice.
Enhanced Diagnosis for Small Engines
Authors: Basso Riccardo , Schacht Hans-Jürgen , Stephan Schmidt , Kirchberger Roland , Rath Matthias , Neumayer Markus , Reisenberger Christian
Published: November 2023

Small engines for non-automotive and two wheeler applications have a reduced number of sensors. For fulfilling emission regulations a cost effective way is an enhanced use of standard sensors in order to obtain more information from the existing sensors. The delivered information can then be used for an on-board diagnosis. Moreover, it is important to control the quality of the product during engine production; therefore an end-of-line cold engine test is often made. With this measure it is possible to detect faults, wrong tolerances or assembly in order not to deliver faulty engines to the customers.

In this paper, an enhanced use of sensors for fault detection will be discussed. It is possible to obtain more information from the signal or to use the sensor for detecting other parameters. For extracting information signal analysis methods will be used with focus on the computational power need since the ECU performance is limited. The starter motor current is a useful indicator for detecting a lack of compression in an end-of-line check. Furthermore, it is possible to assign the fault to a specific cylinder by using one single sensor. It has to be considered that different faults have the same influence on the analyzed signals. Particular attention is put on the cylinder imbalance detection.
Comparison of Optimal and Real-Time Operation Strategy for a Hybrid Electric Motorcycle
Authors: Rieger P. , Schweighofer B. , Wegleiter H. , Zinner Ch. , Schmidt St. , Kirchberger R. , Foxhall N. , Hinterberger W.
Published: November 2023

Within the motorcycle- and powersport sector the hybridization and electrification of the powertrain is increasingly becoming an important topic. In the automotive sector the hybridization of the powertrain is already well established and shows improvements regarding fuel consumption and emission behavior. Also in the motorcycle sector the emission legislation limits are getting stricter and the requirement for a significant reduction of fuel consumption, especially under real drive condition, is being focused. Furthermore, the increasing environmental awareness of the customer requires measures regarding fuel consumption- and emission minimization. Due to the high system complexity and degrees of freedom of hybrid powertrains, the simulation of the complete vehicle is essential for the component dimensioning, concept selection and the development of operation strategies. This publication covers the description of a backward simulation, including dynamic programming (optimal strategy), and the description of a forward simulation, including a real-time strategy, for a hybrid powersport vehicle. With both development tools the same hybridization-level and architecture is investigated and analyzed. Therefore, the vehicle and operation strategies are simulated for the WMTC and a real world driving cycle. The results regarding torque distribution, gear selection, electrical energy and fuel consumption are shown. Furthermore the different assumptions, constraints and boundary conditions for building up the reference and real-time strategy/simulation will be described and discussed. The advantages and disadvantages of these two approaches are illustrated in more detail.
Motorcycle Emission Profiles in Bandung City, Indonesia
Authors: Yudison Adyati , Reksowardojo Iman K. , Sulaeman Aminudin
Published: November 2023

Motorcycles account for almost 80% of private vehicles in Indonesia, with an annual growth rate of 12% per year. This paper aims to investigate the emission profiles of CO2, CO, HC and NOx based on typical fuel and motorcycle types in Indonesia. Questionnaire surveys were undertaken to gather fuel type, engine technology and capacity representing the motorcycle population in Bandung City, Indonesia. Emissions were measured based on six-speed variations on a chassis dynamometer. Questionnaire surveys from 290 respondent show that EURO II and EURO III technology with engine capacity less than 150cc is the most utilized type of motorcycle in Bandung. Most of the users’ chose RON 90 and RON 92 gasoline. Based on the results, four groups of 5 motorcycle of EUROII-RON90, EUROII-RON92, EUROIII-RON90, and EUROIII-RON92 were tested. Emission data showed that the higher the speed, the lower the emission, except for CO and NOx which have a different pattern. The highest CO2 and NOx emission are found in the EUROIII- RON92 group (76.81 and 0.17g/km respectively), EUROII-RON90 for highest CO emission (11.92 g/km), and EUROII-RON92 for highest HC (0.30 g/km). Kruskal Wallis test shows significant differences within the group for all parameters. Good quality fuel on motorcycles will lead to engine performance improvement. It increases CO2 and NOx emission as complete combustion marker and reduces byproduct of incomplete combustion, especially CO emission. This paper shows that to reduce the emission of incomplete combustion product, a proper fuel specification should be used to get expected emission reduction. The results highlight the importance of fuel provision with proper specification in the plan of upgrading motorcycle engine technology.
Clean and Sustainable Energy for Small Urban Car
Authors: Setio Sangriyadi , Arismunandar Wiranto , Ong Rudy , Dwithama Adefrid , Adrian Stefanus , Claudia Angela , Maliky Nu’man Amri , Octavianus Jery , Mabbrur Muhammad Alif , Tjhoi Michell
Published: November 2023

Developing and designing fuel efficient vehicle for a one gallon of fuel marathon is a challenging task. Engines have to be optimized to achieve maximum fuel efficiency. In this study, we evaluate the optimal compression ratio (CR) and ignition timing that produce the best torque in a custom gasoline-based-motorcycle-engine that use ethanol E100 fuel. In the first experiment, CR was adjusted between 9 and 12 to evaluate its effect on the engine mileage’s record. The experiment was conducted on the test track. In the second experiment, Ignition timing was adjusted by a custom-made engine control unit (ECU) between 15° and 45° before top dead center (BTDC). The engine performance was investigated in terms of best torque and brake specific fuel consumption (BSFC), with variation of engine speed between 1500 and 8000. The test was conducted on dynamometer. The test was also performed in constant compression ratio and stoichiometric air-fuel ratio, 9. The best result is used to develop the clean, sustainable, and efficient small urban car for Shell Eco-marathon Asia competition. We achieved the best CR of 12 with the average mileage of 212.3 km/liter. The lowest BSFC is obtained at 4500 rpm, which generates 9.68 N.m.
Development of 2-Cylinder Diesel Engine for European Quadricycle in Compliance with EURO4
Authors: Oso Hiroki , Tanaka Akira , Nagai Kentaro , Yamazaki Takahiro , Goto Hideyuki
Published: November 2023

The EURO4 standard has been enforced since the year 2017 for European quadricycle. The vehicles are regulated upper limit of unladen weight and engine displacement, in addition to the exhaust emissions and the net power. In order to meet those regulations, the engine for European quadricycle is demanded low exhaust emissions and light weight. Further, it is required to be achieved good drivability, low fuel consumption, low noise and more compact. We introduce technologies to meet demand for European quadricycle in compliance with EURO4. The limit values of exhaust emissions have been strengthened in EURO4 standard compared to the previous one. As devices to improve the exhaust emissions, the exhaust-after-treatment devices and the common rail injection system are well known, whereas those devices make engine systems heavier. In addition, to satisfy high torque at low speed for better drivability, larger displacement is effective. However the engines of larger displacement have higher friction loss than smaller one, therefore countermeasures to reduce fuel consumption are necessary. In order to achieve to be lower emissions without additional devices, we improved the in-direct injection system engine. We optimized the shape of the combustion chamber to meet EURO4. To achieve low fuel consumption keeping better drivability with large displacement, we developed the new piston to be lower friction. We optimized the shape of the coating pattern to improve lubrication between piston skirt and cylinder wall. As the result, we attained to meet the requirements of European quadricycle with developing new technologies in compliance with EURO4.
Influence of Engine Speed on Autoignition and Combustion Characteristics in a Supercharged HCCI Engine
Authors: Tanaka Hiroto , Sato Tatsuya , Takano Shuntaro , Motoki Yuya , Hoshino Hyota , Higuchi Yuya , Iijima Akira , Shoji Hideo
Published: November 2023

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest because it achieves high efficiency and can reduce particulate matter (PM) and nitrogen oxide (NOx) emissions simultaneously. However, because HCCI engines lack a physical means of initiating ignition, it is difficult to control the ignition timing. Another issue of HCCI engines is that the combustion process causes the cylinder pressure to rise rapidly. The time scale is also important in HCCI combustion because ignition depends on the chemical reactions of the mixture. Therefore, we investigated the influence of the engine speed on autoignition and combustion characteristics in an HCCI engine. A four-stroke single-cylinder engine equipped with a mechanically driven supercharger was used in this study to examine HCCI combustion characteristics under different engine speeds and boost pressures. The results revealed that the engine speed range can be expanded by a mechanically driven supercharger. It was also found that there was no change in the ignition delay time under conditions of a constant equivalence ratio even at different engine speeds. The findings of this study provide important knowledge for controlling the ignition timing.
The Possibility for Realization of Dual Combustion Cycle for Spark Ignition Engine
Authors: Yoshida Koji
Published: November 2023

The purpose of this study is to operate the spark ignition engine by the dual combustion cycle. The dual combustion cycle has two combustion processes, these are the constant volume combustion and the constant pressure combustion. The lean combustion and the direct fuel injection were applied to realize the dual combustion cycle for spark ignition engines. The combustion of lean mixture was corresponding to the constant volume combustion. The fuel was directly injected to combustion chamber and was burned with the remained oxygen after the lean combustion, so that this was corresponding to the constant pressure diffusion combustion. The combustion experiments were conducted by using the constant volume vessel. The lean propane-air mixture of which equivalence ratios were 0.6, 0.7, 0.8 and 0.9 were used and liquid n-heptane was injected by using the high-voltage electrical discharge.

The luminous flame was observed after the fuel injection and the injected fuel was burned within the burnt gas caused by the lean premixed combustion. The luminescence from the luminous flame of diffusion combustion became weak as the equivalence ratio of lean mixture became lean. It can be considered that the oxygen remained in burnt gas increased for leaner mixture, so that the soot formation was prevented. The time at maximum combustion pressure was advanced as the fuel injection timing became early and was earlier than that of conventional combustion, because the combustion enhancement effect was caused by the fuel injection. Therefore, the dual combustion cycle could be realized for the spark ignition engine.
Durability Prediction of Motorcycle Body Components Using Advanced Fatigue Analysis
Authors: Sakamoto Kazunobu
Published: November 2023

The purpose of this study is to improve the accuracy of durability predictions for motorcycle body components through the implementation of a fatigue analysis that uses the finite element method (FEM) to identify the fatigue failure characteristics of arc welds, die-cast aluminum alloys, and thermo-plastics. In addition to highly accurate load conditions and stress analysis, a fatigue analysis that also takes into consideration the fatigue failure mechanism is essential to making accurate durability predictions. Fatigue tests were carried out under several load conditions using specimens of several different shapes that simplified the actual structures. The fatigue life of the weld toe is assumed to be the difference of the crack propagation rate due to the loading mode. The durability of die-cast aluminum alloys was found to be sensitive to the microscopic structure due to the casting process. The factors that influenced the fatigue behavior of the plastics were the stress gradient and the viscoelastic behavior. These comprehensive fatigue characteristics were applied to the fatigue analysis codes fe-safe and FEMFAT. The master S-N curve approach was used to evaluate the fatigue of the weld zone. Then the correlation between the durability predictions and the actual life were analyzed under rough road running conditions. This procedure was found to be an effective means of accurately predicting the fatigue life of motorcycle body components.
An Investigation on the Design and Manufacturing of Powertrain System for Student Formula Japan (SFJ) Vehicle
Authors: Kagawa Daisuke , Kodama Tomoaki , Honda Yasuhiro
Published: November 2023

The main purpose of Student Formula Japan competition (hereafter called “SFJ”) is to let students learn the basic ability necessary for engineers through design, fabrication and test projects. In this study the authors decided to adopt Honda BC-PC37E which was an engine for motor cycles. Then the engine have strength enough for the light weight, downsizing design. As the course of the competition consists of short straights and many corners for running within equal to or less than middle speed range, the engine must have excellent acceleration performance to reduce the lap times in the corners. The effective engine performance is necessary for the flat torque in all of engine speed range, especially in low engine speed range. As the regulation allows that a turbocharger is fitted to an engine, its introduction is effective for getting high torque in the low engine speed range. In this study the authors investigate the influences of the main specifications and the characteristics of important power train components, such as turbocharger, throttle, air restrictor, air collector, intake manifold (intake system), exhaust manifold (exhaust system), camshaft, valve timing and dual system of injection, on the improvement of the engine performance by analytical methods, experiments and driving tests. The conclusions are as follows: (1) The brake torque of the engine by adopting the turbocharger in the lower range of A/R (Area of inlet port/Radius of turbine, hereafter called “A/R”) has become higher in the low engine speed range. (2) In the case that the length of intake pipe is extended, the brake torque has been increased in the low engine speed range and decreased greatly in the high engine speed range.
Knock Tendency Prediction in Highly Charged SI Engines
Authors: Bevilacqua V. , Boeger M. , Corvaglia G. , Penzel M. , Fuoss K.
Published: November 2023

The continually increasing stringent requirements in terms of emissions and performance lead to the demand for further development of gasoline engines, in order to satisfy the regulations and to be competitive in the market.

One of the main limitations in simultaneously improving the efficiency and performance of SI engines is the knock behaviour. This phenomenon limits either the possibility to adopt a higher compression ratio, which would be beneficial for the engine efficiency, or it causes a poor combustion timing which leads to a higher fuel consumption and a lag in performance. As a result, having the possibility to judge the risk of knock during the design phase can be beneficial to increase the potentials of the engine.

In this work, a methodology for the prediction of the knock tendency in spark ignition engines using a 3D-CFD software has been developed. This method, evaluating the local conditions in the combustion chamber, allows to predict also the area where the autoignition will occur. For this study, two approaches, based on the work of Douaud & Eyzat [3] and the Kinetics-fit model [4], have been considered and compared.

Both approaches were evaluated at low-end torque and peak power, which represent the most significant points to describe the performance of an engine at full load, showing a good accordance with the theory behind the knock.

In conclusion, a comparison between the results in the two operating points has been performed, obtaining an objective criterion, independent of the engine operating conditions, for the prediction of the knock tendency.
Development of a Novel Hybrid-Piston for Application in High Performance Two-Stroke Engines
Authors: Bechter Christian , Jahn Axel , Zimmermann Frieder , Stamm Uwe , Herb Thomas
Published: November 2023

The current development trends for high performance two-stroke engines have been identified in raising combustion pressures and therefore higher cylinder temperatures [1] [2]. Thus, the requirements on piston assembly are increased in such a way that pistons based on aluminium-silicon alloys – as most commonly used in high performance two-stroke engines - reach their application limit. A suitable solution has been shown by research work such as that conducted by Mahle König, by using a piston consisting of different materials. With this approach, the higher stressed piston crown consists of steel, while the lower stressed piston skirt is made out from aluminium. Previous basic examinations showed the high potential of the hybrid piston concept in terms of pressure and temperature increase, while also showing the need for a temperature-stable and pressure-tight joint between crown and skirt.

This paper will focus on the development of two novel hybrid-piston concepts, where the piston crown and the piston skirt are connected in different ways. The first hybrid concept presented uses the piston pin in order to realize a plugconnection between piston crown and piston skirt (a conjunction hereafter known as plug-connection). A second approach is a material joint between piston crown and piston skirt, with the result that the two parts are integrally joined to one another (a conjunction hereafter known as multimaterial joint). During the predevelopment phase the design and dimensioning of the hybrid concepts were carried out with reference to mechanical and thermal operation loads, as well as joining aspects.

A specific joining concept using a bimetal transition joint was created, along with the development of a special adapted laser beam welding procedure. The multi-material joint properties were further verified by FEM simulations as well as by mechanical and thermal tests. Finally, hybrid-piston prototypes were produced in time for first bench tests. In this paper the design concept of the hybrid piston and the joining technology will be presented, along with the results of FEM simulations and material testing.
Sensor Fusion Concept for Improved Rotational Speed Measurement in Small Engines
Authors: Neumayer Markus , Bretterklieber Thomas , Suppan Thomas
Published: November 2023

Future developments for small engines, e.g. engines for handheld working tools, like chain saws require the integration of ECU-systems for engine control. For small engines often only a rotational speed senor is available. The application of additional engine sensors is in many cases unwanted, e.g. due to cost aspects and additional wiring. The lack of sensor data requires tailored control strategies and signal processing techniques to infer information about the engine from the sensor data. E.g. for rotational speed sensors the Δω method has been proposed, where the load is estimated from the temporal variation of the rotational speed. This approach requires a rotational speed sensor with sufficient angular resolution. In this paper we present a simulation study for a sensor fusion concept to improve the temporal resolution of engine speed measurements for low cost engines by means of an additional vibration sensor. The rotational sensor of the engine is assumed to have insufficient resolution to determine variations of the rotational speed over an engine revolution. However, variations of the rotational speed of the engine also cause vibrations of the engine chassis. A vibration sensor can be used to pick up the vibration signal with high temporal resolution. As the transfer function between the variation of the rotational speed and the sensor readings is only approximately known, a sensor fusion concept for the rotational speed sensor and the acceleration sensor has to be applied, which combines the different measurements, while simultaneously estimating the unknown transfer function. We will use an extended Kalman filter for the data fusion and an autoregressive-model for the unknown transfer function.
Investigation of The Effect of Enhanced In-Cylinder Flow on HCCI Combustion in a Rapid Compression and Expansion Machine
Authors: Zhong Yiwen , Ogawa Kazuya , Kuboyama Tatsuya , Moriyoshi Yasuo , Yoshimura Kei
Published: November 2023

The purpose of this paper is to find a way to extend the high load limit of homogeneous charge compression ignition (HCCI) combustion. A newly developed rapid compression and expansion machine (RCEM) was employed to reproduce the typical HCCI high load condition. The in-cylinder turbulence was created by the special piston which equipped with a flow guide plate. Meanwhile, the ambient temperature distribution in the cylinder was determined by the wall temperature controlling system which was controlled by the independent coolant passages. In addition, the numerical simulation by using large eddy method coupled with a detailed chemical reaction was conducted as well. The results show that HCCI mode is potential to be improved at high load condition in full consideration of in-cylinder temperature, flow, and turbulence.