Browse Topic: Micromobility
Micromobility is often discussed in the context of minimizing traffic congestion and transportation pollution by encouraging people to travel shorter (i.e., typically urban) distances using bicycle or scooters instead of single-occupancy vehicles. It is also frequently championed as a solution to the “first-mile/last-mile” problem. If the demographics and intended users of micromobility vary largely by community, surely that means we must identify different reasons for using micromobility. Micromobility, User Input, and Standardization considers potential options for standardization in engineering and public policy, how real people are using micromobility, and the relevant barriers that come with that usage. It examines the history of existing technologies, compares various traffic laws, and highlights barriers to micromobility standardization—particularly in low-income communities of color. Lastly, it considers how engineers and legislators can use this information to effectively
This study was conducted to establish a reliable thermal analysis methodology for the battery module designed for micro-mobility. Analysis and experiments were performed first with a single cell and subsequently with a battery module consisting of 80 cells. The heat generation calculated from a single-cell experiment and realistic thermophysical properties were used in the module analysis to predict the temperature rise and distribution at various discharge rates. A prototype battery module was then built and ten thermocouples were used to measure temperatures at various locations in the module. Good correlation was achieved between the analytical results and experimental data. In particular, the model is accurate in predicting temperature distribution and the locations of peak temperatures. As a next step, the analytical methods developed in this study will be used to optimize the battery pack design and enhance its thermal performance
While riding cycles, cyclists usually experience an aerodynamic drag force. Over the years, there has been a global effort to reduce the aerodynamic drag of a cycle. Fenders affect the aerodynamic drag of a cycle to a large extent, and fender coverage has a pronounced effect on the same. In this article, various fender coverage angles, varying from 60° to 270°, were studied to predict the aerodynamic drag with the help of a validated CFD model in SolidWorks Flow Simulation. The model was based on the Favre-Averaged Navier-Stokes (FANS) equations solved using the k-ɛ model. It was predicted that aerodynamic drag coefficient reduced fender coverage angle up to 135°, and thereafter started increasing. Analyses were carried out at velocities of 6 m/s, 8 m/s and 10 m/s and the results were found to be similar, with a minimum aerodynamic drag coefficient at 135° occurring in all the cases under study. There was an observed optimum decrease in drag coefficient to the extent of 4.6%, 4.5% and
Terminology within this document is limited to the dynamics and handling characteristics of single track, two-wheeled vehicles
As 2019 gets under way, SAE's Global Ground Vehicle Standards staff and committee members are engaged on multiple fronts to establish new task forces and committees focused on new standards activities. The fast-emerging automated/connected vehicle sector, including “micromobility” devices, are of particular focus. Highlights of some of the recent projects include
Lower extremities are easily injured in traffic accidents. During pedestrian-vehicle crashes, pedestrian lower extremities are subjected to the influence of combined shear force and bending force, which could bring about ligament tear and bone fracture. According to 2018 China New Car Assessment Program (C-NCAP) pedestrian testing protocol, where the flexible pedestrian legform impactor (FLEX-PLI) is struck from the right lateral by vehicle, the injuries of the ipsilateral side leg are taken into account for assessing the performance of lower extremities. However, the contralateral leg injuries and deformation are neglected in the current testing protocol and the pedestrian walking gaits and the e-bike riding scenario have been little consideration. The purpose of this study is to investigate the injury characteristics of the contralateral lower extremities in pedestrian-vehicle and bicyclist-vehicle crashes. Impact simulations were conducted by the Total Human Model for Safety (THUMS
Vibrations have become an increasingly important attribute for determining the quality of automotive products. Particularly, this becomes more acute in the case of tactile vibrations of powered two-wheelers - motorcycles and scooters. This paper deals with vibrations of a scooter vehicle. Scooters are normally a two-wheeler with a four stroke single cylinder spark ignited engine. Vibrations of a scooter are mainly caused by the inertial imbalance forces of the engine, combustion forces and road undulations. Vibrations due to road undulations are mostly reduced by toggle link mechanism, resilient mounts of the engine and the shock absorbing suspension of the frame. The power train assembly is designed in such a way that the inertial imbalance forces in the power train assembly are distributed at a required angle called the ellipse angle. This configuration ensures that the engine forces which are spread unequally in different directions are made to align and contribute only to the
A variable cooling system has been developed for scooters equipped with an air cooled, four-stroke, single cylinder gasoline engine. This system opens or closes louver located at the cooling air inlet using an oil-temperature sensitive actuator. When the engine is cold or the engine load is low, the louver shut off the cooling air for a quick warm-up and for maintaining the engine oil temperature high to reduce the friction losses that occur with low oil temperature while eliminating the loss from driving the cooling fan as well. The quick warm-up also decreases supplementary fuel injections necessary when the engine is cold. Consequently, fuel economy improvement by 3.3% was realized in running condition of the Urban Driving Cycle
Butanol is deemed as a potential alternative fuel for vehicle, but there are few studies about applying butanol in engine combustion. This paper focuses on application of butanol-gasoline blend fuel on scooter engine. In this research, different volume percentage of butanol-gasoline blend fuel, B10, B20, B40, B60, B80 and B100 are applied on 125cc scooter engine to conduct engine experiment, and higher than B60 blend fuel is declared as high butanol concentration blend fuel. The test conditions are set at 4000 and 6000rpm under partial load and full load. After executing engine experiment, engine performance, brake specific fuel consumption (BSFC), emissions and combustion analysis are discussed. Furthermore, viscosity and fuel spray are tested with high butanol concentration blend fuel. The engine experimental result shows that B100 fuels can increase engine performance under engine 4000 and 6000rpm. In addition, B10 and B20 fuels can improve not only BSFC but also emissions under
Indian two wheeler market is one of the largest and highly competitive in the world. Indian scooter segment grows at a pace of around 30% YOY. The stiff competition among OEM’s to increase the market share with fuel efficient and high performance products pushes development and calibration engineers to burn the midnight oil to concoct innovative methods to design technology boosted product. Customer expectations are always high in terms of fuel economy, drivability and NVH. Due to higher level of complexity involved in CVT (Continuously Varying Transmission) engine, it is difficult to optimize for achieving best of NVH characteristics along with Fuel Economy, drivability and reduced exhaust emission. This paper describes the experiment conducted during the development of 110cc CVT four stroke scooter engine. The development and calibration of this scooter was mainly based on real world usage pattern (RWUP). In order to obtain best performance from engine, ignition timing, fuel metering
When a scooter is put on main stand, it keeps the vehicle from falling as it rests against the engine crankcase. As the main stand is operated it transmits a large amount of load to the crankcase, thus creating a necessity to check the durability of the later. Practical tests showed that continuous application of the main stand resulted in the failure of its pivot area on the crankcase. This raised questions not just on the feasibility of the crankcase design in terms of durability, but also on the main stand design in terms of a load transmitting member. However, as the project was at its later stage, crankcase design could not be altered; thus it asked for a main stand design optimization. The base main stand model was thus taken for MBD simulation and loads were generated for further FEA analysis. The meshed crankcase model was taken in a commercially available FEA code for checking its durability. Accurate constraints and boundary conditions were applied close to the crankcase’s
This paper discusses various noise sources of cylinder head assembly and focuses on design options developed to reduce the cylinder head noise in a single cylinder, 110cc scooter engine. Various experimental procedures were used for identification and ranking of different noise sources. In case of air-cooled small engines, temperature effects are dominant and as a consequence certain noises stand out in hot condition causing severe noise discomfort. After identifying the reasons for abnormal cylinder head noise, countermeasure mechanisms for reducing unintended impacts of valve train/ rocker arm in the layout were developed. The side-effects due to introduction of these additional mechanisms are studied using performance metrics. It is essential to limit noise deterioration over time to increase customer satisfaction. Simulation cycles were developed to quantify the cylinder head noise deterioration using accelerated testing procedures. Targets have been revised based on engine noise
The belt clutching CVT drive has been developed for the scooter application. It utilizes the belt as a clutching mechanism instead of the traditional centrifugal clutch that is commonly employed in conjunction with the driven clutch of the drive train. By eliminating the centrifugal clutch, 48% mass reduction of the driven clutch has been achieved as well as cost saving. By placing the belt clutching directly at the engine crankshaft, fast throttle response and better vehicle acceleration/deceleration have been attained. The belt clutching mechanism demands a better performance belt to withstand the additional clutching induced wear and tear. The newly developed carbon cord belt, G Force™ C12, meets the challenge. The common edge cord pull-out failure mode is eliminated, and the overall wear is improved. An analytical program PTWork has been developed and proven to be instrumental in integrating CVT clutch hardware with the CVT belt. According to the Federal Test procedure 75 [1], the
A number of methods have been presented previously in the literature for determination of the impact speed of a motorcycle or scooter at its point of contact with another, typically larger and heavier, vehicle or object. However, all introduced methods to date have known limitations, especially as there are often significant challenges in gathering the needed data after a collision. Unlike passenger vehicles and commercial vehicles, most motorcycles and scooters carry no onboard electronic data recorders to provide insight into the impact phase of the collision. Recent research into automobile speedometers has shown that certain types of modern stepper motor based speedometers and tachometers can provide useful data for a collision reconstruction analysis if the instrument cluster loses electrical power during the impact, resulting in a “frozen” needle indication. Given the size and weight of motorcycles, and the location of speedometer and tachometer electrical connections in
The world today is moving more towards convenience and luxury. Auto manufacturers are being constantly challenged to provide innovative additions to conventional vehicles in terms of attractive features. This paper describes one such invention proposed to add convenience and novelty to the use of two wheelers. The proposed system is called a “Keyless Scooter”. Derived from the idea of keyless entry in four wheelers, the system aims at extending this luxury to a larger band of population in India, i.e. users of two wheeled vehicles. The system eliminates use of a mechanical lock and key arrangement. All functions carried out by the mechanical arrangement of lock and key are replaced with an equivalent electronic system. A “Keyless Scooter” is one in which a user can just approach it with a key fob on himself/herself and start the vehicle, open the luggage box, etc. without having to insert a key physically into the lock body. The vehicle is designed to communicate with the key fob
The operating conditions of a typical motorcycle are considerably different than those of a typical passenger car and thus require an oil capable of handling the unique demands. One primary difference, wet clutch lubrication, is already addressed by the current JASO four-stroke motorcycle engine oil specification (JASO T 903:2011). Another challenge for the oil is gear box lubrication, which may be addressed in part with the addition of a gear protection test in a future revision to the JASO specification. A third major difference between a motorcycle oil and passenger car oil is the more severe conditions an oil is subjected to within a motorcycle engine, due to higher temperatures, engine speeds and power densities. Scooters, utilizing a transmission not lubricated by the crankcase oil, also place higher demands on an engine oil, once again due to higher temperatures, engine speeds and power densities. However, because scooter oils do not need to lubricate a wet clutch or protect
The paper describes the development of an innovative test rig for the evaluation of e-bikes in terms of energetic performances and control system. The test rig has been realized starting from a commercial cyclist training system and suitably modified. The test rig is able to reproduce an aforethought route or paths acquired during road tests. It is possible to measure the performance of the e-bike in terms of instantaneous power and speed, by the installed sensors and data acquisition system. The experimental test rig can simulate the resistant torque of a predetermined track and it aims to test and to optimize the control strategy available on the electronic control unit (ECU). An important feature of the system is represented by the possibility to adopt a hardware in the loop approach for the testing of the e-bike and of its control. Indeed, the whole control algorithm can be implemented on a suitable controller board able to execute real time processes. The preliminary tests have
In scooters, the engine is a dynamic component. It is directly connected to the rear wheel and it also acts as a swing arm. Such behavior of an engine entails a requirement of a dynamic link connecting it to the frame. The link employed for this is an engine hanger. An engine hanger sustains a direct load and vibrations from the engine and allows swinging motion of the engine, thereby reducing the vibrations generated by the road undulations. The length of the engine hanger is chosen to minimize the transmission of forces generated by the rear wheel and engine arrangement to the chassis. Whereas, its shape is dictated by the forces acting on it, manufacturing process, available packaging space and its manufacturing cost. An engineer aims at developing an engine hanger that can withstand such loads and vibrations, as well as optimize its weight to meet the cost target. Improper design may lead to failure of the part in running condition. This research aims at optimizing the shape of an
In cold weather conditions, starting and maintaining low speed stability (engine idle RPM) has been difficult for smaller volume (50cc to 200cc) single cylinder engines. In order to improve the cold start ability without causing any inconvenience to user, automatic choke systems (auto-choke) have been employed. These auto-choke systems enrich the fuel-air mixture depending on predefined operating conditions. For Euro III and Bharat Stage IV (India) emission legislations, cold start emissions are very critical. The objective of this study is to investigate the effect of auto-choke systems on CO, HC, NOx and CO2 emissions in addition to studying temperature and light-off characteristics of catalytic converter of a 4-stroke scooter engine. The vehicle was tested on chassis dynamometer to investigate emissions on WMTC and ECE R40 test driving cycles, with and without the auto-choke system. Three durations of auto-choke operations were studied. The experiment was done with and without after
The Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology, has presented several applications of its 2-stroke LPDI (low pressure direct injection) technology in the previous years ([1], [2], [3]). In order to improve the competitiveness of the 2-stroke LPDI technology, an air cooled 50cm3 scooter application has been developed. All previous applications have been liquid cooled. This air cooled application demonstrates the EURO 4 (2017) ability of the technology and shows that the 2S-LPDI technology can also be applied to low cost air-cooled engines. Hence, the complete scooter and moped fleet can be equipped with this technology in order to fulfil both the emission standards and the COP (conformity of production) requirements of Euro 4 emission stage. The paper presents the Euro 4 Scooter results and describes the efficient conversion process of the existing carburetor engine to the LPDI version. Euro 4 results can be achieved with conventional
In scooters, the Continuously Variable Transmission (CVT) is used to transmit the power from the engine to the wheels. The CVT transmission consists of a two pulleys connected to each other through a belt. The change in the transmission ratio is achieved due to the change in the pulley diameters. A centrifugal clutch is attached to the rear pulley to transmit the power to wheels once the engaging engine speed is reached. The heat is generated due to the belt slippage and the engagement of the centrifugal clutch. Excessive heating may damage the belt, clutch and deteriorate its performance. The cooling of the belt, pulleys and the clutch is thus important for its safe operation. The cooling is achieved by the centrifugal cooling fan which forces the air over the belt, pulley and clutch. A clear understanding of the cooling system is important in designing the air flow path for clutch cooling of CVT housing. The efficiency of the cooling system depends on the quantity and direction of
Motor scooters are popular in most parts of the world, especially in countries with local manufacturers. Parking, storage, and traffic issues in crowded cities, along with the easy driving position makes them a popular mode of transportation. Motor scooters are the segment of 2 wheelers which is driven by the entire family with ease unlike motorcycles which is a male dominated segment. Due to the importance that the scooters hold in the present time, it has become very important to manufacture stable, light weight yet robust scooters. For the best product in the market, testing is given a great importance in automotive manufacturing companies. Virtual testing has been the latest development in terms of testing a vehicle during the design stage itself. Multi Body Dynamics approach is used to study - 1) the articulation of various sub-assemblies and 2) the static & dynamic loads generated at various attachment points of the scooter. Integration of sub-assemblies into a final product
A small single cylinder 4 stroke gasoline engine varying capacity from 100cc to 500cc generally used for two wheelers has a wide range of load conditions. Such variation in load on engine demands variation in Transmission ratio at different vehicle speeds for optimum performance, drivability and Economy. A scooter has continuously variable transmission called as CVT which is generally centrifugally controlled with respect to engine speed as against that of series of manual gears used in motor cycle. The work aims at creating a mathematical model for controlling variation in transmission ratio of CVT by converting the generally centrifugally controlled CVT by electronic control. The objective is to implement the mathematical model with a novel electronic controlled CVT in a two wheeler engine for the improvement in performance. The mathematical model done through geometric calculations and modeling is discussed in details. The mathematical model is compared with the actual testing data
The behaviour of scooter undergoing braking is critical in terms of both performance and passenger safety. The brakes are the single-most important safety component on scooter, and are charged with the vital task of stopping the moving vehicle. The basic goals of braking systems are to decelerate a vehicle during stopping, to maintain vehicle speed during downhill operation, and to hold a vehicle stationary on a grade. Like many other aspects of scooter design, brake hardware is conventionally designed as a compromise between the different performance requirements. Furthermore, a factor of safety is designed into the components to assume best performance during ideal testing conditions, this could lead to a limiting performance in unfavourable conditions [5]. New developments in combined braking devices will give brake designers the freedom to control brake force without compromise, in order to ensure optimal braking and vehicle stability under all conditions. This thesis will
The Continuous Variable Transmission (CVT) in scooters is used to transmit the power from the engine to the wheels. The CVT transmission consists of a drive pulley and a driven pulley connected to each other through a belt. The centrifugal clutch is attached to the rear pulley which transmits the power to the wheel. The engagement and disengagement of the clutch generates heat and friction heat is generated between the belt and pulley, thereby requiring continuous external cooling for its safe operation. A centrifugal fan is employed for cooling of the CVT belt. Since the cooling fan takes air from atmosphere, there is always a possibility of dust from the atmosphere entering the system, which might cause wear of pulley and belt, thereby decreasing the performance of the transmission system. The objective of the work is to analyze the dust ingress pattern in to CVT housing. The work aims at simulating the possible conditions for dust entry into the CVT housing for a complete scooter
The aim of the study was to investigate the difference between car-to-e-bikes and car-to-pedestrian accidents. The China In-depth Accident Study (CIDAS) database was searched from 2011 to 2013 for pedestrians and e-bikes struck by car, van and SUV fronts, which resulted in 104 pedestrian and 85 e-bike cases where information was sufficient for in-depth analysis. Reconstruction by PC-Crash was performed for all of the sampled cases. Pre-crash parameters were calculated by a MATLAB code. Focus was on prototypical accident scenarios and causes; speed as well as possible prevention countermeasures. It has been shown that traffic light violations, road priority violations, and unsure safety (these situations included misjudgments, unpreparedness, proximity to other road users, inappropriate speeds, etc.…) are the main causes in both the VRU groups. Distinctions were found for aspects of car collision speed, accident scenario, distribution of head contact points and so on. Pre-impact braking
Scooter segment growth is tremendously increasing in India. The increased competition challenges automotive manufacturers to deliver the high quality and high reliable product to the market. Higher reliability involves increased durability testing which involves time and cost. Stress testing a part of durability is initially conducted on prototype vehicles for structural design validation and then later on production units to ensure its structural integrity. The obtained data from the tests can be used for future structural design improvements. Scooters with small tires, suspension limitations transfers more loads to structure, challenges engineers to design robust structure without compromising on weight much. It is necessary to look at Real World Usage Pattern (RWUP) and to create a stress life cycle block for simulation of accelerated testing, thereby optimizing the testing time and the development costs. The aim of this paper is to provide a procedure for deriving an accelerated
This paper presents a smart electric scooter system consisting of a microprocessor based vehicle controller (integrating an embedded regenerative braking controller), a 300W Permanent Magnet (PM) DC motor, two low-power DC-DC converters to form a higher power DC-DC converter pack, a motor controller, a supercapacitor bank and a capacitor cell balancing sub-system. During acceleration or forward motoring mode, the vehicle controller sets the DC motor into motoring mode to further utilizing motor controller regulate wheel speed and acceleration torque, whereas during deceleration or forward braking mode, sets the DC motor into braking mode and further utilizing regenerative braking controller regulate wheel speed and braking torque, as well as functions as a constant current (whose reference value is adjustable via a potentiometer) generator to charge the supercapacitor bank in a controllable fashion, hence not only successfully replacing frictional braking to certain degree, but also
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