Cam based Infinitely Variable Transmission Theoretic Modelling

Infinitely variable transmission (IVT) is a system which delivers the ratio between two turning elements to a continuous (non-discrete) variation (including zero). This article uses Solidworks software to build and simulate a cam-based IVT system. There are two identical units in the system under examination. Each unit comprises a cam with an oscillating slot connection that swings on a hinge and can be vertically shifted by changing the transmission rate. This modifier can be a power screw or a hydraulic ram. In addition, a grooved wheel and followers or an actuator are included in the system units. The raised wheels swing rotating movement, such that they are coupled by a single-way clutch to the output shaft (ratchet) to move the output shaft one way. During the performance research, cam shapes are considered and examined inside the mechanism. a mixture of the unchanging speed and 1-5 polynomial shapes, used for the current investigation and tailored for The results produced from the simulation generally reveal the theoretical results expected in accordance with the layout of the current IVT system. For all parts in these units, the findings imply a uniform velocity while each unit is powered. In this investigation, nevertheless, the ratchets used cause remarkable fluctuations in the angular speed of the output axis. Further research is therefore urgently needed in the choice and investigation of more efficient ratchets.

INCREASING THE COMFORTABILITY OF THE VEHICLE DURING ACCELERATION BY IMPROVING THE DESIGN AND CONTROL METHODS OF THE MOTOR-TRANSMISSION UNIT

The derivative of acceleration with respect to time is used to evaluate and ensure driving comfort during acceleration and deceleration. Frequent and rapid changes in acceleration means frequent and rapid deformation, which can lead to the destruction of the load. The article proposes to minimize the amount of acceleration due to the rational choice of transmission ratios in intermediate gears and the law of changing the engine torque. The use of continuously variable transmissions allows you to solve the problem by choosing a rational law for changing the gear ratio of the transmission. The method of selection at the stage of car design of the maximum effective engine power and transmission ratio in top gear is proposed, taking into account the improved formula for calculating the aerodynamic resistance to motion. The required laws of change in the efficiency of the torque and engine power have been determined. The use of a continuously variable transmission allows the engine to operate at a constant high-speed mode and provides control over the acceleration of the car by changing the fuel supply. It is determined that the engine power expended on the movement with the adjustment of the acceleration of the car will be less than with unregulated acceleration if the exponent at the speed of the car, obtained experimentally, is less than one. Keywords: car; comfort; continuously variable transmission; motor-transmission unit; power; overclocking; aerodynamic resistance; gear ratio

Kinematic Analysis of V-Belt CVT for Efficient System Development in Motorcycle Applications

Continuous variable transmission (CVT) is a widely used technology for two-wheeler applications due to its cost-effectiveness, lightweight, and reduced size. This kind of transmission involves the accurate matching of the system with the engine characteristics. This paper analyzes the typical design procedure used to develop the transmission system and evaluates the current approach’s critical issues. The paper aims to identify a possible path to improve the system and its customization capacity. It is identified that the critical design stage is the identification of the correct sliding profile for the half pulley of the front assembly of the system. Then, the geometrical parameters of the transmission are accurately identified through a detailed kinematic analysis. The presented kinematic analysis is propaedeutic for developing a mathematical model that defines the rollers’ sliding profile according to the vehicle’s performance.

Method and Test Bench for Hydro-Mechanical Continuously Variable Transmission Based on Multi-Level Test and Verification

According to the structural characteristics of Hydro-mechanical continuously variable transmission (HMCVT), a multi-functional test bench was developed, and the basic structure, working principle, and test functions of the test bench were introduced. The test bench has the following characteristics: To analyze the impact of mechanical transmission and hydraulic transmission on the HMCVT transmission system, the performance can be tested separately by using a test bench; the coupling characteristics of the hydraulic transmission and mechanical transmission can also be tested; it can also test and verify the performance of the HMCVT transmission system and the control system; the test bench has a simple structure, diverse functions, and convenient operation. Using the multi-functional test bench, this paper proposes a method of multi-level test and verification. Through this method, the simulation models are revised and improved many times, and the accuracy of the models is improved, which are consistent with the physical model, and eventually, the accuracy of the simulation result is improved. This method is used to test and verify the hydraulic transmission system, analyze the characteristics of the hydraulic transmission system, and verify the feasibility and practicability of the multi-level verification method.

COVID-19 clusters in schools: frequency, size, and transmission rates from crowdsourced exposure reports

The role of schools in the spread of the COVID-19 pandemic is controversial, with some claiming they are an important driver of the pandemic and others arguing that transmission in schools is negligible. School cluster reports that have been collected in various jurisdictions are a source of data about transmission in schools. These reports consist of the name of a school, a date, and the number of students known to be infected. We provide a simple model for the frequency and size of clusters in this data, based on random arrivals of index cases at schools who then infect their classmates with a highly variable rate, fitting the overdispersion evident in the data. We fit our model to reports for several jurisdictions in the US and Canada, providing estimates of mean and dispersion for cluster size, whilst factoring in imperfect ascertainment. Our parameter estimates are robust to variations in ascertainment fraction. We use these estimates in three ways: i) to explore how uneven the distribution of cases is among different clusters in different jurisdictions (that is, what fraction of cases are in the 20% largest clusters), ii) to estimate how long it will be until we see a cluster a given size in jurisdiction, and iii) to determine the distribution of instantaneous transmission rate β among different index case. We show how these latter distribution can be used in simulations of school transmission where we explore the effect of different interventions, in the context of highly variable transmission rates.

Performance verification test of coaxial centrifugal clutch for motorcycle transmission system

With the popularization of motorcycles, the demand for motorcycles is getting higher and higher. Therefore, the improvement of power output, the reduction of pollutants discharged, the replacement of waste, the improvement of efficiency and the reduction of fuel use, are also relatively important. Stop-and-go on urban driving will keep the clutch in a state of being engaged and not engaged. The clutch cannot be engaged and is constantly worn. The output efficiency of the CVT belt-type continuously variable transmission system clutch used in the transmission is only about 70~80%. Transmission efficiency. Furthermore, since the traditional CVT belt-type system clutch mainly relies on the action of the centrifugal roller to change the reduction ratio, when encountering different driving conditions and need to accelerate and decelerate, this will make the working area of the internal combustion engine in an unstable state. The matching structure between the automatic clutch weight and the telescopic spring in the reciprocating separation state and the fitted state is replaced, which effectively reduces the problem of uneven contact surfaces of the plates in the past, and prevents the elastic aging from affecting the uniform transmission of power, resulting in the entire dry clutch The life span of the engine is improved and the efficiency of power transmission is maintained, thereby reducing fuel consumption and producing more complete engine power. Therefore, the “Design Performance Verification of Coaxial Contact Centrifugal Ball Clutch” is proposed mainly to verify that the coaxial contact centrifugal ball clutch has better performance than the CVT belt-type clutch.

Proposing a Method for Assessing Fuel Consumption and Pollutants Emissions with the Use of Continuously Variable Transmission in Town Cars

The 21st century brings countless social, economic, environmental, and technological challenges to humanity and, to face them, the United Nations (UN) created the Sustainable Development Goals (SDGs). The auto industry, which is part of the private sector, aims to reach them. In this context, this study aims to evaluate the consumption and emissions of pollutants by using an automatic transmission of the CVT (Continuously Variable Transmission) type concerning the automatic transmission of the "Planetary" type. This study will be based on the Consumption/Energy Efficiency tables, published annually by INMETRO (National Institute of Metrology, Quality, and Technology) and whose data will be processed and evaluated using the Quik Sense Software. Thus, the work aims to appraise the advantages of vehicles with automatic transmission of the CVT type about fuel consumption, energy efficiency and emissions, in markets such as Brazil, where these vehicles use ethanol or a mixture of gasoline with up to 27 as fuel % Ethanol. This research can contribute to studies of emission control and approval, benefiting the automotive industry in general, government agencies, the environment, the economy, and society, contributing to the UN's SDGs achievement.