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CVT cooling of a BAJA All-Terrain Vehicle

Maharaja Agrasen Inst Of Technology-Neelesh Dayal, Mukul Singh, Rakesh Saini
Maharaja Agrasen Inst. Of Technology-Vasu Bhardwaj
  • Technical Paper
  • 2020-28-0020
To be published on 2020-04-30 by SAE International in United States
This research paper concentrates on BAJA ATV CVT premises thermal cooling. BAJA event has a 4-hour endurance run, which demands full potential from the drivetrain. In our drive train assembly, we have used CVT coupled with fixed reduction gearbox, while having long run the temperature of CVT unit increases so much that it hinders the efficiency. The main heat generation sources in the CVT chamber is the engine, friction between belt and sheaves, and high ambient outside. It is learned that the CVT working temperature should be reduced. Hence cooling was much required for optimum performance of our vehicle, implemented cooling system involves insulation of CVT from engine while having a passive heat exchanger using super absorbent polymer inside our vehicle to inject cool air on CVT and using insulating material on CVT cover to reduce the overall temperature, whereas passive heat exchanger cools down the injected air. All this leads to a significant temperature drop in the whole assembly.
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Analysis of CVT Element Vibration by In-Situ Measurement

Honda R&D Co., Ltd.-Kenji Matsumoto, Hideharu Koga, Toshihiro Saito
Tokyo City University-Yuji Mihara
  • Technical Paper
  • 2020-01-0906
To be published on 2020-04-14 by SAE International in United States
When the belt of a metal pushing-belt CVT is wrapped around the pulleys, vibration is said to be generated from the friction force caused by the elements that make up the belt rubbing against each other. In order to verify this, a small data logger with a triaxial accelerometer (G Sensor) was developed in house, then fixed on a side surface of a movable pulley and measurements were conducted at engine speeds characteristic of actual driving (1500-2500 rpm). The measurement results showed that there is a difference between the average radius of the belt when it is wrapped around the pulley and when it is not wrapped around the pulley, demonstrating that vibration is occurring.
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Regenerative Braking Cooperative Control of Hybrid Electric Vehicle Based on System Efficiency Optimization

Chongqing University-Yang Yang, Jing Chen, Chang Luo, Qingsong Tang
  • Technical Paper
  • 2019-01-5089
Published 2019-11-19 by SAE International in United States
In order to improve the performance of electro-hydraulic composite braking system of hybrid electric vehicle (HEV), a new type of plug-in HEV with dual motor was taken as the research object. The model of motor loss was built to achieve maximum motor efficiency, and the hydraulic braking system model, which can dynamically control pressure, was built. Based on the optimization of a motor’s continuously variable transmission (CVT) joint efficiency, the real-time optimal allocation strategy based on threshold method and cooperative control strategy of the electro-hydraulic composite braking system were brought out to recover most of the regenerative energy under the premise of ensuring safety. The model was built to verify the performance by AMESim-Simulink. The results show that the control strategy can take the advantages of dual-motor braking recovery system, increase braking energy recovery rate, effectively improve the braking safety and ride comfort of the vehicle, and reduce braking force fluctuation.
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Automatic Transmissions - Schematic Diagrams

Automatic Transmission and Transaxle Committee
  • Ground Vehicle Standard
  • J647_201911
  • Current
Published 2019-11-19 by SAE International in United States
The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.
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A New Parallel Hybrid Concept for Microcars: Propulsion System Design, Modeling and Control

ENEA-Fernando Ortenzi
Positech Consulting s.r.l.-Erminio Maria Ursitti
Published 2019-10-07 by SAE International in United States
Technological and commercial development of vehicles specifically conceived for urban use would certainly be a crucial aspect in making mobility sustainable in urban contexts thanks to their limited in size and low fuel consumption and emissions. Hybrid drive trains are particularly suited to this purpose: if properly designed, very small-sized thermal engines can give all the energy and power required for the application, also making pure electric driving possible when required. The authors are involved since a decade in proposing new low-cost solutions to address this market sector. Market itself explored these possibilities and nowadays offers some BEV solutions in this market share, but it is still lacking in proposing solutions for a parallel full hybrid drive. The main reason must be searched in the complexity of normally applied parallel-hybrid propulsion systems which is not compatible with the limited costs of the application.Taking the lead from these considerations, the authors here propose a simple concept for a parallel-hybrid kit for quadricycles called Hybrid Power Pack (HPP) which is now installed and under long-range testing on…
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Honda R&D Technical Review October 2019

  • Book
  • B-HON-026
Published 2019-10-01 by Honda Motor Co., Ltd. in Japan

Honda R&D Technical Review is a periodical containing research papers related to Honda R&D Center activities worldwide that cover automobile, motorcycle, power products, aircraft engine, and other fundamental technologies. Honda Motor offers a book for October 2019 issue with 103 pages containing 11 papers focusing on the following latest topics:

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MOMENTUM: OCTOBER 2019

  • Magazine Issue
  • 19MOMP10
Published 2019-10-01 by SAE International in United States
Advanced Class Starship Georgia Tech team right on the mark with glider-deploying RC aircraft at SAE Aero Design competition.75 points Much more time and energy go into a Formula SAE Presentation Event than one might think.Major redesign A new electronic CVT highlighted a year of major vehicle upgrades for the historically strong Baja SAE team from ETS.
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Novel RADIALcvt Simulation and Test Results

Varibox CVT Technologies-Jan Naude
Published 2019-04-10 by SAE International in United States
The RADIALcvt is a traction drive continuously variable transmission (CVT) implemented in a new novel radial configuration mechanical assembly. The RADIALcvt functions as a multi-parallel power path (at least six) type of CVT, which consists of only one steel-on-steel, line contact, traction drive interface in each power path. A constant input radius on the traction drive input makes it possible to use a constant clamping force which is provided by mechanical springs, thus eliminating the need for a hydraulic control system. The RADIALcvt has a very large radius variation on the traction drive output which provides the ratio variation. The fact that the RADIALcvt input traction rollers are clamped between two opposite rotating disks results in a clamping force which is about 50% of the equivalent clamping force of a typical traction drive CVT. This paper presents the basic mechanical configuration of the first prototype, a traction drive simulation as well as the test results of the first prototype to include measured values of mechanical efficiency, slip and traction curves at different speeds and loads.…
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CVT, Promising Solutions for Electrification

Bosch Transmission Technology B.V.-Francis Van der Sluis, Luc Romers, Gert-Jan Van Spijk, Ingmar Hupkes
Published 2019-04-02 by SAE International in United States
A single speed transmission for electric vehicles (EV) puts specific requirements on the electric motor and battery to enable the full characteristics as offered by the internal combustion engine such as driving large distances at higher speed or towing a trailer. EV developers are facing several challenges in extending driving range, reducing recharge times and finding a performance and efficiency compromise between low and high-speed conditions. This study proposes a combination of a dedicated electric machine and a Continuously Variable Transmission (CVT) that offers a chance to overcome these challenges. The result is an efficient and cost effective solution where the surplus cost of the CVT is recovered within the powertrain by lowering cost of the electric components, cooling system and battery.A CVT reduces the maximum torque and speed requirement of the electric machine which enables a reduced size and cost of the active parts. The combination of a downsized electric machine and a pushbelt CVT can deliver the good performance that consumers expect from their EV.This paper combines the results of research into various…
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CVT Ratio Scheduling Optimization with Consideration of Engine and Transmission Efficiency

Ford Motor Company-Weitian Chen, Edward Dai, Guopeng Hu, Yang Xu
Western Michigan University-Paresh Deshmukh, Steven Beuerle, Jennifer Hudson
Published 2019-04-02 by SAE International in United States
This paper proposes a transmission ratio scheduling and control methodology for a vehicle with a Continuous Variable Transmission (CVT) and a downsized gasoline engine. The methodology is designed to deliver the optimal vehicle fuel economy within drivability and performance constraints. Traditionally, the Optimum Operating Line (OOL) generated from an engine brake specific fuel consumption map is considered to be the best option for ratio scheduling, as it defines the points at which engine efficiency is maximized. But the OOL does not consider transmission efficiency, which may be a source of significant losses. To develop a CVT ratio schedule that offers the best fuel economy for the complete powertrain, an empirical approach was used to minimize fuel consumption by considering engine efficiency, CVT efficiency, and requested vehicle power. A backward-looking model was used to simulate a standard driving cycle (FTP-75) and develop a new powertrain-optimal operating line (P-OOL). Simulation results using the backward-looking model show a significant improvement in overall fuel economy when using the P-OOL (considers engine and CVT efficiency) compared to the OOL (considers…
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