scholarly journals Performance Evaluation of a Compound Power-Split CVT for Hybrid Powertrains

2021 ◽  
Vol 11 (18) ◽  
pp. 8749
Author(s):  
Giacomo Mantriota ◽  
Giulio Reina ◽  
Angelo Ugenti
Keyword(s):  
Power Flow ◽  
Planetary Gear ◽  
Continuously Variable Transmission ◽  
Operating Conditions ◽  
Design Stage ◽  
Modeling Tools ◽  
Power Split ◽  
Variable Transmission ◽  
Gear Trains ◽  
Flow Configurations

The Power-Split Continuously Variable Transmission is one of the most promising architectures for Hybrid Electric Vehicles. These systems have been introduced to improve vehicle global efficiency since they can maximize the efficiency in varying operating conditions. During the design stage, the availability of modeling tools would play a key role in achieving optimal design and control of these architectures. In this work, a compound power split device that combines an electric Continuously Variable Transmission with two planetary gear trains is analyzed. A comprehensive model is derived that allows the different power flow configurations to be evaluated given the properties of the single subcomponents of the system. The efficiency of the powertrain can be derived as well, and a numerical example is provided. The architecture studied has an efficiency that can be higher than that obtained using one single eCVT for most of the global transmission ratio range, showing that this solution could be suitable as a part of a more complex compound transmission that engages in a specific speed range.

Power split continuously variable transmission systems with high efficiency

2001 ◽  
Vol 215 (3) ◽  
pp. 357-358 ◽  
Author(s):  
G. Mantriota
Keyword(s):  
Power Flow ◽  
High Efficiency ◽  
Continuously Variable Transmission ◽  
Operating Conditions ◽  
Kinetic Characteristics ◽  
The Past ◽  
Power Split ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Functional Solution

Continuously variable transmissions (CVTs) have developed notably in different applications over the past years. This is especially true in the automobile field because of advantages in terms of car handling and efficiency on urban roads. In this work an original functional solution of a power split CVT system is described. The proposed solution allows the generation of a power flow without recirculation. Kinetic characteristics of single-component devices are obtained and the power split CVT system's efficiency is determined by considering how the efficiency of the component devices changes as a function of operating conditions. The advantages for the power split CVT system are therefore shown in terms of power and efficiency in comparison with the single CVT.

Influence of the Operating Conditions of Two-Degree-of-Freedom Planetary Gear Trains on Tooth Friction Losses

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Essam Lauibi Esmail
Keyword(s):  
Power Loss ◽  
Power Flow ◽  
Planetary Gear ◽  
Operating Conditions ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Friction Loss ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Two Degree Of Freedom

In a planetary gear train (PGT), the power loss by tooth friction is a function of the potential power developed within the gear train elements rather than that being transmitted through it. In the present work, we focus on the operating conditions of two-degree-of-freedom (two-DOF) PGTs. Any operating condition induces its own internal power flow pattern; this implies that tooth friction loss depends on the mechanism of power loss developed in the gearing that differs from one case to another over the entire range of operating conditions. The approach adopted in this paper stems from a unification of the kinematics and tooth friction losses of PGTs and is based on potential powers and power ratios. The range of applicability of the power relations is investigated and clearly defined, and tooth friction loss formulas obtained by their use are tabulated. A short comparison with formulas currently available in the literature is also made. The simplicity of the proposed method for analyzing two-input or two-output planetary gear trains is helpful in the design, optimization, and control of hybrid transmissions. It assists particularly in choosing correctly the appropriate operating conditions to the involved application.

scholarly journals The multi-attribute topological graph method and its application on power flow analysis in closed planetary gear trains

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879410 ◽  
Author(s):  
Yahui Cui ◽  
Jing Gao ◽  
Xiaomin Ji ◽  
Xintao Zhou ◽  
Haitao Yan
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Planetary Gear ◽  
Topological Graph ◽  
Template Model ◽  
Power Flow Analysis ◽  
Analysis Process ◽  
Planetary Gear Trains ◽  
Graphical View ◽  
Gear Trains

The concept of multi-attribute topological graph is proposed in this article to represent the characteristics of both structure and state for typical one-degree-of-freedom planar spur closed planetary gear trains. This method is well applied in power flow analysis and provides a graphical view for the types, values, directions, and transmission relationship of power flow, especially for the recirculation power representation. Furthermore, a template model of multi-attribute topological graph for closed planetary gear trains is also presented, which would be helpful to the multi-attribute topological graph generation for some certain types of closed planetary gear trains just by changing symbols in the template model. A corresponding software is also developed to make the analysis process more convenient. By inputting different parameters, the different visual results can be obtained automatically, thus benefiting engineers in conceptual design.

Design and Analysis of a Novel Power-Split Infinitely Variable Power Transmission System

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Ender İnce ◽  
Mehmet A. Güler
Keyword(s):  
Power Flow ◽  
Power Transmission ◽  
Mechanical Efficiency ◽  
Flow Equations ◽  
Power Split ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Variable Power ◽  
New System ◽  
Agricultural Machines

In the last few decades, power-split infinitely variable transmission (IVT) systems have attracted considerable attention as they ensure high driving comfort with high total efficiencies, especially in off-highway vehicles and agricultural machines. In this study, a novel power-split-input-coupled IVT system is developed. The effects of various dynamic parameters such as power flow and Willis transmission ratio on the mechanical efficiency of the systems are investigated. Kinematic analysis of the new system has been carried out. In addition power flow equations are derived as functions of the power that flows through the infinitely variable unit (IVU). The results indicate that the main parameters, which are strictly related to mechanical efficiency are the power and torque flows through the IVU.

Design of a Series-Type Independently Controllable Transmission Mechanism

2012 ◽  
Author(s):  
Guan-Shyong Hwang ◽  
Der-Min Tsay ◽  
Jao-Hwa Kuang ◽  
Tzuen-Lih Chern ◽  
Tsu-Chi Kuo
Keyword(s):  
Angular Velocity ◽  
Planetary Gear ◽  
Transmission Mechanism ◽  
Alternative Form ◽  
Input Shaft ◽  
Planetary Gear Trains ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Gear Trains ◽  
Series Type

This study proposes a design of transmission mechanism which is referred to as a series-type independently controllable transmission (ICT). The series-type ICT is an alternative form of the parallel-types proposed in the former researches. The series-type ICT can serve as a continuously or an infinitely variable transmission mechanism, and it can also produce a required angular output velocity that can be independently manipulated by a controller and not affected by the angular velocity of the input shaft. The series-type ICT mechanism is composed of two planetary gear trains and two transmission-connecting members. Kinematic and dynamic characteristics of the ICT mechanism are analyzed and their analytical equations are derived for application in this study.

scholarly journals Research on Transmission Characteristics of Hydromechanical Continuously Variable Transmission of Tractor

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Junyan Wang ◽  
Changgao Xia ◽  
Xin Fan ◽  
Junyu Cai
Keyword(s):  
Power Flow ◽  
Flow Direction ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Simulation Software ◽  
Transmission Scheme ◽  
Compact Structure ◽  
Theoretical Derivation ◽  
Speed Regulation ◽  
Variable Transmission

This paper proposes a new transmission scheme of hydromechanical continuously variable transmission (HMCVT) for tractors. The HMCVT has 4 working ranges in each of the front and rear directions. The speed characteristic and the torque characteristic of HMCVT are theoretically derived. On the basis of HMCVT power flow direction, the Крейнeс formula is used to calculate the transmission efficiency. Then, the image analysis method is used to study the influence of parameters on the transmission efficiency of HMCVT, and the main influencing factors are found. The results of theoretical derivation demonstrate that, by coordinating control of the HST displacement ratio and the engagement conditions of shifting clutches, the stepless speed regulation of HMCVT at the tractor speed of 0–50 km/h can be realized. The proposed HMCVT has the ability to continuously transmit and change torque over all working ranges. The overall transmission efficiency of HMCVT is at a high level. To verify the theoretical derivation, Amesim simulation software is used for the modeling and simulation of HMCVT. The simulation results are consistent with the theoretical analysis results. Therefore, the HMCVT proposed in this paper has the advantages of compact structure and high transmission efficiency, and it is suitable for matching tractors.

Multi-Range Hydro-Mechanical Continuously Variable Transmission of Tractor

2009 ◽  
Vol 628-629 ◽  
pp. 167-172
Author(s):  
L.Y. Xu ◽  
Zhi Li Zhou ◽  
M.Z. Zhang ◽  
Y. Niu
Keyword(s):  
High Efficiency ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Speed Range ◽  
Displacement Pump ◽  
Variable Transmission ◽  
Variable Displacement ◽  
Wide Speed Range ◽  
Ratio Transmission

In this paper, to improve the transmission ratio discontinuity problem during the gear shift process in the multi-gear fixed step ratio transmission of the tractors, a hydro-mechanical continuously variable transmission (HMCVT) for tractors is developed, which is composed of a single planetary gear differential train, a hydraulic transmission system consisted of the variable displacement pump (PV) and the fixed displacement motor (MF) and a multi-gear fixed step ratio transmission. Its stepless-speed-regulating characteristic, smooth range shifting condition and transmission efficiency are analyzed. The analytical results show that the tractors assembled with HMCVT can gain wide speed range and high transmission efficiency. There are eight high efficiency pure mechanical gears in the whole speed range, which is benefit to improve power and economic capabilities of vehicles.

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