다단 변속기를 이용한 동력분기 설계에 관한 연구

성덕환(Dukhwan Sung) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

A power split design using multi step transmission is proposed to match with engine down-sizing trend. The power split transmission transmits the power in two or more paths by planetary gear set, which can make transmission down-sizing to decrease power flow to each path by power split. Power split structure using one planetary gear set which called three shafts system is classified as input split and output split type according to the place of planetary gear set. In this paper, a power split transmission with four stepped automatic transmission and one planetary gear set is designed in input split structure. As a result of vehicle simulation for 3.3 liter passenger car, the fuel consumption is improved 5% in FTP75 driving cycle and 4% in combined driving cycle.

DESIGN OF POWER SPLIT TRANSMISSION: DESIGN OF DUAL MODE POWER SPLIT TRANSMISSION

Kim, J.,Kang, J.,Kim, Y.,Kim, T.,Min, B.,Kim, H. 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.4

The power split type hybrid system transmits engine power by dividing it into the electrical unit and the mechanical unit. Its power transmission efficiency is highest at the mechanical point (MP), where the full power is transmitted to the mechanical unit. In this study, the equation for the MP was derived for the gear ratios of a general 4-node lever model. The MP characteristics for the transmission ratio (TR) of the input split and compound split structures were examined using the equation derived. Using the examined input split and compound split structures, a systematic design method for the dual mode power split transmission was proposed. In the dual mode power split transmission, the MP could be positioned at the desired TR, and the input split and compound split modes could be selectively used according to the clutch combination, which leads to the operation of the vehicle within a high system efficiency range.

DYNAMIC MODELING OF THE ELECTRO-MECHANICAL CONFIGURATION OF THE TOYOTA HYBRID SYSTEM SERIES/PARALLEL POWER TRAIN

C. MANSOUR,D. CLODIC 한국자동차공학회 2012 International journal of automotive technology Vol.13 No.1

The hybridization of the conventional thermal vehicles nowadays constitutes a paramount importance for car manufacturers, facing the challenge of minimizing the consumption of the road transport. Although hybrid power train technologies did not converge towards a single solution, series/parallel power trains with power-split electromechanical transmissions prove to be the most promising hybrid technology. In fact, these power trains show maximum power train overall efficiency and maximum fuel reduction in almost all driving conditions compared to the conventional and other hybrid power trains. This paper addresses the model and design of the electro-mechanical configuration of one of the most effective HEV power trains: case study of the 2nd generation Prius. It presents the simulation work of the overall operation of the Toyota Hybrid System (THS-II) of the Prius, and explores not only its power-split eCVT innovative transmission system but also its overall supervision controller for energy management. The kinematic and dynamic behaviors of the THS-II power train are explained based on the power-split aspect of its transmission through a planetary gear train. Then, the possible regular driving functionalities that result from its eCVT operation and the energy flow within its power train are outlined. A feedforward dynamic model of the studied power train is next proposed, supervised by a rule-based engineering intuition controller. The energy consumption of the THS-II proposed model has been validated by comparing simulation results to published results on European, American and Japanese regulatory driving cycles.

An improved design of power-cycling hydrodynamic mechanical transmission

Xiaojun Liu,Dongye Sun 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.8

Recent studies have demonstrated that the power-cycling hydrodynamic mechanical (PCHM) transmission has excellent performance in improving power performance and fuel economy of a wheel loader. However, these results have been obtained by assuming that its speed ratio can always change continuously. Hence, this study first investigated the speed ratio of the transmission how to change when shifting from one gear to another. It was found that the concept of the PCHM transmission suggested in the literature is ineffective, even for a configuration with two gears in the gearbox. Then, the configuration of the PCHM transmission was developed as a different one to increase the torque multiplication capacity and efficiency of the transmission. A design method for this transmission is proposed to quantify its performances. The design method is based on a multi-objective optimization problem which is comprised of two objectives, seven design variables and eleven constraints. The relationships between average efficiency of the transmission and maximum tractive force of the vehicle and the seven transmission parameters are qualitatively examined. Results show that the performance of the transmission depends mainly on the number of transmission gears instead of on three parameters of the torque converter. The average efficiency is not sensitive to the maximum tractive force on a globally optimal Pareto front. The PCHM transmission with the new configuration can enable the average efficiency and the maximum tractive force to increase by 2.1 % and by 6.6 %, compared to that of the traditional hydrodynamic mechanical transmission, respectively.

DEVELOPMENT OF A CONTROL STRATEGY BASED ON THE TRANSMISSION EFFICIENCY WITH MECHANICAL LOSS FOR A DUAL MODE POWER SPLIT-TYPE HYBRID ELECTRIC VEHICLE

J. KANG,W. CHOI,김현수 한국자동차공학회 2012 International journal of automotive technology Vol.13 No.5

In this study, a control strategy for a dual mode power split-type hybrid electric vehicle (HEV) is developed based on the powertrain efficiency. To evaluate the transmission characteristics of the dual mode power split transmission (PST), a mechanical loss model of the transmission (TM loss) is constructed. The transmission efficiency, including the TM loss, is evaluated for the dual mode PST. Two control strategies for the dual mode PST are proposed. An optimal operation line (OOL) control strategy is developed to maintain a high engine thermal efficiency by controlling the engine operation point on the OOL. A speed ratio (SR) control strategy is proposed to obtain a greater transmission efficiency by shifting the engine operation point when the dual mode PST operates near the mechanical points. Using the TM loss and the proposed control strategies, a vehicle performance simulation is conducted to evaluate the performance of the two control strategies for dual mode PST. The simulation results demonstrate that, for the SR control strategy, the engine efficiency decreases because the engine operates beyond the OOL. However, the transmission efficiency of the dual mode PST increases because the PST operates near the mechanical point where the PST shows the greatest transmission efficiency. Consequently, the fuel economy of the SR control strategy is improved by 3.8% compared with the OOL control strategy.

Experimental Study on the Input Coupled type CVT combined a Differential Gear and V-Belt type CVU

Kim, Yeon-Su,Park, Sang-Hoon Korean Society for Precision Engineering 2001 International Journal of Precision Engineering and Vol.2 No.1

A continuously variable transmission(CVT) mechanism composed of one differential gear unit and one continuously variable unit(CVU) can be classified according to the coupling of CVU and the direction of power flows. The mechanism has many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range and generation of geared neutral. The CVT mechanism considered here is the input coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type CVU. One shaft of the CVU is connected directly to the input shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations(speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Some useful comparisons between theoretical analysis and experimental results are presented. General properties also are discussed, which connect following power flow modes : (a) power circulation mode; (b) power split mode.

Experimental and Parametric Study on the Output Coupled type Continuously Variable Transmission

Kim, Yeon-Su,Park, Jae-Min,Park, Sang-Hoon Korean Society for Precision Engineering 2002 International Journal of the Korean Society of Pre Vol.3 No.3

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

Mode shift control for a dual-mode power-split-type hybrid electric vehicle

Hong, Sungwha,Choi, Woulsun,Ahn, Sunghyun,Kim, Yongjoo,Kim, Hyunsoo SAGE Publications 2014 Proceedings of the Institution of Mechanical Engin Vol.228 No.10

<P>This paper presents a mode shift control algorithm for reducing the variation in the driveshaft torque for a dual-mode power-split-type hybrid electric vehicle. To evaluate the shift characteristics of this hybrid electric vehicle, dynamic models for the hybrid electric vehicle powertrain were developed. Using the dynamic models, a mode shift performance simulator was developed, and simulations were performed. To analyse the shift characteristics during the mode shift, bond-graph models for the transient state were constructed, and state equations were derived. From the bond-graph models and state equations, it was found that the transient torque occurs because of the inertia torques of the first motor–generator and the second motor–generator. Based on the transient torque, a mode shift control algorithm was proposed, which compensates for the transient torque. To evaluate the performance of the proposed control algorithm, a test bench for the dual-mode power-split-type hybrid electric vehicle was developed. From the simulations and test results, it was found that the variation in the driveshaft torque was reduced by the proposed control algorithm, which provides improved shift quality.</P>

Design and Performance Verification of Compound CVTs with 2K-H I type Differential Gear

Kim Yeon-Su,Park Jae-Min,Choi Sang-Hoon The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.6

This paper defined design constraints for the compound CVTs (continuously variable trans-missions) by combining power-circulation-mode CVTs and power-split-mode CVTs, which were proposed for connecting 2K-H I-type differential gear to V-belt-type CVU (Continuously Variable Unit). The design constraints are the necessary and sufficient conditions to avoid geometrical interferences among elements in the compound CVTs, and to guarantee smooth assembly between the power-circulation-mode CVT and power-split-mode CVT Two com-pound CVTs were designed and manufactured in accordance with the design constraints. With these compound CVTs, theoretical analysis and performance experiments were conducted. The results showed that the design constraints were valid and effective design method, and that the designed compound CVTs had the improved performance.

Design and Performance Verification of Compound CVTs with 2K-H I type Differential Gear

Yeon-Su Kim,Jae-Min Park,Sang-Hoon Choi 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.6

This paper defined design constraints for the compound CVTs (continuously variable transmissions) by combining power-circulation-mode CVTs and power-split-mode CVTs, which were proposed for connecting 2K-H I-type differential gear to V-belt-type CVU (Continuously Variable Unit). The design constraints are the necessary and sufficient conditions to avoid geometrical interferences among elements in the compound CVTs, and to guarantee smooth assembly between the power-circulation-mode CVT and power-split-mode CVT. Two compound CVTs were designed and manufactured in accordance with the design constraints. With these compound CVTs, theoretical analysis and performance experiments were conducted. The results showed that the design constraints were valid and effective design method, and that the designed compound CVTs had the improved performance.