Modeling and Experimental Testing of the Hondamatic Inline Hydromechanical Transmission (iHMT)1

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
X. Hu ◽  
C. Jing ◽  
P. Y. Li
Keyword(s):  
Experimental Testing ◽  
Viscous Friction ◽  
Planetary Gear ◽  
Operating Conditions ◽  
Mechanical Transmission ◽  
Hydraulic Pump ◽  
Valve Mechanism ◽  
Variable Transmission ◽  
Overall Efficiency

Abstract A hydromechanical transmission (HMT) is a continuously variable transmission that transmits power both mechanically and hydraulically. A typical HMT consists of a pair of hydraulic pump/motors and a mechanical transmission in parallel, making it bulky and costly. The Hondamatic transmission is a compact alternative HMT design that uses an inline configuration such that the rotation of the piston barrels of the pump and motor is dual-used for mechanical transmission. This is achieved using a two-shafted pump that plays the role of a planetary gear (PG) and a distributor valve mechanism that replaces the valve plates. This paper provides the operating principle of this inline HMT (iHMT) and analyzes its performance through a combination of modeling and experimentation. Specifically, ideal and lossy average models are developed, and the performance of the Hondamatic is characterized experimentally. The lossy model, fitted with seven empirically determined parameters, is capable of predicting the mechanical and volumetric losses at different ratios and operating conditions. The dominant losses are found to be compressibility losses and no-load viscous friction losses, especially on the motor side. These losses are attributed to be the main causes for the unity transmission ratio to be less efficient than expected. The overall efficiency is between 74 and 86% at the conditions tested experimentally and is predicted to be over 70% under most operating conditions and transmission ratios. This analytical and experimental study is the first study in the open literature on this innovative compact inline HMT configuration.

scholarly journals Study on the Control Strategy of Shifting Time Involving Multigroup Clutches

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Zhen Zhu ◽  
Xiang Gao ◽  
Daoyuan Pan ◽  
Yu Zhu ◽  
Leilei Cao
Keyword(s):  
Control Strategy ◽  
Simulation Analysis ◽  
Planetary Gear ◽  
Simulation Models ◽  
Operating Conditions ◽  
Dynamic Analyses ◽  
Variable Transmission ◽  
Gear Mechanism ◽  
Test Verification ◽  
Planetary Gear Mechanism

This paper focuses on the control strategy of shifting time involving multigroup clutches for a hydromechanical continuously variable transmission (HMCVT). The dynamic analyses of mathematical models are presented in this paper, and the simulation models are used to study the control strategy of HMCVT. Simulations are performed in SimulationXplatform to investigate the shifting time of clutches under different operating conditions. On this basis, simulation analysis and test verification of two typical conditions, which play the decisive roles for the shifting quality, are carried out. The results show that there are differences in the shifting time of the two typical conditions. In the shifting process from the negative transmission of hydromechanical ranges to the positive transmission of hydromechanical ranges, the control strategy based on the shifting time is switching the clutches of shifting mechanism firstly and then disengaging a group of clutches of planetary gear mechanism and engaging another group of the clutches of planetary gear mechanism lastly. In the shifting process from the hydraulic range to the hydromechanical range, the control strategy based on the shifting time is switching the clutches of hydraulic shifting mechanism and planetary gear mechanism at first and then engaging the clutch of shifting mechanism.

The Magnitude of The Losses in the Steel Pushing V-Belt Continuously Variable Transmission

1996 ◽  
Vol 210 (1) ◽  
pp. 57-62 ◽  
Author(s):  
J D Micklem ◽  
D K Longmore ◽  
C R Burrows
Keyword(s):  
Its Region ◽  
Continuously Variable Transmission ◽  
Maximum Efficiency ◽  
Hydraulic Pump ◽  
Pulley System ◽  
Engine Efficiency ◽  
Passenger Vehicles ◽  
Variable Transmission ◽  
Torque Loss ◽  
Overall Efficiency

This paper investigates the reasons why in current passenger vehicles the steel pushing V-belt continuously variable transmission (CVT) has failed to achieve an improvement in fuel economy even though the CVT is correctly controlled and allows the engine to operate near to its region of maximum efficiency. It is shown that the overall efficiency of the transmission is low, especially at the lower vehicle speeds. The main losses are due to the belt torque loss, the hydraulic pump loss and the loss due to slip in the belt-pulley system. It is shown that a considerable improvement in vehicle economy is obtainable by controlling the transmission so that the sum of these losses is minimized as well as seeking to optimize the engine efficiency. This improved overall efficiency is achieved by operating the CVT with much lower pulley clamping pressures than have previously been considered desirable.

Transmission Analysis—Automatic Derivation of Relationships

1993 ◽  
Vol 115 (4) ◽  
pp. 1031-1037 ◽  
Author(s):  
A. Hedman
Keyword(s):  
Computer Program ◽  
Planetary Gear ◽  
Mechanical Transmission ◽  
Transmission Systems ◽  
Human Errors ◽  
Planetary Gear Trains ◽  
Computer Aided Analysis ◽  
Analysis And Synthesis ◽  
Gear Trains ◽  
Overall Efficiency

A method for derivation of relationships for general mechanical transmission systems is given. It is adapted for computer-aided analysis and synthesis of the kinematics, loads, and power flows. Losses are included. All relationships are handled by a computer program. No manual dealing with equations is necessary. The user only describes the transmission systems: (1) The transmission units, e.g., gear transmissions, planetary gear trains, clutches and input shafts. (2) How the shafts of those units are connected. Then, the computer program formulates the relationships, and a computer algebra program performs algebraic eliminations. Symbolic, non-numerical, relationships between speeds and torques of two arbitrary shafts can be derived, e.g., the overall efficiency. Special algorithms handle the power flows in split-power transmissions. The method saves time and eliminates the risk for human errors.

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.

Dynamic Model of a Novel Alternating Flow (AF) Hydraulic Pump

2017 ◽  
Author(s):  
Mengtang M. Li ◽  
Ryan Foss ◽  
Kim A. Stelson ◽  
James D. Van de Ven ◽  
Eric J. Barth
Keyword(s):  
Dynamic Model ◽  
High Efficiency ◽  
Check Valve ◽  
Viscous Friction ◽  
Operating Conditions ◽  
Hydraulic Systems ◽  
Displacement Control ◽  
Hydraulic Pump ◽  
Wide Range ◽  
Variable Displacement

High power density and good controllability are the most appealing characteristics that make hydraulic systems the best choice for many applications. Current state of the art hydraulic variable displacement pumps show high efficiency at high displacement while they have poor efficiencies at low displacement. This paper proposes a novel alternating flow (AF) variable displacement hydraulic pump to 1) eliminate metering losses by acting as a high-bandwidth pump for displacement control, 2) achieve high efficiency across a wide range of operating conditions and displacements, and 3) allow multiple units to be easily common-shaft mounted for a compact multi-actuator displacement control system from a single prime-mover. A dynamic model using first principles describes the cylinder pressure, flows between pairs of cylinders, and net inlet and outlet flows as a function of the pump’s phase shift angle. The model captures hydraulic check valve dynamics, the effective bulk modulus, leakage flows, and viscous friction. Piston kinematics and dynamics are discussed and energy loss models are presented and used to guide the design for a first prototype of the AF hydraulic pump. The paper presents simulation results from the model that offer an initial evaluation of this novel pump concept and potential applications.

MG-IVT: An Infinitely Variable Transmission With Optimal Power Flows

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Francesco Bottiglione ◽  
Giacomo Mantriota
Keyword(s):  
Planetary Gear ◽  
Operating Conditions ◽  
Gear Train ◽  
Transmission Ratio ◽  
Kinetic Characteristics ◽  
Optimal Power ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Zero Values ◽  
Optimal Efficiency

The infinitely variable transmissions (IVTs) allow the transmission ratio to vary with continuity, offering the possibility of also reaching zero values for the transmission ratio and the motion inversion. In this paper an original infinitely variable transmission system is described (MG-IVT). MG-IVT is made up of the coupling of a continuously variable transmission, a planetary gear train, and two ordinary transmissions with a constant transmission ratio. By means of two frontal clutches, the MG-IVT is allowed to get two different configurations. The main purpose is to get the configurations that make the optimal efficiency of the transmission at different transmission ratios. Kinetic characteristics of single component devices are obtained, and the MG-IVT system’s performance is determined by considering how the efficiency of the component devices change as a function of operating conditions. The advantages of the MG-IVT are therefore shown in terms of power and efficiency in comparison to the traditional IVT.

Improving the Efficiency of a Compact Inline Hydro-Mechanical Transmission (i-HMT) at Lock-Up

2021 ◽  
Author(s):  
Johnathan (Hans) Barkei ◽  
Perry Y. Li
Keyword(s):  
Planetary Gear ◽  
Continuously Variable Transmission ◽  
Transmission Ratio ◽  
Mechanical Transmission ◽  
Operating Condition ◽  
Hydrostatic Transmission ◽  
Variable Transmission ◽  
Low Efficiency ◽  
Opening And Closing ◽  
Efficient Transmission

Abstract A hydro-mechanical transmission (HMT) transmits power both mechanically and hydraulically allowing continuously variable transmission ratios and more efficient transmission than hydrostatic transmission. A conventional HMT tends to be costly and bulky since it has a hydrostatic transmission in parallel with a mechanical transmission. An alternative is a compact inline configuration that utilizes a two-shafted pump that is mechanically and hydraulically connected to a motor. This avoids the need for a planetary gear set while providing the HMT functionality. When the pump/motor displacement is zero, all of the power is transmitted mechanically and the transmission ratio is unity, a condition referred to as lock-up that is expected to be very efficient. Previous research however has shown significant losses at this operating condition in experiments. This is thought to be caused primarily by compressibility losses due to the repeated unnecessary opening and closing of the distributor valves. This paper first models the Hondamatic in simulations to confirm that compressibility losses contribute to the low efficiency at lock-up. Second, the paper proposes a solution to reduce these compressibility losses by means of a second cam mode that closes the distributor valves to prevent flow between the piston and the high and low pressure volumes. The performance of the existing inline HMT and the proposed solution at lock-up are modeled in simulations and compared. The results indicate a 10% increase in efficiency at lock-up.

Role of Reynolds and Archimedes numbers in particle-fluid flows

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Haim Kalman
Keyword(s):  
Flow Regime ◽  
Power Function ◽  
Fluid Flows ◽  
Limited Range ◽  
Operating Conditions ◽  
Pneumatic Conveying ◽  
Particulate Materials ◽  
Simple Power ◽  
Simple Power Function

AbstractAny scientific behavior is best represented by nondimensional numbers. However, in many cases, for pneumatic conveying systems, dimensional equations are developed and used. In some cases, many of the nondimensional equations include Reynolds (Re) and Froude (Fr) numbers; they are usually defined for a limited range of materials and operating conditions. This study demonstrates that most of the relevant flow types, whether in horizontal or vertical pipes, can be better described by Re and Archimedes (Ar) numbers. Ar can also be used in hydraulic conveying systems. This paper presents many threshold velocities that are accurately defined by Re as a simple power function of Ar. Many particulate materials are considered by Ar, thereby linking them to a common behavior. Using various threshold velocities, a flow regime chart for horizontal conveying is presented in this paper.

Optimization for speed regulation strategy of compound coupled hydro-mechanical transmission

2020 ◽  
pp. 095440702098056
Author(s):  
Jin Yu ◽  
Pengfei Shen ◽  
Zhao Wang ◽  
Yurun Song ◽  
Xiaohan Dong
Keyword(s):  
Fuel Consumption ◽  
Dynamic Programming Algorithm ◽  
Operating Conditions ◽  
Programming Algorithm ◽  
Speed Ratio ◽  
Mechanical Transmission ◽  
Speed Regulation ◽  
Ratio Change ◽  
Low Efficiency ◽  
Wheel Loaders

Heavy duty vehicles, especially special vehicles, including wheel loaders and sprinklers, generally work with drastic changes in load. With the usage of a conventional hydraulic mechanical transmission, they face with these problems such as low efficiency, high fuel consumption and so forth. Some scholars focus on the research to solve these issues. However, few of them take into optimal strategies the fluctuation of speed ratio change, which can also cause a lot of problems. In this study, a novel speed regulation is proposed which cannot only solve problems above but also overcome impact caused by speed ratio change. Initially, based on the former research of the Compound Coupled Hydro-mechanical Transmission (CCHMT), the basic characteristics of CCHMT are analyzed. Besides, to solve these problems, dynamic programming algorithm is utilized to formulate basic speed regulation strategy under specific operating condition. In order to reduce the problem caused by speed ratio change, a new optimization is applied. The results indicate that the proposed DP optimal speed regulation strategy has better performance on reducing fuel consumption by up to 1.16% and 6.66% in driving cycle JN1015 and in ECE R15 working condition individually, as well as smoothing the fluctuation of speed ratio by up to 12.65% and 19.01% in those two driving cycles respectively. The processes determining the speed regulation strategy can provide a new method to formulate the control strategies of CCHMT under different operating conditions particularlly under real-world conditions.

N-Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism

Synthesis ◽  
2020 ◽  
Author(s):  
Jeong Kyun Im ◽  
Ilju Jeong ◽  
Jun-Ho Choi ◽  
Won-jin Chung ◽  
ByeongDo Yang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Reaction Conditions ◽  
Ring Contraction ◽  
Silyl Group ◽  
Favorskii Rearrangement ◽  
Mechanistic Analysis ◽  
Group A ◽  
Overall Efficiency ◽  
Trichloroisocyanuric Acid

AbstractAn unprecedented N-chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n-Bu4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O-silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.

Sign in / Sign up

Export Citation Format

Share Document