Planetary Automatic Transmission Research Articles

Fuel Control Systems for Planetary Transmission Vehicles: A Contribution to the LPG-fueled Vehicles Community

The bi-fuel system vehicle (gasoline/LPG) has been developed for a long time because it has the ability to switch fuels, both built as an original equipment manufacturer (OEM) or as a modified vehicle. However, on vehicles with planetary automatic transmissions, additional control systems are needed to produce optimal performance, both on gasoline and LPG operations, especially on uphill roads. Old vehicles with planetary automatic transmissions are not equipped with road slope angle sensors, so on uphill roads and the driver has not mastered road conditions, the engine tends to stop suddenly. Therefore, this study aims to develop a fuel control system (LPG operation) on a planetary automatic transmission to control gear shifts based on the level of the road slope. A simulation with MATLAB Simulink we used to create a control system, with objective function and constraint defined. As a result, the control system can recognize the level of the road slope to control the speed gear shift. This control system is promising and reliable to be implemented in real conditions.

A New Methodology for Multistage Multispeed Planetary Transmission Design Based on Geometry

Abstract In the planetary automatic transmission design, efficiency is one of the primary performance indicators determining the final selection from multiple candidates. However, efficiency evaluation is the last step of conceptual design, thereby causing the trial result is often known at the end of the design. A new methodology based on geometry is presented for multistage planetary automatic transmission design, ranging from clutching sequence synthesis to efficiency evaluation. The emphasis is placed on a unified model for design steps with different analysis principles to predict power transfer characteristics earlier. Some new results and improvements are also presented, such as general speed ratio (SR) change law, simultaneous traversal of different shift types, and the efficiency formula. An example is provided to illustrate the applicability to a 3-DOF planetary automatic transmission and shows that early identification of power transfer characteristics can lock in necessary subsequent calculations, thereby eliminating unnecessary analysis and speeding up the design process.

Coordinated Torque, Energy and Clutch Control Strategy for Downshifts in P2 Parallel xHEV Powertrains

<div class="section abstract"><div class="htmlview paragraph">This paper describes a methodology for investigating the controls coordination of clutch and propulsion torque sources relative to clutch energy, electrification energy consumption and output torque profile for offgoing controlled downshifts in P2 parallel xHEV powertrain configurations. The focus is on an 8 speed planetary automatic transmission, but the approach is equally applicable to any powerflow design with clutch-to-clutch shifting. The modeling technique is for an overall control strategy relative to achieving a targeted transmission input speed profile. A reduced order model of the transmission system is presented that accounts for input shaft acceleration and compensation of inertial contributions to offgoing clutch torque and transmission output torque. The coordinated control of offgoing clutch, engine and P2 electric motor torques are explored in the context of power on and off downshifts for clutch energy, P2 energy consumption and output torque trajectory that directly translates to responsiveness and/or perceived shift quality. The presence of a torque converter and lockup clutch and the influence of the lockup clutch state control on downshifting coordination and torque disturbance is also incorporated in the analysis. Potential improvements in downshift response, clutch controllability and output torque trajectory are provided for the particular 8 speed transmission powerflow considered. The methodology presented can easily be applied to any clutch-to-clutch transmission architecture and powerflow, whether planetary, dual clutch or other.</div></div>

Influence of Time-varying Mesh Stiffness Excitation on Vibration of Planetary Automatic Transmission

Based on the energy method, the time-varying mesh stiffness models of the internal and external meshing of the planetary gears are established. The translationrotation coupled dynamics differential equation of the planetary transmission system is established through the concentrated mass method. Analyze the influence of time-varying mesh stiffness excitation on the vibration of planetary gear transmission. The results show that the vibration response of the planetary gear sets is mainly related to the connection form under the excitation of the time-varying mesh stiffness. The time-varying mesh stiffness has the greatest influence on the vibration of the planet gear. The vibration of the planet gear is obviously more serious than the other components of the same planetary. When multiple planetary gear sets are connected, the vibration of the output component is smaller than the other components. Moreover the vibration of the input planetary set is generally greater than the rear planetary set except the planet gear.

Unified modelling and control for the power-on gear shift of a planetary transmission

Estimation of the oil hydraulic pressure for the gear-shift elements can be useful for the development of closed-loop control of the automatic transmission fitted to a heavy off-highway vehicle for a good gear-shift quality, to reduce the dissipated energy and the vehicular shift jerk in complex working conditions. The unified dynamic model for a three-degree-of-freedom planetary automatic transmission is presented, and the power-on upshift from first gear to second gear is considered as an example. The unified model is more efficient than the conventional model for the dynamic analysis; furthermore, it provides a computational method for the inertia of the transmission when in gear. From a phased characteristic analysis, real-time estimation of the oil pressure for the gear-shift elements in the sliding process, i.e. the torque phase and the inertia phase, is addressed; then the improved control scheme for the power-on upshift from first gear to second gear is developed and validated using a heavy off-highway vehicle equipped with a high-power full-range speed-regulating diesel engine. The experimental results show that the model-based oil pressure estimation is able to reflect the dynamic characteristics of the system in changing conditions, and the corresponding control strategy can improve the gear-shift quality and the vehicular performance effectively.

On-line Identification of a Torque Converter Model

Abstract Most passenger cars on the road today employ planetary automatic transmissions, which use torque converters for vibration isolation and torque amplification at vehicle launch. Torque converter models have been used primarily for analysis and design, but have seen some use for on-line estimation and control. Since model parameters vary with operating conditions such as temperature as well as the condition of the transmission fluid, there is a need for on-line identification of these parameters for validity of the model across a wide range of operating conditions. In the current study, a novel method to update torque converter model parameters on-line is presented. Importantly, exponential convergence of the model parameter estimates to their respective true values is demonstrated. The proposed method is numerically validated for a vehicle under realistic driving conditions. The simulation results indicate that the proposed method is capable of on-line torque converter model identification under slowly varying operating conditions.

Основы плана угловых скоростей трехстепенных планетарных автоматических коробок передач, обеспечивающих девять и десять передач переднего хода

Основы плана угловых скоростей трехстепенных планетарных автоматических коробок передач, обеспечивающих девять и десять передач переднего хода

Основы плана угловых скоростей трехстепенных планетарных автоматических коробок передач, обеспечивающих восемь передач переднего хода

Основы плана угловых скоростей трехстепенных планетарных автоматических коробок передач, обеспечивающих восемь передач переднего хода

Control of Gear Shift for Planetary Transmission Based on Pressure Estimation of Shifting Actuators

On-line estimation of oil pressure for shifting actuators can be useful for the development of close-loop control of automatic transmission fitted to heavy off-road vehicle for good shift quantity under complex working condition. The unified dynamic model for a 3 degree-of-freedom planetary automatic transmission is given, and the power-on 1st-2nd up shift is considered as an example. The unified model is more efficient than conventional model for the dynamic analysis, meanwhile, it provides a computational method for the inertia of transmission in-gear. The real-time estimation of oil pressure for shifting actuators during sliding viz. torque phase and inertia phase is addressed. The changes of vehicle operating conditions is reflected in the pressure estimation, and the regulate of pressure for shifting actuators is improved. Then the up shift controlling scheme is developed and validated via a heavy off-road vehicle test bench. Experimental results show that the model-based oil pressure estimation is able to reflect the system dynamic characteristics in the changing condition, and the according control strategy can improve the shift quality and the vehicular performance effectively.

Active damping of transient vibration in dual clutch transmission equipped powertrains: A comparison of conventional and hybrid electric vehicles

The purpose of this paper is to investigate the active damping of automotive powertrains for the suppression of gear shift related transient vibrations. Conventionally, powertrain vibration is usually suppressed passively through the application of torsional dampers in dual clutch transmissions (DCT) and torque converters in planetary automatic transmissions (AT). This paper presents an approach for active suppression of transient responses utilising only the current sensors available in the powertrain. An active control strategy for manipulating engine or electric machine output torque post gear change via a proportional-integral-derivative (PID) controller is developed and implemented. Whilst conventional internal combustion engine (ICE) powertrains require manipulation of the engine throttle, for HEV powertrains the electric machine (EM) output torque is controlled to rapidly suppress powertrain transients. Simulations for both conventional internal combustion engine and parallel hybrid vehicles are performed to evaluate the proposed strategy. Results show that while both the conventional and hybrid powertrains are both capable of successfully suppressing undesirable transients, the EM is more successful in achieving vibration suppression.

Synthesis of an eight-speed automatic transmission for hybrid drives

IAV develops future transmission generations by using computer-aided synthesis programs. The new eight-speed planetary automatic transmission for transverse applications results from a total solution amount of 1.6 billion transmission variants. The derivable modular transmission system comprises a conventional transmission as well as a mild and a full hybrid version. It offers numerous advantages in comparison with current systems regarding speed number, hybrid functions, efficiency, size and costs.

Synthesis of an eight-speed

IAV develops future transmission generations by using computer-aided synthesis programs. The new eight-speed planetary automatic transmission for transverse applications results from a total solution amount of 1.6 billion transmission variants. The derivable modular transmission system comprises a conventional transmission as well as a mild and a full hybrid version. It offers numerous advantages in comparison with current systems regarding speed number, hybrid functions, efficiency, size and costs.

A Kinematics and Power Flow Analysis Methodology for Automatic Transmission Planetary Gear Trains

A generalized formulation for analyzing speeds and forces of the gear components of planetary automatic transmissions is proposed. The formulation is capable of analyzing any typical one-degree-of-freedom automatic transmission gear train containing any number of simple, compound or complex-compound planetary gear sets. The formulation consists of three components: a kinematic analysis formulation to compute rotational speeds of gears and carriers, a gear ratio and kinematic configuration search algorithm, and a power flow analysis formulation. The kinematics component computes rotational speeds of gears and carriers. Given the type and number of planetary gear sets, the search algorithm determines all possible kinematic configurations and gear tooth count combinations that result in a required set of gear ratios while eliminating all kinematic redundancies and unfavorable clutching sequences. The third component, the power-flow analysis formulation, performs a complete static force (power-flow) analysis to determine all gear and bearing forces and moments, and clutch and connection torque values. A five-speed transmission example is considered to highlight the capabilities of the proposed formulation.