一種具混合動力功能的扭力分配差速器之理念設計與分析

Abstract

本研究提出一種以馬達調控，而同時具備混合動力功能的扭力分配差速器（Hybrid Torque-vectoring Differential, H-TD）。本研究所提出之扭力分配差速器是以一般開放式差速器為基礎搭配行星齒輪組、馬達、煞車以及離合器，來同時達成混合動力與扭力分配之功能。此機構可以馬達將輸入至差速器之主動力於兩輸出軸之間分配，亦可以馬達之動力與主動力形成同時輸出之混合動力功能。本研究首先提出H-TD之概念原型，並且以機構拓樸搜尋一定範圍內所有可能之構型，以找到最佳的機構組合。接著本研究提出此機構的空間布局方式，以及此系統之操作模式與模式切換策略。接下來以最佳化之方式設定H-TD之細部設計參數，以完成一可行設計。完成機構參數設計後，本研究討論H-TD在一般四輪車輛上的動力總成配置，最後推導各種動力總成配置下的車輛動力分配動態模型。完成系統之設計後，本研究將以數值模擬程式進行分析，程式包含可替換之駕駛模型、動力分配模型、輪胎模型、車輛模型，以求得不同操作情形與環境下之車輛動態表現。模擬情境包含單輪打滑、定轉角轉向、轉向時單輪打滑、加速打滑、混合動力加速、混合動力回充等情境。結果顯示本研究提出之H-TD可在車輛遭遇打滑時保有較佳的驅動力、轉向時提升車輛之轉向能力，並且在混合動力模式下，為車輛提供更佳的動力表現或者更多元的能量管理方式。

A motor-controlled torque-vectoring differential with electric hybrid functionality (Hybrid Torque-vectoring Differential, H-TD) is proposed in this study. The structure of H-TD is based on an open differential with a planetary gear set, an electric motor, a clutch brake, and a clutch to achieve both torque-vectoring and hybrid functionality. The mechanism can utilize electric motor to distribute torque between two output shafts, or use motor to provide additional power. This study first comes up with a conceptual prototype of H-TD, then uses mechanism topology to search all possible configurations within a certain range to find the best-suited mechanism for the system. Next, this study presents a conceptual spatial layout for the system, and proposes the operation modes of the system, as well as the control strategy. Afterwards, this study uses optimum design method to obtain design parameters of the system. Following is discussion about possible powertrain configurations of H-TD on four-wheeled vehicles, and derivation of the dynamic model for each configuration. After completing the conceptual design of H-TD, this study uses a numerical simulation program, which includes a replaceable driver model, a power distribution model, a tire model, and a vehicle dynamic model, to obtain vehicle dynamic performance under different system operating modes and driving situations. The simulation scenarios include single wheel slipping while driving, constant cornering, single-wheel-slip constant cornering, slipping during acceleration, hybrid power acceleration, and hybrid regenerative mode. Simulation results show that H-TD proposed in this study is capable of maintaining better tractive force when the vehicle encounters slipping, and improving the cornering performance. In addition, H-TD can provide better power performance and energy management due to its hybrid functionality.