Hybrid Propulsion Torque Control for Urban Driving Comfort
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Solution Overview
Problem
Parallel hybrid vehicles experience a deterioration in driving comfort due to excessive regenerative braking in urban traffic, which affects battery charging efficiency.
Innovation Solution
The method involves varying the torque curve delivered or absorbed by the electric motor generator based on the current vehicle speed, with discrete straight lines corresponding to different speed thresholds, allowing the torque to adjust proportionally to the accelerator pedal position and speed, ensuring a smooth transition between driving and braking phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is applied to charge the battery during deceleration, then battery charging efficiency is improved, but driving comfort deteriorates due to excessively strong braking
Solution Approach 1:
The patent applies dynamics by making the electric motor generator's torque delivery/absorption characteristic variable rather than fixed. The system dynamically adjusts the braking torque based on real-time vehicle speed, transitioning from strong regenerative braking at high speeds to gentler braking at low speeds. This speed-dependent dynamic adjustment resolves the contradiction by adapting the braking force to match driver expectations and comfort requirements across different operating conditions.
Solution Approach 2:
The patent changes the parameter of torque absorption by the electric motor generator as a function of vehicle speed. By varying the braking torque parameter according to speed thresholds, the system achieves strong energy recovery at high speeds while providing smooth, comfortable braking at low speeds. This parameter change strategy allows the system to optimize both battery charging efficiency and driving comfort across the entire speed range.
2Use of energy by moving object
If the coasting interval is extended based on initial speed value, then energy recovery is improved, but the response to driver acceleration requests becomes slower
Solution Approach 1:
The patent implements feedback by continuously monitoring vehicle speed and using this real-time information to adjust the electric motor generator's torque output. When the driver releases the accelerator, the system feedback-based control transitions from coasting to regenerative braking as speed decreases, ensuring timely response to driver intentions while maximizing energy recovery. This closed-loop feedback mechanism resolves the contradiction between extended coasting and rapid acceleration response.
3Power
If the electric motor generator delivers constant torque during acceleration, then acceleration performance is improved, but energy consumption increases
Solution Approach 1:
The patent applies partial action by having the electric motor generator deliver torque only when necessary, rather than maintaining constant torque during acceleration. The system provides supplemental electric torque to assist the combustion engine during acceleration phases, but adjusts the level of assistance based on power demands and available battery capacity. This partial action strategy improves acceleration performance when needed while reducing overall energy consumption by avoiding excessive torque delivery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances driving comfort by providing a proportional braking torque to vehicle speed, maintaining battery charging efficiency without penalizing comfort, and allowing for energy recovery even at low speeds.
Implementation Method 1
The electric motor generator is supplied with power by batteries which are charged by the motor generator itself in predetermined operating phases of the vehicle. For example, they are charge when the vehicle is driven at a constant speed or when it slows down. In the second case, we usually speak of regenerative braking. It exploits the inertia of the vehicle to charge the vehicle batteries
Implementation Method 2
They can use either one or both of them for driving the vehicle. The delivered or braking torque generated/absorbed by the electric motor generator is a function of the position of the accelerator pedal and of the current speed of the vehicle
Implementation Method 3
It exploits the inertia of the vehicle to charge the vehicle batteries when the accelerator pedal is completely released
Data Source
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Figure 3~4
AI summary
The method for managing the propulsion of a parallel hybrid vehicle comprising an accelerator pedal and a sensor connected thereto to detect a relative value of inclination, wherein a torque curve (EMTrq) delivered/supplied by a relative electric motor generator of the hybrid vehicle is a function of two variables, wherein a first variable depends on a position of the accelerator pedal and a second variable depends on a speed of the hybrid vehicle.