Hybrid Powertrain Control for Smoother Acceleration With Fewer Gear Shifts
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Solution Overview
Problem
Contemporary hybrid powertrains are not capable of providing sufficiently smooth and uniform acceleration and deceleration, especially in larger vehicles like buses and trucks operating in urban environments with frequent stop-start cycles.
Innovation Solution
The hybrid powertrain employs a slipping-type clutch and an electric machine arrangement that extends the range of rotation rates, reducing the frequency of gear changes for smoother acceleration and deceleration, with regenerative braking, and a central control unit managing the interaction between the combustion engine and electric machine to optimize power distribution based on shaft revolution rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional hybrid powertrains use combustion engines for high-speed cruising and electric motors for stop-start urban traffic, then fuel economy is improved, but acceleration smoothness deteriorates due to frequent gear changes
Solution Approach 1:
The patent applies dynamics by making the powertrain system adaptable through real-time control of the clutch engagement state. The control unit dynamically adjusts between engaged and disengaged states based on operating conditions (vehicle speed, acceleration demand, gear position), allowing the system to optimize both fuel economy and acceleration smoothness under different scenarios rather than using a fixed configuration
Solution Approach 2:
The clutch serves as an intermediary element between the combustion engine and the transmission system. By controlling the clutch engagement state, the patent mediates the power transmission to reduce the impact of gear changes on acceleration smoothness. The clutch allows selective decoupling of the engine from the transmission during gear transitions, preventing torque interruptions that would otherwise cause jerky acceleration
2Speed
If electric motors provide high starting torque for rapid acceleration, then vehicle launch performance is improved, but system complexity increases due to additional components
Solution Approach 1:
The electric machine arrangement is designed to perform multiple functions: providing high starting torque for rapid acceleration, extending the rotation rate range to reduce gear change frequency, and operating in motor mode during acceleration and generator mode during regenerative braking. This multi-functionality reduces the need for additional specialized components
Solution Approach 2:
The patent combines the combustion engine and electric machine arrangement into a unified hybrid powertrain system with integrated control. The clutch couples or decouples these two power sources, allowing them to work together synergistically rather than as separate systems, thereby managing overall system complexity while achieving improved acceleration performance
3Use of energy by moving object
If gear changes are performed frequently to maintain optimal engine operation, then fuel efficiency is improved, but mechanical wear increases on gearbox and clutch
Solution Approach 1:
The control unit implements feedback control by continuously monitoring operating conditions (vehicle speed, acceleration demand, current gear position) and adjusting the clutch engagement state accordingly. This feedback mechanism allows the system to maintain optimal engine operation for fuel efficiency while simultaneously managing gear change frequency to reduce mechanical wear on the gearbox and clutch
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 results in reduced gear changes, smoother acceleration and deceleration, and enhanced fuel efficiency, reducing wear on the gearbox and clutch while maintaining smooth vehicle operation, particularly in urban environments.
Implementation Method 1
an electric machine arrangement (60), operable to generate rotational mechanical power and thus drive torque when excited by electrical energy
Implementation Method 2
The hybrid powertrain employs a slipping-type clutch and an electric machine arrangement that extends the range of rotation rates
Implementation Method 3
with regenerative braking, and a central control unit managing the interaction between the combustion engine and electric machine to optimize power distribution
Data Source
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AI summary
There is provided a hybrid powertrain (10) including (i) a combustion engine (20) operable to output rotational power thereat, (ii) an electric machine arrangement (60) being operable to output rotational power thereat, (iii) a gearbox arrangement (200) for receiving rotational power from at least one of the combustion engine (20) and the electric machine arrangement (60), and being operable to couple motive power to a load (230) coupled to the gearbox arrangement (200). The gearbox arrangement (200) is operable to provide a plurality of gearing ratios. The electric machine arrangement (60) is employable to extend a rotation rate range provided in a given gearing ratio: (a) at higher rotation rates prior to a gear change from said given gearing ratio to a gearing ratio subsequent thereto; or (b) at both lower rotation rates when accelerating from a standstill or from a preceding gear, and at higher rotation rates prior to a gear change from said given gearing ratio to a gearing ratio subsequent thereto