Hybrid Vehicle Power Limit Control for Smooth EV-Series Switching
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Solution Overview
Problem
Existing hybrid electrical vehicles face challenges in optimizing the change in driving force when switching from EV traveling to series traveling, which affects marketability.
Innovation Solution
A control device that includes operation modes to manage the transition from EV traveling to series traveling by adjusting the driving force limit values based on battery power and generator output, allowing for smooth transitions and improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the upper limit value of vehicle request driving force is instantly increased from the first upper limit value to the second upper limit value when switching from EV traveling to series traveling, then the vehicle responsiveness is improved, but the driving force change becomes abrupt and uncomfortable for the driver
Solution Approach 1:
The patent applies dynamics by making the upper limit value of vehicle request driving force changeable over time rather than fixed. When switching from EV traveling to series traveling, the upper limit value is gradually increased from the first upper limit value (maximum electric power from battery) to the second upper limit value (larger value including generator power) over a predetermined period. This dynamic adjustment allows the driving force to transition smoothly while maintaining improved responsiveness, resolving the contradiction between speed of response and smoothness of transition.
2Stability of the object's composition
If the upper limit value of vehicle request driving force is gradually increased over a long period when switching from EV traveling to series traveling, then the driving force change becomes smooth, but the vehicle responsiveness deteriorates
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the graduation period based on vehicle operating conditions. The control device sets different graduation periods according to factors such as vehicle speed, accelerator pedal depression amount, and battery state of charge. This allows the system to achieve smooth driving force transitions while maintaining appropriate responsiveness by adapting the transition speed to current driving conditions, rather than using a fixed long graduation period.
Solution Approach 2:
The patent applies parameter changes by modifying the upper limit value of vehicle request driving force and the graduation period based on operating conditions. The control device adjusts these parameters dynamically - increasing the upper limit value from first to second when switching modes, and adjusting the graduation period based on vehicle speed, accelerator pedal position, and battery state. This allows optimization of both smoothness and responsiveness by changing key parameters according to real-time conditions.
3Use of energy by moving object
If the vehicle operates in EV traveling mode with the first upper limit value set to maximum battery power, then energy efficiency is improved, but the available driving force is limited when high power is needed
Solution Approach 1:
The patent applies dynamics by implementing two distinct operation modes with different upper limit values. In EV traveling mode, the first upper limit value is set to the maximum electric power that can be supplied from the battery, optimizing energy efficiency. When switching to series traveling mode, the upper limit value is gradually increased to the second upper limit value that includes generator power, thereby increasing available driving force. This dynamic switching between modes allows the system to optimize for energy efficiency when appropriate while providing access to higher power when needed.
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
The solution optimizes the driving force change during mode transitions, enhancing vehicle responsiveness and marketability by ensuring smooth transitions and efficient energy use.
Implementation Method 1
a generator configured to generate electric power by power of the internal combustion engine
Implementation Method 2
an electric motor capable of outputting a driving force to drive wheels
Data Source
AI summary
A control device includes: a first operation mode the first operation mode in which a first upper limit value is set to a maximum electric power capable of being supplied from a battery to an electric motor; and the second operation mode in which a second upper limit value is set to a value larger than the maximum electric power. When any one of a plurality of conditions for determining an end of the first operation mode is satisfied in a state in which a vehicle operates in the first operation mode, the first operation mode is switched to the second operation mode, an upper limit value is gradually increased from the first upper limit value to the second upper limit value, and an increasing speed at which the first upper limit value is increased to the second upper limit value is changed in accordance with the satisfied condition.