Hybrid Drive Control Unit Speed Limits
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Solution Overview
Problem
In parallel hybrid vehicles, the high-capacity secondary battery required for electric power leads to increased costs and charge/discharge losses, and fuel economy is not sufficiently improved by relying solely on motor drive during vehicle acceleration and low-speed driving.
Innovation Solution
An electromotive drive device with a small motor and low-capacity battery, featuring an inverter for power transformation and a control unit that sets upper vehicle speed limits and maximum driving force differently during powering and regeneration, optimizing energy usage and conversion ratios to enhance fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high-capacity secondary battery is used to secure electric power for driving the motor in parallel hybrid vehicles, then the motor can provide sufficient power, but the cost increases and charge/discharge losses occur
Solution Approach 1:
The patent dynamically changes the operating parameters of the motor by setting different upper vehicle speed limits for powering and regeneration modes. This allows the system to optimize energy usage without requiring a high-capacity battery, as the control strategy maximizes regenerative energy capture and efficient powering within adjusted operational boundaries.
2Loss of energy
If the upper vehicle speed limit during regeneration is set higher, then more regenerative energy can be captured, but the motor may operate less efficiently during powering
Solution Approach 1:
The patent implements dynamic adjustment of the upper vehicle speed limit based on the operational mode. The control unit sets a higher upper vehicle speed limit during regeneration to maximize energy recovery, and a lower limit during powering to maintain motor efficiency. This dynamic parameter adjustment resolves the contradiction by adapting the speed limit to the current operational requirements.
3Use of energy by moving object
If the maximum driving force during powering is limited more strictly, then energy consumption is reduced, but the vehicle acceleration performance deteriorates
Solution Approach 1:
The patent applies partial action by implementing different maximum driving force limits for different operational modes. During powering, a stricter limit is applied to reduce energy consumption, while during regeneration, the system allows for more flexible force application to maximize energy recovery. This partial application of force limits resolves the contradiction by optimizing energy usage without completely restricting acceleration capability 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
This configuration effectively improves fuel economy by dynamically adjusting motor operation parameters based on battery state and vehicle conditions, reducing energy losses and enhancing regenerative energy utilization.
Implementation Method 1
an inverter transforming power output from the battery into alternating current to supply the alternating current to the motor, and also transforming power regenerated by the motor into direct current to supply the direct current back to the battery
Implementation Method 2
a motor for driving the vehicle; a battery storing electrical energy to rotate the motor
Data Source
AI summary
An electromotive drive system including a small motor and a small-capacity battery more effectively improves the fuel economy of an engine-driven vehicle. An electromotive drive system includes: a motor for driving a vehicle; a battery storing electrical energy to rotate the motor; an inverter; a converting mechanism transmitting rotation of the motor to a drive shaft at a predetermined conversion ratio independently of a conversion ratio at which an engine is driven; and a control unit controlling an operation of the inverter. The control unit is configured so that upper vehicle speed limits, to which the motor is allowed to operate, can be set separately during powering and during regeneration, respectively.