Hybrid EV Transition Control Using Predicted Battery Output Limits
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Solution Overview
Problem
Hybrid electric vehicles experience hesitation during transitions from motor travel to hybrid travel due to insufficient motor power, leading to reduced acceleration and potential increases in fuel consumption and emissions if frequent transitions to motor travel are not permitted.
Innovation Solution
A hybrid electric vehicle system with a clutch, motor, and control device that calculates a predicted battery output upper limit, sets a determination value based on this limit, and determines whether to transition to motor travel based on vehicle speed, ensuring sufficient power is available for smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output upper limit value of the battery is small, then hesitation is suppressed, but transition to motor travel is not permitted frequently, leading to increased fuel consumption and exhaust emission
Solution Approach 1:
The control device calculates a predicted upper limit value of battery output before the transition occurs, using this prediction to determine in advance whether transition is permitted. This preliminary calculation prevents hesitation by ensuring sufficient power availability is confirmed before initiating transition to motor travel
Solution Approach 2:
The determination value for vehicle speed is dynamically adjusted based on the predicted upper limit value of battery output. When the predicted value is higher, the determination value increases, allowing transition at higher speeds. This dynamic adjustment optimizes the balance between transition smoothness and fuel consumption by adapting to real-time battery capabilities
2Productivity
If the determination value is set high, then transition to motor travel is permitted at higher vehicle speeds, but hesitation may occur due to insufficient motor power
Solution Approach 1:
The control device uses feedback from the calculated predicted upper limit value to adjust the determination value. The system continuously monitors battery output capabilities and adjusts the vehicle speed threshold for transition accordingly, ensuring that transition is only permitted when sufficient motor power is guaranteed to be available
Solution Approach 2:
The determination value is changed based on the predicted upper limit value parameter. When battery output capability is predicted to be high, the determination value is increased to allow transition at higher speeds. When battery output capability is low, the determination value is reduced to prevent hesitation, thus optimizing both transition frequency and smoothness
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
Ensures smooth transitions to motor travel while minimizing hesitation, thereby improving acceleration and reducing fuel consumption and emissions.
Implementation Method 1
a motor disposed on the power transfer path from the clutch to the wheels and capable of starting up the engine by cranking the engine with the clutch engaged
Data Source
AI summary
Hybrid electric vehicle includes a control device that switches between hybrid-type driving and motor-type driving. The control device includes a setting unit configured to set a determination value based on a predicted upper limit value which is a predicted value of an output upper limit value of a battery when the start of the engine is completed during the running of the motor during the hybrid running. The setting unit sets, as the determination value, a vehicle speed at which a sufficient output value, which is a value obtained by adding a predetermined margin value to a necessary output value, becomes the predicted upper limit value. The required output value is an output value per unit time of the battery for each vehicle speed that can be maintained by the motor when starting of the engine is completed. The margin value decreases as the vehicle speed decreases.