Hybrid Vehicle Motor Control Device for Engine Start Shock Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles using two electric motors for propulsion, the first electric motor is often overloaded with the dual functions of engine start and motor running, leading to increased complexity and a higher likelihood of engine start shock during transitions.
Innovation Solution
A control device that selectively uses one or two electric motors for propulsion based on the charging capacity of the electric storage device, prioritizing motor running by two motors when the capacity is sufficient and switching to engine power when it falls below a threshold, thereby extending the duration of motor running by two motors and reducing the frequency of engine start shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If motor running by two motors is selected to generate larger drive force and operate at efficient points, then drive force and efficiency are improved, but engine start control becomes complicated and engine start shock is more likely to occur
Solution Approach 1:
The control device changes the threshold value for selecting two-motor running based on the continuous operation time under high load running state. By dynamically adjusting this parameter (threshold value or selection criteria), the system resolves the contradiction by allowing two-motor running only when appropriate conditions are met, thereby maintaining drive force while preventing excessive control complexity and engine start shock
2Power
If motor running by two motors is selected to generate larger drive force, then drive force is improved, but the time until switching to engine running is extended, increasing the likelihood of engine start shock
Solution Approach 1:
The control device dynamically adjusts the operating mode based on continuous operation time under high load running state. The system transitions from static mode selection to dynamic mode switching, where the selection between one-motor and two-motor running changes based on real-time conditions (continuous operation time), thereby resolving the contradiction between maintaining extended two-motor running for drive force and preventing excessive duration that leads to engine start shock
3Device complexity
If the first electric motor is used for both engine start and motor running, then device complexity is reduced, but engine start shock is more likely to occur during transitions
Solution Approach 1:
The control device performs preliminary assessment of the continuous operation time under high load running state before allowing transitions involving the first electric motor. By evaluating the current operating conditions in advance and adjusting the threshold value accordingly, the system prepares for potential mode transitions, thereby reducing engine start shock while maintaining the simplified dual-function motor configuration
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 prolongs the time before engine start during motor running by two motors, allowing for smoother transitions and reducing the occurrence of engine start shocks by delaying the switch to engine power.
Implementation Method 1
an electric storage device giving/receiving electric power to/from each of the first and second electric motors
Implementation Method 2
a first electric motor outputting a starting torque for an engine start
Implementation Method 3
a second electric motor coupled to wheels
Data Source
AI summary
A vehicle control device is configured to select a single motor running, a multiple motor running and an engine running, such that a level of a charging capacity of an electric storage device in which the multiple motor running is selectable is higher than a level of the charging capacity in which the single motor running is selectable. During the single motor running performed with the charging capacity being equal to or greater than a first threshold value, the control device is configured, upon increase of the drive force requested by a driver of the vehicle, to select the multiple motor running when the charging capacity is equal to or greater than a second threshold value that is higher than the first threshold value, and to select the engine running when the charging capacity of the electric storage device is less than the second threshold value.