Vehicle Control Unit Voltage Raising for Hybrid Mode Shift
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Solution Overview
Problem
Hybrid vehicles face a torque output issue when switching from EV mode to parallel mode due to insufficient torque during the shift period, leading to inefficient acceleration and potential clutch durability problems.
Innovation Solution
A vehicle control unit that includes a switching control unit and a voltage raising control unit, which temporarily raises the voltage input to the driving motor using a DC-DC converter, ensuring smooth torque output by engaging the clutch and engine only when necessary, thereby enhancing the driving motor's output and extending the EV mode vehicle speed range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the driving mode is switched from EV mode to parallel mode by engaging the clutch, then the vehicle can utilize both engine and motor for higher torque output, but the torque output becomes insufficient during the shift period causing inefficient acceleration
Solution Approach 1:
The control unit starts voltage raising control in advance before the clutch engagement is completed. By raising the voltage to the driving motor prior to full engine connection, the system ensures sufficient torque is available during the transition period, preventing torque deficiency and maintaining smooth acceleration throughout the mode shift.
2Stability of the object's composition
If the clutch is engaged earlier to ensure smooth transition, then torque continuity is improved, but fuel consumption increases due to unnecessary engine operation
Solution Approach 1:
The system dynamically adjusts the voltage parameter supplied to the driving motor during the mode transition. By controlling the voltage raising timing and magnitude, the system optimizes torque output to match actual vehicle needs, ensuring smooth transition only when necessary while minimizing unnecessary engine operation and fuel consumption.
3Speed
If the voltage is raised continuously to maintain torque output, then acceleration performance is improved, but energy loss increases due to excessive power consumption from the battery
Solution Approach 1:
The voltage raising control is applied periodically and temporarily only during the specific transition period when mode switching occurs, rather than continuously. The control unit raises voltage to enhance torque output during the clutch engagement phase, then returns to normal voltage levels, thereby maintaining acceleration performance during transitions while minimizing unnecessary energy consumption during steady-state operation.
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 ensures smooth torque output during mode shifts, reduces fuel consumption, and improves fuel economy by extending the EV mode vehicle speed range and enhancing regeneration efficiency.
Implementation Method 1
a voltage raising means configured to execute a voltage raising control in which a voltage of the electric power inputted from the battery is raised for output to the driving motor
Implementation Method 2
temporarily raises the voltage input to the driving motor using a DC-DC converter
Data Source
Figure 1
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AI summary
A control unit for a vehicle, which comprises an engine (12), a driving motor (13), an engaging/disengaging means (16), and a voltage raising means, includes a switching control unit and a voltage raising control unit controlling the voltage raising means. The switching control unit switches between a first driving mode in which the vehicle is driven by a driving force of the driving motor with the engaging/disengaging means released and a second driving mode in which the vehicle is driven by the driving force of the engine with the engaging/disengaging means engaged. In a case where a driving mode is switched from the first driving mode to the second driving mode, the switching control unit starts an engagement of the engaging/disengaging means and switches the driving mode to the second driving mode, after the voltage raising control unit starts the voltage raising control in the first driving mode.