Hybrid AWD Mode Switching to Prevent Engine Startup Shock
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Solution Overview
Problem
When a vehicle driver selects the low-gear all-wheel driving mode, there is a risk of discomfort due to immediate engine startup and potential shock in hybrid electric vehicles, as the engine may start concurrently with mode switching, which can be jarring for the driver.
Innovation Solution
A control apparatus for hybrid electric vehicles that maintains the engine in a stopped state until the mode switching from high-gear to low-gear all-wheel driving mode is complete, then starts the engine, preventing concurrent engine startup and mode switching, thus minimizing driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine is started immediately when the low-gear all-wheel driving mode is selected, then the drive power is available quickly, but the driver experiences discomfort and shock due to concurrent engine startup and mode switching
Solution Approach 1:
The control apparatus completes the mode switching operation before initiating engine startup. The control unit monitors the completion of mode switching (from high-gear to low-gear all-wheel driving mode) and only then commands the engine to start. This preliminary completion of switching action eliminates the harmful concurrent operation that causes driver shock and discomfort.
2Object-affected harmful factors
If the engine startup is delayed until mode switching is complete, then driver comfort is improved, but the time to obtain drive power is increased
Solution Approach 1:
The control apparatus dynamically adjusts the engine startup timing based on the real-time status of mode switching. Rather than using a fixed delay, the system continuously monitors whether mode switching has been completed and adapts the engine startup command accordingly. This dynamic control approach minimizes unnecessary time delay while ensuring driver comfort is maintained.
3Productivity
If the engine and mode switching operate concurrently, then the system response is faster, but the reliability of smooth operation is reduced due to potential shock
Solution Approach 1:
The control unit implements a feedback mechanism that monitors the completion status of mode switching and uses this information to determine the appropriate timing for engine startup. The feedback signal from the mode switching completion status ensures that engine startup is synchronized with the end of switching operations, thereby maintaining reliable smooth operation while preserving system responsiveness.
Data Source
AI summary
A control apparatus for a hybrid electric vehicle includes: an engine control portion for controlling an operation state of an engine; and a driving-mode control portion for controlling the vehicle so as to realize selected at least one of driving modes. The driving modes include a low-gear all-wheel driving mode and a high-gear all-wheel driving mode. In a case in which the low-gear all-wheel driving mode is selected in the high-gear all-wheel driving mode when the engine is in a stopped state with a vehicle power transmission apparatus being in a non-driving position that disables transmission of a drive power, the engine control portion maintains the stopped state of the engine until completion of switching from the high-gear all-wheel driving mode to the low-gear all-wheel driving mode, and starts the engine after the completion of the switching from the high-gear all-wheel driving mode to the low-gear all-wheel driving mode.