Tachometer Display Control for Responsive Automatic Shifts
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Solution Overview
Problem
Existing engine rotation speed display devices in vehicles with automatic transmissions experience delays in responding to changes in engine speed, particularly during shifts with large changes in rotation speed, leading to discomfort for drivers due to inadequate responsiveness and feeling of engine sound changes.
Innovation Solution
A prime mover rotation speed display device that includes a prime mover rotation speed acquisition unit, a shift target rotation speed calculation unit, a shift instruction rotation speed calculation unit, and a meter display control unit, which calculates and adjusts the meter display rotation speed based on vehicle speed, transmission state, and accelerator pedal position to simulate quick shift responses and fixed transmission ratios, using upper and lower limit controls to maintain synchronization with shift instruction speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the meter display rotation speed is calculated based on the actual prime mover rotation speed, then the display reflects the true engine speed, but the responsiveness during shifts is delayed and insufficient
Solution Approach 1:
The system calculates a shift instruction rotation speed in advance based on the shift target rotation speed before the actual shift occurs. During shift execution, the meter display uses this pre-calculated shift instruction rotation speed rather than waiting for the actual rotation speed to change, thereby achieving responsive display without sacrificing accuracy.
2Measurement precision
If the meter display rotation speed follows the actual prime mover rotation speed during shifts, then the display is accurate, but the driver feels discomfort due to inability to follow acceleration/deceleration feeling
Solution Approach 1:
The system pre-calculates the shift instruction rotation speed that represents the expected rotation speed during shift. The meter display uses this pre-calculated value to show rotation speed that follows the driver's acceleration/deceleration feeling, thereby improving driver comfort while maintaining display accuracy through proper calculation.
Solution Approach 2:
The shift instruction rotation speed acts as an intermediary between the actual prime mover rotation speed and the meter display. It mediates the information flow by transforming the actual rotation speed into a display value that better reflects driver perception, thus resolving the discomfort without losing accuracy.
Data Source
AI summary
A prime mover rotation speed display device includes: a prime mover rotation speed acquisition unit configured to acquire a rotation speed; a shift target rotation speed calculation unit configured to calculate a shift target rotation speed; a shift instruction rotation speed calculation unit configured to calculate a shift instruction rotation speed; and a meter display control unit configured to calculate a meter display rotation speed provided for meter display, wherein the meter display control unit calculates the meter display rotation speed based on at least the rotation speed of the prime mover, calculates the meter display rotation speed based on at least the shift instruction rotation speed, performs upper limit control and lower limit control of setting the meter display rotation speed to the shift target rotation speed if the meter display rotation speed is expected to be higher or to be lower than the shift target rotation speed.