Predictive Tachometer Profile for Transmission Shift Delays
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Solution Overview
Problem
Tachometers in vehicles often exhibit delayed responses due to communication delays between engine speed sensors and the instrumentation panel, leading to a mismatch between the engine speed indication and actual engine performance, which can negatively impact the driver's perception of powertrain performance.
Innovation Solution
A predictive tachometer profile is generated based on computed shift completion percentage, the difference between current and commanded gear speeds, and commanded engine torque, accounting for delays to provide a more accurate representation of engine speed, thereby improving responsiveness and user experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional tachometer signal processing is used, then the system is simple and reliable, but the response delay causes the displayed engine speed to lag behind actual engine speed
Solution Approach 1:
The patent applies preliminary action by detecting transmission shift events in advance and pre-calculating the expected tachometer response profile. When a shift event is detected, the system predicts the future engine speed trajectory and displays this predicted profile instead of the delayed actual measurements, effectively showing the engine speed before the delay occurs.
Solution Approach 2:
The patent introduces an intermediary predictive algorithm that acts as a mediator between the actual engine speed sensor data and the displayed tachometer reading. This intermediary component processes the raw sensor data, detects shift events, generates predicted profiles, and blends them with actual measurements to produce the final displayed output, compensating for signal transmission delays.
2Measurement precision
If predictive tachometer profile is generated during shift events, then the displayed engine speed matches actual engine speed better, but the system complexity increases
Solution Approach 1:
The patent applies partial action by implementing predictive profile generation only during specific transmission shift events rather than continuously. The system detects when a shift event occurs and activates the predictive algorithm only during these transient periods, then returns to displaying actual engine speed measurements during normal operation, thus reducing overall system complexity while maintaining accuracy during critical moments.
Solution Approach 2:
The patent applies dynamics by making the tachometer display mode adaptive - switching between displaying actual engine speed measurements during normal operation and displaying predictive profiles during detected shift events. The system dynamically adjusts its processing based on operating conditions, using blend factors that transition smoothly between actual and predicted values.
3Reliability
If the tachometer displays delayed engine speed information, then the driver may shift gears at inappropriate times, but adding predictive processing may increase computational load
Solution Approach 1:
The patent applies preliminary action by detecting transmission shift events in advance using sensors that monitor transmission input and output speeds. When a shift event is detected, the system pre-calculates the expected tachometer response profile before the delay would affect the driver's decision-making, allowing the driver to see the predicted engine speed trajectory and make informed shifting decisions.
Data Source
AI summary
Methods and systems are provided for generating a predictive tachometer profile at a tachometer of a vehicle. When an inertia phase of a transmission shift event is determined to be in progress, the predictive tachometer profile can be computed based on: a computed shift completion percentage; a difference between the current attained gear speed and the commanded gear speed; and a commanded engine torque that is determined based on the accelerator pedal position and the vehicle speed. The predictive tachometer profile can then be displayed at the tachometer. The predictive tachometer profile accounts for delays in a signal path between an engine speed sensor and the tachometer.