Planetary Gear Vehicle Shift Control via Rotation Energy Variation
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Solution Overview
Problem
In vehicles with a planetary gear mechanism between the internal combustion engine and the transmission, controlling engine power to facilitate smooth shifting is challenging due to variations in rotation energy, leading to potential shift stagnation, as the correlation between engine power and transmission input shaft rotation variation can become negative, unlike in ordinary engine vehicles with a steady positive correlation.
Innovation Solution
A vehicle with an engagement device and differential mechanism, including at least three rotating elements, where a controller adjusts engine power and transmission power based on rotation energy variations, using a planetary gear mechanism with a sun gear, ring gear, and carrier, and optionally a rotary electric machine and electrical storage device, to ensure appropriate shifting times by correcting power generation and transmission accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotation speed of the ring gear is controlled during shifting of the transmission, then shift shock is suppressed, but shift stagnation occurs and appropriate shifting time cannot be attained
Solution Approach 1:
The invention changes the control parameters from only ring gear rotation speed to include both ring gear rotation speed and engine power output. By adjusting engine power in conjunction with ring gear speed control, the system can manage the negative correlation between engine power and transmission input shaft rotation, preventing shift stagnation while maintaining smooth shifting.
Solution Approach 2:
The invention implements feedback control by monitoring the rotation speed of the transmission input shaft and adjusting both ring gear speed and engine power accordingly. This dual-feedback mechanism ensures that the transmission shifts smoothly without stagnation by dynamically responding to the actual rotational state of the transmission system.
2Productivity
If engine power is corrected based on ordinary vehicle methods (steady positive correlation), then shifting is facilitated, but shift stagnation occurs in planetary gear vehicles due to negative correlation
Solution Approach 1:
The invention inverts the conventional approach to engine power correction. Instead of applying steady positive correlation correction as in ordinary vehicles, the system applies correction based on negative correlation detection, reversing the direction of power adjustment to match the unique characteristics of planetary gear mechanisms and prevent shift stagnation.
Solution Approach 2:
The invention makes the engine power correction dynamic by detecting the actual correlation state (positive or negative) between engine power and transmission input shaft rotation in real-time. The control strategy adapts dynamically based on the detected correlation, allowing the system to switch between different correction modes to ensure reliable shift completion.
3Adaptability or versatility
If the correlation between engine power and transmission input shaft rotation becomes negative due to planetary gear mechanism state, then conventional power correction methods fail, but the system lacks the capability to adapt to this varying correlation
Solution Approach 1:
The invention changes the control parameters to include detection of the correlation state between engine power and transmission input shaft rotation. By identifying whether the correlation is positive or negative, the system can adapt its control strategy accordingly, enhancing adaptability to different planetary gear mechanism states while maintaining ease of shifting control.
Data Source
AI summary
A vehicle includes a transmission between an engine and a drive wheel and includes a differential mechanism (planetary gear mechanism) between the engine and an engagement device (transmission). A controller (ECU) included in the vehicle calculates a variation rate in the whole rotation energy of the planetary gear mechanism when it is in the inertia phase of a shift. The ECU increasingly corrects an engine generated power and decreasingly corrects a transmission transfer power when the variation rate is higher than 0. The ECU decreasingly corrects the engine generated power and increasingly correct the transmission transfer power when the variation rate is lower than 0.