Vehicle Shift Control for Fast Engagement Without Shock
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Solution Overview
Problem
Existing vehicle control devices experience engagement shocks and slow engagement issues when switching from non-traveling to traveling positions due to stepwise pressure increases in mechanical transmission devices, especially when differential rotation occurs.
Innovation Solution
A control device with an electric motor controller and garage controller that performs a quick engagement command by increasing command pressure stepwise and then executes rapid garage control to suppress engagement shocks, only allowing this when specific start conditions such as low input and output rotation speeds, normal electric oil pump operation, and appropriate hydraulic oil temperature are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the command pressure of the predetermined engagement device is increased stepwise to quickly engage it, then the engagement speed is improved, but an engagement shock occurs
Solution Approach 1:
The control device stops torque output from the electric motor before increasing command pressure to engage the predetermined engagement device. By removing the torque load in advance, the engagement shock is prevented while allowing rapid pressure increase for quick engagement.
Solution Approach 2:
The control device dynamically adjusts the command pressure based on real-time conditions. When quick engagement is needed and conditions are appropriate (no torque output, low rotation speeds), the command pressure is increased stepwise; otherwise, gradual pressure increase is used to avoid shock.
2Object-generated harmful factors
If the command pressure is increased gradually to suppress engagement shock, then the smoothness of engagement is improved, but the engagement speed becomes slow
Solution Approach 1:
The control device dynamically switches between two pressure increase strategies: gradual pressure increase when shock suppression is prioritized, and stepwise pressure increase when quick engagement is needed and conditions permit (no torque output, low rotation speeds).
3Speed
If the predetermined engagement device is quickly engaged in a state with differential rotation, then the engagement speed is improved, but the engagement shock is likely to occur
Solution Approach 1:
The control device reduces input and output rotation speeds to predetermined values or lower before engaging the predetermined engagement device. By equalizing rotation speeds in advance, differential rotation is minimized, allowing quick engagement without shock.
Solution Approach 2:
The control device monitors rotation speeds and dynamically adjusts the engagement strategy. When rotation speeds are within acceptable ranges, stepwise pressure increase is applied for quick engagement; otherwise, gradual pressure increase is used.
4Object-generated harmful factors
If the output torque from the electric motor is stopped before engagement, then the engagement shock is suppressed, but the productivity is reduced
Solution Approach 1:
The control device stops torque output from the electric motor in advance before engagement is needed. This preliminary action removes the source of engagement shock, enabling subsequent quick engagement without harmful effects.
Solution Approach 2:
When conditions are appropriate (low rotation speeds, no torque needed), the control device skips the gradual pressure increase phase and directly applies stepwise pressure increase for rapid engagement, maintaining productivity while avoiding shock.
Data Source
AI summary
In a case where a predetermined switching operation to a state in which a traveling position is selected from a state in which another shift position of a mechanical transmission device is selected is performed by a driver, a quick engagement command to quickly engage a predetermined engagement device is performed in a state in which output of a predetermined torque is stopped, and then a rapid garage control of increasing a rotation speed of an electric motor at a rotation speed equal to or higher than a predetermined rotation speed is executed. The rapid garage control is executed in a case where a predetermined start condition is established.