Transmission Hydraulics Controller N-Control Disengagement
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Solution Overview
Problem
Existing automatic transmission systems face energy loss issues when the vehicle is stopped in the D range due to delayed and insufficient disengagement of friction engagement elements during the N-control process, leading to increased fuel consumption.
Innovation Solution
A transmission hydraulics controller with a manual valve, hydraulic control valve, and range switch mechanism driven by an electric actuator, which includes a pressure regulating passage with a pressure regulating valve and check valve to quickly disengage friction engagement elements by switching hydraulic pressure through a bypass passage, allowing the N-control process to start early and maintain disengagement for a longer duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic control valve maintains hydraulic pressure at engagement pressure to keep friction engagement elements engaged during vehicle stop in D range, then the transmission remains in first gear position, but fuel consumption worsens due to large energy loss
Solution Approach 1:
The system performs preliminary disengagement action by switching to the pressure regulating passage before the vehicle actually needs to move. The manual valve is switched to connect the pressure regulating passage to the hydraulic pressure supply passage, reducing hydraulic pressure to disengage friction engagement elements in advance, so that when acceleration is needed, the elements can be quickly re-engaged without delay
Solution Approach 2:
The system dynamically switches between two hydraulic pressure supply modes: the normal hydraulic control passage for engaged state and the pressure regulating passage for disengaged state. The manual valve acts as a dynamic switch that changes the hydraulic circuit configuration based on whether the vehicle is stopped or moving, allowing the friction engagement elements to transition between engaged and disengaged states as needed
2Stability of the object's composition
If the N-control process waits for line pressure to stabilize before reducing hydraulic pressure, then the hydraulic control system operates stably, but the start timing of N-control is delayed and energy loss reduction is insufficient
Solution Approach 1:
The hydraulic pressure control is segmented into two independent pathways: the normal hydraulic control passage for stable pressure control during movement, and the pressure regulating passage for rapid pressure reduction during N-control. By segmenting the pressure control functions, the system can quickly switch to the pressure regulating passage without waiting for line pressure stabilization, achieving both speed and stability
Solution Approach 2:
The manual valve serves as an intermediary switching device that redirects hydraulic pressure flow from the normal hydraulic control passage to the pressure regulating passage. This intermediary mechanism allows the system to bypass the stable but slow hydraulic control valve and use the dedicated pressure regulating valve for rapid pressure reduction, achieving quick N-control initiation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables early initiation and extended duration of the N-control process, reducing energy losses by maintaining friction engagement elements in a disengaged state for a longer period, thus improving fuel efficiency without the need for a dedicated motive power source.
Implementation Method 1
a check valve that prevents reverse flow of hydraulic oil supplied to the friction engagement element
Implementation Method 2
a pressure regulating valve that regulates the hydraulic pressure supplied to the friction engagement element to be a predetermined pressure, the predetermined pressure being lower than an engagement pressure of the friction engagement element
Implementation Method 3
a hydraulic control valve that controls a hydraulic pressure applied to the friction engagement element
Data Source
AI summary
A pressure regulating passage includes a pressure regulating valve and a check valve. The pressure regulating valve regulates a hydraulic pressure supplied to a friction engagement element to be a predetermined pressure lower than an engagement pressure. The check valve prevents reverse flow of hydraulic oil supplied to the friction engagement element. An operative position of a manual valve is switched so as to switched between a passage that supplies hydraulic pressure to the hydraulic pressure supply passage while bypassing the pressure regulating passage and a passage that supplies hydraulic pressure to the hydraulic pressure supply passage through the pressure regulating passage. Accordingly, when an automatic transmission is in a D range and a vehicle is stopped, regardless of a line pressure, an N control process is performed to disengage the friction engagement element.