Automatic Transmission Manual Valve Control Orifice
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Solution Overview
Problem
Conventional automatic transmissions experience abrupt changes in hydraulic fluid flow, leading to a clunky or bumpy sensation when shifting from Drive to Neutral or Park, due to rapid release of stored energy in the driveline, which is perceived as a defect by users.
Innovation Solution
A modified manual valve configuration with an additional control apparatus, such as a narrowing of a port, is introduced in the hydraulic circuit to allow gradual venting of hydraulic fluid, enabling a controlled release of energy by maintaining solenoid pressure and slowly disengaging the underdrive clutch during gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic fluid flow is abruptly interrupted during gear shift, then gear switching speed is improved, but shift quality deteriorates due to clunky sensation
Solution Approach 1:
A control orifice (intermediary element) is introduced in the hydraulic circuit between the manual valve and the underdrive clutch. This orifice mediates the abrupt pressure change by restricting and controlling the fluid flow rate, allowing the clutch to disengage gradually rather than instantly, thereby eliminating the clunky sensation while maintaining acceptable shift speed.
Solution Approach 2:
The invention changes the hydraulic parameter (flow rate/pressure) by introducing a control orifice with specific dimensions. This orifice transforms the abrupt high-speed pressure change into a controlled, gradual pressure reduction, allowing the clutch engagement state to transition smoothly and improve shift quality.
2Speed
If hydraulic pressure is rapidly released from underdrive clutch, then gear shift speed is improved, but vibration and noise increase
Solution Approach 1:
The control orifice serves as an intermediary that restricts the rapid release of hydraulic pressure from the underdrive clutch. By controlling the fluid flow through this orifice, the clutch disengages gradually, preventing the sudden energy release that causes vibration and noise, while still achieving timely gear shifts.
Solution Approach 2:
The control orifice provides beforehand cushioning by pre-limiting the rate of pressure reduction in the underdrive clutch circuit. This prevents the abrupt energy release that would otherwise cause harmful vibrations and noise during the gear shift process.
3Ease of operation
If control apparatus is added to gradually vent hydraulic fluid, then shift quality is improved, but device complexity increases
Solution Approach 1:
Instead of modifying the entire hydraulic system, the invention applies a localized solution by adding a single control orifice at the specific location where hydraulic fluid vents from the manual valve to the reservoir. This localized modification improves shift quality without requiring complex system-wide changes.
Solution Approach 2:
The invention simplifies the control approach by using a passive geometric feature (orifice size) rather than an active control mechanism. The orifice parameter (its dimensional size) is optimized to provide the desired flow restriction, achieving improved shift quality through a simple parameter change rather than complex control logic.
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 reduces the abrupt sensation during shifts from Drive to Neutral or Park, improving shift quality by gradually releasing hydraulic pressure and maintaining solenoid pressurization, while allowing rapid swaps between solenoids during other gear changes.
Implementation Method 1
the control apparatus allows for the gradual venting of hydraulic fluid following a gear shift. More specifically, the control apparatus allows for the gradual release of hydraulic pressure from the underdrive clutch
Implementation Method 2
giving the solenoid an opportunity to, in connection with the control apparatus, slowly disengage the underdrive clutch
Data Source
AI summary
A modification to the manual valve of an automatic transmission is provided which improves the shift quality of the automatic transmission when the transmission is shifted from a drive gear to either Park or Neutral. More particularly, the invention provides a control orifice which regulates the release of hydraulic fluid from one or more clutch circuits such that pressure to one or more clutches is gradually released. The gradual release of pressure form the one or more clutches provides an improved shift quality. In alternate embodiments, the present invention provides a further modification to an automatic transmission which allows the control orifice to be circumvented in situations where a rapid swap of pressure from on clutch control solenoid to another is required.