Automatic Transmission Valve Body Layout for EMI Shielding
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Solution Overview
Problem
In automatic transmissions, the proximity of electronic controllers to solenoid valves leads to interference from electromagnetic waves generated by the solenoid valves, affecting the central processing unit and other electronic components, and existing arrangements do not effectively mitigate this issue.
Innovation Solution
The solenoid valves are positioned on one side of the valve body, and the electronic control unit is on the opposite side, with the valve body interposed between them, allowing electromagnetic waves to be naturally shielded without the need for additional shielding. Additionally, the solenoid valves are submerged in lubricating oil to absorb vibrations and heat, and a film-shaped wiring harness with an extendable portion is used to connect them securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electronic controller is arranged close to the solenoid valves on the valve body, then the wiring harness can be simplified, but electromagnetic waves generated by the solenoid valves interfere with the electronic controller's central processing unit and other electronic parts
Solution Approach 1:
The valve body is divided into two distinct sides: a first side for mounting solenoid valves and a second side for mounting the electronic controller. This segmentation physically separates components that generate electromagnetic interference from those sensitive to it, eliminating the need for additional electromagnetic shielding while maintaining compact wiring harness arrangement.
Solution Approach 2:
The valve body itself serves as an intermediary barrier between the solenoid valves and the electronic controller. By positioning the valve body between these two components on opposite sides, it naturally blocks electromagnetic waves from reaching the electronic controller, using the existing structural component as a shield without adding separate shielding elements.
2Temperature
If the solenoid valve is submerged in lubricating oil, then vibration and noise are absorbed and heat is released, but air may enter the solenoid valve and affect hydraulic control precision
Solution Approach 1:
The lubricating oil, which could potentially allow air ingress, is utilized to provide beneficial damping effects. The oil absorbs vibration and noise generated by the solenoid valve actuation and serves as a heat sink to dissipate heat from the solenoid coil, converting the potential harm of air exposure into beneficial thermal and vibrational management.
Solution Approach 2:
The solenoid valve is designed with selective exposure to lubricating oil: the solenoid coil and body are submerged in oil for thermal management and vibration damping, while the electrical connection areas and internal hydraulic passages are protected from air ingress. This localized quality approach allows different parts of the same component to have different environmental exposures based on their functional requirements.
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 arrangement effectively shields the electronic control unit from electromagnetic interference, reduces noise and vibration, enhances hydraulic control precision, and prevents air ingress, while allowing for secure electronic connection even in tight spaces.
Implementation Method 1
the valve body is interposed between the electronic control unit and the solenoid valve. Therefore, even without any electromagnetic shield, the electromagnetic wave generated by the actuation of the solenoid valve can be shielded by the valve body
Implementation Method 2
the solenoid valve can be in the oil and the vibration and noise generated by the activation of the solenoid valve can be absorbed with the damping effect of the lubricating oil
Implementation Method 3
heat generated at the solenoid valve can be released to the oil and the temperature of the solenoid valve can be more effectively controlled
Data Source
AI summary
There is provided, in one aspect of the present description, an automatic transmission. In one example, the automatic transmission comprises a transmission case, a valve body which is arranged in the transmission case, a control valve mechanism which controls oil pressures in parts of the automatic transmission and is installed in the valve body, and a solenoid valve which is attached to the valve body and is arranged at a first side of the valve body and in the transmission case. The automatic transmission further comprises an electronic control unit which controls the solenoid valve, is attached to the valve body, and is arranged at a second side of the valve body that is opposite to the first side across the valve body.