Valve Timing Adjusting Device Noise Suppression
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Solution Overview
Problem
Existing valve timing adjusting devices for internal combustion engines generate noise due to superimposed switching operations of switching elements, which can interfere with the engine and other electronic devices, limiting design flexibility and increasing noise influence.
Innovation Solution
The implementation of a valve timing adjusting device with separate motors and driving circuits for each camshaft, where the switching elements operate at different frequencies to prevent noise superimposition, allowing for independent control of intake and exhaust valve timings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If switching elements in driving circuits operate at the same switching frequency, then control precision is improved, but noise superimposition occurs causing harmful interference
Solution Approach 1:
The patent applies parameter changes by setting different switching frequencies for the first and second switching elements in the driving circuits. Specifically, when the intake camshaft rotating phase is advanced, the first switching element operates at a first switching frequency, and when the exhaust camshaft rotating phase is advanced, the second switching element operates at a second switching frequency that is different from the first. This frequency differentiation prevents noise superimposition while maintaining precise control of valve timing.
2Object-generated harmful factors
If separate driving circuits are used for each camshaft, then noise interference is suppressed, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the driving system into separate driving circuits for the intake camshaft and exhaust camshaft. Each camshaft has its own motor and driving circuit with dedicated switching elements operating at different frequencies. This segmentation isolates noise sources to prevent superimposition, while the modular structure maintains manageable system complexity through functional separation.
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 effectively suppresses noise interference, enabling more precise control of valve timings, downsizing of engine systems, and increased design freedom by separating noise sources, thus improving the operational efficiency and design of internal combustion engines.
Implementation Method 1
a first motor configured to generate a torque to shift a rotation phase of a first camshaft
Implementation Method 2
a second motor configured to generate a torque to shift a rotation phase of a second camshaft
Data Source
AI summary
A valve timing adjusting device adjusts an opening/closing timing of a first valve driven by a rotation of a first camshaft and an opening/closing timing of a second valve driven by a rotation of a second camshaft. The valve timing adjusting device includes a first driving circuit controlling a first motor configured to generate a torque to shift a rotation phase of the first camshaft and a second driving circuit controlling a second motor configured to generate a torque to shift a rotation phase of the second camshaft. A first switching element of the first driving circuit operates at a switching frequency that is different from that of a second switching element of the second driving circuit.