Piezoelectric RF Transmitter for Variable Valve Activation Diagnostics
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Solution Overview
Problem
Current diagnostic strategies for two-mode variable valve activation devices in internal combustion engines are inadequate in detecting low-lift or zero-lift failure modes, particularly at high engine speeds, leading to potential mechanical failure and compromising fuel economy benefits.
Innovation Solution
Integration of a piezo-electric Radio Frequency (RF) transmitter in each two-mode variable valve activation device, which uses a wireless RF approach to detect the mode by differentiating between high-lift and low-lift or zero-lift modes through the presence or absence of RF signals, allowing for direct measurement and reliable detection of malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive diagnostic strategies relying on existing engine management data are used, then device complexity is reduced, but measurement precision and reliability of detecting low-lift or zero-lift failure modes deteriorate
Solution Approach 1:
The patent replaces passive mechanical/diagnostic strategies with an active piezoelectric sensing system. Piezoelectric elements are integrated into the variable valve activation device to directly measure mechanical parameters (valve lift, camshaft position) and convert them to electrical signals for accurate failure mode detection, thereby achieving high measurement precision without excessive complexity increase
Solution Approach 2:
The patent introduces piezoelectric elements as intermediary sensing components between the mechanical valve activation mechanism and the diagnostic system. These elements serve as mediators that directly sense mechanical displacement and convert it to measurable electrical signals, enabling precise detection of low-lift or zero-lift failure modes that passive strategies cannot detect
2Productivity
If two-mode variable valve activation devices operate at high engine speeds in low-lift or zero-lift mode, then fuel economy benefits are achieved, but the risk of mechanical failure increases due to lost motion spring limitations
Solution Approach 1:
The patent implements preliminary diagnostic action by continuously monitoring valve activation device status using piezoelectric sensors before mechanical failure occurs. The system detects low-lift or zero-lift failure modes in advance and can trigger protective measures or warnings, preventing catastrophic mechanical failure while allowing the engine to operate in fuel-efficient modes when conditions are normal
Solution Approach 2:
The patent establishes a feedback mechanism where piezoelectric elements continuously monitor the operational status of variable valve activation devices and provide real-time data to the engine control system. This feedback loop enables the system to detect failure modes, adjust operation accordingly, and prevent mechanical damage while maintaining fuel economy benefits during normal operation
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 provides a more reliable and efficient diagnostic method that reduces the risk of mechanical failure, maintains fuel economy benefits, and enables early detection of malfunctions, protecting the engine from high-speed damage.
Implementation Method 1
a piezo-electric element positioned adjacent to the lost motion spring and such that a load from absorbing the displacement of the cam lobe results in a compression load upon the piezo-electric element
Data Source
AI summary
A method for detecting a low-lift or zero-lift failure mode in a variable valve activation system of an internal combustion engine includes the steps of positioning a piezo-electric element that acts as a radio frequency transmitter relative to a lost motion spring of a two-mode variable valve activation lost motion device, subjecting the piezo-electric element to a compression load when a load from displacement of a lobe of a camshaft acts on the lost motion spring, broadcasting a radio frequency signal each time the piezo-electric element is subjected to the compression load, and evaluating the presence or absence of the broadcasted radio frequency signal in relation to an expected presence or absence of the radio frequency signal. The direct measurement of the mode of each two-mode device is both more reliable and more efficient in the use of engine controller resources compared to currently existing diagnostic methods.