Valve Degradation Detection Using Spark Duration
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Solution Overview
Problem
Existing methods for determining valve degradation in internal combustion engines, particularly in vehicles with variable event valvetrains, fail to diagnose exhaust valve degradation when intake valves are deactivated, as they rely on intake manifold pressure changes, which are not affected by exhaust valve operation.
Innovation Solution
The method involves initiating a spark in a cylinder during scheduled deactivation to assess cylinder pressure, using spark duration and breakdown voltage to determine exhaust valve position and degradation, allowing for evaluation of exhaust valve operation even when intake valves are closed, and subsequently deciding on fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intake manifold pressure rate of change is used to determine valve degradation, then intake valve degradation can be detected, but exhaust valve degradation cannot be detected when intake valves are deactivated
Solution Approach 1:
The patent uses spark duration as an intermediary measurement to indirectly assess cylinder pressure and exhaust valve position. Instead of directly measuring exhaust valve position or cylinder pressure with complex sensors, the spark duration serves as a mediator that reflects the underlying physical state, enabling exhaust valve degradation detection without additional hardware.
Solution Approach 2:
The patent replaces mechanical pressure sensing systems with an electrical measurement approach. By using spark duration (an electrical/timing measurement) to infer cylinder pressure conditions and valve position, the system eliminates the need for pressure transducers and other mechanical sensors, thereby enabling exhaust valve degradation detection without additional hardware.
2Measurement precision
If pressure transducers are used to determine cylinder pressure for valve degradation assessment, then accurate measurement is achieved, but system cost and complexity increase
Solution Approach 1:
The patent makes the existing spark plug system serve a dual function: its primary function for ignition and an additional function for sensing. By monitoring spark duration from the existing ignition system, the patent enables cylinder pressure assessment and valve degradation detection without requiring separate sensing hardware, thereby reducing system complexity and cost.
Solution Approach 2:
The patent enables the spark plug/ignition system to perform multiple functions: combustion ignition and cylinder pressure/valve position sensing. This multi-functionality eliminates the need for dedicated pressure sensors, reducing device complexity while maintaining measurement capability for valve degradation assessment.
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 approach enables rapid and reliable evaluation of both intake and exhaust valve degradation without requiring pressure transducers, reducing engine emissions and implementation costs, and effectively determines valve degradation before cylinder reactivation.
Implementation Method 1
Spark duration (i.e., the length of time from the beginning of a spark to the end of a spark) can be related to cylinder pressure
Implementation Method 2
breakdown voltage may be used as an indication of cylinder pressure
Data Source
AI summary
A method for determining degraded valve operation. According to the method, valve degradation can be determined from the duration of a spark event. This method allows for the determination of both intake and exhaust valve degradation.