Engine Knock Noise Determination During Cylinder Deactivation
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Solution Overview
Problem
Existing engine systems face challenges in determining engine knock background noise levels efficiently, particularly when one or more engine cylinders are deactivated, which can lead to reduced controller processor utilization and potential impacts on emissions and fuel economy.
Innovation Solution
The method involves deactivating a cylinder for one or more cycles, learning the base engine knock background noise level during this time, and adjusting engine operation based on this learned noise level, allowing for improved processor utilization and reduced emissions and fuel economy effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller continues to generate knock windows and sample the knock sensor for deactivated cylinders, then the engine knock detection coverage is maintained, but the controller processor utilization is reduced
Solution Approach 1:
The patent extracts the knock window generation and knock sensor sampling functions specifically for deactivated cylinders, separating them from the normal knock detection process. This allows the controller to eliminate unnecessary processing for deactivated cylinders while maintaining detection coverage for active cylinders, thereby improving processor utilization without compromising reliability.
2Loss of energy
If the engine operates with deactivated cylinders to improve fuel economy, then fuel consumption is reduced, but the ability to determine engine background noise levels is compromised
Solution Approach 1:
The patent implements preliminary action by determining engine background noise levels during periods when all cylinders are active, before any cylinders are deactivated. The controller stores these pre-determined background noise levels for later use during cylinder deactivation, allowing the engine to operate with deactivated cylinders for improved fuel economy while still having accurate background noise data available for knock detection.
3Measurement precision
If the controller adjusts valve timings to determine background noise levels for different cylinders, then accurate cylinder-specific noise levels are obtained, but the device complexity and processing requirements increase
Solution Approach 1:
The patent applies universality by determining that a single engine background noise level can serve as a common reference for all cylinders, eliminating the need for separate cylinder-specific adjustments. The controller uses this universal background noise level for knock detection across all cylinders, significantly reducing processing requirements and device complexity while maintaining sufficient measurement precision for practical knock detection purposes.
Data Source
AI summary
Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders. The contributions of individual noise sources may be determined when engine cylinders are deactivated.