Variable Displacement Engine Knock Control via Cylinder Group Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing engine systems face challenges in detecting engine knock due to combustion noise and vibration, which can mask the signals from knock sensors, making it difficult to accurately detect and manage engine knock, especially when cylinders are deactivated.
Innovation Solution
The method involves operating the engine with different groups of combusting cylinders and adjusting spark timing based on indications from multiple knock sensors during varying engine conditions, allowing for improved detection of engine knock by optimizing sensor usage and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple knock sensors are deployed to detect engine knock, then the detection coverage is improved, but the ability to accurately distinguish engine knock from combustion noise and vibration is degraded
Solution Approach 1:
The patent divides the engine into different cylinder groups (first group and second group of cylinders) and assigns different knock sensors to monitor each group. This segmentation allows the system to isolate and analyze knock signals from specific cylinder groups, reducing interference from combustion noise and vibration in other groups.
Solution Approach 2:
The patent dynamically adjusts which knock sensors are active based on the operating condition. When cylinders are deactivated, the system switches to using only the knock sensor associated with the active cylinder group, adapting the sensor configuration to the current engine state to minimize noise interference.
2Power
If all engine cylinders are activated and combusting air and fuel, then the engine power output is improved, but the combustion noise increases and degrades knock sensor signal quality
Solution Approach 1:
The patent segments the cylinder group into first and second groups, each monitored by dedicated knock sensors. This allows the system to analyze knock signals from active cylinders while ignoring noise from deactivated cylinders, maintaining good signal-to-noise ratio even when some cylinders are combusting.
Solution Approach 2:
The patent applies different sensor monitoring strategies to different cylinder groups based on their operational state. When certain cylinders are deactivated, the system focuses knock detection resources on the active cylinder group, providing locally optimized detection quality for each region.
3Measurement precision
If cylinder deactivation is implemented to reduce combustion noise, then the signal to noise ratio of knock sensors is improved, but the complexity of managing different sensor configurations increases
Solution Approach 1:
The patent divides the cylinder group into first and second groups with dedicated knock sensors for each. This segmentation creates a straightforward mapping between cylinder groups and sensors, simplifying the management of sensor configurations during cylinder deactivation by clearly defining which sensors should be active based on which cylinder group is operating.
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 enhances engine knock sensing accuracy, reduces the risk of engine degradation, and improves detection even when cylinders are deactivated, leading to better engine performance and reduced noise interference.
Implementation Method 1
The second ignition after the spark ignition is produced by rising pressure in the cylinder and it causes a pressure oscillation in the cylinder that produces a ping or knocking sound in the engine
Implementation Method 2
the air-fuel mixture is ignited at a location in the cylinder outside of a flame front in the cylinder created by the spark
Data Source
AI summary
Systems and methods for detecting and controlling knock in an engine are presented. In one example, engine knock sensors are selected based on whether or not certain cylinders are activated and combusting air and fuel or deactivated and not combusting air and fuel. Output of selected knock sensors is the basis for adjusting engine spark timing.