Vehicle Level Control with Dual Tolerance Ranges
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Solution Overview
Problem
Existing level control devices for vehicles with electronically controlled air suspension systems face challenges in maintaining driving safety and comfort due to delayed responses to significant deviations in vehicle level from the target level, which can lead to critical situations and inefficient air consumption.
Innovation Solution
Implementing a dual tolerance range system where minor deviations within a first tolerance range are filtered out with a longer delay, and significant deviations exceeding a second tolerance range trigger immediate adjustment back to the target level, reducing the risk of critical situations and unnecessary air consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a control delay is used to filter out temporary level changes during driving, then driving comfort is improved and unnecessary air consumption is reduced, but response time to significant level deviations is delayed which may lead to critical situations
Solution Approach 1:
The patent divides the tolerance range into two segments: a first tolerance range (smaller threshold) and a second tolerance range (larger threshold). When the actual level deviates within the first tolerance range, a longer control delay is applied to filter temporary changes. When the deviation exceeds the second tolerance range, a shorter control delay is applied to ensure rapid response. This segmentation allows the system to differentiate between normal driving variations and critical level deviations.
Solution Approach 2:
The control delay duration is made dynamic rather than fixed. The system automatically adjusts the control delay based on the magnitude of level deviation: using a first (longer) control delay for minor deviations within the first tolerance range, and a second (shorter) control delay for significant deviations exceeding the second tolerance range. This dynamic adjustment optimizes both comfort and safety response.
2Device complexity
If a single tolerance threshold is used for level control, then the control logic is simple, but it cannot differentiate between normal driving variations and critical deviations leading to either excessive air consumption or delayed safety response
Solution Approach 1:
The patent segments the single tolerance threshold into two distinct thresholds: a first tolerance range threshold and a second tolerance range threshold. This creates two distinct control zones that allow the system to apply different control strategies appropriately. The segmentation enables the system to maintain relatively simple control logic while significantly improving its ability to detect and respond to critical deviations.
3Measurement precision
If constant level control activation is used to maintain precise target level, then level precision is improved, but air consumption increases significantly due to continuous valve operations
Solution Approach 1:
Instead of continuously activating the control system, the patent applies control only partially - specifically when level deviations exceed the first tolerance range threshold. For minor deviations within the first tolerance range, no control action is taken, allowing temporary variations to pass without triggering valve operations. This partial action approach maintains adequate level precision while dramatically reducing unnecessary air consumption.
Solution Approach 2:
The control system operates periodically rather than continuously, with control activation occurring only when deviations exceed the first tolerance range. The control delay mechanism creates periodic control cycles rather than continuous valve operations, reducing air consumption while maintaining precision when needed.
Data Source
Figure 1~2
AI summary
The method involves comparing actual level (s-ist) with predetermined reference level (s-soll). Reference level-tolerance limit (s-2) and time interval (t-2) assigned to the tolerance limit are determined, where value of the tolerance limit is larger than value of another reference level-tolerance limit (s-1). Duration of the time internal is smaller than duration of another time interval (t-1) such that the actual level is adjusted to the reference level with smaller control delay during exceeding of the former tolerance limit than during exceeding of the latter tolerance limit. Independent claims are also included for the following: (1) a level regulating device (2) a controlling and evaluation device.