Rough Road Determination via Crank Angle Amplitude Fluctuation
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Solution Overview
Problem
Existing rough road determination devices face delays in outputting results, especially at low engine rotational speeds and when rotational speeds fluctuate, making it difficult to accurately determine rough road conditions in a timely manner.
Innovation Solution
A rough road determination device that compares the amplitude fluctuation of a single pulse from a crank angle sensor with a predetermined value, using a processor and comparator to quickly identify rough road conditions by analyzing the amplitude difference, even at low rotational speeds and during fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis of crank angle sensor output values is used to determine rough road conditions, then determination can be made based on rotational speed intervals, but a relatively long time is required until determination results are output in low rotational speed regions
Solution Approach 1:
The patent changes the determination parameter from rotational speed intervals to amplitude fluctuation of single pulse signals. By monitoring amplitude fluctuations directly rather than calculating intervals between multiple output values, the system achieves rapid determination even at low rotational speeds, resolving the time delay problem while maintaining determination accuracy
Solution Approach 2:
The patent pre-determines the relationship between rotational speed and amplitude fluctuation amounts through experiments or simulations and stores this data in advance. This preliminary action allows the system to quickly compare actual amplitude fluctuations against pre-established patterns without performing complex real-time calculations, thereby reducing determination response time
2Measurement precision
If frequency analysis of rotational speed is used for rough road determination, then determination can be made based on output intervals, but determination cannot be made when engine rotational speed fluctuates
Solution Approach 1:
The patent shifts from using rotational speed intervals to using amplitude fluctuation characteristics of single pulse signals. Amplitude fluctuations are inherently more stable and detectable even when rotational speed varies, allowing the system to maintain determination accuracy and reliability under fluctuating engine conditions
Solution Approach 2:
The patent continuously monitors amplitude fluctuation amounts and compares them against pre-determined patterns. This feedback mechanism allows the system to adapt to varying rotational speed conditions by constantly comparing actual amplitude characteristics against expected patterns, maintaining reliable determination even when engine speed fluctuates
3Measurement precision
If multiple pulse output values are analyzed to determine rotational speed, then rotational speed can be calculated, but a relatively long time is required until rough road determination results are output
Solution Approach 1:
The patent extracts only the essential feature (amplitude fluctuation of single pulse) needed for rough road determination, eliminating the need to process multiple pulse intervals. This extraction of the critical parameter enables rapid determination while still providing sufficient information for accurate rough road detection
Solution Approach 2:
The patent pre-determines amplitude fluctuation patterns at various rotational speeds through experiments or simulations and stores this reference data in advance. This preliminary preparation allows the system to quickly match actual amplitude fluctuations against pre-stored patterns without performing complex real-time analysis, thereby increasing determination output speed
Data Source
AI summary
A rough road determination device (100) is mounted on a vehicle (1) that is equipped with an internal combustion engine (10) having a crank angle sensor (31). This rough road determination device is equipped with determination means (20) for determining whether or not a road on which the vehicle travels is a rough road, by comparing a first amplitude fluctuation amount as an amplitude fluctuation amount of one pulse of an output of the crank angle sensor, which is determined in advance on the basis of a rotational speed of the internal combustion engine, with a second amplitude fluctuation amount as an amplitude fluctuation amount of one pulse that is actually output from the crank angle sensor.