Vehicle Control System Input Shaft Speed Detection
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Solution Overview
Problem
Existing vehicle control systems face challenges in mitigating impacts between driving power transmission members engaged with a slack, leading to discomfort for the driver due to rotational speed differences, and require costly sensors to prevent misdetetection from chain clattering.
Innovation Solution
A control system that detects the non-contact state of driving power transmission members based on the change rate of the input shaft rotational speed, allowing for controlled reduction of rotational speed differences without the need for downstream sensors, thereby reducing costs and improving driving feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sensors are attached on the output shaft to detect rotational speed for impact mitigation, then the impact between driving power transmission members can be reduced, but the cost increases and the sensors may be misdetected by chain clattering
Solution Approach 1:
The patent extracts the rotational speed detection function from the output shaft area (where chain clattering occurs) and relocates it to the input shaft area. By attaching the rotational speed sensor to the input shaft or its vicinity rather than the output shaft, the system maintains the ability to detect rotational speed for impact mitigation while avoiding the harmful chain clattering that causes misdetection and requires additional protection structures.
Solution Approach 2:
The patent uses the input shaft rotational speed as an intermediary parameter to indirectly monitor the state of the driving power transmission members. Instead of directly measuring output shaft speed near the chain, the system measures input shaft speed and uses this information to predict and mitigate impacts, serving as an intermediary detection point that avoids the clattering problem while still providing necessary control data.
2Reliability
If sensors are attached on the output shaft to detect rotational speed, then impact mitigation control can be achieved, but additional protection structures are needed to prevent chain clattering from causing misdetection
Solution Approach 1:
The patent removes the sensor from the problematic output shaft area where chain clattering occurs and places it on the input shaft instead. This extraction eliminates the need for additional protection structures like dampers or metal covers while maintaining reliable rotational speed detection for impact mitigation control.
Solution Approach 2:
The input shaft area naturally provides a stable detection environment without requiring additional protection structures. The sensor attached to the input shaft self-services by being inherently protected from chain clattering, eliminating the need for external protection mechanisms and reducing overall system complexity.
3Object-affected harmful factors
If the rotational speed difference between input shaft and output shaft is not controlled, then the driving power transmission members collide and generate impact, but controlling it requires detecting both input and output shaft speeds which increases cost
Solution Approach 1:
The patent extracts the speed detection requirement from the output shaft and eliminates it entirely from the system design. By using only input shaft rotational speed detection combined with predetermined gear ratios, the system achieves impact mitigation control without needing output shaft speed sensors, thereby reducing cost and complexity.
Solution Approach 2:
The patent creates a calculated copy of the output shaft speed information by using the input shaft speed multiplied by the predetermined gear ratio. This calculated value serves as a proxy for actual output shaft speed, allowing the system to control rotational speed differences and prevent collisions without physically measuring output shaft speed, thus avoiding additional sensor costs.
Data Source
AI summary
A control system in a vehicle in which at least one pair of driving power transmission members are engaged with each other with a slack on a driving power transmission path, comprises an input shaft rotational speed detector for detecting a rotational speed of an input shaft located upstream of engaged portions of the driving power transmission members in a direction in which the driving power is transmitted, a determiner for determining whether or not the driving power transmission members are in a non-contact state at the engaged portions for a period of time based on a change rate of the detected input shaft rotational speed, and a controller for controlling the vehicle to reduce a rotational speed difference between the input shaft and an output shaft located downstream of the engaged portions, when the determiner determines that the driving power transmission members are in the non-contact state.