Hybrid Vehicle Axle Speed Calibration for Clutch Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicles with multiple driving sources, accurately synchronizing rotation speeds for clutch engagement is challenging due to the lower detection precision of wheel speed sensors compared to rotation speed sensors in the driving source, leading to difficulties in power transmission efficiency and performance.
Innovation Solution
A control unit that calculates axle rotation speed using high-precision sensors for the driving sources and corrects wheel speed sensor data to achieve precise synchronization, enhancing the accuracy of rotation synchronization during clutch engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wheel speed sensor is used to detect axle rotation speed, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces an intermediary calculation process that uses the known gear ratio as a mediator to convert the wheel speed sensor output into axle rotation speed. Instead of directly measuring axle speed with a low-precision sensor, the system uses the gear ratio relationship to calculate the axle speed from wheel speed, thereby maintaining device simplicity while improving measurement precision through computational correction.
Solution Approach 2:
The patent changes the parameter used for speed detection by introducing the gear ratio as a correction factor. Rather than relying solely on the raw wheel speed sensor data, the system transforms the parameter by multiplying wheel speed by the gear ratio to obtain accurate axle rotation speed, thereby improving measurement precision without adding physical sensors.
2Device complexity
If wheel speed sensor data is used directly for clutch engagement control, then device complexity is reduced, but manufacturing precision of synchronization deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating the gear ratio and storing it in the control unit before clutch engagement occurs. This allows the control system to have the correction factor ready in advance, enabling accurate synchronization calculation when the clutch engagement moment arrives, thereby improving manufacturing precision of synchronization without complicating the control system structure.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors wheel speed, calculates axle rotation speed using the gear ratio, compares it with the driving source rotation speed, and adjusts the clutch engagement timing based on the synchronization state. This closed-loop feedback ensures accurate rotation synchronization while maintaining a relatively simple control system structure.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle includes connecting/disconnecting mechanisms (20, 30) disposed on power transmission paths between first rotating electric machines (3,4) mounted on the vehicle and an output shaft (12) that drives a wheel, a first rotating electric machine speed sensor (43,44) that detects a rotation speed of the first rotating electric machine (3,4) as a first rotation speed (Nm,Ng), and a wheel speed sensor (42) that detects a rotation speed of the wheel as a wheel speed (Nw). A control unit (5) includes: a first calculator (5B) that calculates an axle rotation speed (Nam,Nag) representing a rotation speed of the output shaft (12) based on the first rotation speed (Nm,Ng) in a state where the first connecting/disconnecting mechanism (20,30) is engaged; a monitoring unit (5C) that calculates a deviation (X,Y) between the axle rotation speed (Nam,Nag) calculated by the first calculator (5B) and the wheel speed (Nw); and a second calculator (5D) that calculates the axle rotation speed (Nax,Nay) by calibrating the wheel speed (Nw) based on the calculated deviation (X,Y) in a state where the first connecting/disconnecting mechanism (20,30) is disengaged.