Hybrid DCT Clutch Control via Engine Speed Substitution
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Solution Overview
Problem
Hybrid type vehicles with dual clutch transmission (DCT) face overheating issues due to inaccurate motor speed detection, leading to clutch failure, as the friction characteristic of the dry clutch is lost when continuous slip occurs, and existing methods fail to accurately determine slip and prevent overheating.
Innovation Solution
A driving control method that includes receiving motor speed, determining engine clutch engagement, implementing full lock control with a safety torque margin, and transitioning to a limp home driving stage to prevent clutch overheating by shifting the driving stage and replacing clutch speed with motor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor speed is used to determine clutch slip in hybrid vehicles with DCT, then clutch protection can be implemented, but inaccurate motor speed detection leads to incorrect slip determination and clutch overheating
Solution Approach 1:
The patent introduces an intermediary mechanism by using engine speed as a substitute measurement when motor speed detection fails. The controller detects motor speed abnormality and switches to using engine speed (obtained through engine clutch engagement) to determine clutch slip, thereby maintaining measurement capability despite the failure of the primary measurement system.
Solution Approach 2:
The patent implements beforehand cushioning by preparing alternative measurement methods in advance. When motor speed abnormality is detected, the system has pre-established procedures to engage the engine clutch and use engine speed as a backup measurement source, ensuring continuous clutch protection capability without interruption.
2Temperature
If clutch slip control is implemented to protect the clutch, then clutch temperature can be managed, but continuous clutch slip under heat generation conditions causes loss of friction characteristic and clutch failure
Solution Approach 1:
The patent implements feedback control by continuously monitoring clutch slip conditions and adjusting control strategies accordingly. When abnormal clutch slip is detected through speed comparison, the controller activates protective measures including engine clutch engagement and limp home mode, creating a closed-loop system that responds to actual clutch conditions.
Solution Approach 2:
The patent applies periodic action through the limp home mode control strategy. The system periodically checks clutch engagement status and alternates between normal operation and protective limp home mode, allowing the clutch to periodically rest and cool down, preventing continuous heat generation and friction characteristic loss.
3Productivity
If limp home control is implemented to protect the clutch, then vehicle can continue operating with protected clutch, but additional control steps increase system complexity
Solution Approach 1:
The patent applies universality by making the engine clutch serve multiple functions: normal power transmission during regular operation and protective measurement/actuation during clutch protection mode. This multi-functionality allows the same component to support both normal vehicle operation and protective limp home control, reducing the need for additional dedicated components.
Data Source
AI summary
The present disclosure provides a driving control method for hybrid type vehicles with a DCT. The method includes: receiving the motor speed from a driving motor; when abnormality of the motor speed is detected, requesting driving of an engine and determining whether an engine clutch is engaged; if it is determined that the engine clutch is released, controlling a clutch of a current driving stage using a clutch torque higher than a transmission input torque; controlling the current driving stage to be a limp home driving stage set in advance to be in a limp home driven status.