Vehicle Clutch Control for Engine Start Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicles equipped with automatic engine stop-start systems and drivetrain mode changers, the simultaneous operation of engine startup and clutch synchronization can lead to voltage drops in the battery, causing clutch instability, noise, and reduced durability, while also causing driver anxiety due to delayed engine startup.
Innovation Solution
The vehicle's electronic control unit manages the engine state and drivetrain mode changes by ensuring that engine startup and clutch mode changes do not overlap, delaying clutch operation until the battery voltage has recovered, thereby prioritizing engine startup and maintaining clutch stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive mode is changed by operating the clutch while the engine is being started, then the drive mode can be changed to prepare for re-acceleration, but the battery voltage steeply decreases causing the clutch to be engaged in a state where synchronization is not enough, leading to vibration, noise, or decreased durability
Solution Approach 1:
The system checks whether the clutch is in the process of being operated before allowing engine startup. If clutch operation is detected, the engine startup is delayed until the clutch operation completes. This preliminary check prevents the harmful overlap between clutch synchronization and engine startup, ensuring clutch durability while maintaining the ability to change drive modes when safe to do so.
2Reliability
If the engine startup is prohibited while the clutch is being operated to change drive mode, then clutch synchronization can be completed properly, but the driver experiences a feeling of anxiety from the situation that the engine is not started immediately
Solution Approach 1:
The system continuously monitors the operational status of the clutch and uses this feedback to control engine startup timing. When clutch operation is detected, the system feedback-controls the engine startup to be delayed. Once clutch operation completes, the restriction is lifted and engine startup is permitted. This feedback mechanism ensures clutch engagement quality while minimizing startup delays, thereby reducing driver anxiety.
3Productivity
If the clutch operation and engine startup overlap, then the drive mode can be changed in preparation for re-acceleration, but vibration and noise occur due to insufficient clutch synchronization
Solution Approach 1:
The system takes preliminary anti-action by preventing engine startup when clutch operation is detected. This proactive restriction avoids the harmful overlap that would cause vibration and noise from insufficient clutch synchronization. The system prioritizes smooth clutch engagement by delaying engine startup until the clutch operation completes, thereby eliminating the harmful effects before they can occur.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces vibration and noise, prevents clutch durability issues, and ensures a prompt engine startup, enhancing driver satisfaction by avoiding delays and battery voltage-related problems during mode changes.
Implementation Method 1
The starter motor of the engine and the clutch are configured to be supplied with electric power from the same battery
Implementation Method 2
Each of the first and second clutches is a dog clutch that is operated by an electromagnetic actuator
Data Source
AI summary
Each of a first clutch and a second clutch is, for example, an electromagnetic clutch that is operated by an electromagnetic actuator, and is supplied with electric power from the same in-vehicle battery as a starter motor of an engine. An electronic control unit is configured to not change a drive mode during a stop of the engine, and, after a predetermined period has elapsed from a start of operation of the starter motor at a startup of the engine (for example, the startup has completed) and a battery voltage has been recovered, change the drive mode to any one of a two-wheel drive mode and a four-wheel drive mode with the first clutch and the second clutch.