Motor Generator Stop Control with Friction Clutch Pre-engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional vehicle control methods fail to optimize fuel efficiency when the motor/generator is driven during vehicle stops, leading to inefficiencies.
Innovation Solution
The motor/generator is stopped during vehicle stops, with the friction clutch kept released by hydraulic pressure from an electric oil pump, and upon a stoppage cancellation request, the rotational speed is increased while limiting torque to less than what's required to maintain the target speed, with torque limitation canceled if clutch slip is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor/generator is driven during vehicle stops to maintain readiness, then the vehicle response readiness is improved, but the fuel efficiency deteriorates
Solution Approach 1:
The friction clutch is pre-engaged before the vehicle actually needs to move, using hydraulic pressure from the electric oil pump. This preliminary engagement eliminates the need to drive the motor/generator during stops, as the clutch is already ready to transmit torque immediately when needed, thus improving fuel efficiency while maintaining response readiness.
Solution Approach 2:
The electric oil pump acts as an intermediary to provide hydraulic pressure for pre-engaging the friction clutch. This mediator allows the clutch to be engaged without requiring the motor/generator to be running, decoupling the clutch engagement function from the motor/generator operation and enabling fuel savings during stops.
2Speed
If the motor/generator rotational speed is increased quickly upon stoppage cancellation, then the vehicle acceleration response is improved, but the torque control stability deteriorates
Solution Approach 1:
The torque limitation is dynamically adjusted based on the engagement state of the friction clutch. Initially, torque is limited to prevent instability during clutch engagement. As the clutch engagement progresses and slip is detected, the torque limitation is gradually released, allowing the rotational speed to increase more rapidly. This dynamic adjustment resolves the contradiction between fast response and stability.
Solution Approach 2:
The control system uses feedback from clutch slip detection to adjust torque limitation. When slip is detected during clutch engagement, this feedback signal triggers the release of torque limitation, allowing the motor/generator to increase rotational speed more aggressively. This closed-loop feedback mechanism enables the system to achieve both stability during engagement and rapid acceleration afterward.
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 improves fuel efficiency by stopping the motor/generator during stops and optimizing acceleration responses by reducing torque limitations, thereby enhancing overall motor/generator efficiency.
Implementation Method 1
the friction clutch is kept released by the hydraulic pressure from an electric oil pump in a state in which the slack in a stroke is eliminated
Implementation Method 2
a friction clutch that connects/disdisconnects the torque transmission between the motor/generator and the drive wheels
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The purpose of the present invention is to stop a motor/generator when a vehicle stops; maintain the release of a friction clutch when slack in the stroke is eliminated by the hydraulic oil pressure from an electric oil pump; raise the rotational speed of the motor/generator toward a target rotational speed if a request has been made to cancel stoppage of the motor/generator; and restrict the torque to a torque that is less than the motor generator torque at which the target rotational rate can be maintained when the rotational rate of the motor generator is raised toward the target rotational rate.