Hybrid Vehicle Controller Adaptive Clutch Engagement
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Solution Overview
Problem
Hybrid electric vehicles face challenges in transitioning from electric vehicle mode to parallel mode, particularly in terms of noise, vibration, and harshness (NVH) performance, and the time required for this transition, due to sub-optimal engine speed control when the internal combustion engine is placed under load.
Innovation Solution
A controller for a hybrid electric vehicle that adjusts its control signals based on the speed of the actuator and the amount of torque transfer by the releasable torque transmitting means, such as a multiplate wet clutch, to maintain or attain a target speed, adapting to changing effective moment of inertia and torque capacity, and considering factors like temperature and driver-demanded torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the engine speed is controlled to maintain a given value during clutch engagement, then the engine can be held at steady idle speed, but the control parameters become sub-optimum when the engine is placed under load, resulting in poor transition performance
Solution Approach 1:
The patent applies dynamics by making the control parameters adaptive rather than fixed. The controller dynamically adjusts engine speed control parameters based on the clutch engagement state and load conditions. As the clutch transitions from disengaged to engaged, the controller modifies the target engine speed and control gains in real-time, optimizing performance across different operating phases of the transition.
Solution Approach 2:
The patent implements parameter changes by varying the target engine speed and control parameters according to the clutch torque transfer state. During EV mode, the engine runs at idle speed. During transition, the target speed is dynamically adjusted based on clutch capacity and load. This parameter adaptation resolves the contradiction between maintaining stability and achieving rapid transition.
2Force
If the clutch capacity increases with clutch pressure, then more torque can be transmitted, but the transition time and NVH performance are not optimized
Solution Approach 1:
The patent applies preliminary action by pre-positioning the engine at an optimal speed before clutch engagement and actively managing the engagement process. The controller prepares the engine by adjusting its speed and torque output in advance of full clutch engagement, and then controls the rate of torque transfer during engagement. This proactive management reduces transition time and optimizes NVH performance.
Solution Approach 2:
The patent implements feedback by continuously monitoring clutch torque transfer, engine speed, and vehicle load, then using this information to adjust clutch pressure and engine control in real-time. The controller modulates clutch engagement rate based on feedback about torque transfer progress, optimizing both speed and NVH performance throughout the transition.
3Ease of operation
If the engine speed controller is optimized for no-load conditions, then idle speed control is stable, but the controller performance deteriorates when the engine is coupled to the driveline under load
Solution Approach 1:
The patent resolves this contradiction by implementing dynamic control parameter adaptation. The controller automatically adjusts its behavior based on the operating phase: using idle-speed-optimized parameters when the clutch is disengaged, and transition-optimized parameters during engagement. This dynamic switching maintains ease of operation during idle while achieving superior transition performance.
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 driveability by enabling smoother and more rapid transitions between modes, reducing NVH and allowing for faster torque transfer, thereby enhancing the transition from electric vehicle to parallel mode while maintaining or improving NVH performance.
Implementation Method 1
If an engine is producing 100Nm of torque, substantially all of this torque will be transmitted by the clutch as soon as the clutch capacity reaches 100Nm. That is, as soon as the clutch pressure is sufficiently high to permit 100Nm of torque to be transmitted by the clutch.
Implementation Method 2
The torque transmitting capacity of the clutch (or 'clutch capacity') is typically dependent on the amount of hydraulic pressure ('clutch pressure') applied to the plates of the clutch. The clutch capacity typically increases linearly with clutch pressure.
Implementation Method 3
an internal combustion engine (ICE) connected in parallel to a driveline of the vehicle
Data Source
Figure 1
Figure 2
AI summary
Embodiments of the present invention provide a controller for a hybrid electric vehicle having a first actuator and a second actuator operable to drive a driveline of the vehicle, the vehicle having releasable torque transmitting means operable releasably to couple the first actuator to the driveline, the releasable torque transmitting means being operable between a first condition in which the first actuator is substantially disconnected from the driveline and a second condition in which the first actuator is substantially connected to the driveline, the controller being operable to control the vehicle to transition between a first mode in which the releasable torque transmitting means is in the first condition and a second mode in which the releasable torque transmitting means is in the second condition, when a transition from the first mode to the second mode is required the controller being arranged to provide a control signal to the first actuator to control the speed thereof, the control signal being responsive to the speed of the first actuator and the amount of torque transfer provided by the releasable torque transmitting means.