Engine Restart Strategy Using Transmission State Classification
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Solution Overview
Problem
Existing engine start/stop systems face challenges in balancing seamless and fast engine restarts, particularly in minimizing noise, vibration, and harshness while ensuring quick torque delivery to the wheels, as they often fail to differentiate between driver-induced and system-induced restart conditions.
Innovation Solution
The system classifies restart conditions as either no wheel torque or wheel torque conditions, adjusting the transmission state accordingly to optimize noise, vibration, and harshness (NVH) versus time to torque delivery, using a dual mode strategy that sets the transmission to engaged, active neutral, or full neutral states based on the restart type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the transmission is set to engaged state for fast torque delivery, then engine restart time is reduced, but noise, vibration, and harshness increase
Solution Approach 1:
The patent segments the engine restart process into two distinct modes: wheel torque restart conditions (where transmission is set to engaged state for fast torque delivery) and no wheel torque restart conditions (where transmission is set to neutral state for reduced NVH). This segmentation allows the system to optimize for different priorities depending on the specific restart scenario.
Solution Approach 2:
The transmission state is dynamically adjusted based on the classified restart condition. The control system transitions the transmission between engaged and neutral states depending on whether wheel torque is needed, making the system adaptable rather than static.
2Object-affected harmful factors
If the transmission is set to neutral state to minimize noise, then NVH is reduced, but torque delivery time increases
Solution Approach 1:
The patent applies different transmission states (engaged vs. neutral) to different restart condition categories. Instead of using a single transmission state for all restarts, the system applies the appropriate transmission state locally to each specific restart scenario based on its characteristics.
Solution Approach 2:
The control system changes the transmission state parameter based on the restart condition classification. When wheel torque is needed, the transmission is set to engaged state; when it is not needed, the transmission is set to neutral state, thereby optimizing the balance between NVH and torque delivery time.
3Device complexity
If a single restart strategy is used for all conditions, then system complexity is reduced, but performance optimization is limited
Solution Approach 1:
The control system performs preliminary classification of the restart condition before initiating the restart process. By determining whether the restart is wheel torque or no wheel torque type in advance, the system can pre-set the appropriate transmission state, optimizing performance without adding significant complexity.
Solution Approach 2:
The system uses feedback from sensors to detect operator actions and determine the appropriate restart condition classification. This feedback mechanism allows the control system to adaptively select the optimal restart strategy based on real-time vehicle and driver state information.
Data Source
AI summary
A method of controlling a vehicle, where the vehicle includes an internal combustion engine and a transmission having a neutral state and an engaged state, includes setting the state of the transmission. The state of the transmission is set as the neutral state or the engaged state based on a restart condition, where the restart condition is one of: (i) a no wheel torque restart condition, and (ii) a wheel torque restart condition. The method additionally includes starting the engine.