Dynamic Fill Torque Control for Hybrid Axle Response Delay
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Solution Overview
Problem
Vehicles with different propulsion systems, such as internal combustion engines and electric motors, experience delayed torque response due to factors like ignition timing and throttle valve parameters, leading to compromised drivability and responsiveness.
Innovation Solution
A system with a controller that estimates the torque applied to a primary axle, calculates a dynamic fill torque based on the difference between the requested and actual torque, and applies it to a secondary axle using an electric motor to compensate for delays, enhancing drivability and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a combustion engine is used to drive the primary axle, then the vehicle can achieve sustained power output, but the torque response is delayed due to ignition timing and throttle valve parameters
Solution Approach 1:
The controller calculates a dynamic fill torque in advance based on the difference between the requested torque and the estimated torque from the combustion engine. This preliminary calculation allows the electric motor to be pre-positioned to deliver compensating torque immediately when needed, rather than waiting for the combustion engine's delayed response to be detected and processed.
Solution Approach 2:
The electric motor acts as an intermediary torque source between the driver's torque request and the combustion engine's actual torque delivery. When the combustion engine cannot meet the requested torque immediately, the electric motor provides the difference, mediating the gap between demand and supply without requiring mechanical coupling between the two propulsion systems.
2Speed
If the torque request is increased to improve responsiveness, then the vehicle acceleration improves, but the combustion engine's delayed response causes drivability compromises
Solution Approach 1:
The system merges the torque outputs of two mechanically independent propulsion systems - the combustion engine and the electric motor - to achieve a combined torque delivery that is both responsive and smooth. The controller coordinates both systems so that their torque contributions are combined at the wheel level, providing immediate response when needed while maintaining the combustion engine's sustained power capability.
Solution Approach 2:
The controller dynamically changes the torque parameter distribution between the two propulsion systems based on real-time conditions. When rapid acceleration is requested, the controller increases the electric motor's torque contribution to compensate for the combustion engine's delay. The system monitors various parameters including state of charge, lateral acceleration, and vehicle operating mode to adjust the torque split optimally.
3Loss of time
If a second propulsion system is added to compensate for torque delays, then responsiveness improves, but the system complexity increases
Solution Approach 1:
The vehicle propulsion system is segmented into two mechanically independent parts: the primary axle driven by the combustion engine and the secondary axle driven by the electric motor. This segmentation allows each system to operate independently with its own control strategy, simplifying the overall control architecture compared to a mechanically coupled system. The controller manages each axle's torque contribution separately based on the calculated dynamic fill torque needs.
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
The system improves drivability and responsiveness by compensating for delayed torque delivery in vehicles with multiple propulsion systems, providing a smoother and more immediate torque response without re-calibrating existing systems or adding complex hardware.
Implementation Method 1
the second propulsion system including an electric motor configured to drive a secondary axle
Data Source
AI summary
A system for controlling torque in a vehicle includes first and second propulsion systems, the first propulsion system including a combustion engine configured to drive a primary axle, the second propulsion system including an electric motor configured to drive a secondary axle, where the first propulsion system and the primary axle are mechanically independent from the second propulsion system and the secondary axle. A controller is configured to perform a method that includes estimating a first amount of torque applied to the primary axle in response to a primary axle torque request, determining a difference between the first amount of torque applied to the primary axle and the primary axle torque request, and based on the difference exceeding a selected threshold, calculating a dynamic fill torque and applying a second amount of torque to the secondary axle via the electric motor according to the calculated dynamic fill torque.