Vehicle Shift Assist Torque Compensation Control
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Solution Overview
Problem
Existing control devices for vehicle drive systems with rotating electrical machines and speed change mechanisms often fail to achieve sufficient torque output, leading to inadequate downshift control and increased shift shock, especially when the rotating electrical machine cannot provide the required torque.
Innovation Solution
A control device that includes a shift assist control section to increase the rotational speed of the input-side rotating member by enhancing the torque of the rotating electrical machine, a possibility determining section to assess the machine's torque output capability, and a torque compensating section to use either the internal combustion engine or shift engagement device torque to compensate for any shortfall, depending on the selected shift mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only the rotating electrical machine is used to increase the rotational speed of the input-side rotating member during downshift, then the control system remains simple, but sufficient torque may not be output depending on the situation, leading to inadequate shift control and increased shift shock
Solution Approach 1:
The patent combines multiple torque sources (rotating electrical machine, internal combustion engine, and shift engagement device) into a unified torque compensation system. When the rotating electrical machine alone cannot provide sufficient torque for downshift, the system merges additional torque from the engine or shift engagement device to ensure reliable shift control and minimize shift shock.
2Speed
If the rotating electrical machine outputs maximum torque for shift assist, then responsive downshift is achieved, but fuel efficiency deteriorates due to excessive energy consumption
Solution Approach 1:
The patent dynamically adjusts the torque output strategy based on real-time conditions. The control device determines whether the rotating electrical machine can output the required input torque according to a predetermined target rotational speed change rate, and selectively engages additional torque sources only when necessary, thereby optimizing the balance between downshift responsiveness and fuel efficiency.
3Power
If multiple torque sources are used to compensate for torque shortfall, then sufficient torque is guaranteed for responsive downshift, but the control system complexity increases
Solution Approach 1:
The control device incorporates self-diagnostic and self-adjustment capabilities. It automatically determines whether the rotating electrical machine can meet the torque requirements and selectively activates additional torque sources (engine or shift engagement device) only when needed, allowing the system to guarantee sufficient torque while minimizing unnecessary control complexity.
Data Source
AI summary
A control device for a vehicle. A shift assist control section executes shift assist control of increasing a rotational speed of an input-side rotating member of the speed change mechanism. A possibility determining section that determines whether or not the rotating electrical machine can output required input torque. A mode selecting section that selects one shift mode from a first shift mode and a second shift mode that is different from the first shift mode in at least one of a condition for starting the downshift and processing. A torque compensating section that, if it is determined that the rotating electrical machine cannot output the required input torque, compensates for a shortfall in the required input torque in the shift assist control by using at least one of output torque of the internal combustion engine and torque that is transferred by the shift engagement device according to the shift mode.