Hybrid Vehicle Torque Control for Smooth Upshifts
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Solution Overview
Problem
Hybrid vehicles face challenges in smoothly executing transmission upshifts due to the difference in responsiveness between engine and electric motor torques, leading to shift shocks and discomfort for occupants.
Innovation Solution
A control apparatus that includes a torque processor to temporarily decrease both engine and electric motor torques during upshifts, and adjusts the torque proportion of the electric motor relative to the drive wheel torque before the upshift, using a combination of processors and sensors to manage the powertrain operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the transmission mechanism switches between fixed gear ratios to perform upshift, then the vehicle speed range is extended, but shift shocks occur due to the difference in responsiveness between engine and electric motor torques
Solution Approach 1:
The control apparatus adjusts the torque proportion of the electric motor before the upshift occurs. Specifically, it decreases the electric motor's torque proportion relative to the drive wheel torque in advance of the gear ratio switch, preparing the torque distribution to match the upcoming transmission change and prevent abrupt torque transitions that cause shift shocks.
Solution Approach 2:
The control apparatus dynamically changes the torque proportion parameter of the electric motor based on the transmission state. By adjusting this parameter before and during the upshift, the system optimizes the torque distribution between the engine and electric motor, ensuring smooth transition through the gear change while maintaining the extended vehicle speed range benefit.
2Object-affected harmful factors
If the torque of the electric motor and engine are temporarily decreased upon execution of upshift, then shift shocks are reduced, but the power output is momentarily reduced
Solution Approach 1:
The torque proportion adjustment is performed in advance before the upshift execution, allowing the torque distribution to be optimized prior to the gear change. This preliminary adjustment ensures that when the upshift occurs, the torque transition is already minimized, reducing shift shocks without requiring a sudden power output reduction at the moment of shifting.
Solution Approach 2:
The control apparatus dynamically adjusts the torque proportion of the electric motor based on the real-time transmission state and driving conditions. This dynamic adjustment allows the system to maintain optimal power output while smoothly managing the torque transition during upshift, balancing the reduction of shift shocks with the maintenance of power delivery.
3Stability of the object's composition
If the proportion of the torque of the electric motor to the drive wheel torque is decreased before upshift, then the torque distribution is optimized for the upcoming gear change, but the electric motor utilization is reduced
Solution Approach 1:
The control apparatus dynamically adjusts the electric motor's torque proportion based on the transmission state and driving conditions. This dynamic adjustment allows the system to optimize torque distribution stability during upshift while minimizing the reduction in electric motor utilization. The adjustment is temporary and state-dependent, allowing the electric motor to return to higher utilization levels after the upshift is complete.
Solution Approach 2:
The torque proportion parameter of the electric motor is changed in response to the transmission state. This parameter change optimizes the torque distribution for the upcoming gear change, improving stability during the transition. The parameter is adjusted only when necessary (during upshift preparation), allowing the electric motor to maintain high utilization during normal operating conditions.
Data Source
AI summary
A control apparatus for a vehicle is configured to be applied to a hybrid vehicle that includes an electric motor and an engine that are coupled to a drive wheel. The control apparatus includes a transmission mechanism and a torque processor. The transmission mechanism is to be provided between the engine and the drive wheel, and configured to switch between a plurality of fixed gear ratios to perform a shift. The torque processor is configured to temporarily decrease a torque of the electric motor and a torque of the engine upon execution of an upshift of the transmission mechanism, and configured to decrease, before the execution of the upshift of the transmission mechanism, a proportion of the torque of the electric motor to a drive wheel torque of the drive wheel as compared with a recent proportion of the torque of the electric motor to the drive wheel torque.