Dynamic Speed Ratio Control for Centrifugal Supercharger Torque
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Solution Overview
Problem
In vehicle drive systems with internal combustion engines and centrifugal superchargers combined with stepped transmissions, engine speed decreases during gear upshift operations, leading to reduced supercharging pressure and torque, causing discomfort due to inconsistent vehicle acceleration.
Innovation Solution
A control device that dynamically adjusts the speed ratio of the rotary drive shaft during upshift operations to maintain or increase the centrifugal supercharger speed, ensuring the supercharging pressure remains at a target level by raising the speed ratio initially and then reducing it to the final value, thereby stabilizing engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gear stage of the stepped transmission is shifted up, then the vehicle speed ratio increases, but the engine speed decreases causing the centrifugal supercharger speed to decline and actual supercharging pressure to drop
Solution Approach 1:
The patent applies dynamics by making the speed ratio of the rotary drive shaft dynamically adjustable during upshift operations. The control device changes the speed ratio in real-time based on the operational phase (initial phase vs. subsequent phase) to maintain centrifugal supercharger speed and supercharging pressure, transforming a static transmission system into a dynamic one that adapts to changing conditions.
Solution Approach 2:
The patent changes the speed ratio parameter of the rotary drive shaft during upshift operations. By adjusting this parameter - increasing it during the initial phase and then reducing it in the subsequent phase - the system maintains the centrifugal supercharger speed and supercharging pressure despite the overall engine speed decrease associated with gear upshifting.
2Productivity
If the engine speed decreases with upshift operation, then the gear stage shifts up for better fuel efficiency, but the speed of the centrifugal supercharger declines causing torque reduction and vehicle acceleration inconsistency
Solution Approach 1:
The system dynamically adjusts the speed ratio during upshift operations to maintain engine torque and vehicle acceleration consistency. By making real-time adjustments to the rotary drive shaft speed ratio, the system prevents the torque drop that would otherwise occur when engine speed decreases during gear upshifting, ensuring smooth power delivery while maintaining fuel efficiency benefits.
Solution Approach 2:
The control device uses feedback from the upshift operation status to adjust the speed ratio. By detecting the upshift event and the resulting engine speed changes, the system applies appropriate speed ratio adjustments to maintain supercharging pressure and torque output, creating a closed-loop control that responds to actual operating conditions.
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 effectively suppresses the decrease in engine torque and vehicle acceleration differences during gear shifts, enhancing driving comfort by maintaining consistent supercharging pressure and airflow rates.
Implementation Method 1
The centrifugal supercharger pumps out the air, taken from a central suction port, toward a peripheral protruding port with centrifugal force. The air in the centrifugal supercharger is subjected to outward centrifugal force and inward pressure
Data Source
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AI summary
A mechanical supercharging system includes a stepped transmission (46) that connects a crankshaft (20) of an internal combustion engine (10) with driving wheels, a centrifugal supercharger (18) including a rotary drive shaft (22) connected to the crankshaft (20), a variable speed ratio device (28) that changes a speed ratio of the rotary drive shaft (22) to the crankshaft (20), the variable speed ratio device (28) being provided between the crankshaft (20) and the rotary drive shaft (22); and a control device (60) configured to control the speed ratio. The control device (60) increases the speed ratio during the upshift operation more than the speed ratio before start of the upshift operation.