Automatic Transmission Speed Ratio Control for Rapid Acceleration Response
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Solution Overview
Problem
Existing vehicle control systems face challenges in providing an adequate response to the operator's acceleration demands, particularly when the rate of accelerator pedal operation is high, leading to delayed engine response and potential dissatisfaction in acceleration performance.
Innovation Solution
Implementing a speed ratio selection control strategy for automatic transmissions that temporarily selects a higher gear position during rapid accelerator pedal operations and then shifts to a lower gear position, while ensuring fuel economy and minimizing shifting unease, by managing the engine's operating state and supercharger pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the automatic transmission is shifted according to the shifting map to immediately select the first speed ratio value, then the fuel economy is improved, but the response of the vehicle to accelerator pedal operation is delayed when the rate of increase is high
Solution Approach 1:
The patent applies dynamics by making the transmission speed ratio selection adaptable based on the rate of change of accelerator pedal operation. When the rate of increase is high, the system dynamically selects a second speed ratio value that keeps the engine in the second operating state, thereby improving vehicle response. When the rate of increase is low, it selects the first speed ratio value for better fuel economy. This dynamic adaptation resolves the contradiction between fuel economy and response speed.
Solution Approach 2:
The patent changes the operating state parameter of the engine based on the accelerator pedal operation rate. By switching between the first operating state (for fuel economy) and the second operating state (for response speed), the system optimizes performance according to driving conditions. This parameter change allows the system to achieve both fuel economy and responsive acceleration under different circumstances.
2Power
If the engine is switched from the second operating state to the first operating state during rapid acceleration, then the supercharge effect is achieved, but the operating response delay increases with higher accelerator pedal operation rates
Solution Approach 1:
The patent applies preliminary action by anticipating the need for power and maintaining the engine in the second operating state during rapid acceleration, rather than switching to the first operating state. This prevents the response delay that would occur during state switching and ensures immediate power delivery when the operator demands acceleration.
Solution Approach 2:
The patent applies preliminary anti-action by preventing the harmful effect of response delay through countermeasures. When the rate of increase of accelerator pedal operation is high, the system actively maintains the second operating state to counteract the potential delay that would result from switching to the first operating state, thereby ensuring timely power delivery.
3Speed
If the automatic transmission temporarily selects a higher gear position during rapid acceleration, then the vehicle response is improved, but the shifting frequency increases causing operator discomfort
Solution Approach 1:
The patent applies partial action by implementing speed ratio selection control only under specific conditions (when the rate of increase of accelerator pedal operation is higher than a predetermined value). This selective application provides the necessary acceleration response improvement without causing frequent shifting under normal driving conditions, thereby maintaining operator comfort.
Data Source
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AI summary
Disclosed is a control device for a vehicle drive device whereby an improvement in vehicle response to accelerator operation by the driver can be achieved, in a vehicle equipped with an internal combustion engine, a supercharger and an automatic transmission. Gear ratio selection control means (80), when the engine (12) is operating in NA condition, if the engine (12) comes to operate in a supercharged condition on change of ratio of the automatic transmission (16) to a first gear ratio (γ1at) in accordance with the gear-change map, performs gear ratio selection control so as to alter the method of selection of the gear ratio (γat) of the automatic transmission (16) in accordance with an increased rate (SPacc) of opening (Acc) of the accelerator. Specifically, in this gear ratio selection control, at the side where the increased rate (SPacc) of opening (Acc) of the accelerator is least, the automatic transmission (16) changes to a first gear ratio (γ1at), but, at the side where the increased rate (SPacc) of degree of opening (Acc) of the accelerator is greatest, the engine (12) is still maintained in the aforementioned NA condition and the automatic transmission (16) is changed to a second gear ratio (γ2at), which is larger than the first gear ratio (γ1at).