Hydraulic Control Method for Automatic Vehicle Driving
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Solution Overview
Problem
In vehicles with automatic driving modes, conventional hydraulic pressure control methods require high operation pressures due to sudden driver operations, leading to increased engine load, reduced fuel efficiency, and noise, as they do not utilize future information from driving plans.
Innovation Solution
A hydraulic pressure control system that sets a margin value for operation pressure based on a predetermined driving plan, allowing for reduced hydraulic pressure and improved fuel efficiency and noise reduction by using future information on engine torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sufficiently large operation pressure is generated in advance to cope with sudden driver operations, then the responsiveness of hydraulic pressure control is improved, but the engine load increases and fuel efficiency deteriorates
Solution Approach 1:
The system performs preliminary action by predicting future hydraulic pressure requirements based on the driving plan before they are actually needed. The operation pressure is adjusted in advance according to predicted accelerator operations or brake releases, rather than reacting to sudden driver inputs. This allows the hydraulic system to be ready when needed while avoiding continuous high-pressure generation, thus improving responsiveness without permanently increasing engine load.
Solution Approach 2:
The operation pressure is made dynamic rather than static. Instead of maintaining a constantly high operation pressure, the system continuously adjusts the operation pressure based on real-time comparison between predicted requirements from the driving plan and actual vehicle state. This dynamic adjustment ensures adequate pressure is available when needed while minimizing unnecessary high-pressure generation during normal operation, resolving the contradiction between responsiveness and fuel efficiency.
2Reliability
If a sufficiently large operation pressure is generated in advance to cope with sudden driver operations, then the reliability of hydraulic pressure control is improved, but the noise increases
Solution Approach 1:
The system uses preliminary action by predicting future hydraulic pressure needs from the driving plan and adjusting operation pressure in advance. This ensures reliable hydraulic pressure control is ready when sudden driver operations occur, while avoiding continuous high-pressure generation that would produce unnecessary noise. The prediction mechanism ensures reliability is maintained without the harmful side effect of constant noise-generating high-pressure operation.
Solution Approach 2:
The operation pressure is dynamically adjusted based on predicted requirements rather than maintained at a constant high level. This dynamic control ensures reliability by having pressure ready when needed (as predicted from driving plan) while minimizing noise by avoiding unnecessary high-pressure generation during periods when lower pressure suffices.
3Use of energy by moving object
If the margin value of operation pressure is reduced to improve fuel efficiency, then the fuel efficiency is improved, but the ability to cope with sudden driver operations is compromised
Solution Approach 1:
The system performs preliminary action by predicting future hydraulic pressure requirements from the driving plan before they are actually needed. This allows the system to reduce the margin value (improving fuel efficiency) while still maintaining the ability to cope with sudden driver operations, because the prediction mechanism proactively adjusts pressure in advance based on anticipated accelerator operations or brake releases, eliminating the need for large safety margins.
Solution Approach 2:
The system uses feedback by continuously comparing the predicted hydraulic pressure requirements from the driving plan with the actual vehicle state and operation pressure. This feedback loop ensures that even with a reduced margin value, the system can detect when actual requirements diverge from predictions and adjust accordingly, maintaining reliability while improving fuel efficiency through the reduced baseline margin.
4Device complexity
If conventional hydraulic pressure control is applied to automatic driving mode without using future information, then the control method is simple, but the fuel efficiency deteriorates due to unnecessary high operation pressure
Solution Approach 1:
The system applies preliminary action by utilizing future information from the driving plan to predict hydraulic pressure requirements before they are needed. This allows the system to optimize operation pressure in advance, reducing unnecessary high-pressure generation and improving fuel efficiency. The complexity increase is minimal, as it primarily involves accessing existing driving plan data and comparing predictions with actual state, while the fuel efficiency benefit is significant.
Solution Approach 2:
The system uses feedback by comparing predicted hydraulic pressure requirements from the driving plan with actual vehicle operation. This feedback mechanism enables the system to adjust operation pressure optimally, avoiding unnecessary high pressure and improving fuel efficiency. The feedback approach adds only moderate complexity by utilizing existing sensors and driving plan data, while delivering substantial fuel efficiency improvements.
Data Source
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AI summary
The present invention improves fuel efficiency of a vehicle and decreases a noise, by decreasing a margin value of a hydraulic pressure supplied to a hydraulic pressure control target and decreasing the hydraulic pressure supplied to the hydraulic pressure control target, when the vehicle is driven automatically. In a hydraulic pressure control device 1 for a vehicle that controls a line pressure or an operation pressure (hydraulic pressure) supplied to a clutch 40 or a transmission 41 (hydraulic pressure control target) provided in the vehicle, the hydraulic pressure control device 1 includes an operation pressure control unit 10 (hydraulic pressure setting device) that sets margin values α1 and α2 of the operation pressure (line pressure) supplied to hydraulic circuits 31 and 31 of the clutch 40 or the transmission 41, on the basis of a predetermined driving plan (refer to FIG. 2) in the case of driving the vehicle automatically.