Vehicle Oil Pump Control Using Predictive Speed Estimation
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Solution Overview
Problem
Existing oil pump control systems face issues with lag in hydraulic pressure build-up during rapid deceleration and unnecessary power consumption during moderate deceleration, as they rely on detecting pressure and speed thresholds without predictive capabilities.
Innovation Solution
An oil pump control apparatus that includes a look-ahead vehicle speed estimation section to predict potential discharge pressure lacks and a second-oil-pump control section to proactively start the sub oil pump, using look-ahead vehicle speed and deceleration rate to determine the need for hydraulic pressure supplementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sub oil pump is started up when the detected pressure or speed reaches a given threshold value, then the hydraulic pressure supply lack during rapid deceleration can be prevented, but the sub oil pump operates wastefully during moderate deceleration causing unnecessary power consumption
Solution Approach 1:
The control apparatus predicts future vehicle speed using a look-ahead vehicle speed estimation section that calculates predicted vehicle speed based on current speed and deceleration rate. The sub oil pump is started in advance when the predicted speed falls below a threshold, rather than waiting for actual speed to reach the threshold. This preliminary action ensures hydraulic pressure is available when needed while avoiding unnecessary operation during moderate deceleration events
Solution Approach 2:
The system uses feedback from detected vehicle speed and deceleration rate to continuously update the predicted vehicle speed. The control apparatus monitors actual deceleration and compares it against predicted deceleration patterns, adjusting the sub oil pump control strategy accordingly. This feedback mechanism enables the system to distinguish between rapid deceleration requiring pressure supplementation and moderate deceleration not requiring intervention
2Loss of time
If the sub oil pump is started up early to ensure hydraulic pressure during rapid deceleration, then the hydraulic pressure build-up lag is reduced, but the sub oil pump operates during moderate deceleration causing energy waste
Solution Approach 1:
The control apparatus calculates predicted vehicle speed in advance using the look-ahead estimation section. When the predicted speed indicates future threshold crossing, the sub oil pump is started beforehand, allowing hydraulic pressure to build up during the prediction window rather than during actual deceleration. This eliminates pressure build-up lag without requiring continuous early operation
Solution Approach 2:
The system dynamically adjusts the control threshold from a fixed speed/pressure value to a predicted future value based on current deceleration rate. By changing the parameter from static threshold to dynamic predicted threshold, the system optimizes the timing of sub oil pump activation to match actual hydraulic pressure needs
3Device complexity
If the control system uses fixed threshold values for pressure and speed, then the control logic is simple, but the system cannot respond appropriately to rapid deceleration causing hydraulic pressure supply lack
Solution Approach 1:
The control apparatus introduces a look-ahead vehicle speed estimation section that performs preliminary calculation of future vehicle speed based on current state and deceleration rate. This prediction mechanism is added to the control system to enable proactive sub oil pump activation before hydraulic pressure deficiency occurs, improving reliability without requiring complex real-time pressure sensing and reaction
Data Source
AI summary
In an oil pump control apparatus of a vehicle includes a first driving power source for propelling the vehicle, a first oil pump driven by the first driving power source, a second oil pump driven by a second driving power source, and a hydraulically-operated portion supplied with working oil from the first and second pumps, a look-ahead vehicle speed estimation section is provided for estimating, based on a vehicle running condition, a look-ahead vehicle speed, which may occur a given elapsed time later. Also provided is a second-oil-pump control section configured to predict, based on the look-ahead vehicle speed, whether a lack in discharge pressure produced by the first pump from a required hydraulic pressure, and further configured to start up the second pump, when it is predicted that a lack in discharge pressure of the first pump from the required hydraulic pressure occurs.