Engine Lubrication System Hydraulic Pressure Control
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Solution Overview
Problem
Existing engine lubrication systems face challenges in securing sufficient hydraulic pressure for piston cooling, especially at low engine speeds and high oil temperatures, leading to inadequate cooling efficiency and potential carbonization of lubrication oil.
Innovation Solution
An engine lubrication system that includes an automatic transmission and an oil pump driven by the engine, with a control mechanism that adjusts the gear stage of the automatic transmission to increase engine speed and thereby enhance the hydraulic pressure of the oil pump, ensuring adequate hydraulic pressure for piston cooling through hydraulic pressure state determination and oil temperature detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the requested hydraulic pressure is set to be higher than the actuation pressure of the oil jet mechanism to secure piston cooling effect, then the piston cooling efficiency is improved, but the oil pump cannot generate the required hydraulic pressure at low engine speeds
Solution Approach 1:
The patent applies dynamics by making the target hydraulic pressure variable rather than fixed. The control device dynamically adjusts the target hydraulic pressure based on detected engine operating conditions (engine speed, load, oil temperature). At low engine speeds, the target pressure is set lower to match pump capability, while at high speeds it increases to ensure adequate piston cooling, thus resolving the contradiction between cooling effectiveness and pump generation capability.
Solution Approach 2:
The patent changes the parameter of hydraulic pressure from a constant high value to a variable value that adapts to engine operating conditions. By modifying the target hydraulic pressure parameter according to engine speed and load conditions, the system ensures the oil pump can generate the required pressure while maintaining sufficient piston cooling effect across different operating ranges.
2Speed
If the hydraulic pressure is excessively high, then the flow speed of lubrication oil increases, but the lubrication oil spreads in the form of a fine mist reducing cooling efficiency
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the target hydraulic pressure based on engine operating conditions. By lowering the hydraulic pressure at conditions where it would cause excessive atomization, and raising it when adequate pressure is needed for cooling, the system optimizes the balance between oil flow speed and cooling effectiveness.
3Stress or pressure
If the hydraulic pressure is excessively low, then the flow speed of lubrication oil is reduced, but the amount of injection oil required to cool the piston cannot be sprayed
Solution Approach 1:
The patent dynamically changes the target hydraulic pressure parameter according to engine operating conditions. By raising the target pressure when adequate injection amount is needed, and adjusting it based on pump generation capability at different engine speeds, the system ensures sufficient injection oil quantity is delivered to the piston for effective cooling.
4Productivity
If the limit hydraulic pressure of the oil pump is reduced at low engine speeds, then the discharge volume capable of generating target hydraulic pressure is set, but the limit hydraulic pressure falls below the actuation pressure of the oil jet mechanism
Solution Approach 1:
The patent resolves this contradiction by making the target hydraulic pressure a variable parameter that adapts to engine speed. Instead of maintaining a fixed high target pressure that exceeds pump capability at low speeds, the system lowers the target pressure to match what the pump can generate, ensuring both the discharge volume requirement and the minimum pressure threshold are satisfied.
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
The system effectively secures the required injection oil amount for piston cooling across various operating conditions, minimizing specification changes and maintaining the reliability of the automatic transmission by actively adjusting engine speed and gear shifts.
Implementation Method 1
an oil jet mechanism that injects oil fed or pressure-fed by this oil pump to a piston
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The engine lubrication system includes: an automatic transmission; an oil pump; oil jets, each of which injects oil pressure-fed from this oil pump to a piston; an ECU that can set a target hydraulic pressure of the oil injected from each of these oil jets according to an operation state of an engine; and a hydraulic pressure sensor that can detect a hydraulic pressure of the oil injected from each of these oil jets. The ECU has a hydraulic pressure state determination section that can determine a hydraulic pressure state of the oil injected from each of the oil jets. When a period in which a deviation between an actual hydraulic pressure that is detected by the hydraulic pressure sensor and the target hydraulic pressure is equal to or larger than a threshold value continues for a specified time, a hydraulic pressure state determination section determines a hydraulic pressure insufficient state, and a gear stage of the automatic transmission is shifted to a lower gear stage.