Variable Capacity Oil Pump Duty Cycle Control

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Solution Overview

Problem

Existing variable-capacity oil pumps face challenges in reducing electric power consumption and achieving enhanced responsiveness, especially when using oil of low viscosity, due to high electric power consumption and the need for high hydraulic pressure to control discharge amounts effectively.

Innovation Solution

The oil pump device incorporates a pump body with a pump casing that swings in response to hydraulic pressures, supported by return springs and an electrically operated control valve, which balances the urging forces of the springs to maintain the pump casing at an intermediate position, reducing electric power consumption and allowing for precise control of discharge amounts without high hydraulic pressure requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If excitation current is constantly supplied to the electrically operated control valve in low load operation mode, then the discharge amount of the oil pump can be controlled to decrease, but electric power consumption increases

Engineering Contradiction:

Improvedischarge amount controlVSAvoidelectric power consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using a duty cycle control method where the electrically operated control valve is energized intermittently rather than continuously. The controller supplies excitation current in a pulsed manner with a duty cycle between 5% and 50%, allowing the pump casing to swing toward the decrease side while reducing average power consumption significantly compared to constant energization.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent employs dynamics by making the control system adaptive to engine operating conditions. The controller adjusts the duty cycle of the control valve based on real-time engine operating state, enabling the oil pump to dynamically adjust its discharge amount to match actual engine needs while optimizing power consumption across different operating modes.

Inventive Principle:

Principle #15Dynamics

2Speed

If high hydraulic pressure is supplied to the decrease-side control pressure chamber to swing the pump casing toward the decrease side, then the discharge amount decreases with enhanced responsiveness, but the required hydraulic pressure becomes excessively high

Engineering Contradiction:

Improveresponsiveness of pump casing swingVSAvoidhydraulic pressure

Core Design Contradiction:

SpeedVSStress or pressure

Solution Approach 1:

The patent applies dynamics by using a feedback control mechanism where the controller monitors the actual discharge amount and adjusts the duty cycle of the control valve accordingly. This dynamic adjustment allows the system to achieve the desired pump casing swing and discharge amount control without requiring excessively high hydraulic pressure, as the system adapts to maintain optimal pressure levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback control to regulate the hydraulic pressure applied to the decrease-side control pressure chamber. The controller receives information about engine operating state and discharge amount, then adjusts the control valve duty cycle to maintain appropriate pressure levels, preventing the need for excessively high pressure while ensuring responsive pump casing swing.

Inventive Principle:

Principle #23Feedback

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 configuration maintains an intermediate discharge amount, reducing electric power consumption and enhancing responsiveness, even with low viscosity oil, by balancing spring forces and adjusting hydraulic pressures, thus improving fuel economy and operational efficiency.

Implementation Method 1

a decrease-side return spring disposed in the decrease-side control pressure chamber in a compressed state between the pump body and the pump casing, and configured to constantly urge the pump casing in the discharge amount decrease direction; and an increase-side return spring disposed in the increase-side control pressure chamber in a compressed state between the pump body and the pump casing, and configured to constantly urge the pump casing in the discharge amount increase direction

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

an electrically operated control valve which changes a discharge amount of oil from the oil pump

Methodology Applied

Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentUS10197055B2Oil pump device

Publication Date: 2019.02.05 MAZDA MOTOR CORP

AI summary

An oil pump device includes an oil pump (10) and an electrically operated control valve (20). The valve adjusts hydraulic pressures to be applied to a decrease-side control pressure chamber (15A) for causing a pump casing (14) to swing in the discharge amount decrease direction and an increase-side control pressure chamber (15B) for causing the pump casing to swing in the discharge amount increase direction so as to hold the pump casing at a predetermined approximately intermediate position between the maximum swing position in the discharge amount decrease direction and the maximum swing position in the discharge amount increase direction by balancing the urging forces of a decrease-side return spring (16) for urging the pump casing in the discharge amount decrease direction and an increase-side return spring (17) for urging the pump casing in the discharge amount increase direction when supply of current to the valve is stopped.