Variable Camshaft Phaser Using Torque-Driven Pressure Pulsations

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Solution Overview

Problem

Existing variable camshaft phasers face a trade-off between optimizing performance and minimizing parasitic power losses caused by engine oil pumps, as larger pumps enhance performance but compromise fuel economy.

Innovation Solution

A phaser design that utilizes internal oil pressure fluctuations caused by camshaft torque reversals to control fluid flow between pockets, allowing for enhanced performance without increasing engine oil pump capacity, through a control ring system that adjusts the timing of pocket communication based on pressure differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the capacity of the engine oil pump is increased to optimize phaser performance, then the phaser control performance is improved, but the parasitic power losses increase and fuel economy deteriorates

Engineering Contradiction:

Improvephaser control performanceVSAvoidparasitic power losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention utilizes periodic pressure fluctuations generated by camshaft torque reversals to drive fluid flow between pockets. The control valve opens and closes periodically to allow pressure differential-driven fluid transfer, converting the harmful periodic torque reversals into useful phasing control without requiring continuous high-capacity pumping

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The invention converts the harmful parasitic torque reversals of the camshaft into beneficial pressure differentials for phaser control. The torque reversals create pressure fluctuations that are normally wasted energy, but this patent uses them to drive fluid flow and control rotor position, thereby eliminating the need for a larger oil pump

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If a larger engine oil pump is used to enhance phaser performance, then the fluid supply to control valves is improved, but the fuel economy gains are offset by increased parasitic losses

Engineering Contradiction:

Improvephaser response capabilityVSAvoidfuel economy

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The system uses its own internal pressure fluctuations to drive the fluid flow needed for phaser control. The torque reversals of the camshaft itself generate the pressure differentials required to move fluid between pockets, making the system self-sufficient and eliminating the need for an externally powered high-capacity pump

Inventive Principle:

Principle #25Self-service

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 design improves phaser performance by leveraging inherent pressure pulsations, reducing the need for a larger oil pump and maintaining fuel economy gains, by modulating fluid flow using pressure differences and a control ring mechanism.

Implementation Method 1

the vane divides the recess into a first pocket and a second pocket, the pockets being able to receive fluids under pressure, wherein the introduction of a fluid into the first pocket causes the rotor to move in a first rotational direction relative to the stator, and in that the introduction of a fluid in the second pocket causes the rotor to move in the opposite rotational direction relative to the stator

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

control means for controlling the fluid pressure on opposite sides of the vanes to thereby control the angular position of the rotor with respect to the stator; wherein the control means comprise means for selectively adjusting the timing of the opening and closing of a connection between the first and second pockets in order to allow fluid to flow between the pockets using the pressure difference of the fluid in each of the pockets

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentUS7523728B2Phaser for controlling the timing between a camshaft and a timing gear

Publication Date: 2009.04.28 DELPHI INT OPERATIONS LUXEMBOURG SARL

AI summary

A phaser for controlling the timing between a camshaft and a timing gear having a rotor with at least one vane and a stator with at least one recess the phaser allowing limited rotational movement of the rotor with respect to the stator. The vane divides the recess into first and second pockets, wherein the introduction of a fluid into the first pocket causes the rotor to move in a first rotational direction relative to the stator, and in that the introduction of a fluid in the second pocket causes the rotor to move in the opposite rotational direction. A control ring is provided for selectively opening and closing a fluid connection between the pockets to allow fluid to flow between the pockets using the pressure difference of the fluid in each of the pockets to transport the fluid from the one to the other pocket.