Engine Piston Cooling Nozzle With Adjustable Plunger

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Solution Overview

Problem

Conventional cooling jet nozzles fail to provide adequate cooling to engine pistons at high engine speeds due to insufficient oil jet speed, which is not proportionally increased with engine speed, making it difficult to efficiently cool pistons over a range of engine speeds.

Innovation Solution

A cooling jet nozzle with a varying internal cross-sectional pathway and an axially moveable plunger that adjusts the jet speed and pressure by changing its position in response to the pressure of the cooling feedstream, allowing for efficient cooling over a range of engine speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional fixed-orifice jet nozzles are used, then the structure is simple, but the jet speed is insufficient at high engine speeds to provide adequate piston cooling

Engineering Contradiction:
Improvejet speedVSAvoidadaptability to varying engine speeds
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The nozzle employs a moveable plunger that dynamically adjusts the orifice area in response to changing oil pressure conditions. As engine speed increases and oil pressure rises, the plunger moves axially to reduce the effective orifice area, thereby maintaining optimal jet speed across varying operating conditions rather than using a fixed geometry nozzle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The nozzle changes the geometric parameter of the orifice area through plunger movement. By varying the cross-sectional area of the cooling jet outlet based on operating conditions (oil pressure), the system optimizes jet velocity to match piston cooling requirements across different engine speeds.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If oil flow rate is increased at high engine speeds, then more cooling fluid is available, but the jet speed is not proportionally increased making cooling less effective

Engineering Contradiction:
Improveoil flow rateVSAvoidjet speed
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The nozzle decouples the relationship between flow rate and jet speed by dynamically adjusting the orifice area. When oil flow rate increases at high engine speeds, the plunger responds to the increased oil pressure by reducing the orifice area, which concentrates the higher flow into a smaller area to maintain or increase jet velocity, ensuring effective piston cooling.

Inventive Principle:
Principle #35Parameter changes

3Speed

If a plunger mechanism is added to adjust jet speed, then jet speed and pressure can be optimized, but the device complexity increases

Engineering Contradiction:
Improvejet speedVSAvoidnozzle structure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The plunger mechanism is designed to be self-actuating, utilizing the oil pressure itself as the actuating force. The increased oil pressure at high engine speeds automatically pushes the plunger to adjust the orifice area, eliminating the need for external actuators, control systems, or additional energy input, thereby minimizing added complexity while achieving the desired speed optimization.

Inventive Principle:
Principle #25Self-service

4Reliability

If the nozzle is designed to provide adequate cooling at high engine speeds, then piston cooling effectiveness is improved, but the nozzle structure becomes more complex

Engineering Contradiction:
Improvecooling effectivenessVSAvoidnozzle structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The nozzle transitions from a static fixed-orifice design to a dynamic adjustable-orifice design. The moveable plunger allows the nozzle to adapt its geometry in real-time based on operating conditions, ensuring reliable piston cooling across the entire engine speed range without requiring multiple nozzles or complex external control systems.

Inventive Principle:
Principle #15Dynamics

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 nozzle provides a cooling jet with the necessary speed and pressure to efficiently cool engine pistons across varying engine speeds, ensuring improved durability and efficiency by adjusting its internal dimensions to match changing engine conditions.

Implementation Method 1

the plunger is axially moveable within the pathway in response to the pressure of the cooling feedstream

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

Oil jets are typically sprayed into channels on the underside of the pistons during operation of the engine in order to cool the pistons

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3649333B1A nozzle for cooling engine pistons
Publication Date: 2023.06.14 VOLVO TRUCK CORP
  • EP3649333B1 patent drawingFigure 1
  • EP3649333B1 patent drawingFigure 2~3
  • EP3649333B1 patent drawingFigure 4~5

AI summary

The present invention relates to a cooling jet nozzle (10) for an engine piston. The nozzle (10) comprises a cooling stream pathway (14), in which the internal cross-sectional dimensions of the pathway vary along the length of the pathway; and a plunger (28) located within the cooling stream pathway to impinge a cooling feedstream received within the pathway to provide a cooling jet. The plunger (28) is axially moveable within the pathway to adjust the internal cross-sectional dimensions of the cooling jet.