Piston Cooling via Intermittent Lubricant Injection

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Solution Overview

Problem

Existing methods for cooling and lubricating pistons in internal combustion engines are inefficient, leading to high fuel consumption and environmental impact, as they often rely on continuous lubricant supply regardless of engine operating conditions.

Innovation Solution

A method and device that introduce an interruption phase during the multi-stroke cycle of the engine, temporarily halting lubricant supply to the piston during upward movement, particularly during the compression or exhaust phases, using an electrically controllable solenoid valve or rotating rotary valve to reduce lubricant consumption and pump power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If continuous lubricant supply is used to cool the piston, then piston cooling effectiveness is maintained, but lubricant consumption increases and fuel efficiency deteriorates

Engineering Contradiction:
Improvepiston temperatureVSAvoidlubricant consumption
Core Design Contradiction:
TemperatureVSLoss of substance

Solution Approach 1:

The patent implements periodic interruption of lubricant supply to the piston by controlling the switching valve to close during specific crankshaft rotation intervals (interruption phases). This periodic action reduces lubricant consumption while maintaining cooling effectiveness by timing the interruptions during upward piston movement when cooling demand is lower.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts lubricant supply based on real-time engine operating conditions (load, speed, temperature) by using the control unit to calculate optimal switching valve actuation timing. The interruption phases are adaptively determined according to piston position and engine state, making the cooling system responsive to varying operational requirements.

Inventive Principle:
Principle #15Dynamics

2Loss of substance

If lubricant supply is interrupted during upward piston movement, then lubricant consumption is reduced, but cooling effectiveness during that phase may be compromised

Engineering Contradiction:
Improvelubricant consumptionVSAvoidpiston cooling reliability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The control system calculates and prepares the switching valve actuation timing in advance based on predicted engine operating conditions and piston position. The interruption phases are predetermined based on crankshaft angle and engine state, ensuring that lubricant supply is interrupted only when piston cooling demand is naturally lower, thus maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit continuously monitors engine operating parameters (load, speed, temperature) and uses this feedback to dynamically adjust the switching valve control strategy. This feedback mechanism ensures that interruption phases are optimized in real-time to maintain adequate piston cooling while maximizing lubricant savings under varying operating conditions.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If switching valve control is implemented to reduce lubricant consumption, then fuel efficiency improves, but device complexity increases

Engineering Contradiction:
Improvefuel consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control unit integrates multiple functions: it monitors engine operating conditions, calculates optimal switching valve actuation timing, controls the switching valve, and adapts to varying engine states. This multi-functionality consolidates control logic into a single existing engine control unit, avoiding the need for separate dedicated control hardware and minimizing additional system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control system utilizes existing engine operating data (load, speed, temperature sensors already present in the engine) to autonomously determine optimal lubricant supply timing. The system self-regulates based on its own operational state without requiring external control inputs, reducing the complexity of the control architecture.

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 approach significantly reduces lubricant consumption, decreases the size and power requirements of the lubricant pump, and lowers overall fuel consumption while minimizing the impact on piston cooling, especially during upward movements where the cooling effect is less effective.

Implementation Method 1

The switching valve (6) is an electrically controllable solenoid valve which is open or closed according to the actuation signal from the control unit (7)

Methodology Applied
Scientific EffectElectromagnetic force: Solenoid

Implementation Method 2

lubricant is supplied to the piston (2) via a nozzle device (5), in particular by injection

Methodology Applied
Scientific EffectFluid spray: Fluid Spray

Data Source

PatentEP3453855B1Method and device for cooling and/or lubrication of a piston and/or a path of travel of a cylinder in a reciprocating piston engine
Publication Date: 2020.04.01 MAN TRUCK & BUS SE
  • EP3453855B1 patent drawingFigure 1
  • EP3453855B1 patent drawingFigure 2
  • EP3453855B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device for cooling and/or lubricating a piston and/or the cylinder bore of a reciprocating internal combustion engine, wherein lubricant is supplied to the piston via a nozzle device, in particular by injection. The invention further relates to a motor vehicle, in particular a commercial vehicle, with such a device. According to the invention, at least one interruption phase (P) is provided during the multi-stroke, in particular the four-stroke, operating cycle of the reciprocating internal combustion engine, during which the supply of lubricant to the piston via the nozzle device (5) is interrupted.