Compressed Air Engine Starter with Pulsed Engagement

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Solution Overview

Problem

Internal combustion engines using compressed air starting systems face challenges in overcoming breakaway torque, which can be critical due to residual water in the cylinder chamber, leading to potential damage to the connecting rod during high-speed rotation after initial cranking.

Innovation Solution

A method involving a first starting sequence where the starter is engaged with pulsed compressed air and the decompression valve is opened, followed by a second sequence where the decompression valve is closed and the starter is loaded with constant compressed air, using a system controller to manage the compressed air paths via engagement and starting valves, and employing PWM signals to control the transition smoothly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the starter is engaged with compressed air to overcome breakaway torque, then the internal combustion engine can be started, but the high-speed rotation for a short time can cause damage to the connecting rod due to residual water in the cylinder chamber

Engineering Contradiction:
Improveengine starting reliabilityVSAvoidconnecting rod damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies periodic action by using pulsed compressed air to engage the starter during the first starting sequence. The compressed air is supplied in pulses rather than continuously, which allows the starter to engage gently and avoid sudden high-speed rotation. This periodic supply of compressed air enables the starter to overcome breakaway torque while preventing the harmful high-speed rotation that could damage the connecting rod due to residual water in the cylinder chamber.

Inventive Principle:
Principle #19Periodic action

2Productivity

If the starter is engaged using compressed air to initiate cranking, then the engine can begin to rotate, but the transition from stationary to rotating can be harsh and cause damage

Engineering Contradiction:
Improveengine starting speedVSAvoidconnecting rod strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies dynamics by making the compressed air supply adaptive rather than static. During the first starting sequence, the compressed air is supplied in pulses with adjustable duration and interval, allowing the system to dynamically adjust the engagement force. This dynamic control enables the starter to engage smoothly and achieve the desired starting speed without causing harsh transitions or damage to the connecting rod.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of compressed air supply from continuous to pulsed during the first starting sequence. By controlling the pulse duration and interval, the system optimizes the engagement force to achieve gentle starting. This parameter change allows the engine to reach the target speed without experiencing the harmful high-speed rotation that would occur with continuous compressed air supply, thereby protecting the connecting rod from damage.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If decompression valve is opened during first starting sequence, then water can be pumped away from cylinder chamber, but the valve must be closed in second sequence to maintain pressure

Engineering Contradiction:
Improvewater removal from cylinderVSAvoiddecompression valve control
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the starting process into two distinct sequences with different decompression valve states. In the first starting sequence, the decompression valve is opened to allow water removal from the cylinder chamber. In the second starting sequence, the decompression valve is closed to maintain pressure for efficient engine operation. This segmentation of the starting process into distinct phases with different valve states simplifies the control logic and ensures proper water removal without compromising subsequent pressure maintenance.

Inventive Principle:
Principle #1Segmentation

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 ensures a gentle transition from stationary to rotating engine, reduces the risk of connecting rod damage, and provides a reliable and cost-neutral solution that can be retrofitted without additional hardware, enhancing process reliability and safety.

Implementation Method 1

a starting system with a compressed air reservoir (10) for supplying the compressed air

Methodology Applied
Scientific EffectCompressed air: Compression

Implementation Method 2

the cylinders are equipped with decompression valves to relieve the cylinder working space

Methodology Applied
Scientific EffectPressure relief: Depressurisation

Implementation Method 3

the starter has to apply a considerable breakaway torque for the initial cranking of the internal combustion engine

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP3526456B1Method for starting an internal combustion engine
Publication Date: 2021.11.17 ROLLS ROYCE SOLUTIONS GMBH
  • EP3526456B1 patent drawingFigure 1
  • EP3526456B1 patent drawingFigure 2A
  • EP3526456B1 patent drawingFigure 2B

AI summary

A method for starting an internal combustion engine (1) by means of a compressed air starting system (2) is proposed in which in a first starting sequence the engagement of the starter (3) is brought about by means of compressed air, a decompression valve for relieving the cylinder working space is acted on in the opening direction, and starting of the internal combustion engine (1) is initiated by pulsed compressed air being applied to the starter (3), and in which in a second starting sequence the decompression valve is acted on in the closing direction, and constant compressed air is applied to the starter (3).