Passive Fuzing for Multi-Pulse Propulsion

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Solution Overview

Problem

Conventional multi-pulse propulsion systems are cumbersome and costly due to the need for extensive electronics and igniters to actively initiate each pulse, which occupies valuable space and reduces propellant volume and mass.

Innovation Solution

A multi-pulse rocket motor with a passive fuzing system that uses sensors to initiate additional pulses independently of the main system controller, reducing complexity and volume constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional active initiation systems with electronics and igniters are used for each pulse, then reliable pulse initiation is achieved, but system volume and complexity increase significantly

Engineering Contradiction:
Improvepulse initiation reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the electronic control system from the pulse initiation process, removing the need for complex electronics and igniters. Instead, the system uses passive initiation where propellant charges are ignited by thermal conduction from hot exhaust gases of previous pulses, eliminating disturbing electronic components while maintaining reliable pulse initiation through carefully designed propellant placement and thermal coupling

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The propulsion system initiates subsequent pulses automatically using the thermal energy from its own exhaust gases. The hot exhaust from one pulse naturally heats and ignites the next propellant charge without external intervention, allowing the system to self-initiate multiple pulses in sequence without requiring active electronic control for each pulse

Inventive Principle:
Principle #25Self-service

2Reliability

If conventional active initiation systems with electronics and igniters are used for each pulse, then reliable pulse initiation is achieved, but system volume increases reducing propellant volume

Engineering Contradiction:
Improvepulse initiation reliabilityVSAvoidpropellant volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent removes electronic initiators and control systems from each pulse chamber, extracting the volume-consuming components that previously occupied space within the propulsion system. This frees up significant volume within the vehicle platform for increased propellant loading while maintaining reliable pulse initiation through thermal conduction mechanisms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the initiation function into the propellant charge design itself, where the propellant is configured to be ignited by thermal conduction from exhaust gases. This integration eliminates separate igniter components and combines the propellant storage and initiation functions into a single unified system, maximizing propellant volume

Inventive Principle:
Principle #5Merging (Combining)

3Extent of automation

If conventional active initiation systems with electronics and igniters are used for each pulse, then controlled multi-pulse propulsion is achieved, but system cost increases

Engineering Contradiction:
Improvemulti-pulse control capabilityVSAvoidsystem cost
Core Design Contradiction:
Extent of automationVSEase of manufacture

Solution Approach 1:

The patent replaces expensive electronic igniters and control systems with simple, inexpensive propellant charges designed for single-use passive initiation. Each propellant charge is a low-cost component that relies on thermal conduction from exhaust gases rather than expensive electronic initiators, significantly reducing overall system cost while maintaining multi-pulse capability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system eliminates the need for expensive electronic control systems by using self-initiating propellant charges that automatically ignite from exhaust heat. This removes the need for complex electronic controllers, sensors, and power systems, dramatically reducing manufacturing costs while preserving automated multi-pulse propulsion functionality

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

The passive fuzing system allows for more efficient use of space and resources, enabling the integration of multi-pulse propulsion into smaller vehicle platforms and reducing the cost and complexity of retrofitting existing vehicles.

Implementation Method 1

the sensor being configured to sense an environmental condition and/or a ballistic condition

Methodology Applied
Scientific EffectSensor detection:

Implementation Method 2

the second igniter being configured to provide a stimulus that causes ignition of the at least one additional propellant

Methodology Applied
Scientific EffectIgnition: Combustion

Implementation Method 3

at least one pulse chamber containing at least one propellant for igniting during at least one pulse

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4232701B1Multi-pulse propulsion system with passive initiation
Publication Date: 2025.06.11 RAYTHEON CO
  • EP4232701B1 patent drawingFigure 1
  • EP4232701B1 patent drawingFigure 2~3
  • EP4232701B1 patent drawingFigure 4~5

AI summary

A multi-pulse propulsion system (10) includes at least one pulse chamber (20) containing at least one propellant (22) for igniting during at least one pulse of the multi-pulse propulsion system, at least one additional pulse chamber (24) containing at least one additional propellant (26) for igniting during at least one additional pulse of the multi-pulse propulsion system, and at least one passive fuzing system (34) configured to initiate the at least one additional pulse. The at least one passive fuzing system includes a sensor (36) and an igniter (38). The sensor is configured to sense an environmental condition and/or a ballistic condition. The igniter is configured to provide a stimulus that causes ignition of the at least one additional propellant in response to the sensor sensing that the environmental condition and/or the ballistic condition has reached or exceeded one or more threshold values.