Auxiliary Power Unit Exhaust Routing for Emissions Management

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Solution Overview

Problem

Auxiliary power unit engines generate excessive emissions due to idling, and traditional aftertreatment systems are costly or impractical for secondary engines, which cannot effectively regenerate typical aftertreatment systems.

Innovation Solution

An engine aftertreatment system with an exhaust routing device that selectively routes exhaust from both primary and secondary engines to an emissions treatment device, using an actuator to control valves and ensure efficient emissions management, and a controller to monitor and adjust the routing based on engine states and fault conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a dedicated aftertreatment system is installed for the secondary engine, then emissions control is improved, but system cost increases significantly

Engineering Contradiction:

Improveemissions controlVSAvoidsystem cost

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the aftertreatment function into the primary engine system by routing the secondary engine's exhaust through the primary engine's existing aftertreatment device. This eliminates the need for a separate aftertreatment system for the secondary engine, reducing overall system cost while maintaining emissions control effectiveness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The primary engine's aftertreatment device is designed to handle exhaust from both the primary engine and the secondary engine. The exhaust routing device enables the aftertreatment system to perform multiple functions by treating exhaust from different sources through a single treatment device, thereby reducing system complexity and cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Power

If the secondary engine operates continuously to power accessories, then electrical power supply is improved, but emissions increase significantly

Engineering Contradiction:

Improveelectrical power supplyVSAvoidemissions

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The exhaust routing device acts as an intermediary between the secondary engine and the aftertreatment device. It selectively connects or disconnects the exhaust flow path, enabling the aftertreatment system to activate only when needed, thus reducing unnecessary emissions while maintaining electrical power supply capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses periodic control of the exhaust routing device to activate aftertreatment only when the secondary engine is operating and emissions control is required. This periodic activation pattern allows the system to maintain electrical power supply while minimizing emissions treatment costs and system complexity.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If the secondary engine is used to power accessories, then operational flexibility is improved, but the engine cannot provide conditions needed to regenerate aftertreatment systems

Engineering Contradiction:

Improveoperational flexibilityVSAvoidaftertreatment regeneration capability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The controller monitors engine operating conditions and uses feedback control to manage the exhaust routing device. It activates the aftertreatment system based on real-time conditions from both engines, ensuring that regeneration occurs when thermodynamic conditions are favorable while maintaining operational flexibility of the secondary engine for accessory power.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The exhaust routing device is dynamically controlled based on real-time engine operating conditions. The system can switch between different exhaust flow paths and activate aftertreatment functions according to changing operational requirements, maintaining both operational flexibility and aftertreatment effectiveness without requiring the secondary engine to maintain specific regeneration conditions.

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

This system effectively reduces emissions by ensuring that either the primary or secondary engine's exhaust is treated, preventing unnecessary emissions and maintaining system functionality while minimizing costs.

Implementation Method 1

an emission treatment device to treat exhaust from the first engine and the second engine

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS8365520B2System and method for auxilary power unit emissions management

Publication Date: 2013.02.05 CUMMINS POWER GENERATION IP INC

AI summary

A system is disclosed including a primary engine that provides vehicle propulsion and a secondary engine that drives a generator to provide auxiliary power. The system further includes a first exhaust gas passageway from the primary engine and a second exhaust gas passageway from the secondary engine. The system further includes an emission treatment device including an exhaust inlet to treat exhaust from the primary and secondary engines. The system further includes an exhaust routing device that selectively routes exhaust from the first passageway or the second passageway to the exhaust inlet. The exhaust routing device at least partially blocks the first passageway or the second passageway from fluid communication with the exhaust inlet.