Gaseous Fuel Engine Crankcase Accumulation Control

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Solution Overview

Problem

Gaseous fuel engines, particularly those using hydrogen, face challenges in managing blowby, where unburned fuel accumulates in the crankcase, risking ignition and catastrophic failure, due to the flammability of hydrogen fuels.

Innovation Solution

A method and system that monitor engine parameters to control gaseous fuel delivery location, timing, and mixing with air within the cylinder to maintain crankcase accumulation below the flammability limit, using a fueling control unit to adjust fuel delivery splits and in situ mixing, thereby reducing blowby and preventing fuel accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If gaseous fuel is delivered to the cylinder for combustion, then the engine produces power, but unburned fuel accumulates in the crankcase reaching flammability limits

Engineering Contradiction:

Improveengine power outputVSAvoidcrankcase fuel accumulation

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic control of fuel delivery parameters (location, timing, mixing) based on real-time monitoring of engine operating conditions. The fueling control unit continuously adjusts these parameters to optimize combustion efficiency while preventing crankcase accumulation, transforming static fuel delivery into a dynamic adaptive system that responds to varying engine loads and conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes multiple fuel delivery parameters simultaneously - delivery location (between intake valve and piston), delivery timing (during intake stroke), and in-situ mixing (with intake air). By modifying these parameters, the system achieves more complete combustion and reduces unburned fuel reaching the crankcase, while maintaining or improving engine power output.

Inventive Principle:

Principle #35Parameter changes

2Power

If fuel delivery is increased to maintain power output, then engine performance is maintained, but crankcase fuel accumulation increases

Engineering Contradiction:

Improveengine power outputVSAvoidfuel accumulation in crankcase

Core Design Contradiction:

PowerVSQuantity of substance

Solution Approach 1:

The patent employs a feedback control system where the fueling control unit monitors engine operating parameters and uses this information to continuously adjust fuel delivery settings. This closed-loop control ensures that fuel delivery is optimized for each operating condition, achieving complete combustion at power-requiring loads while reducing fuel delivery or improving mixing at partial loads, thereby preventing crankcase accumulation across the entire operating range.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent delivers fuel preliminarily mixed with intake air during the intake stroke, before combustion occurs. This preliminary mixing ensures homogeneous fuel distribution and complete combustion during the power stroke, leaving minimal unburned fuel to blowby into the crankcase. The fuel is introduced at an optimal timing and location to maximize combustion efficiency before the compression and power strokes.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If traditional fuel delivery methods are used, then engine operation is simple, but hydrogen blowby cannot be controlled below flammability limits

Engineering Contradiction:

Improveengine operation simplicityVSAvoidcrankcase fuel safety

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary control system (fueling control unit) that mediates between the fuel delivery system and the engine operation. This intermediary monitors operating conditions and automatically adjusts fuel delivery parameters, making the complex safety controls transparent to the operator. The system handles the complexity of hydrogen blowby management while maintaining ease of operation through automated control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical fuel delivery systems with an electronically controlled system that can precisely regulate fuel delivery location, timing, and mixing. This substitution enables fine-grained control of fuel parameters to prevent crankcase accumulation, while the electronic control system manages the complexity, maintaining ease of operation through automated adjustment based on sensor feedback.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Effectively limits crankcase accumulation of gaseous fuel below the flammability limit, preventing ignition risks and improving engine efficiency by reducing the amount of fuel that blows by into the crankcase, while also conserving energy by minimizing the need for ventilation.

Implementation Method 1

maintain crankcase accumulation of the gaseous fuel below a flammability limit

Methodology Applied

Scientific EffectFlammability limit:

Data Source

PatentUS20240044296A1Gaseous fuel engine system and operating strategy for limiting crankcase fuel accumulation

Publication Date: 2024.02.08 CATERPILLAR INC

AI summary

Operating a gaseous fuel engine system includes controlling at least one of a delivery location, a delivery timing, or in situ mixing of a gaseous fuel with air, based on at least one engine system parameter upon the basis of which a blowby amount of a gaseous fuel to a crankcase varies. Crankcase accumulation of the gaseous fuel is maintained below a flammability limit. Related apparatus and control logic is also disclosed.