Open Loop EFI Genset for Gaseous Fuel Operation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Genset engines equipped with open loop electronic fuel injection (EFI) systems are not known to operate on gaseous fuels, particularly liquefied petroleum gas (LPG), due to the inability to accurately control the air-to-fuel ratio (AFR), which is critical for efficient performance and emissions.

Innovation Solution

Integration of air sensors such as air flow, manifold air temperature (MAT), and manifold absolute pressure (MAP) sensors into the open loop EFI system to determine the optimal AFR, allowing the electronic control unit (ECU) to actuate the fuel injector and provide the correct amount of gaseous fuel for efficient combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If open loop EFI system is used with gaseous fuels, then device complexity is reduced compared to closed loop systems, but air-to-fuel ratio control precision deteriorates making efficient operation impossible

Engineering Contradiction:

Improvefuel injection system complexityVSAvoidair-to-fuel ratio control precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system changes the operational parameters by using pre-calibrated AFR values specific to gaseous fuels in the ECU software, adjusting the fueling strategy to account for the different physical properties of gas versus liquid fuel while maintaining open loop control architecture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The ECU uses pre-determined AFR values that are calculated and stored in advance for gaseous fuel operation, allowing the system to execute precise fuel injection without real-time feedback by having the optimal parameters prepared beforehand

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If carbureted fuel system is used for gaseous fuels, then ease of manufacture is improved, but air-to-fuel mixture accuracy deteriorates resulting in poor engine performance

Engineering Contradiction:

Improvefuel system implementation easeVSAvoidair-to-fuel mixture accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical carburetor system with an electronically controlled fuel injection system that uses sensors and an ECU to precisely meter gaseous fuel, substituting electronic control for mechanical mixing while maintaining relative simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If open loop EFI system is used with gaseous fuels, then system cost is reduced compared to closed loop systems, but engine performance deteriorates due to inability to maintain narrow AFR band

Engineering Contradiction:

Improvecontrol system complexityVSAvoidengine performance

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The ECU incorporates gaseous fuel-specific AFR calibration data and uses temperature compensation parameters to adjust fuel injection timing and quantity, optimizing engine performance for gas fuel operation while maintaining open loop control

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses pre-calibrated fuel injection timing and duration values stored in the ECU that are specifically optimized for gaseous fuels, allowing the engine to achieve peak performance without real-time feedback by executing predetermined optimal injection strategies

Inventive Principle:

Principle #10Preliminary action

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

Enables genset engines to operate efficiently on gaseous fuels, including LPG, by maintaining the air-to-fuel mixture within a narrow band, improving starting and running performance without the complexity and cost of closed loop systems.

Implementation Method 1

An air flow sensor senses the mass of air that flows past it and transmits this data to the ECU

Methodology Applied

Scientific EffectMass flow sensing:

Implementation Method 2

Fuel is forcibly pumped through an injector and the fuel is then mixed with air and is either indirectly or directly placed in the combustion chamber

Methodology Applied

Scientific EffectFuel injection: Injector

Implementation Method 3

The ECU electrically actuates the fuel injector so that fuel mixes with the air flow to reach the AFR determined by the ECU

Methodology Applied

Scientific EffectElectrical actuation:

Implementation Method 4

the pressure of the fuel vapor is reduced, generally to about 0.4 psi

Methodology Applied

Scientific EffectPressure reduction: Depressurisation

Data Source

PatentUS8413642B2Genset that uses an open loop electronic fuel injection system and operates on gaseous fuels

Publication Date: 2013.04.09 CUMMINS POWER GENERATION INC

AI summary

A genset engine that operates on an open loop EFI system and runs on gaseous fuels is described. The integration of various air sensors, including for example a manifold air temperature (MAT) sensor, a manifold absolute pressure (MAP) sensor, or an air flow sensor(s), can provide optimal engine performance when using gaseous fuels and when starting from a cold state. The sensors employed send data to the electronic control unit (ECU) and such data is used to determine the optimal air-to-fuel ratio (AFR). The ECU actuates the injector and the injector sends the requested amount of gaseous fuel to mix with the air flow to be combusted. This provides the engine with a gaseous fuel and air mixture that is at the requested relative AFR and the engine is able to start and meet performance.