Multi-Fuel Engine Combustion Control for Knock Mitigation

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Solution Overview

Problem

Internal combustion engines face inefficiencies and increased fuel consumption due to the combustion of petroleum-based fuels, which can lead to knocking and preignition issues, limiting their operational efficiency and environmental impact.

Innovation Solution

The use of a combination of low and high octane fuels, where low octane fuel is used at low and intermediate loads and high octane fuel is added at high loads to mitigate knocking, along with retarding combustion phasing to reduce peak pressure and temperature, allowing for more efficient use of petroleum-based fuels and minimizing specific fuel consumption and carbon dioxide emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If low octane fuel is used at high loads, then fuel consumption is reduced and cost is lowered, but knocking occurs which limits engine efficiency

Engineering Contradiction:

Improvefuel consumptionVSAvoidknocking prevention

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent segments the fuel supply system into two separate fuel injectors: one for low octane fuel (e.g., gasoline) and one for high octane fuel (e.g., alcohol). This allows selective injection of different fuel types based on engine operating conditions, enabling low octane fuel to be used at low loads and high octane fuel to be added at high loads to prevent knocking while maintaining overall fuel efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the fuel mixture composition based on engine load conditions. The control system monitors engine operating parameters and adjusts the proportion of high octane fuel injected relative to low octane fuel, transitioning from predominantly low octane fuel at low loads to a mixed fuel approach at high loads, thereby optimizing both fuel consumption and knocking prevention across the operating range.

Inventive Principle:

Principle #15Dynamics

2Reliability

If high octane fuel is used at all loads, then knocking is prevented, but fuel consumption increases and cost rises

Engineering Contradiction:

Improveknocking preventionVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by injecting high octane fuel only when necessary (at high loads where knocking occurs) rather than continuously at all operating conditions. The control system modulates the high octane fuel injection quantity based on actual engine needs, using it partially during low load conditions and increasing injection during high load conditions, thereby reducing overall fuel consumption while maintaining knocking prevention where required.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If combustion phasing is retarded to reduce peak pressure and temperature, then preignition is mitigated, but engine power output may be reduced

Engineering Contradiction:

ImprovepreignitionVSAvoidengine power output

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The patent changes the combustion phasing parameter by retarding the spark timing relative to the position of maximum brake torque. This retardation reduces peak in-cylinder pressure and temperature, thereby mitigating preignition and abnormal combustion phenomena. The control system adjusts the spark timing parameter dynamically based on operating conditions, fuel mixture composition, and detected combustion characteristics to balance preignition mitigation with acceptable power output.

Inventive Principle:

Principle #35Parameter changes

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 reduces the amount of high octane fuel required, decreases preignition occurrences, and lowers fuel impingement, resulting in improved engine efficiency, reduced wear, and minimized fuel consumption while maintaining engine operation without knocking.

Implementation Method 1

combusting the fuel mixture with a spark plug

Methodology Applied

Scientific EffectSpark ignition: Electric Spark

Implementation Method 2

combusting the fuel mixture with a spark plug to translate a piston housed in the engine cylinder and rotate a crank shaft coupled to the piston

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11125172B2Internal combustion engines which utilize multiple fuels and methods for the operation of such

Publication Date: 2021.09.21 SAUDI ARABIAN OIL CO

AI summary

According to one or more embodiments, an internal combustion engine may be operated by a method which includes one or more of passing a first fuel and a second fuel into an engine cylinder to form a fuel mixture, and combusting the fuel mixture with a spark plug to translate a piston housed in the engine cylinder and rotate a crank shaft coupled to the piston. The first fuel may comprise a greater octane rating than the second fuel. A target CA50 may correspond to a minimum in specific fuel consumption of the fuel mixture. The spark plug may initiate combustion at a time such that the internal combustion engine operates with an operational CA50 that is within 20 degrees of the target CA50.