Skip Fire Engine Early Direct Fuel Injection

Solution Overview

Problem

In skip fire controlled internal combustion engines, the timing of direct fuel injection is self-limiting, as fuel injected before the completion of a working cycle is expelled with combusted gases, limiting the time for fuel vaporization and mixing with air, resulting in less clean and efficient combustion.

Innovation Solution

An engine controller is used to command early direct injection of fuel into a cylinder during a skipped working cycle, allowing more time for vaporization and mixing with air before the next working cycle, thereby improving combustion efficiency and cleanliness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fuel is direct-injected prior to completion of the previous working cycle, then the timing control precision is improved, but the fuel is expelled along with combusted gases resulting in longer vaporization time needed

Engineering Contradiction:

Improvetiming control precisionVSAvoidvaporization time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by injecting fuel into the cylinder during the compression stroke before combustion occurs. This allows the fuel to begin vaporization and mixing with air during the compression phase, rather than after combustion has completed. The fuel injection timing is advanced to occur during the compression stroke of the current working cycle, providing head start for vaporization before the next combustion event.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If direct-injection timing is limited to after previous working cycle completion, then harmful factors are avoided, but the combustion efficiency deteriorates due to insufficient vaporization and mixing time

Engineering Contradiction:

Improvefuel expulsion with combusted gasesVSAvoidcombustion efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by injecting fuel into the cylinder during the compression stroke before combustion occurs. This allows the fuel to begin vaporization and mixing with air during the compression phase, rather than after combustion has completed. The fuel injection timing is advanced to occur during the compression stroke of the current working cycle, providing head start for vaporization before the next combustion event.

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

This approach enhances fuel vaporization and mixing, leading to cleaner and more efficient combustion in the next working cycle, improving engine performance and reducing emissions.

Implementation Method 1

the amount of time the fuel has to vaporize and mix with air within the chamber ahead of the compression and combustion strokes of the next working cycle is therefore limited

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 2

the amount of time the fuel has to vaporize and mix with air within the chamber ahead of the compression and combustion strokes

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

combustion of the fuel during the next working cycle is both cleaner and more efficient

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11333099B2Early direct fuel injection for internal combustion engines

Publication Date: 2022.05.17 TULA TECHNOLOGY INC

AI summary

A skip fire engine controller is disclosed that commands an early direct-injection of fuel during a skipped working cycle in which a cylinder is not exhausted. With early direct injection, the fuel has more time to vaporize and mix with air for combustion in an immediately following working cycle in which the cylinder is fired. By increasing the degree of vaporization and mixing, the combustion is both cleaner and more efficient.