Direct-Injection HCCI Combustion Timing Control
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Solution Overview
Problem
Existing HCCI engine technologies face inefficiencies in operating efficiency and emission control performance due to the need for fuel-rich mixtures and spark ignition, which increase nitrogen oxide production and combustion noise.
Innovation Solution
A method involving direct fuel injection into the combustion chamber, where a first stage fuel ignites by compression self-ignition, allowing a leaner air-fuel ratio and controlling the timing of a second stage fuel injection to achieve compression self-ignition, reducing peak combustion pressure and noise, and improving efficiency and emission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spark ignition is used to start first stage combustion, then self ignition timing can be reliably controlled, but fuel consumption increases and nitrogen oxide emissions worsen
Solution Approach 1:
The patent extracts the spark ignition function from the combustion initiation process and replaces it with compression self-ignition. By removing the spark plug intervention, the system achieves reliable self-ignition timing control through compression alone, eliminating the need for fuel-rich mixtures around the spark plug and thereby reducing fuel consumption.
Solution Approach 2:
The combustion system serves itself by using compression to automatically ignite the fuel without external spark assistance. The compression process naturally raises the temperature and pressure to ignition point, creating a self-service ignition mechanism that eliminates the energy waste associated with spark ignition and fuel-rich mixture preparation.
2Ease of operation
If fuel rich mixture is used for spark ignition, then combustion can be initiated, but nitrogen oxide production increases
Solution Approach 1:
The patent removes the spark ignition mechanism that requires fuel-rich mixtures. By extracting this dependency, the system can operate with leaner air-fuel ratios that naturally reduce nitrogen oxide formation while still achieving reliable combustion initiation through compression self-ignition.
Solution Approach 2:
The patent changes the ignition mechanism from spark-based to compression-based, which fundamentally alters the required air-fuel ratio parameters. This parameter change enables operation in a leaner regime that produces less nitrogen oxide while maintaining effective combustion initiation.
3Device complexity
If single combustion of long combustion period is used, then torque control is simplified, but combustion noise increases
Solution Approach 1:
The patent segments the combustion process into multiple distinct combustion events rather than a single long combustion period. This segmentation divides the combustion noise into separate, shorter events that are less perceptible and harmful, while the overall torque control remains manageable through timed injection sequences.
Solution Approach 2:
The patent employs periodic combustion events with specific timing intervals between them. This periodic action creates a more manageable noise pattern compared to continuous long-duration combustion, while the regular timing maintains effective torque control through predictable pressure cycles.
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 operating efficiency and emission control performance by reducing nitrogen oxide production and combustion noise through controlled compression self-ignition, while maintaining reliable torque control.
Implementation Method 1
injecting a first stage fuel into a combustion chamber so as to complete the injection during a middle stage of a compression stroke at the latest in a cylinder cycle... causing combustion of the injected fuel by its compression self-ignition
Implementation Method 2
injecting a second stage fuel into the combustion chamber in a period when the determined combustion of the first stage fuel continues at a timing determined so as to cause combustion of the second stage fuel with its compression self-ignition
Implementation Method 3
combustion of the first stage fuel initiated by its compression self-ignition... combustion of the second stage fuel with its compression self-ignition
Data Source
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AI summary
Various systems and methods are disclosed for controlling an internal combustion engine system having an internal combustion engine, and a fuel injector which directly injects fuel into a combustion chamber of the internal combustion engine. One example method comprises, when a desired torque for the internal combustion engine system is in a first range (12), injecting a first stage fuel into the combustion chamber so that it ends during a middle stage of a compression stroke at the latest in a cylinder cycle; determining combustion of the first stage fuel initiated by its compression self-ignition; and injecting a second stage fuel into the combustion chamber in a period when the determined combustion of the first stage fuel continues at a timing determined so as to cause combustion of the second stage fuel with its compression self-ignition.