Engine Fuel Injection Control for Soot Reduction
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Solution Overview
Problem
In direct-injection internal combustion engines, existing control apparatuses struggle to effectively suppress soot adhesion to the piston crown surface at low engine temperatures, despite attempts to inject fuel near the theoretical mixing ratio in the latter half of the compression stroke and retarding ignition timing.
Innovation Solution
A control apparatus with an electronic control unit that adjusts fuel injection timing and frequency between the intake and compression strokes, injecting fuel in an 'injectable area' from the start of the intake stroke to the end of the compression stroke, with settings that include up to four injections, based on engine speed and intake air amount to minimize soot adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel is injected in the latter half of the compression stroke with retarded ignition timing, then combustion efficiency is improved, but soot adhesion to the piston crown surface increases
Solution Approach 1:
The fuel injection process is divided into multiple separate injections (first injection and second injection) within the compressible area, rather than a single injection. This segmentation allows the fuel to be introduced in stages, improving mixing with intake air and reducing soot formation while maintaining combustion efficiency.
Solution Approach 2:
The injection timing is specifically controlled to occur within the compressible area (from intake stroke start to compression stroke end), creating optimal local conditions for fuel-air mixing before combustion. This localized timing control reduces soot adhesion while maintaining overall combustion efficiency.
2Object-generated harmful factors
If fuel injection timing is extended into the compression stroke, then soot adhesion is reduced, but the complexity of control increases
Solution Approach 1:
The injection timing is dynamically adjusted based on engine operating conditions, with the second injection timing being set later than the first injection timing within the compressible area. This dynamic timing adjustment optimizes fuel distribution and reduces soot adhesion while managing control complexity through systematic timing progression.
Solution Approach 2:
The control system implements periodic multi-stage injection cycles within each engine cycle, with regular intervals between the first and second injections. This periodic action pattern simplifies control by establishing a repeating injection sequence that reduces soot adhesion through consistent timing relationships.
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 effectively reduces soot adhesion to the piston crown surface by optimizing fuel injection patterns, improving combustion efficiency and reducing soot formation, especially at low engine temperatures.
Implementation Method 1
a fuel injector arranged to inject a fuel into a combustion chamber facing the piston in the cylinder
Implementation Method 2
injecting the fuel in an injectable area from a first crank angle at which an intake stroke is started to a second crank angle at which a compression stroke is ended
Data Source
AI summary
An internal combustion engine control apparatus is configured to control an internal combustion engine including a piston reciprocating in a cylinder and a fuel injector arranged to inject a fuel into a combustion chamber facing the piston in the cylinder. The internal combustion engine control apparatus includes an electronic control unit having a microprocessor and a memory. The microprocessor is configured to perform controlling the fuel injector so as to inject the fuel in an injectable area from a first crank angle at which an intake stroke is started to a second crank angle at which a compression stroke is ended, and setting an injection frequency of the fuel injected by the fuel injector in the injectable area. The microprocessor is configured to perform the setting including setting the injection frequency between once and four times.