Fuel Injection Timing Control for Soot Reduction
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Solution Overview
Problem
Direct injection engines produce soot due to partial combustion of fuel when conditions change, such as engine load or exhaust gas recirculation, leading to increased emissions and particulate filter regeneration frequency.
Innovation Solution
Adjusting the start of fuel injection timing in response to changes in engine load by temporarily advancing and then retarding it to reduce fuel deposition on cylinder surfaces, allowing more fuel to vaporize and minimizing soot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct fuel injection is used to improve engine performance and reduce fuel puddles, then engine performance increases and fuel vaporization improves, but soot production increases during transient conditions
Solution Approach 1:
The injection timing is made dynamic by temporarily advancing it during transient load changes and then retarding it back to the optimal steady-state timing. This dynamic adjustment allows the system to adapt to changing conditions, reducing soot formation during transients while maintaining optimal performance during steady-state operation.
Solution Approach 2:
The injection timing is advanced before the transient condition fully develops, allowing fuel to be injected at a crankshaft angle that promotes better vaporization and reduces surface deposition. This preliminary timing adjustment prevents soot formation before it can occur during the load transition.
2Object-generated harmful factors
If injection timing is advanced to reduce fuel deposition on surfaces, then soot formation decreases, but injection timing must be temporarily adjusted away from optimal steady-state timing
Solution Approach 1:
The injection timing adjustment occurs periodically during transient conditions and then returns to the steady-state timing. This periodic action between advanced timing (during transients) and optimal timing (during steady-state) manages soot formation while maintaining overall engine performance.
Solution Approach 2:
The injection timing parameter is temporarily changed during transient conditions and then returned to its optimal value. This parameter adjustment allows the system to reduce soot formation during transients without permanently compromising steady-state performance, managing the trade-off through controlled parameter variation.
3Object-generated harmful factors
If larger exhaust gas aftertreatment devices are used to capture soot, then emissions are reduced, but system cost and device size increase
Solution Approach 1:
The invention converts the harmful effect of transient conditions into a benefit by using the timing adjustment to reduce soot formation at its source. By advancing injection timing during transients, the system prevents soot formation rather than treating it downstream, eliminating the need for larger aftertreatment devices.
Solution Approach 2:
The engine control system itself serves to reduce emissions by adjusting injection timing, rather than relying entirely on separate exhaust gas aftertreatment devices. This self-service approach to emissions control reduces the need for additional heavy equipment in the exhaust system.
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 method reduces soot production, improves engine emissions, and decreases the need for larger exhaust gas aftertreatment devices and less frequent particulate filter regeneration.
Implementation Method 1
vaporization of injected fuel can extract heat energy from an incoming cylinder charge so that additional air can enter an engine cylinder and increase the cylinder charge
Implementation Method 2
a compression device having a compression chamber and disposed downstream of the particulate filter, the compression device compressing the intake system gases to a desired pressure
Implementation Method 3
a combustion device disposed downstream of the compression device, the combustion device combusting the compressed gases
Data Source
AI summary
A method for reducing particulate matter emitted by an engine is disclosed. In one example, the start of fuel injection timing is adjusted in response to a change in engine operating conditions. In particular, start of injection timing may be advanced and then retarded to promote fuel vaporization.