Spark-Ignition Engine Combustion Mode Transition
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Solution Overview
Problem
In-cylinder injection type spark-ignition internal combustion engines face misfire issues when changing spray transfer modes due to continuous interpolation of fuel injection and ignition timing, preventing optimal utilization of fuel economy and NOx reduction benefits.
Innovation Solution
An in-cylinder injection type spark-ignition internal combustion engine with a mode change determination means and injection timing and ignition timing calculation means to stepwise adjust fuel injection and ignition timing, allowing a change between stratified combustion modes while maintaining engine torque, avoiding misfire regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel injection timing and ignition timing are changed continuously by interpolation to prevent torque steps, then torque smoothness is improved, but misfire occurs due to prolonged stay in misfire region
Solution Approach 1:
The patent divides the continuous timing change into discrete steps. Instead of continuously interpolating fuel injection timing and ignition timing, the system determines specific timing values at distinct intervals, creating a stepped transition that avoids prolonged residence in misfire regions while maintaining torque smoothness.
Solution Approach 2:
The patent implements periodic determination of fuel injection timing and ignition timing values. By periodically calculating and updating timing parameters at specific intervals rather than continuously, the system achieves both smooth torque transition and avoidance of misfire regions through rhythmic adjustment cycles.
2Object-generated harmful factors
If spray transfer mode is changed depending on engine load, then fuel economy and NOx reduction are improved, but misfire occurs due to continuous interpolation in coexistence region
Solution Approach 1:
The patent segments the timing adjustment process into discrete steps when changing spray transfer modes. By determining specific fuel injection timing and ignition timing values at distinct intervals rather than continuous interpolation, the system transitions between combustion modes (spray-guide and wall-guide methods) without prolonged停留 in misfire regions, maintaining combustion stability while achieving NOx reduction.
Solution Approach 2:
The patent changes timing parameters (fuel injection timing and ignition timing) in discrete steps rather than continuously. This parameter change strategy allows the system to switch between different spray transfer modes depending on engine load while avoiding the misfire region, thereby reducing NOx emissions without sacrificing combustion reliability.
3Power
If fuel injection timing and ignition timing are changed continuously, then torque step is prevented, but fuel economy and NOx reduction benefits cannot be fully utilized
Solution Approach 1:
The patent implements segmented timing adjustment where fuel injection timing and ignition timing are changed in discrete steps rather than continuously. This segmentation allows the system to maintain torque smoothness by carefully selecting timing values at each step while enabling effective transitions between spray transfer modes for optimal fuel economy and NOx reduction.
Solution Approach 2:
The patent employs periodic determination and adjustment of timing parameters. By periodically calculating optimal timing values and implementing stepped changes, the system achieves both torque smoothness and effective utilization of fuel economy and NOx reduction benefits through rhythmic timing adjustments.
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
Enables seamless transition between spray transfer modes, preventing misfire and torque steps, thus optimizing fuel economy and NOx suppression by ensuring the engine operates in the most suitable combustion mode for current conditions.
Implementation Method 1
a piston arranged to be able to turn back the fuel spray which has passed by the electrode part of the spark plug so that the fuel spray is transferred again to near the electrode part
Implementation Method 2
a fuel injection valve for injecting fuel directly into a combustion chamber
Implementation Method 3
ignition is made at the time when the fuel spray injected by the fuel injection valve passes by the electrode part of the spark plug
Implementation Method 4
stratified lean combustion can be carried out, where ignition is made at an overall very lean air/fuel ratio
Data Source
AI summary
When, in a coexistence region where stratified combustion by a spray-guide method (SG combustion) and stratified combustion by a wall-guide method (WG combustion) are both practicable, a change from the SG combustion to the WG combustion is carried out, an ECU obtains point b giving a set of a fuel injection timing and an ignition timing capable of achieving the same target torque as a target torque in the SG combustion before the change, by the WG combustion, and changes the fuel injection timing and ignition timing stepwise from point a within an SG region to point b within a WG region, jumping across a misfire region, and then continuously to point c giving an optimal set of a fuel injection timing and an ignition timing corresponding to an MBT.