Internal Combustion Engine Cylinder Ignition Timing Control
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Solution Overview
Problem
Internal combustion engines experience vibrations due to crankshaft bending, which are not effectively suppressed by existing retard control methods for ignition timing.
Innovation Solution
A control method for internal combustion engines that uses a knock sensor to detect vibrations and adjusts ignition timing. When the vibration exceeds a predetermined threshold, the method retards the ignition timing of all cylinders to suppress knocking. Additionally, it specifically retards the ignition timing of a specific cylinder identified as contributing to crankshaft bending vibrations, using a lower vibration judgment threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ignition timing of all cylinders is retarded to suppress knocking vibrations, then the knocking vibrations are suppressed, but the engine output performance is reduced
Solution Approach 1:
The invention segments the vibration suppression control by identifying and treating only the specific cylinder that generates crankshaft bending vibrations, rather than uniformly retarding all cylinders. The controller divides the multiple cylinders into a specific cylinder (source of bending vibration) and other cylinders, applying different ignition timing strategies to each group.
Solution Approach 2:
The invention applies local quality by implementing targeted ignition timing retardation only for the specific cylinder identified as the source of crankshaft bending vibrations. The specific cylinder receives a retarded ignition timing to suppress bending vibrations, while other cylinders maintain their original ignition timing to preserve engine output performance.
2Object-affected harmful factors
If the ignition timing of the specific cylinder is retarded to suppress crankshaft bending vibrations, then the bending vibrations are suppressed, but the engine output performance is reduced
Solution Approach 1:
The controller segments the vibration suppression by identifying the specific cylinder responsible for crankshaft bending vibrations and applying retardation only to that cylinder. This segmentation allows targeted suppression of bending vibrations while preserving the output performance of other cylinders.
Solution Approach 2:
The invention applies local quality by implementing ignition timing retardation specifically for the identified problem cylinder. The specific cylinder's ignition timing is retarded to suppress its contribution to crankshaft bending vibrations, while other cylinders maintain optimal ignition timing for maximum power output.
3Device complexity
If the knock threshold value is used for judging crankshaft bending vibrations, then the vibration judgment is simplified, but the vibration suppression effectiveness is insufficient
Solution Approach 1:
The invention changes the vibration judgment parameter by introducing a vibration threshold value that is lower than the conventional knock threshold value. This parameter change enables the system to detect and suppress crankshaft bending vibrations that would otherwise be missed using the higher knock threshold, thereby improving vibration suppression effectiveness without complicating the judgment logic.
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 suppresses vibrations caused by crankshaft bending while maintaining engine output performance, by selectively retarding the ignition timing of specific cylinders within predetermined driving conditions.
Implementation Method 1
a knock sensor configured to sense the vibration of a multiple cylinder internal combustion engine
Data Source
AI summary
When vibration sensed by knock sensor configured to sense the vibration of a multiple cylinder internal combustion engine is greater than a predetermined knock threshold value, a controller performs a first ignition timing control to retard ignition timings of cylinders so that the vibration becomes equal to or smaller than the knock threshold value; previously specifies a specific cylinder relating to a specific vibration due to a bending of a crank shaft; and in a state in which a driving state is in a predetermined specific driving region where there is a possibility that the specific vibration will be generated, when the vibration of the specific cylinder is greater than a predetermined specific vibration judgment threshold value that is smaller than the knock threshold value, performs a second ignition timing control to retard only the ignition timing of the specific cylinder by a predetermined amount.