Cylinder Identification via Crankangle Signal Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing four-stroke cycle internal combustion engines with an odd number of cylinders face challenges in precise cylinder-identification due to disorder and phase shift in intake manifold pressure signals, leading to reduced detection reliability and accuracy, especially during transient operating conditions.
Innovation Solution
A method utilizing a crankangle sensor to generate a first signal with pulses at predetermined crankangles and a second signal oscillating with a period corresponding to the number of cylinders, integrating these signals over preset intervals to calculate integrated values, which are then compared to identify cylinder positions and phases without relying on a cam angle sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the derivative of the intake manifold pressure signal is used to detect extremes, then the current stroke of each cylinder can be determined, but detection reliability deteriorates due to signal disorder and phase shift
Solution Approach 1:
The invention changes the parameter from using the derivative (rate of change) of the intake manifold pressure signal to using the integral (accumulated value) of the signal. This parameter transformation eliminates the sensitivity to phase shifts and signal disorders that plague derivative-based methods, thereby maintaining detection reliability while preserving cylinder identification capability.
Solution Approach 2:
The invention introduces a new intermediary element - the integrated value of the intake manifold pressure signal - which serves as a more reliable mediator for detecting cylinder stroke positions. This intermediary accumulates signal information over time, making it less susceptible to transient disorders and phase variations compared to direct derivative calculations.
2Ease of operation
If the derivative of the intake manifold pressure signal is used, then stroke detection is possible, but detection accuracy decreases during transient operating conditions
Solution Approach 1:
By transforming from derivative-based detection to integral-based detection, the system achieves more stable and accurate stroke detection during transient conditions. The integral accumulates pressure information over the engine cycle, providing a more robust measurement that is less affected by rapid pressure changes and signal noise during cranking and transient operation.
3Measurement precision
If a cam angle sensor is used for cylinder identification, then appropriate fuel injection and ignition timing can be achieved, but the system complexity increases
Solution Approach 1:
The invention enables the intake manifold pressure sensor to serve dual purposes: both monitoring engine operating conditions and providing the basis for cylinder identification. By using the integral of the pressure signal in combination with crankangle information, the system eliminates the need for a separate cam angle sensor, reducing overall system complexity while maintaining accurate cylinder identification capability.
Solution Approach 2:
The intake manifold pressure sensor is made multi-functional, serving both as an operating condition monitor and as a cylinder identification sensor. This universal usage of the pressure sensor eliminates the need for additional dedicated sensors, thereby reducing system complexity while preserving measurement precision.
Data Source
Figure 1~2
Figure 3
AI summary
An internal combustion engine employs an odd number of cylinders. A crankangle sensor of 360° crankangle (CA) provides a POS signal including a pulse train having pulses generated at each 10° CA. This POS signal includes a specific portion 28' generated at each 360° CA by a gap portion of the crankangle sensor. The time required for a 10° CA change is calculated for each 10° CA as a second signal, and the time is integrated for intervals A, B, and C. Since the second signal oscillates with a period according to the number of the cylinders in response to a change in stroke of each cylinder, intervals T1 and T4, for example, can be identified by comparing the integrated values. Thus, the cylinders can be identified by only the signal from the crankangle sensor of 360° CA without depending on a cam angle sensor of 720° CA.