Semiconductor Data Processing for Engine Toothless Part Detection
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Solution Overview
Problem
Current pulse detection techniques in engine control systems face challenges in accurately detecting the toothless part of a crank signal, particularly at the top dead point of a piston's combustion process, leading to potential misjudgment and reduced real-time control efficiency, especially in hybrid cars with increased engine vibration at low speeds.
Innovation Solution
A semiconductor data processing apparatus utilizing two counters and corresponding registers to differentiate between large and small pulse intervals by detecting specific states, allowing for improved detection accuracy and reduced processing time through hardware-based counting and comparison operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the toothless part is detected by comparing count values at pulse intervals before and after the toothless part, then the detection accuracy is improved, but the processing time is increased and real-time property deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing reference count values in a ROM memory during system initialization or normal operation. These reference values represent expected count values at pulse intervals when no toothless part is present. During actual toothless part detection, the system only needs to compare current count values against these pre-stored references, eliminating the need for real-time calculation and division operations, thus significantly reducing processing time while maintaining detection accuracy.
2Power
If the crank has acceleration increased at position just after dead point of piston, then the engine power is improved, but the count value at pulse interval may not reach reference value leading to mistaken detection
Solution Approach 1:
The patent applies parameter changes by introducing a threshold parameter (set to 0.7 times the reference count value) to accommodate variations in count values caused by engine acceleration. Instead of requiring exact matching or using a fixed high threshold, the system uses this lowered threshold to determine toothless parts. This allows the detection to remain reliable even when engine acceleration causes the count value to temporarily fall below the original reference value, thus preventing mistaken detection while allowing normal engine power operation.
3Speed
If vibration of engine and rotation sensor is increased in traveling at low speed, then the hybrid car mobility is improved, but error in count value at pulse interval is increased leading to mistaken detection
Solution Approach 1:
The patent applies beforehand cushioning by implementing a threshold-based detection mechanism that anticipates and compensates for errors caused by vibration. The threshold (set at 0.7 times the reference count value) acts as a cushion that absorbs the impact of vibration-induced count value variations. When vibration causes the count value to deviate, the threshold ensures that detection decisions are not overly sensitive to these fluctuations, thereby preventing mistaken detection while allowing the hybrid car to operate at low speeds with improved mobility.
Data Source
AI summary
The reliability in detection of toothless part is improved. A first counter counts a clock signal from an initial value for each of pulse intervals of a predetermined event pulse train and the count value of the first counter is held in a register for each of pulse intervals. Further, the second counter counts the clock signal from an initial value so that the count value thereof is equal to plural times of the count value of the first counter for each of the pulse intervals. A timer function which can detect any of a first state in which the count value of the first counter is equal to or larger than a first reference value and a second state in which the count value of the second counter is equal to or smaller than the value held in the register for each of the pulse intervals is adopted.