Internal Combustion Engine Ignition Device Ion Current Detection
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Solution Overview
Problem
Conventional internal combustion engine ignition devices face issues with accurately detecting ion currents due to high temperatures causing pre-ignition and leakage currents, leading to a wide dynamic range requirement for input voltage, which increases circuit complexity and cost, and inaccuracies in ion signal transfer due to ground potential differences.
Innovation Solution
An internal combustion engine ignition device with a pulse generation circuit, pulse detection circuit, ion bias circuit, ion-current detection circuit, and ion-signal detection/control circuit that generates a single or multiple pulse signals to accurately detect and control ion currents, setting the input voltage to a high level when no pulse signals are supplied and lowering it briefly to recognize energization or de-energization signals, allowing for precise ion current detection and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dynamic range of input voltage is set wide to detect ion current at timing when ignition signal is supplied, then ion current detection capability is improved, but circuit scale of ECU becomes large and cost increases
Solution Approach 1:
The patent applies periodic action by using pulse signals with extremely short duration to periodically interrupt the primary coil current. This allows the system to detect ion currents during specific time windows when the ignition signal is not active, avoiding the need for wide dynamic range detection during ignition events. The periodic pulsing creates distinct detection phases separated from ignition phases.
Solution Approach 2:
The patent implements preliminary action by setting the input voltage to a high level during periods when no pulse signals are supplied, preparing the detection circuit in advance for optimal ion current detection. This preliminary voltage setting ensures the circuit is ready to detect ion currents accurately during the next detection window without requiring wide dynamic range adjustment during ignition events.
2Measurement precision
If the dynamic range of input voltage is set wide to detect ion current at timing when ignition signal is supplied, then ion current detection capability is improved, but cost increases
Solution Approach 1:
By using periodic pulse signals with extremely short duration, the system creates distinct time windows for ion current detection that are separate from ignition signal periods. This allows standard voltage range circuits to suffice, avoiding the need for expensive wide dynamic range components while maintaining accurate ion current detection capability during the designated detection windows.
3Measurement precision
If ground potential difference occurs between ECU and coil driver, then ion signal transfer accuracy deteriorates, but this is a natural phenomenon that cannot be avoided
Solution Approach 1:
The patent uses the coil-driver input signal line as an intermediary medium to transfer ion signals from the coil driver to the ECU. By utilizing the existing signal line infrastructure and controlling the timing of signal transfer during periods when the line is not actively driving ignition signals, the system achieves accurate ion signal transfer without requiring additional dedicated signal paths or complex ground potential equalization circuits.
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 accurate ion current detection within a 5-Volt system, even in high-temperature conditions, without expanding the dynamic range of the input voltage, enhancing the ignition system's functionality and reducing costs, while ensuring accurate ion signal transfer across ground potential differences.
Implementation Method 1
an ignition coil having a primary coil and a secondary coil and a switching element that generates an ignition high voltage across the secondary coil of the ignition coil by flowing and interrupting an electric current for the primary coil
Data Source
AI summary
An internal combustion engine ignition device is provided in which an ECU (200) includes a pulse generation circuit (201) that outputs pulse signals (Igt1 and Igt2) and an ion-signal detection/control circuit (300), and a coil driver (400) includes a pulse detection circuit (7) that recognizes a signal received from the pulse generation circuit (201) and an ion-current detection circuit (9); when the pulse signals are not outputted, an ion current is detected and a signal is outputted at the same line as a coil-driver input signal line.