Oil Jet Abnormality Detection via Ignition Delay
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Solution Overview
Problem
Existing oil jet abnormality determination methods in internal combustion engines face challenges in accurately detecting valve abnormalities without additional sensors, such as hydraulic pressure sensors, which are difficult to install and operate effectively.
Innovation Solution
The method involves monitoring the ignition time delay of the sparking plug to determine if the oil jet is functioning correctly, using a predetermined threshold value to assess the delay angle and determine if the oil jet is abnormal, thereby avoiding the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hydraulic pressure sensor is provided on the downstream side of the oil jet switching valve to determine abnormality, then measurement precision of oil jet status is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The system uses existing sensors (knock sensor, crank angle sensor, oil jet switching valve position sensor) to determine oil jet abnormality without requiring additional dedicated sensors. The ECU self-diagnoses by analyzing data from these existing components, making the system self-sufficient and avoiding increased device complexity.
Solution Approach 2:
Existing sensors serve multiple functions: the knock sensor detects both knocking vibrations and oil jet abnormalities, the crank angle sensor provides both ignition timing control and abnormality determination data, and the oil jet switching valve position sensor provides both control feedback and diagnostic information. This multi-functionality eliminates the need for separate oil jet detection sensors.
2Reliability
If ignition time is delayed to prevent knocking when oil jet is abnormal, then reliability of engine operation is improved, but productivity and power output decrease
Solution Approach 1:
The system applies ignition time delay only partially - specifically when oil jet abnormality is detected and knocking is confirmed. When no abnormality exists, the system maintains optimal ignition timing for maximum power output. This selective application balances reliability improvement with productivity preservation.
Solution Approach 2:
The ignition timing control is dynamic and adaptive, adjusting in real-time based on detected conditions. The system continuously monitors oil jet status and knocking presence, advancing or retarding ignition timing as needed. This dynamic control allows the system to optimize between reliability and productivity based on current engine state.
Data Source
AI summary
An MBT ignition time and a knock ignition time are acquired from an engine rotation speed and engine load, and an ignition time on a delay angle side, out of these ignition times, is set as the most advance angle ignition time. An ignition time on the delay angle side only by the KCS learning value with respect to the most advance angle ignition time is set as a required ignition time, and when an actual ignition time set by a knock control system exceeds a predetermined amount and is positioned on the delay angle side with respect to the required ignition time, it is determined that abnormality occurs in an oil jet. Fail-safe processing to the effect that the opening degrees of a throttle valve are corrected to a closed side is executed in response to the abnormality determination.