Knock Sensor Diagnosis via Combustion Phasing

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Solution Overview

Problem

Current methods for determining the functionality and wiring of knock sensors in combustion engines require engine shutdown and only indicate the presence of the sensor, not its proper functioning or correct wiring.

Innovation Solution

A method and system that process data from knock sensors to derive combustion and valve signatures, comparing their phasing against known crank angles and timed events using a lookup table to determine if the knock sensor is functioning properly and correctly wired without shutting down the engine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If impedance measurement method is used to check knock sensor, then the sensor presence can be determined, but the engine must be shut down and only presence not proper functioning can be detected

Engineering Contradiction:

Improveknock sensor functionality detectionVSAvoidengine shutdown requirement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary diagnostic actions by analyzing the phasing relationship between valve events and combustion events during normal engine operation. The processor compares the timing of valve closure events with combustion events to determine if the knock sensor is properly wired and functioning, without requiring engine shutdown. This preliminary check during operation resolves the contradiction by enabling reliability assessment while maintaining operational status.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If impedance measurement is performed, then knock sensor presence is indicated, but proper wiring and functioning cannot be determined

Engineering Contradiction:

Improveknock sensor proper functioningVSAvoidwiring correctness information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system uses feedback from the knock sensor signal itself to diagnose sensor functionality and wiring correctness. The processor analyzes the phasing relationship between valve events and combustion events detected by the knock sensor. If the sensor is properly wired, the combustion events will occur at the expected phase relative to valve events. This feedback mechanism provides information about wiring correctness and proper functioning without losing diagnostic information.

Inventive Principle:

Principle #23Feedback

3Productivity

If continuous monitoring is implemented, then engine operation is optimized, but diagnostic capability must be maintained without shutdown

Engineering Contradiction:

Improvecontinuous monitoring capabilityVSAvoidsensor diagnostic accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The knock sensor diagnostic system performs self-service by using the sensor's own output signal to assess its functionality and wiring correctness. During continuous engine operation, the processor analyzes the phasing relationship between events detected by the knock sensor without requiring external testing equipment or engine shutdown. This self-service approach maintains measurement precision while enabling continuous monitoring and optimal engine operation.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP3054134B1Method and system of diagnosing a knock sensor

Publication Date: 2018.04.18 GENERAL ELECTRIC CO

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AI summary

A method (122) of diagnosing a knock sensor (23) includes steps of receiving data (124) from the knock sensor, the knock sensor configured to be coupled to an engine (10), processing (126) the data to derive one or more events from the data, and determining (136) whether the one or more events took place at a known time or a known crank position.