Engine Ignition Timing Control Using Intake Air Humidity
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Solution Overview
Problem
Existing engine ignition timing control methods fail to account for external humidity conditions, leading to decreased engine efficiency and knocking issues in dry climates, and do not ensure smooth and stable fuel combustion across varying humidity regions and seasons.
Innovation Solution
An engine ignition timing control method that acquires intake air humidity and calculates corrections based on EGR rate and engine operating points, using specific maps for different EGR operation scenarios to adjust ignition timing, ensuring efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ignition timing control methods are used without considering humidity, then the control system remains simple, but engine efficiency decreases and knocking occurs in dry climates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing ignition timing correction values in lookup tables based on different humidity conditions and engine operating parameters. The ECU retrieves pre-computed correction values from maps based on measured humidity and current engine state, rather than performing complex real-time calculations. This approach improves reliability by accounting for humidity effects while keeping the control system simple through use of pre-prepared data structures.
Solution Approach 2:
The patent changes the control parameter from fixed ignition timing to variable ignition timing that adapts to humidity conditions. By introducing humidity as a new control parameter and creating corresponding correction maps, the system optimizes combustion under different atmospheric conditions. This resolves the contradiction by making the control system adaptive to environmental parameters without requiring fundamentally new control architecture.
2Productivity
If ignition timing is advanced to improve combustion efficiency, then fuel combustion improves, but knocking occurs in dry climates
Solution Approach 1:
The patent applies local quality by providing different ignition timing correction strategies for different humidity conditions. Separate lookup tables are maintained for high humidity, low humidity, and normal humidity conditions, each containing optimized correction values tailored to that specific environmental context. This allows the system to advance ignition timing for efficiency in humid conditions while retarding it in dry conditions to prevent knocking, treating each humidity regime with specialized control parameters.
Solution Approach 2:
The patent changes the ignition timing parameter dynamically based on measured humidity levels. By introducing humidity-dependent correction values that modify the base ignition timing, the system optimizes combustion efficiency in humid conditions while preventing knocking in dry conditions. The correction maps contain pre-determined timing adjustments that account for the different combustion characteristics under varying atmospheric moisture content.
3Object-generated harmful factors
If EGR rate is increased to reduce emissions, then emission control improves, but ignition timing stability decreases due to humidity variations
Solution Approach 1:
The patent applies feedback by continuously measuring intake air humidity with a dedicated sensor and using this information to adjust ignition timing corrections. The humidity sensor provides real-time feedback about atmospheric conditions, and the ECU uses this feedback to select appropriate correction values from lookup tables. This closed-loop approach compensates for humidity-induced variations in combustion characteristics, maintaining ignition timing stability even when EGR rates are varied for emission control.
Solution Approach 2:
The patent applies preliminary action by pre-calculating ignition timing corrections for various combinations of EGR rates and humidity conditions and storing them in multi-dimensional lookup tables. When the ECU needs ignition timing adjustment, it simply retrieves the pre-computed correction value corresponding to the current EGR rate and measured humidity level. This approach maintains stability by using pre-optimized values rather than attempting complex real-time calculations, while still accounting for both EGR and humidity effects on combustion.
Data Source
AI summary
An engine ignition timing control method includes: acquiring, by an engine control unit (ECU), intake air humidity of an engine using a humidity sensor; calculating, by the ECU, an amount of first ignition timing correction based on the intake air humidity and an EGR rate; calculating, by the ECU, an amount of second ignition timing correction based on an engine operation region; and correcting, by the ECU, ignition timing of the engine using the amount of first ignition timing correction and the amount of second ignition timing correction.