Ignition Timing Control for Alcohol Fuel Switching
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Solution Overview
Problem
When switching between fuels with different alcohol concentrations in an internal combustion engine, existing ignition timing control devices face challenges in maintaining fuel efficiency while ensuring knocking resistance, as the alcohol concentration sensor readings can be affected by residual fuels and engine vibrations, leading to incorrect ignition timing settings.
Innovation Solution
An ignition timing control device that includes an operating state acquisition unit, alcohol concentration sensor, reference ignition timing calculation unit, and a system to restrict and cancel advance correction amounts based on fuel switching, ensuring the target ignition timing is set based on the actual fuel composition after complete switching, thereby maintaining knocking resistance and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the alcohol concentration sensor is disposed upstream from the delivery pipe to detect alcohol concentration, then the sensor is less affected by engine heat, but residual fuel in the delivery pipe causes incorrect alcohol concentration readings during fuel switching
Solution Approach 1:
The control unit determines the start and end of fuel switching in advance by monitoring alcohol concentration changes, and proactively restricts the advance correction amount during the switching period. This preliminary detection and preventive control ensures that ignition timing is adjusted only after complete fuel switching, preventing knocking caused by residual fuel.
Solution Approach 2:
The system continuously monitors alcohol concentration from the sensor and provides feedback to the control unit. The control unit uses this feedback to determine fuel switching status, adjust the advance correction amount accordingly, and ensure ignition timing matches the actual fuel composition, thereby maintaining measurement accuracy despite sensor positioning.
2Use of energy by moving object
If the advance correction amount is calculated based on high alcohol concentration to enhance fuel efficiency, then fuel efficiency is improved, but knocking resistance deteriorates when residual low-alcohol fuel is injected
Solution Approach 1:
The control unit applies preliminary anti-action by restricting the advance correction amount to a value corresponding to low alcohol concentration during the fuel switching period. This prevents the harmful effect of advanced ignition timing on residual low-alcohol fuel, which would cause knocking, while allowing full advance correction to be applied after switching is complete to maximize fuel efficiency.
3Productivity
If the target ignition timing is set based on advance correction amount corresponding to sensor alcohol concentration, then fuel efficiency is maximized, but knocking resistance deteriorates during fuel switching period
Solution Approach 1:
The system dynamically adjusts the advance correction amount based on the fuel switching status. During the switching period, the advance correction amount is restricted to a conservative value to prevent knocking from residual fuel. After switching is complete, the advance correction amount is updated to reflect the new fuel composition, maximizing fuel efficiency. This dynamic adjustment resolves the contradiction between productivity and harmful factors.
Data Source
AI summary
An ignition timing control device for an internal combustion engine including: a setting unit configured to set a target ignition timing of the internal combustion engine based on a reference ignition timing and an advance correction amount; a start determination unit configured to determine, based on change in an alcohol concentration, whether or not the fuel injected from a fuel injection valve starts to switch from a first fuel to a second fuel higher in the alcohol concentration than the first fuel; a completion determination unit configured to determine whether or not switching to the second fuel is completed; a restriction unit configured to restrict the advance correction amount during a switching period to the advance correction amount corresponding to the alcohol concentration of the first fuel or lower; and a cancel unit configured to cancel restriction of the advance correction amount after the completion of the switching is determined.