Engine Control Device Fuel Cut for Pre-Ignition Protection
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Solution Overview
Problem
Existing engine control devices fail to adequately protect engine hardware during fuel shortages, as they can cause pre-ignition and catalyst damage due to lean air-fuel ratios and increased engine load.
Innovation Solution
An engine control device with modules for detecting fuel tank levels, engine rotation speed, load, and air-fuel ratios, which executes fuel cuts when pre-ignition or catalyst protection regions are detected, using sensors and a microcomputer to prevent damage by controlling fuel supply based on threshold values and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel supply is reduced during fuel shortage, then fuel consumption is optimized, but pre-ignition occurs and engine hardware is damaged
Solution Approach 1:
The control device dynamically changes the fuel supply parameter based on detected engine operating conditions (rotation speed and load). When the engine operates in a pre-ignition occurring region, the fuel supply is stopped; when operating in a catalyst protection region, fuel supply is maintained. This parameter change approach resolves the contradiction by adapting fuel supply to specific operating conditions rather than uniformly reducing it.
Solution Approach 2:
The control device uses feedback from the rotation speed detection unit and load calculating module to continuously monitor engine operating conditions. Based on this feedback, the fuel cut execution control module adjusts fuel supply in real-time, stopping fuel when pre-ignition risk is detected and maintaining fuel supply when catalyst protection is needed. This closed-loop feedback mechanism resolves the contradiction by making fuel supply decisions based on actual engine state.
2Object-affected harmful factors
If fuel supply is stopped to prevent pre-ignition, then engine hardware is protected, but engine operation is disrupted
Solution Approach 1:
The control device applies different fuel supply strategies to different operating conditions by defining distinct regions (pre-ignition occurring region vs. catalyst protection region) in the engine's operating map. Fuel supply is stopped only in the pre-ignition occurring region while maintaining fuel supply in the catalyst protection region. This local differentiation approach protects engine hardware while minimizing disruption to overall engine operation.
3Loss of energy
If fuel supply is reduced to extend fuel tank duration, then fuel economy improves, but catalyst damage occurs due to lean air-fuel ratio
Solution Approach 1:
The control device changes the fuel supply parameter based on the detected operating region. In the catalyst protection region, fuel supply is maintained to prevent catalyst damage, while in other regions during fuel shortage, fuel supply may be reduced. This conditional parameter change resolves the contradiction by protecting the catalyst when operating conditions require it while still extending fuel duration when safe to do so.
Data Source
AI summary
An engine control device includes: a pre-ignition determination module that determines whether an operation state of an engine indicated by a rotation speed detected by a rotation speed detection unit and a load calculated by a load calculating module is in a pre-ignition occurring region; a catalyst protection determination module that determines whether the operation state of the engine is in a catalyst protection region; and a fuel cut execution control module that stops a fuel supplied to the engine, when a remaining amount of a fuel tank is determined to be smaller than a tank threshold value and the operation state is determined to be in the pre-ignition occurring region, and when the remaining amount of the fuel tank is determined to be smaller than the tank threshold value and the operation state is determined to be in the catalyst protection region.