Compression-Ignition Engine Control System Switching Logic
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Solution Overview
Problem
Existing compression-ignition internal combustion engines face challenges in preventing premature ignition and misfire, which affect drivability and fuel consumption performance, particularly when switching between spark-ignition and compression-ignition operations.
Innovation Solution
A control system that includes a prohibitive condition determiner to assess whether certain conditions are met to prohibit switching from spark-ignition to compression-ignition operation, utilizing a gas temperature regulator, DBW mechanism, and turbocharger to manage gas temperature and torque requirements, ensuring normal operation and preventing premature ignition and misfire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine switches to compression-ignition operation based on coolant temperature alone, then the engine can achieve higher thermal efficiency and fuel consumption performance, but premature ignition and misfire occur affecting drivability
Solution Approach 1:
The patent applies parameter changes by considering multiple parameters (coolant temperature, intake air temperature, engine load, engine speed) instead of relying solely on coolant temperature. The ECU calculates a specific parameter (intake air temperature corrected value) to determine the appropriate timing for switching to compression-ignition operation, ensuring both fuel efficiency and drivability stability.
Solution Approach 2:
The system uses feedback by continuously monitoring multiple sensor inputs (coolant temperature sensor, intake air temperature sensor, load sensor, speed sensor) and using this information to dynamically adjust the switching decision. The ECU processes this feedback information to determine the optimal timing for compression-ignition operation, preventing premature ignition while maintaining fuel efficiency.
2Device complexity
If the engine switches to compression-ignition operation without considering multiple factors, then the control system is simple, but misfire and premature ignition occur affecting fuel consumption performance
Solution Approach 1:
The ECU performs multiple functions by integrating temperature monitoring, load detection, speed sensing, and switching control into a single control unit. This multi-functional approach allows the system to consider multiple factors for optimal switching decisions without significantly increasing overall system complexity, maintaining both simplicity and fuel consumption performance.
Solution Approach 2:
The patent changes the control parameter from a single parameter (coolant temperature) to a composite parameter that incorporates multiple factors including intake air temperature correction. This parameter transformation allows the system to make more accurate switching decisions without requiring a fundamentally more complex control architecture.
3Use of energy by moving object
If the engine uses higher compression ratios for compression-ignition operation, then thermal efficiency is improved, but the risk of premature ignition increases affecting overall performance
Solution Approach 1:
The system performs preliminary action by calculating the intake air temperature corrected value and determining the appropriate switching timing before actual compression-ignition operation begins. This advance preparation allows the engine to switch to compression-ignition mode at the optimal moment, maximizing thermal efficiency while preventing premature ignition through proper timing control.
Solution Approach 2:
The patent uses parameter changes by introducing the intake air temperature corrected value as a key parameter for determining switching timing. This parameter transformation allows the system to account for environmental conditions and adjust the compression-ignition switching point optimally, enabling higher compression ratios to be used safely for improved thermal efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively prevents premature ignition and misfire, maintaining drivability and fuel efficiency by prohibiting undesirable switches and ensuring stable combustion conditions.
Implementation Method 1
ignition in which the air-fuel mixture supplied to the combustion chamber auto-ignites and burns as a result of being compressed by the piston
Implementation Method 2
compression-ignition, i.e., ignition in which the air-fuel mixture supplied to the combustion chamber auto-ignites and burns as a result of being compressed by the piston
Implementation Method 3
spark-ignition, i.e., ignition in which the air-fuel mixture is ignited to burn by a spark plug
Data Source
AI summary
In a control system for a compression-ignition engine whose operation is switchable between a compression-ignition operation in which an air-fuel mixture supplied to a combustion chamber auto-ignites to burn owing to compression and a spark-ignition operation in which the air-fuel mixture is ignited to burn by a spark of a spark plug, it is determined whether a predetermined prohibitive condition to prohibit switching from the spark-ignition to the compression-ignition operation is satisfied, and switching from the spark-ignition operation to the compression-ignition operation is prohibited when the predetermined prohibitive condition is satisfied, thereby enabling to avoid premature ignition and misfire and to prevent drivability and fuel consumption performance from being affected therefrom.