Engine Control Device Humidity-Based Compression Ratio Adjustment
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Solution Overview
Problem
Existing control devices for internal combustion engines with variable compression ratio mechanisms face challenges in synchronizing compression ratio and ignition timing adjustments according to humidity, leading to control delays and inefficiencies, particularly in preventing abnormal combustion.
Innovation Solution
A control device that determines corresponding characteristics between compression ratio and ignition timing based on humidity and operational conditions, allowing for real-time adjustments of the compression ratio and ignition timing to maximize efficiency and prevent abnormal combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compression ratio is increased to improve thermal efficiency and reduce fuel consumption, then the thermal efficiency is improved, but the pressure and temperature in the engine are increased causing abnormal combustion such as knocking
Solution Approach 1:
The patent implements a variable compression ratio mechanism that dynamically adjusts the compression ratio based on operating conditions (load, speed, humidity). The system transitions from a fixed compression ratio to a dynamically adjustable one, allowing the engine to optimize thermal efficiency at low loads while preventing knocking at high loads by reducing compression ratio when necessary.
Solution Approach 2:
The system changes the compression ratio parameter according to operating conditions and humidity levels. By detecting humidity and adjusting the target compression ratio accordingly, the system optimizes combustion efficiency while preventing abnormal combustion. The control unit modifies the compression ratio parameter in real-time based on sensor inputs and operational state.
2Reliability
If the variable compression ratio mechanism is controlled to change compression ratio according to humidity, then the appropriate compression ratio is achieved, but there is a control delay until the target compression ratio is realized
Solution Approach 1:
The control unit determines the target compression ratio in advance based on detected humidity and operational state before the actual compression ratio change is complete. By calculating the target value proactively, the system minimizes delay in achieving the appropriate compression ratio setting.
Solution Approach 2:
The system continuously monitors the actual compression ratio and compares it with the target compression ratio. The control unit adjusts the variable compression ratio mechanism based on feedback from the actual state, ensuring the target is achieved accurately while minimizing overall control delay through iterative adjustment.
3Use of energy by moving object
If the ignition timing is controlled based on compression ratio changes, then the combustion efficiency is optimized, but it is impossible to control appropriate ignition timing until the compression ratio change is completed
Solution Approach 1:
The control unit determines the appropriate ignition timing in advance based on the target compression ratio and detected humidity, even before the actual compression ratio change is complete. This preliminary determination of ignition timing allows the system to optimize combustion efficiency without waiting for the compression ratio adjustment to finish.
Solution Approach 2:
The ignition timing is dynamically adjusted based on the current compression ratio state and target compression ratio. The system continuously updates the ignition timing as the compression ratio changes, rather than waiting for the compression ratio to be fully adjusted before modifying ignition timing.
4Loss of energy
If the compression ratio is increased to maximize fuel consumption reduction, then the fuel consumption is reduced, but the setting of appropriate compression ratio varies depending on engine output and rotational speed requiring complex control
Solution Approach 1:
The system uses humidity as an additional parameter to determine the target compression ratio, alongside engine load and speed. By incorporating humidity detection and using it as a key input parameter, the system simplifies the control logic while achieving optimal fuel consumption reduction across varying operating conditions.
Solution Approach 2:
The control system integrates multiple functions into a single control unit that manages both the variable compression ratio mechanism and ignition timing based on humidity and operational state. This multi-functional approach reduces overall system complexity by consolidating control functions rather than using separate systems for each parameter.
Data Source
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AI summary
It is an object of the present invention to provide a control device for an internal combustion engine capable of appropriately controlling compression ratio and ignition timing before the target compression ratio that is set according to humidity is attained. A control device for an internal combustion engine controls the internal combustion engine including a cylinder, humidity detection means for detecting humidity of outside air supplied to the cylinder, a variable compression ratio mechanism for changing a compression ratio of the cylinder, and an ignition device igniting air-fuel mixture in the cylinder, and the control device includes: a compression ratio control unit controlling the variable compression ratio mechanism; and an ignition control unit controlling ignition timing of the ignition device, wherein corresponding characteristics between compression ratio and ignition timing are determined for each humidity according to a predetermined condition of an operation state of the internal combustion engine, the compression ratio control unit determines a target compression ratio of the variable compression ratio mechanism according to the detected humidity, and while the variable compression ratio mechanism changes a compression ratio to the target compression ratio, the ignition control unit controls the ignition device on the basis of corresponding characteristics determined according to the detected humidity.