Engine Control Device for Pre-ignition Prevention
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Solution Overview
Problem
Existing engine control methods fail to effectively prevent pre-ignition in low-revolution, high-load operation ranges without significantly deteriorating engine output, particularly in high compression ratio engines and those with superchargers.
Innovation Solution
An engine control device with a first fuel injection valve and a second fuel injection valve, where the second valve injects less fuel to the cylinder wall, adjusts the fuel injection ratio and timing based on cooling water temperature to prevent pre-ignition, increasing the fuel injection ratio of the second valve as temperature falls and advancing or retarding injection timing as necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel injection ratio of the second fuel injection valve is increased to prevent pre-ignition in low-revolution, high-load operation range, then pre-ignition prevention is improved, but engine output may deteriorate
Solution Approach 1:
The fuel injection ratio is made dynamically adjustable based on cooling water temperature. The control device increases the fuel injection ratio of the second fuel injection valve when cooling water temperature is low (indicating cold engine conditions in low-revolution, high-load range), and reduces it when temperature is high. This dynamic adjustment prevents pre-ignition when needed while maintaining engine output under normal conditions.
Solution Approach 2:
The invention changes the parameter of fuel injection ratio based on cooling water temperature. By detecting temperature and adjusting the injection ratio accordingly, the system adapts fuel distribution to thermal conditions, preventing pre-ignition during cold operation without compromising performance during warm operation.
2Reliability
If conventional methods (lowering supercharging pressure or retarding intake valve) are used to prevent pre-ignition, then pre-ignition prevention is improved, but engine output is markedly deteriorated
Solution Approach 1:
Instead of globally reducing supercharging pressure or retarding intake valve timing, the invention applies a localized solution by adjusting fuel injection ratio specifically for the second fuel injection valve. This targeted approach addresses pre-ignition in the cold engine condition without affecting overall engine performance parameters.
Solution Approach 2:
The invention segments the fuel injection system into two separate injection valves with different functions. The first valve provides main fuel injection, while the second valve provides additional fuel specifically when needed for pre-ignition prevention. This segmentation allows independent control of pre-ignition prevention without compromising main fuel delivery.
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
Effectively prevents pre-ignition occurrences without substantial engine output degradation by optimizing fuel distribution and timing in response to cooling water temperature, specifically in low-revolution, high-load conditions.
Implementation Method 1
a cooling water temperature detecting means (25) for detecting a temperature of cooling water for cooling the engine
Implementation Method 2
a first fuel injection valve (A); a second fuel injection valve (B) provided at such a position that an amount of fuel injected by the second fuel injection valve (B) and adhering to an inner peripheral wall of the cylinder is smaller than an amount of fuel injected by the first fuel injection valve (A) and adhering to the inner peripheral wall of the cylinder
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2F
AI summary
In order to effectively prevent the occurrence of pre-ignition without markedly deteriorating engine output, an engine control device is provided which includes a first fuel injection valve (A) and a second injection valve (B) provided at such a position that the amount of fuel injected by the second fuel injection valve and adhering to the inner peripheral wall of a cylinder is smaller than that of fuel injected by the first fuel injection valve and adhering to the inner peripheral wall of the cylinder. The engine control device further includes a cooling water temperature detecting means (25) for detecting the temperature of cooling water for cooling an engine (1), and an injection ratio determining means (21) for determining the ratio between the amount of fuel injected by the first fuel injection valve and the amount of fuel injected by the second fuel injection valve based on the temperature of cooling water. The injection ratio determining means (21) stores an injection amount adjustment operation range (R) in which the injection ratio determining means is configured to increase the fuel injection ratio of the amount of fuel injected by the second fuel injection valve to the total amount of fuel injected by the first fuel injection valve and the second fuel injection valve, when the temperature of cooling water falls.