Engine Control Unit Ignition Timing and Fuel Injection Strategy
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Solution Overview
Problem
Internal combustion engines face the challenge of overheating catalysts when ignition timing is retarded, as existing solutions rely on increasing fuel injection amounts which may not be immediate enough to prevent overheating.
Innovation Solution
A control device for internal combustion engines that calculates and adjusts ignition timing and fuel injection amounts at specific crank angles before compression top dead center, allowing for early ignition retardation while minimizing catalyst overheating by performing additional fuel injections before ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the ignition timing is retarded to perform torque down, then the exhaust gas temperature increases, but the catalyst may be overheated
Solution Approach 1:
The system performs preliminary action by calculating the required additional fuel injection amount based on the ignition timing retard amount in advance, before the actual injection occurs. This allows the ECU to prepare the correct fuel quantity that will be injected to suppress catalyst overheating while enabling the ignition retard for torque down.
Solution Approach 2:
The system changes the fuel injection amount parameter in response to ignition timing retardation. When the ignition timing is retarded, the ECU increases the fuel injection amount proportionally to the retard amount, thereby using the heat of vaporization of the additional fuel to suppress the rise in exhaust gas temperature and catalyst temperature.
2Temperature
If the fuel injection amount is increased to suppress catalyst overheating, then the exhaust gas temperature is suppressed, but the implementation of ignition retard must be delayed
Solution Approach 1:
The ECU performs preliminary calculation of the additional fuel injection amount based on the ignition timing retard amount before the actual injection occurs. This preliminary action allows the system to implement ignition retard immediately without waiting for the fuel injection to be processed, thereby eliminating the time delay while still achieving temperature suppression through the subsequently injected fuel.
Solution Approach 2:
The fuel injection process is segmented into regular injection and additional injection. The additional injection is specifically controlled based on the ignition timing retard amount, allowing independent optimization of each injection phase. This segmentation enables the system to implement ignition retard immediately while the additional fuel is injected separately to suppress temperature rise.
3Temperature
If the fuel injection amount is increased when ignition timing is retarded, then the catalyst overheating is suppressed, but the response speed of fuel injection increase is insufficient
Solution Approach 1:
The ECU performs preliminary calculation of the additional fuel injection amount based on the ignition timing retard amount before the actual injection occurs. This preliminary calculation of the injection amount based on predetermined crank angle enables the system to immediately implement ignition retard while ensuring the correct fuel quantity is injected without delay, thereby achieving both fast response and effective temperature suppression.
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
Enables early ignition timing retardation while effectively suppressing catalyst overheating by ensuring timely and increased fuel injection, even in high-load and high-speed conditions.
Implementation Method 1
it is possible to suppress a rise in the temperature of the exhaust gas and the catalyst by the heat of vaporization of the fuel
Data Source
AI summary
A control device for an internal combustion engine capable of performing additional injection in addition to regular injection includes an electronic control unit. The electronic control unit is configured to calculate an ignition timing at a predetermined crank angle before a compression top dead center. The electronic control unit is configured to calculate an injection amount of fuel at a predetermined time interval and to calculate an injection amount of the fuel at the predetermined crank angle. The electronic control unit is configured to control the fuel injection valve such that the fuel injection valve additionally injects the fuel in an increase amount before ignition, when the injection amount calculated at the predetermined crank angle is increased due to retardation of the ignition tinting calculated after the fuel in the injection amount calculated at the predetermined time interval is regularly injected.