Engine Restart Control for Hot Catalyst Protection
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Solution Overview
Problem
High catalyst temperatures in internal combustion engines lead to catalyst deterioration when oxygen-rich gases flow into the exhaust control catalyst during engine restart, causing premature wear.
Innovation Solution
Implementing an early start mode that uses specific start processes and stop position control to minimize oxygen entry into the catalyst, where the engine is started using both first and second start processes when the catalyst temperature is high, and adjusting fuel injection timing based on outside air temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine is restarted immediately after stopping, then the engine can quickly resume operation, but oxygen-rich gases flow into the high-temperature catalyst causing catalyst deterioration
Solution Approach 1:
The control device stores the crank stop position detected when the engine stops, and uses this stored position to immediately determine the crank angle for fuel injection and ignition upon restart. This preliminary preparation eliminates the need for cylinder identification during restart, enabling immediate combustion without delaying engine resumption while preventing oxygen-rich gases from damaging the hot catalyst.
Solution Approach 2:
The system changes the operational parameters of fuel injection and ignition timing based on the stored crank stop position. By adjusting these parameters according to the pre-stored positional data, the system achieves immediate combustion upon restart without requiring the engine to rotate through multiple cycles, thus protecting the catalyst from oxygen exposure while maintaining quick restart capability.
2Measurement precision
If fuel injection and ignition are delayed until cylinder identification is complete, then accurate combustion control is achieved, but oxygen enters the catalyst during the delay period
Solution Approach 1:
The crank stop position is stored in advance when the engine stops, serving as pre-prepared data that eliminates the need for real-time cylinder identification during restart. This preliminary action allows the control device to immediately determine the correct crank angle for fuel injection and ignition, achieving both measurement precision and immediate combustion without oxygen exposure.
Solution Approach 2:
The system uses a copy of the crank stop position data stored in memory during engine stop to replace the need for real-time sensor detection during restart. This copied positional information enables immediate and accurate combustion control without requiring the engine to rotate through additional cycles for cylinder identification, thus preventing oxygen from reaching the catalyst.
3Stability of the object's composition
If the crankshaft rotates multiple times during restart, then the engine stabilizes operation, but extended oxygen exposure accelerates catalyst deterioration
Solution Approach 1:
By storing the crank stop position in advance and using it to immediately control fuel injection and ignition upon restart, the system achieves combustion in the first expansion stroke. This eliminates the need for multiple crankshaft rotations to stabilize operation, thereby minimizing the duration of oxygen exposure to the catalyst while maintaining engine stability.
Solution Approach 2:
The system skips the traditional multi-rotation stabilization period by using the stored crank stop position to achieve immediate combustion upon restart. This rushing through of the startup process reduces the time oxygen is exposed to the catalyst while still achieving stable engine operation through precise crank angle control from the beginning.
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
Reduces catalyst deterioration by minimizing oxygen entry during high-temperature restarts and optimizing fuel injection timing, effectively extending catalyst life while maintaining engine performance.
Implementation Method 1
exhaust control catalyst (hereinafter sometimes simply referred to as the 'catalyst')
Implementation Method 2
combustion can be performed in the first expansion stroke
Data Source
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AI summary
A powertrain system includes a port injection internal combustion engine. A first start process is a process in which fuel is enclosed in a compression stroke cylinder when the engine is stopped, and based on a stored crank stop position, ignition is performed in a first cycle of the compression stroke cylinder upon engine start. A second start process is a process in which, based on the stored crank stop position, fuel injection is performed for an intake stroke cylinder while the engine is stopped, and based on the stored crank stop position, ignition is performed in the first cycle of the intake stroke cylinder upon engine start. When a catalyst temperature at the time engine start is requested is equal to or higher than a first threshold, a control device starts the internal combustion engine by at least one of the first start process and the second start process.