Engine Combustion Control for Catalyst Warm-up
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Solution Overview
Problem
Vehicles equipped with engines performing combustion strokes at uneven intervals face challenges in suppressing unburned gas emissions during warm-up operations due to insufficient catalyst purification efficiency at low temperatures and interference from crankshaft acceleration.
Innovation Solution
Implementing a control method that switches between normal and pause modes, where the pause mode suppresses the shortest combustion interval, thereby reducing unburned gas generation, and uses the pause mode for warm-up operations to enhance catalyst temperature and purification efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the engine performs combustion strokes at uneven intervals to improve traction recovery, then wheel traction is improved during combustion intervals, but unburned gas emissions increase during warm-up operations
Solution Approach 1:
The patent dynamically adjusts the combustion interval pattern based on operating conditions. During warm-up operations, the control device switches from uneven interval combustion (which improves traction) to equal interval combustion (which reduces unburned gas emissions). This dynamic switching allows the system to optimize for different priorities depending on the operational phase.
Solution Approach 2:
The control device changes the combustion interval parameter from uneven to equal intervals during warm-up operations. This parameter change directly addresses the emission problem by ensuring sufficient combustion time for all cylinders, while maintaining the uneven interval pattern during normal operation for traction benefits.
2Speed
If the catalyst operates at low temperature during warm-up to enable early operation, then the vehicle can start quickly, but the catalyst cannot sufficiently purify unburned gas
Solution Approach 1:
The control device performs preliminary action by detecting warm-up conditions and proactively switching to equal interval combustion mode before significant unburned gas emissions occur. This preliminary switch ensures that during the critical warm-up phase when the catalyst is ineffective, the combustion pattern already optimized for emission reduction is in place.
Solution Approach 2:
The control device uses feedback from temperature sensors and operational condition detection to determine when to switch combustion patterns. By monitoring engine temperature and operational state, the system automatically adjusts the combustion interval pattern to match the current thermal state of the catalyst and engine.
3Speed
If the combustion period of a cylinder is insufficient due to crankshaft acceleration effects, then the engine responds quickly to traction demands, but unburned gas generation increases
Solution Approach 1:
The system dynamically selects between uneven interval patterns (for rapid response) and equal interval patterns (for complete combustion). During warm-up, the equal interval pattern is selected to ensure sufficient combustion time. During normal operation, the uneven interval pattern is selected to maximize traction response, accepting the trade-off of potential unburned gas that the active catalyst can handle.
Solution Approach 2:
The control device changes the combustion timing parameter based on operational phase. By adjusting the interval between combustions from unequal to equal during warm-up, the system ensures adequate combustion duration for each cylinder while maintaining the flexibility to switch back to unequal intervals for performance optimization.
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 reduces unburned gas emissions during warm-up by optimizing combustion intervals and ensuring efficient catalyst activation, improving engine performance and emissions control.
Implementation Method 1
a catalyst is used to purify the unburned gas... since a temperature of the catalyst is low during execution of a warm-up operation, there is a possibility that the catalyst cannot sufficiently exert the function of purifying unburned gas
Implementation Method 2
a plurality of cylinders to sequentially perform a combustion stroke... due to an effect of acceleration of a crankshaft caused by a cylinder which performed the first combustion stroke
Data Source
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AI summary
It is possible to suppress the amount of unburned gas to be emitted during execution of a warm-up operation. A vehicle includes an engine which causes cylinders to perform a combustion stroke at a first interval where a crankshaft rotates at a first angle, at a second interval where the crankshaft rotates at a second angle smaller than the first angle, and at a third interval where the crankshaft rotates at a third angle smaller than the second angle, respectively, a catalyst configured to purify gas emitted from the cylinders, and a controller configured to perform a normal mode which causes the cylinders to perform the combustion stroke so that the combustion stroke occurs at the first interval, at the second interval, and at the third interval, and a pause mode which causes one cylinder to pause the combustion stroke while causing the other cylinders to perform the combustion stroke, and in the vehicle, the one cylinder performs an explosion at a boundary between the second interval and the third interval that are successive in the normal mode, and before the normal mode, the controller performs a warm-up operation to increase a temperature of the catalyst by the pause mode.