Engine Control Device Managing Catalyst Oxygen Storage During Temperature Raising
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The NOx reduction capability of catalysts in internal combustion engines is compromised during the fuel cut process and subsequent temperature raising processes, leading to reduced efficiency and increased fuel consumption.
Innovation Solution
A control device and method for internal combustion engines that execute a temperature raising process with a stopping and rich process, followed by a recovery-time process to manage the air-fuel ratio and oxygen storage in the catalyst, ensuring optimal NOx reduction and minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the temperature raising process is executed to raise the post-processing device temperature, then the temperature of the post-processing device is improved, but the NOx reduction capability of the catalyst is lowered after the process is stopped
Solution Approach 1:
The patent applies preliminary action by executing a recovery-time process before normal operation resumes after the temperature raising process. This process pre-adjusts the air-fuel ratio to a specific value that ensures the catalyst maintains sufficient oxygen storage capacity, preventing the deterioration of NOx reduction capability that would otherwise occur after the temperature raising process stops.
Solution Approach 2:
The patent applies preliminary anti-action by introducing a recovery-time process that counteracts the harmful effect of oxygen depletion in the catalyst. By controlling the air-fuel ratio to a specific value during this recovery period, the system preemptively restores oxygen storage capacity in the catalyst, neutralizing the negative impact caused by the temperature raising process before it affects NOx reduction performance.
2Temperature
If the air-fuel ratio is made richer than the stoichiometric air-fuel ratio during the temperature raising process, then the temperature of the post-processing device is raised, but the amount of oxygen stored in the catalyst becomes large
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the air-fuel ratio through a multi-stage control strategy. During the temperature raising process, the air-fuel ratio is set to a first specific value to raise temperature. After stopping the process, a recovery-time process adjusts it to a second specific value to restore oxygen storage. Finally, during normal operation, it transitions to a third specific value for optimal fuel efficiency, creating a dynamic adaptation to different operational phases.
Solution Approach 2:
The patent applies periodic action by implementing a cyclic control pattern with distinct phases: the temperature raising process with rich air-fuel ratio, followed by the recovery-time process with adjusted air-fuel ratio, and then normal operation with stoichiometric or lean mixtures. This periodic switching allows the system to repeatedly raise and restore oxygen storage capacity as needed, maintaining catalyst performance over time.
3Use of energy by moving object
If the fuel cut process is executed to stop fuel supply during vehicle deceleration, then fuel consumption is reduced, but the NOx reduction capability of the catalyst is lowered when the process is stopped
Solution Approach 1:
The patent applies preliminary action by executing a recovery-time process immediately after the fuel cut process stops. This process adjusts the air-fuel ratio to a specific value that restores oxygen storage capacity in the catalyst before normal operation resumes, preventing the deterioration of NOx reduction capability that would otherwise result from the fuel cut process.
Solution Approach 2:
The patent applies preliminary anti-action by introducing the recovery-time process that counteracts the harmful effect of oxygen depletion caused by the fuel cut process. By controlling the air-fuel ratio during this recovery period, the system preemptively restores the catalyst's oxygen storage capacity, neutralizing the negative impact on NOx reduction performance before it manifests.
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
The solution effectively suppresses the reduction in NOx reduction capability and maintains efficient fuel consumption by strategically adjusting the air-fuel ratio and oxygen storage in the catalyst during and after the temperature raising process.
Implementation Method 1
a catalyst having an oxygen storage capability and provided in an exhaust passage of the internal combustion engine
Implementation Method 2
the capability of the catalyst to reduce NOx
Implementation Method 3
unburned fuel and oxygen into exhaust gas
Data Source
AI summary
A control device and a control method for a multi-cylinder internal combustion engine including a post-processing device are provided. The control device includes an electronic control unit executing a temperature raising process of raising the temperature of the post-processing device and a recovery-time process. The temperature raising process includes a stopping process and a rich process. In the stopping process, supply of fuel to several of cylinders is stopped. In the rich process, the air-fuel ratio of an air-fuel mixture for different ones of the cylinders other than the several cylinders is made lower than the stoichiometric air-fuel ratio. In the recovery-time process, the concentration of unburned fuel in exhaust gas discharged to the exhaust passage is made higher than an equivalent concentration, when the temperature raising process is stopped. The equivalent concentration is the concentration of unburned fuel being just enough to react with oxygen in the exhaust gas.