Aftertreatment Temperature Control During Jake and Exhaust Braking
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Solution Overview
Problem
The temperature of the aftertreatment system in vehicles is not effectively maintained during braking, leading to decreased catalyst purification efficiency and emission of harmful nitrogen oxides when auxiliary brakes are used, causing the selective catalytic reduction system to malfunction.
Innovation Solution
A method and device that control the engine by operating a retarder, jake brake device, or exhaust brake device to manage the temperature of the exhaust gas introduced into the aftertreatment system, including adjusting air supply, exhaust gas recirculation, and using a bypass passage to maintain optimal temperature and prevent catalyst temperature degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a jake brake device or exhaust brake device is operated to reduce engine RPM during downhill braking, then the braking force is improved, but the exhaust gas temperature decreases causing aftertreatment system temperature degradation
Solution Approach 1:
The patent introduces a control system as an intermediary that manages the interaction between the brake devices and the aftertreatment system. The controller monitors temperatures and selectively operates brake devices only when the aftertreatment system temperature is above a threshold, mediating between the braking requirement and temperature maintenance needs
Solution Approach 2:
The system changes the operational parameters of the brake devices based on temperature conditions. When the aftertreatment system temperature is sufficient, the brake devices are operated normally; when temperature drops below the threshold, the brake devices are restricted or disabled, dynamically adjusting the braking parameter to maintain temperature
2Power
If auxiliary brakes are used during downhill driving, then the driving force control is improved, but the catalyst purification efficiency decreases due to temperature drop
Solution Approach 1:
The system implements feedback control by continuously monitoring the aftertreatment system temperature and using this information to control the operation of auxiliary brakes. The controller receives temperature signals and adjusts brake device operation accordingly, creating a closed-loop control system that maintains catalyst temperature within the effective purification range
Solution Approach 2:
The system takes preliminary anti-action by preventing the temperature drop before it can harm the catalyst efficiency. The controller predicts temperature degradation and restricts auxiliary brake operation before the temperature actually drops to harmful levels, maintaining the temperature above the threshold required for effective purification
3Temperature
If the exhaust gas flow is increased to maintain aftertreatment system temperature, then the temperature maintenance is improved, but the nitrogen oxide emissions increase
Solution Approach 1:
The system dynamically adjusts the exhaust gas flow based on real-time temperature conditions. Rather than maintaining a constant high flow rate, the controller modulates the exhaust flow to match the actual temperature needs, increasing flow only when necessary to prevent temperature drop and reducing flow when temperature is sufficient, thereby minimizing NOx emissions while maintaining purification efficiency
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 ensures the aftertreatment system operates normally without degrading catalyst purification efficiency, maintaining the temperature and preventing nitrogen oxide emissions by managing exhaust gas temperature effectively during braking.
Implementation Method 1
discharges a fuel-air mixture compressed in an explosion stroke of an engine
Implementation Method 2
blocks a discharge of the exhaust gas of the engine to a rear end of the exhaust pipe
Implementation Method 3
an amount of the exhaust gas, of which a temperature is lowered due to the operation of the jake brake device or the exhaust brake device, introduced into the aftertreatment system is decreased
Data Source
AI summary
A method of maintaining a temperature of an aftertreatment system of a vehicle, the method including: operating, by a controller, a retarder reducing driving force of a propeller shaft of the vehicle in response to a retarder operation request signal; operating, by the controller, a jake brake device which discharges a fuel-air mixture compressed in an explosion stroke of the engine to an exhaust pipe and decreases revolutions per minute (RPM) of the engine or an exhaust brake device which blocks a discharge of the exhaust gas of the engine to a rear end of the exhaust pipe and decreases the RPM of the engine, in order to remove the output error value; and controlling, by the controller, the engine so that an amount of exhaust gas introduced into the aftertreatment system is decreased.