Exhaust Valve Timing for Efficient Temperature Control
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Solution Overview
Problem
Current methods for increasing exhaust flow temperatures in internal combustion engines are inefficient, particularly at low power output, and often result in emissions spikes or require user intervention, with limited precision and slow response times.
Innovation Solution
A method and system that dynamically adjust the crankshaft angle for exhaust valve opening to efficiently increase exhaust flow temperatures by interpreting temperature requirements and engine operating conditions, using a controller with modules for temperature determination, operating condition monitoring, and actuation to engage the exhaust valve open mode at specific crankshaft angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If in-cylinder dosing is used to increase exhaust flow temperature, then the exhaust flow temperature increases to facilitate aftertreatment regeneration, but there is a significant time lag between dosing and temperature increase, and emissions may spike during dosing phase
Solution Approach 1:
The system performs preliminary actions by adjusting exhaust valve timing before fuel dosing is required. By pre-positioning the exhaust valve to create optimal pressure pulses, the system reduces the time lag between initiating temperature increase and achieving the desired effect in aftertreatment devices.
Solution Approach 2:
The system employs periodic exhaust valve timing adjustments synchronized with engine cycles to generate repeated pressure pulses. This periodic action maintains sustained temperature increases in the exhaust flow, ensuring continuous effective regeneration of aftertreatment components rather than single transient spikes.
2Temperature
If in-cylinder dosing is used to increase exhaust flow temperature, then the exhaust flow temperature increases to facilitate aftertreatment regeneration, but emissions may spike during dosing phase with EGR shut off
Solution Approach 1:
The exhaust valve timing adjustment serves as an intermediary mechanism that indirectly influences exhaust temperature through pressure pulse generation. This intermediary approach allows temperature control without directly injecting fuel, thereby avoiding the emissions spikes associated with traditional dosing methods.
Solution Approach 2:
The system utilizes the engine's own exhaust gas flow and pressure dynamics to achieve temperature increases. By manipulating valve timing to create pressure pulses that leverage existing exhaust energy, the system self-regulates temperature without requiring additional fuel injection that would generate harmful emissions.
3Temperature
If exhaust valve timing changes are used to produce pressure pulses, then temperature increases are generated in the aftertreatment device, but the response is modal with no control over generated pressure pulses and limited effect on temperature generation
Solution Approach 1:
The system dynamically adjusts exhaust valve timing based on real-time engine operating conditions and aftertreatment device temperature requirements. This dynamic control enables precise modulation of pressure pulse characteristics, transforming the static modal response into a controllable, adaptive system that can precisely target desired temperature ranges.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor exhaust flow temperature and aftertreatment device status, then adjust exhaust valve timing accordingly. This closed-loop feedback enables precise control over generated pressure pulses, ensuring optimal temperature generation while preventing excessive or insufficient heating.
4Temperature
If current methods are used to increase exhaust flow temperature, then regeneration of aftertreatment components is achieved, but the methods lack capability at low engine exhaust flow and power output
Solution Approach 1:
The system changes operational parameters by adjusting exhaust valve timing angles and duration based on engine operating conditions. At low power output, the system optimizes valve timing to maximize pressure pulse efficiency, enabling effective temperature generation across the full range of engine operating conditions rather than only at high power levels.
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
This approach allows for precise and efficient temperature control within a given range, improving the operation and efficiency of aftertreatment components without emissions spikes, even at low engine power output.
Implementation Method 1
utilizes modest changes in exhaust valve timing to produce pressure pulses across an aftertreatment device
Data Source
AI summary
An apparatus, system, and method are disclosed for efficiently increasing exhaust flow temperature for an internal combustion engine. The method includes excepting a user input to disable an exhaust valve opening mechanism. The method further includes monitoring exhaust gas mass flows and temperatures, interpreting required exhaust temperatures for aftertreatment devices, and surveying a plurality of operating conditions for a combustion engine. The method includes determining a crankshaft angle for dynamically engaging an exhaust valve open mode based on the exhaust temperature, the required exhaust temperature, and the engine operating conditions. Dynamically engaging the exhaust valve open mode includes selecting a specific crankshaft angle for each combustion cycle of the engine.