Variable Event Valvetrain Power and Emissions Control
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Solution Overview
Problem
Existing methods for controlling valves in internal combustion engines during starting and stopping often reduce valve power consumption at the expense of increased engine emissions, and restrict the functionality of variable event valvetrains.
Innovation Solution
A method that involves positioning variably actuated valves based on operating conditions to reduce power consumption and emissions, by closing intake valves and releasing exhaust valves to a neutral position, thereby controlling oxygen storage in the exhaust system and optimizing energy use during engine stops and starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If valves are left in neutral position during engine stop to reduce power consumption, then power consumption is reduced, but oxygen enters the engine and exhaust system increasing emissions
Solution Approach 1:
The patent segments the valve control strategy by treating intake valves and exhaust valves differently during engine stop. Intake valves are closed to prevent oxygen entry and emissions, while exhaust valves are released to neutral position to reduce power consumption. This segmentation allows simultaneous optimization of both emissions control and energy savings.
2Use of energy by moving object
If a single starting sequence is executed during engine start, then valve power consumption is reduced, but the functionality of variable event valvetrain is unnecessarily restricted
Solution Approach 1:
The patent implements dynamic valve control during engine start by executing multiple starting sequences with different valve timing patterns. The system can switch between different valve operation modes (e.g., all valves closed, selective valve opening, different crankshaft position sequences) depending on engine conditions, thereby maintaining full valvetrain functionality while optimizing power consumption through adaptive control.
Data Source
AI summary
A method for controlling stopping and starting of an engine having a variable event valvetrain is described. According to the method engine valves may be used to reduce engine evaporative emissions as well as engine starting emissions.