Exhaust Restriction Valve for Cold-Start Emission Control
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Solution Overview
Problem
Existing systems for reducing cold-start emissions in internal combustion engines face challenges such as increased design and manufacturing costs due to the addition of traps and baffles in the exhaust system, and incomplete release of liquid exhaust, leading to potential system failure and increased complexity.
Innovation Solution
A cold-start exhaust recycling system that uses a restriction valve to divert a portion of engine exhaust to the compressor inlet during cold-start conditions, reducing the amount of exhaust flowing through the catalytic converter until it reaches light-off temperature, while allowing a remaining portion to flow through for heating, and utilizing a pre-catalyst exhaust recycling passage to recirculate exhaust gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a trap and baffle system is used to condense and store liquid exhaust, then cold-start emissions are reduced, but design complexity and manufacturing costs increase
Solution Approach 1:
The patent extracts the emission control function from the complex trap-and-baffle system and implements it through a simple restriction valve that selectively blocks exhaust flow. This removes unnecessary components (trap, baffle, sensors) while maintaining the core function of reducing cold-start emissions by preventing exhaust from reaching the catalyst during cold-start conditions.
Solution Approach 2:
Instead of condensing exhaust into liquid and storing it in a trap, the patent inverts the approach by using a restriction valve to directly block exhaust flow path. This inversion simplifies the system by eliminating the need for condensation and storage mechanisms, achieving the same emission reduction goal through a different physical principle.
2Object-affected harmful factors
If a trap system is used to store liquid exhaust, then emissions are controlled, but system reliability decreases due to incomplete release and accumulation
Solution Approach 1:
The patent removes the trap system entirely, eliminating the reliability issues associated with incomplete release and accumulation. The simple restriction valve provides a reliable binary state (open/closed) that can be controlled consistently, avoiding the complex release mechanisms required to empty a trap.
3Ease of operation
If additional sensors and connections are added to monitor the trap system, then system control is improved, but manufacturing costs and design complexity increase
Solution Approach 1:
The patent eliminates the need for sensors and monitoring connections by removing the trap system entirely. The restriction valve's operation is controlled directly by engine management based on temperature conditions, without requiring continuous monitoring of liquid exhaust levels or trap status.
4Object-affected harmful factors
If the restriction valve blocks all exhaust flow during cold-start, then emissions are maximally reduced, but catalyst heating is prevented
Solution Approach 1:
The patent applies partial action by designing the restriction valve to block only a portion of exhaust flow during cold-start conditions, not all flow. This allows sufficient exhaust to reach the catalyst for heating while preventing excessive flow that would cause emissions problems. The valve opening is optimized to achieve the right balance between emission control and catalyst warm-up.
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 reduces cold-start emissions by minimizing exhaust flow through the catalytic converter before it reaches operating temperature, improving exhaust quality and reducing system complexity and costs.
Implementation Method 1
a restriction valve positioned upstream of an emission control device and downstream of a turbine and a wastegate in the exhaust passage opposite an oxygen sensor
Implementation Method 2
A remaining portion of the exhaust not blocked by the restriction valve may flow through the catalytic converter to enable heating of the catalyst
Data Source
AI summary
Systems and methods are provided for recycling internal combustion engine feedgas exhaust emissions during cold-start conditions. By adjusting a restriction valve provided in an exhaust passage upstream of a catalytic converter, an amount of engine exhaust flowing through the catalytic converter prior to the catalytic converter reaching its operational temperature may be reduced.