Cold Start Catalyst Light-Off via Water Electrolysis
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Solution Overview
Problem
Conventional engine exhaust aftertreatment systems face challenges in achieving low tailpipe emissions immediately after a cold engine start due to low catalyst conversion efficiency, often requiring compromises in exhaust system backpressure, durability, longevity, cost, and complexity to achieve faster light-off temperatures.
Innovation Solution
An internal combustion engine system utilizing a water electrolyzer to produce hydrogen and oxygen gases, which are combusted in the engine intake to rapidly warm the catalytic converter to light-off temperature, thereby reducing emissions without using gasoline fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional catalyst heating methods are used, then the catalyst can reach light-off temperature, but the system experiences high exhaust backpressure, reduced durability, and increased complexity
Solution Approach 1:
A thermal management system acts as an intermediary between the engine and catalytic converter, using a heat exchanger to transfer thermal energy from exhaust gas to the catalyst. This mediator approach allows controlled heating of the catalyst without subjecting the entire exhaust system to excessive temperatures, thereby improving durability while achieving light-off temperature.
Solution Approach 2:
The system performs preliminary heating of the catalytic converter before the engine reaches normal operating temperature. By activating the thermal management system during cold start conditions, the catalyst is pre-heated to light-off temperature in advance, allowing the engine to reach operational speed without prolonged high backpressure conditions that would损害 durability.
2Temperature
If faster light-off temperature is achieved through conventional methods, then emissions are reduced, but exhaust system backpressure increases
Solution Approach 1:
The thermal management system segments the heating function from the exhaust flow path. The heat exchanger is positioned to transfer heat from exhaust gas to the catalyst without requiring the exhaust gas to flow through a restricted path, thereby achieving fast catalyst heating while minimizing backpressure increases in the exhaust system.
3Temperature
If conventional heating methods are used, then the catalyst reaches light-off temperature, but system complexity and cost increase
Solution Approach 1:
The thermal management system is designed to serve multiple functions: it heats the catalyst during cold start, manages thermal energy from exhaust gas, and can operate under various engine loading conditions. This multi-functionality reduces the need for separate dedicated heating components, thereby reducing overall system complexity and cost while achieving reliable catalyst light-off.
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 system effectively reduces cold start emissions by rapidly warming the catalytic converter, minimizing hydrocarbons and carbon monoxide emissions, and achieving efficient catalyst conversion without the drawbacks of conventional methods.
Implementation Method 1
an electrolyzer configured to perform an electrolysis of water to produce a mixture of hydrogen and oxygen gases
Implementation Method 2
supplying the mixture of hydrogen and oxygen gases to the engine intake for combustion therein to facilitate rapidly warming the catalytic converter
Data Source
AI summary
An internal combustion engine system includes an internal combustion engine, an exhaust aftertreatment system with a catalytic converter configured to receive exhaust gas from the internal combustion engine, and a light-off catalyst system including an electrolyzer configured to perform an electrolysis of water to produce a mixture of hydrogen and oxygen gases. A conduit is in fluid communication between the electrolyzer and an intake of the internal combustion engine. A controller is configured to supply the mixture of hydrogen and oxygen gases to the engine intake during a cold start to facilitate rapidly warming the catalytic converter to a light-off temperature.