Hybrid Vehicle Catalyst Thermal Management with Phase Change Insert
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Solution Overview
Problem
Hybrid vehicles face challenges in maintaining catalyst temperature and efficiency due to frequent stop-start operations, leading to reduced pollutant emission treatment effectiveness and increased fuel consumption and CO2 emissions, as the thermal management of conventional systems is inadequate for hybrid vehicle operation.
Innovation Solution
A catalytic system with a heat storage insert made of phase change materials, such as potassium nitrate, is integrated downstream of the catalytic bar to slow down cooling and maintain temperature during shutdown or low-power phases, minimizing the quantity of storage materials needed and optimizing thermal inertia without impacting the catalyst's activation phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the heat engine is stopped frequently to reduce emissions, then pollutant emissions from the engine are reduced, but the catalyst temperature drops below the minimum required temperature for effective treatment
Solution Approach 1:
The patent applies preliminary action by pre-heating the phase change material to its melting point before engine shutdown. The material is prepared in advance to store thermal energy that will be released when solidifying, ensuring the catalyst maintains its minimum operating temperature during engine stop periods without requiring frequent restarts.
Solution Approach 2:
The patent utilizes phase transitions of the phase change material (melting and solidification) to manage catalyst temperature. During engine operation, the material absorbs heat and melts, storing thermal energy. During engine shutdown, the material solidifies and releases the stored heat to maintain catalyst temperature above the minimum threshold for effective pollutant treatment.
2Productivity
If the catalyst is kept active by maintaining higher temperature through frequent engine restarts, then pollutant treatment efficiency is improved, but fuel consumption and CO2 emissions increase
Solution Approach 1:
The phase change material undergoes reversible melting and solidification cycles to store and release thermal energy. This passive thermal management system maintains catalyst temperature without requiring frequent engine restarts, thereby preserving treatment efficiency while avoiding the additional fuel consumption that would result from repeated engine cycling.
Solution Approach 2:
The phase change material serves the catalyst's thermal needs autonomously through its inherent phase transition properties. The material automatically absorbs heat during engine operation and releases it during shutdown periods, eliminating the need for active thermal management systems or frequent engine restarts to maintain catalyst activity.
3Loss of energy
If thermal energy is stored using conventional insulation methods, then heat loss is reduced, but the system complexity and manufacturing cost increase
Solution Approach 1:
Instead of using complex multi-layer insulation systems, the patent employs a phase change material that passively manages heat through phase transitions. The material's latent heat of fusion provides thermal energy storage and release capabilities, simplifying the thermal management system architecture while effectively reducing heat loss from the catalyst during engine shutdown periods.
Solution Approach 2:
The patent changes the thermal management approach from passive insulation to active thermal energy storage using phase change materials. By selecting materials with appropriate melting points and latent heat values, the system optimizes heat retention without requiring complex insulation structures, thereby reducing system complexity while maintaining effective heat loss prevention.
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 maintains catalyst activity during electric traction phases and rapid re-starts, ensuring effective pollutant conversion and reducing the need for frequent engine re-starts, thereby optimizing fuel efficiency and reducing CO2 emissions.
Implementation Method 1
The insert can be a solid cylinder. Said heat storage materials can be phase change materials (PCMs).
Implementation Method 2
The type of material and its latent heat of fusion may be those described in US-6875407.
Implementation Method 3
said insert is held by an insulating plug or an insulating ring to plug the hole necessary for the introduction of said insert during manufacturing and to limit heat exchanges downstream of the catalytic bar.
Data Source
Figure 1A~1B
Figure 2~3
AI summary
- The present invention relates to a catalytic system for treating the exhaust gases of a vehicle, comprising a catalytic block through which said gases circulate, characterized in that it comprises at least one insert of heat storage material (1) in a downstream zone of the block, relative to the direction of gas flow and in that the insert is substantially in the center of the downstream zone.