Diesel Exhaust Combustion and WHR for Lambda-1 Catalyst Operation
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Solution Overview
Problem
Existing Diesel cycle engines face inefficiencies and pollutant emission challenges due to the use of after-treatment systems (ATS), particularly with urea-based SCR systems, which cause urea crystallization and clogging, and 3-way catalysts are ineffective with excess oxygen.
Innovation Solution
Implementing a system with a lambda value of 1.0 in the exhaust gases by controlling supercharging pressure and adding second combustion chambers downstream, using a 3-way catalyst compatible with Diesel engines, and integrating a waste heat recovery (WHR) cycle to manage exhaust gases effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Diesel cycle engine is integrated in a combined cycle with waste heat recovery, then engine efficiency is improved, but the backpressure in the exhaust circuit increases
Solution Approach 1:
The supercharging pressure is dynamically controlled in proportion to the increase in backpressure caused by the recovery cycle. This dynamic adjustment allows the system to maintain optimal performance while compensating for the increased backpressure, resolving the contradiction between improved efficiency and increased pressure stress.
Solution Approach 2:
The invention changes the supercharging pressure parameter to compensate for the backpressure increase. By adjusting this parameter in proportion to the backpressure change, the system maintains the necessary exhaust flow characteristics while exploiting the waste heat for improved overall efficiency.
2Object-generated harmful factors
If second injection means and combustion chamber are added downstream to achieve lambda value of 1.0, then pollutant treatment effectiveness is improved, but device complexity increases
Solution Approach 1:
The second injection means and combustion chamber are integrated into the existing exhaust circuit, allowing the same components to serve multiple functions: waste heat recovery, lambda value control for effective 3-way catalyst operation, and pollutant reduction. This multi-functionality approach improves pollutant treatment without proportionally increasing device complexity.
Solution Approach 2:
The invention merges the waste heat recovery function with the pollutant treatment function by positioning the second combustion chamber within the exhaust circuit. This integration allows both functions to be achieved using a unified system architecture, reducing the overall complexity compared to separate systems.
3Productivity
If supercharging pressure is controlled in proportion to backpressure increase, then engine performance is maintained, but control system complexity increases
Solution Approach 1:
The control system uses feedback from the backpressure increase to automatically adjust the supercharging pressure in proportion. This feedback mechanism maintains engine performance without requiring complex manual intervention or overly sophisticated control algorithms, as the system self-regulates based on the measured backpressure change.
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 maintenance costs, enhances engine efficiency, and allows the use of a cost-effective 3-way catalyst, effectively treating pollutants while maintaining engine performance.
Implementation Method 1
The heat exchanger of this recovery cycle causes a pressure increase in the exhaust gases upstream of said heat exchanger
Implementation Method 2
fuel is introduced and burnt so as to consume all the oxygen still present in the exhaust gases, so as to exactly reach a lambda value equal to 1. This causes a temperature increase in the exhaust gases of the engine
Data Source
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AI summary
Engine system for vehicles and fixed installations based on Diesel cycle comprising, downstream of the Diesel engine (E), second means (N) for introducing and burning fuel and a Rankine cycle, which is arranged immediately downstream of the second means (N), and wherein said second means (N) are controlled so as to maintain the lambda value in the exhaust gases entering a pollutants converting device (ATS) equal to 1.0.