Rankine Cycle Waste Heat Recovery Control for Engine Aftertreatment
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Solution Overview
Problem
Existing waste heat recovery systems are inefficient in capturing and converting heat energy from internal combustion engine exhaust and aftertreatment systems, leading to wasted thermal energy and reduced engine efficiency.
Innovation Solution
A Rankine cycle-based waste heat recovery system that includes an exhaust gas heat exchanger, an energy conversion device, and a control module to capture and convert heat energy from the engine exhaust and aftertreatment system, optimizing energy conversion and thermal management through predictive parameter adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a Rankine cycle waste heat recovery system is added to the exhaust aftertreatment system, then waste heat energy recovery is improved, but device complexity increases
Solution Approach 1:
The patent combines the waste heat recovery system with the exhaust aftertreatment system by integrating the heat exchanger downstream of the aftertreatment components. This merging allows the system to utilize the exhaust gas that has already passed through the aftertreatment process, thereby recovering waste heat without interfering with the primary aftertreatment function while avoiding the need for separate independent systems.
Solution Approach 2:
The exhaust gas heat exchanger serves multiple functions: it recovers waste heat energy from the exhaust stream and simultaneously utilizes the exhaust gas that has already been processed by the aftertreatment system. This multi-functionality allows a single component to address both energy recovery and complement the aftertreatment process, reducing the need for additional separate systems.
2Reliability
If the heat exchanger is placed downstream of the aftertreatment system, then aftertreatment performance is preserved, but heat recovery efficiency may be reduced due to lower exhaust temperature
Solution Approach 1:
The system performs preliminary aftertreatment of the exhaust gas through the DOC and PF before the heat recovery process. By placing the heat exchanger downstream of these components, the exhaust gas is preprocessed to remove harmful particles and chemicals, ensuring that the aftertreatment performance is preserved while the remaining heat is recovered in a controlled manner.
Solution Approach 2:
The system accepts and adapts to the temperature reduction that occurs after aftertreatment processing. The Rankine cycle system is designed to operate with the lower temperature exhaust gas emerging from the aftertreatment components, adjusting its operational parameters to effectively recover heat at these reduced temperatures rather than requiring high-temperature exhaust.
3Productivity
If the Rankine cycle subsystem parameters are dynamically controlled based on aftertreatment events, then energy conversion efficiency is improved, but control system complexity increases
Solution Approach 1:
The control module continuously monitors aftertreatment events and system operational parameters, using this feedback information to dynamically adjust the Rankine cycle subsystem parameters. This feedback mechanism enables the system to optimize energy conversion efficiency by adapting to changing operational conditions while maintaining a manageable control architecture that leverages existing sensor and control infrastructure.
Solution Approach 2:
The system transitions from static to dynamic operation by allowing the Rankine cycle subsystem parameters to vary in response to aftertreatment events and operational conditions. This dynamic control enables the system to optimize performance across different operating scenarios, adjusting parameters such as heat exchanger operation and working fluid flow rates to match real-time demands.
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 recaptures and converts waste heat energy, enhancing engine efficiency and aftertreatment efficiency, while also producing additional electrical or mechanical power, thereby improving overall energy recovery and thermal management.
Implementation Method 1
an exhaust gas heat exchanger fluidly coupled downstream of an exhaust aftertreatment system and adapted to transfer heat from the exhaust gas to a working fluid of the RC subsystem
Implementation Method 2
an energy conversion device fluidly coupled to the exhaust gas heat exchanger and adapted to receive the working fluid having the transferred heat and convert the energy of the transferred heat
Implementation Method 3
a condenser fluidly coupled to the energy conversion device and adapted to receive the working fluid from which the energy was converted
Data Source
AI summary
The disclosure provides a waste heat recovery (WHR) system including a Rankine cycle (RC) subsystem for converting heat of exhaust gas from an internal combustion engine, and an internal combustion engine including the same. The WHR system includes an exhaust gas heat exchanger that is fluidly coupled downstream of an exhaust aftertreatment system and is adapted to transfer heat from the exhaust gas to a working fluid of the RC subsystem. An energy conversion device is fluidly coupled to the exhaust gas heat exchanger and is adapted to receive the vaporized working fluid and convert the energy of the transferred heat. The WHR system includes a control module adapted to control at least one parameter of the RC subsystem based on a detected aftertreatment event of a predetermined thermal management strategy of the aftertreatment system.