Rankine Cycle Charge Cooling for Emissions Compliance
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Solution Overview
Problem
Current waste heat recovery systems using Rankine cycles struggle to efficiently cool charge gases, such as exhaust gas recirculation (EGR) and charge air, to meet stringent emissions regulations, particularly in internal combustion engines, as they often fail to maintain the required temperature thresholds effectively.
Innovation Solution
A Rankine power cycle subsystem is integrated into the internal combustion engine to provide emissions-critical charge cooling, utilizing a boiler to transfer heat from EGR or charge air to a working fluid, an energy conversion device to convert this heat into useful energy, and a condenser to manage the working fluid's temperature, with a controller adjusting parameters to maintain the input charge flow within predetermined emission limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Rankine cycle system is used to recover waste heat, then energy efficiency is improved, but the ability to cool charge gases to meet emissions standards deteriorates
Solution Approach 1:
The heat recovery system is divided into two separate heat exchangers: a first heat exchanger dedicated to cooling charge gases (EGR and/or charge air) and a second heat exchanger dedicated to heating the working fluid for power generation. This segmentation allows independent optimization of cooling performance for emissions compliance and heat recovery efficiency, resolving the contradiction between energy efficiency improvement and charge gas temperature control.
2Loss of energy
If heat is transferred from charge gases to working fluid, then waste heat recovery is improved, but charge gas cooling performance deteriorates
Solution Approach 1:
The system uses separate heat exchangers for charge gas cooling and working fluid heating, allowing the charge gases to be cooled to meet emissions standards while a portion of the recovered heat is used to heat the working fluid for power generation, thus maintaining both emissions compliance and waste heat recovery effectiveness.
Solution Approach 2:
The system adjusts operating parameters such as working fluid flow rate, heat exchanger surface area, and temperature differences to optimize the balance between charge gas cooling performance and working fluid heating efficiency, ensuring emissions compliance while maximizing waste heat recovery.
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 solution effectively recovers waste heat, enhancing engine efficiency while ensuring compliance with emissions regulations by maintaining the input charge flow temperature below critical thresholds, thereby optimizing energy conversion and reducing emissions.
Implementation Method 1
a boiler fluidly coupled to the input charge flow and adapted to transfer heat from the input charge flow to a working fluid of the Rankine power cycle subsystem and vaporize the working fluid
Implementation Method 2
transfer heat from the input charge flow to a working fluid of the Rankine power cycle subsystem and vaporize the working fluid
Implementation Method 3
an energy conversion device fluidly coupled to the boiler and adapted to receive vaporized working fluid and convert the energy of the transferred heat
Implementation Method 4
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 system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.