Enhanced waste heat recovery system and method allowing global optimal control

Abstract

A waste heat recovery system and control system and method of controlling a waste heat recovery system and control system is provided. The waste heat recovery system and control system comprises a pump, a heat exchanger, an expansion device, a condenser, a plurality of sensors, and a controller. The heat exchanger is in thermal communication with an exhaust of the internal combustion engine. The condenser is in thermal communication with the expansion device and the pump. The plurality of sensors is in communication with the waste heat recovery system. The controller is in communication with the plurality of sensors. In response to information obtained from the plurality of sensors, the controller calculates an efficiency of the waste heat recovery system based on models of the waste heat recovery system and implements a set of control inputs to implement the calculated efficiency on the waste heat recovery system.

What is claimed is: 
     
         1 . A waste heat recovery system and control system for use with an internal combustion engine, the waste heat recovery system and control system comprising:
 a pump;   a heat exchanger in fluid communication with the pump and thermal communication with an exhaust of the internal combustion engine;   an expansion device in fluid communication with the heat exchanger;   a condenser in thermal communication with the expansion device and the pump;   a plurality of sensors in communication with the waste heat recovery system; and   a controller in communication with the plurality of sensors, wherein in response to information obtained from the plurality of sensors, the controller calculates an efficiency of the waste heat recovery system based on models of the waste heat recovery system and implements a set of control inputs to implement the calculated efficiency on the waste heat recovery system.   
     
     
         2 . The waste heat recovery system and control system according to  claim 1 , further comprising an expander bypass and bypass valve, the bypass valve in communication with the controller. 
     
     
         3 . The waste heat recovery system and control system according to  claim 1 , further comprising a heat exchanger bypass and exhaust bypass valve, the exhaust bypass valve in communication with the controller. 
     
     
         4 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a temperature sensor and a mass flow sensor in the exhaust of the internal combustion engine. 
     
     
         5 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a temperature sensor and a pressure sensor configured to measure an air pressure of an ambient environment of the waste heat recovery system. 
     
     
         6 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a sensor configured to measure a pressure at an inlet or an outlet of the expander. 
     
     
         7 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a sensor configured to measure a pressure at an inlet or an outlet of the expander. 
     
     
         8 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a sensor configured to measure at least one of a rotational speed of the expander and a rotational speed of the pump. 
     
     
         9 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a sensor configured to measure a state of operation of the internal combustion engine through an engine control unit. 
     
     
         10 . The waste heat recovery system and control system according to  claim 1 , wherein the plurality of sensors include a sensor configured to measure a state of operation of a portion of a driveline associated with the internal combustion engine through a gearbox controller. 
     
     
         11 . A method of controlling a waste heat recovery system and control system for use with an internal combustion engine, the method comprising the steps of:
 providing the waste heat recovery system comprising:
 a pump; 
 a heat exchanger in fluid communication with the pump and thermal communication with an exhaust of the internal combustion engine; 
 an expansion device in fluid communication with the heat exchanger; and 
 a condenser in thermal communication with the expansion device and the pump; 
   providing the control system comprising:
 a plurality of sensors in communication with the waste heat recovery system; and 
 a controller in communication with the plurality of sensors; 
   obtaining information from the plurality of sensors;   calculating an efficiency of the waste heat recovery system based on models of the waste heat recovery system using the controller; and   implementing a set of control inputs to implement the calculated efficiency on the waste heat recovery system.   
     
     
         12 . The method of controlling a waste heat recovery system and control system according to  claim 11 , wherein the step of calculating an efficiency of the waste heat recovery system is performed using static or dynamic models. 
     
     
         13 . The method of controlling a waste heat recovery system and control system according to  claim 12 , wherein the models used in calculating the efficiency of the waste heat recovery system are focused on components of the waste heat recovery system that have slow dynamics. 
     
     
         14 . The method of controlling a waste heat recovery system and control system according to  claim 12 , wherein when the step of calculating an efficiency of the waste heat recovery system is performed using a dynamic model, the controller takes into account a past performance of the waste heat recovery system before and/or after a particular modeled event to determine a most efficient way to proceed. 
     
     
         15 . The method of controlling a waste heat recovery system and control system according to  claim 11 , further comprising the step of maintaining constraints on the states of the waste heat recovery system. 
     
     
         16 . The method of controlling a waste heat recovery system and control system according to  claim 15 , wherein the constraints include at least maintaining a minimal rotational speed and a maximal rotational speed of the pump and the expander, maintaining a minimal pressure and a maximal pressure within the waste heat recovery system, maintaining temperature limits within the waste heat recovery system, and maintaining a presence of positive superheating within the expander. 
     
     
         17 . The method of controlling a waste heat recovery system and control system according to  claim 11 , further comprising the step of using the dynamic models of the waste heat recovery system to predict a future state of the waste heat recovery system.