# US 8,783,032 B2 · Method for recovering heat losses of an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,783,032 B2 - Document ID: US8783032B2 - Status: Granted - Kind: B2 - Application number: 12/802,798 - Filed: 2010-06-14 - Published: 2011-03-10 - Granted: 2014-07-22 - Earliest claimed: 2007-12-22 - Assignees: Daimler AG - Applicants: Jan Gärtner; Thomas Koch; Andreas Zygan; Jozsef Mercz; Piroska Merczne - Inventors: Jan Gärtner; Thomas Koch; Jozsef Marton Mercz; Andreas Zygan - Web page: https://patentgrep.com/patent/US8783032B2 ## CPC - F02G 5/02: Profiting from waste heat of exhaust gases - F01K 23/065: {the combustion taking place in an internal combustion piston engine, e.g. a diesel engine} - F01K 23/101: {Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence)} - Y02T 10/12: Improving ICE efficiencies - F02G: HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS (steam engine plants, special vapour plants, plants operating on either hot gas or combustion-product gases together with other fluid F01K; gas-turbine plants F02C; jet-propulsion plants F02K); USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR - F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a method for recovering energy from the heat dissipated by an internal combustion engine and to an internal combustion engine wherein the pressure and temperature of a liquid working medium are increased from a lower process pressure and a first temperature to an upper process pressure at which the working fluid is heated to a second temperature whereby it is converted to a gaseous phase; the working medium is then expanded back to the lower process pressure whereby mechanical power is generated and the working medium is converted back to a liquid phase, the upper process pressure being adjusted in such a way that the working medium is expanded into the wet steam area close to the saturated steam limit. ## Claims ### Claim 1 A method for recovering heat dissipated by an internal combustion engine (2) in a recovery circuit including a pump unit (3), a heat exchanger (4), an expansion device (5), a condenser (6) and a first control unit (7) for controlling the pump unit (3) and first temperature and pressure sensors (7.1, 7.2) connected to the first control unit (7) for sensing the temperature and pressure of the working fluid leaving the heat exchanger (4) and a second control unit (8) for controlling a lower process pressure (pu) as well as a second pressure sensor (8.1) for sensing the lower process pressure, said method comprising the following steps: compressing a liquid working medium (A) from a the lower process pressure (pu) and a first temperature (T1) to an upper process pressure (po) and a second temperature (T2) in the pump unit (3); vaporizing the working medium (A) in the heat exchanger (4) by transferring heat from a hot medium containing heat dissipated by the internal combustion engine (2) to the working medium (A), whereby the working medium (A) is heated to a third temperature (T3) while being vaporized during passage through the wet vapor area (NG) of a vapor pressure-enthalpy diagram to a superheat area (TG); expanding the working medium (A) approximately to the lower process pressure (pu), which is adjustable depending on engine operating conditions so that the working fluid is expanded and its temperature is reduced to a point which is close to a fourth temperature (T4) in the expansion device (5), while generating mechanical energy; condensing the working medium (A) in the condenser (6) and transferring the working medium (A) to the pump unit (3), adjusting the upper process pressure (po) by the first control unit (7) in an operating region of the internal combustion engine (2) to such a value that the working medium (A) is expanded in the expansion device (5) approximately to a point close to the saturated vapor limit (S) and adjusting the lower process pressure (pu) by the second control unit in an operating range of the internal combustion engine within a pre-settable pressure range by controlling the load on the expansion device (5). ### Claim 2 (depends on 1) The method according to claim 1, wherein the upper process pressure (po) is adjusted in dependence on a nominal value for the lower process pressure (pu) and on the superheat temperature (T3) of the working medium (A) downstream of the heat exchanger (4). ### Claim 3 An internal combustion engine (2) with a heat recovery device (1), comprising: a pump unit (3) for compressing an at least largely liquid working medium (A) from a lower process pressure (pu) and a first temperature (T1) to an upper process pressure (po) and a second temperature (T2), a heat exchanger (4) for heating, vaporizing and superheating the working medium (A) at the upper pressure (po) by heat transfer from a hot medium (M) to the working medium (A), so that the working medium (A) is heated to a superheat temperature (T3), an expansion device (5) for expanding the superheated working medium (A) to the lower process pressure (pu) and to a fourth temperature T4, whereby mechanical power is generated in the expansion device (5), and a condenser (6) for condensing the working medium (A), so that the working medium (A) has approximately the first temperature (T1) after flowing through the condenser (6), the pump unit (3), the heat exchanger (4), the expansion device (5) and the condenser (6) being interconnected in a closed circuit, a temperature sensor (7.1) provided downstream of the first heat exchanger (4) for sensing the superheat temperature (T3) of the medium (A), a pressure sensor (7.2) for sensing the upper process pressure (po) of the liquid working medium (A), and a first control unit (7) for controlling the upper process pressure (po) by controlling the pump unit (3) in dependence on an operating state of the internal combustion engine (2), and a second control unit (8) for controlling the lower process pressure (pu) by controlling the expansion load of the expansion device (5) in dependence on the operating state of the internal combustion engine (2) within a pre-settable pressure range. ### Claim 4 (depends on 3) The internal combustion engine (2) according to claim 3, wherein a mass flow of the working medium is adjustable by the first control unit (7) controlling the pump unit (3) in dependence on measuring variables of the sensors for sensing the operating state. ### Claim 5 (depends on 3) The internal combustion engine (2) according to claim 3, wherein the pressure sensor (7.2) is arranged downstream of the first heat exchanger (4). ### Claim 6 (depends on 3) The internal combustion engine (2) according to claim 3, wherein the expansion device (5) is used for controlling the lower process pressure (pu) in dependence on the operating state of the internal combustion engine (2). ### Claim 7 (depends on 6) The internal combustion engine (2) according claim 6, wherein for regulating the lower process pressure (pu) a second control unit (8) is provided, with the help of which a load of the expansion device (5) can be adjusted. ### Claim 8 (depends on 3) The internal combustion engine (2) according to claim 3, wherein the expansion device (5) is one of a turbine and a piston expansion machine. ### Claim 9 (depends on 3) The internal combustion engine (2) according to claim 3, wherein the expansion device (5) is coupled to at least one of a generator, an electrical motor and a motor/generator unit (9). ### Claim 10 (depends on 9) The internal combustion engine (2) according to claim 9, wherein a load of the expansion device (5) is adjustable by means of at least one of the generator, the electric motor and the motor/generator unit (9).