# US 2023/0264679 A1 · Method for operating a hybrid drive system of a motor vehicle, hybrid drive system, and motor vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0264679 A1 - Document ID: US20230264679A1 - Status: Published application - Kind: A1 - Application number: 18/112,248 - Filed: 2023-02-21 - Published: 2023-08-24 - Earliest claimed: 2022-02-22 - Assignees: Volkswagen Aktiengesellschaft - Applicants: Volkswagen Aktiengesellschaft - Inventors: Stefan PAUKNER; Falk-Christian VON CEUMERN-LINDENSTJERNA; Johannes WESTENDORF - Web page: https://patentgrep.com/patent/US20230264679A1 ## CPC - B60K 6/48: Parallel type - B60W 20/15: Control strategies specially adapted for achieving a particular effect - B60K 6/387: Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means - B60W 10/02: including control of driveline clutches - B60W 10/06: including control of combustion engines - B60W 10/08: including control of electric propulsion units, e.g. motors or generators - B60W 10/18: including control of braking systems - B60W 20/14: in conjunction with braking regeneration - B60W 20/40: Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)} - B60K 2006/4808: {Electric machine connected or connectable to gearbox output shaft} - B60W 2710/021: Clutch engagement state - B60W 2710/06: Combustion engines, Gas turbines - Y02T 10/62: Hybrid vehicles - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for operating a hybrid drive system of a motor vehicle, in which an internal combustion engine with a belt-driven starter generator coupled thereto is operated in an overrun mode for braking of the motor vehicle, wherein, in order to avoid a delivering of air to an exhaust system of the hybrid drive system, the internal combustion engine is configured in such a manner that intake valves and/or exhaust valves of the internal combustion engine remain closed during a rotation of a crankshaft of the internal combustion engine. Also provided is a hybrid drive system for a motor vehicle and to a motor vehicle having a hybrid drive system. ## Claims ### Claim 1 A method for operating a hybrid drive system of a motor vehicle, wherein the hybrid drive system comprises an internal combustion engine with a belt-driven starter generator coupled thereto, a transmission, a drivetrain generator, an exhaust system for the internal combustion engine, a control device, and an output, a first clutch is arranged between the internal combustion engine and the transmission, the method comprising: bringing, via the control device, the motor vehicle to a first speed by controlling the hybrid drive system; bringing, via the control device, about an operating state of the hybrid drive system in which the first clutch is disengaged; shutting off, via the control device, the internal combustion engine; detecting, via the control device, a braking demand for braking of the motor vehicle; engaging, via the control device, the first clutch for overrunning the internal combustion engine as well as for operating the belt-driven starter generator in a recuperation mode; and configuring, via the control device, the internal combustion engine such that intake valves and/or exhaust valves of the internal combustion engine remain closed during a rotation of a crankshaft of the internal combustion engine. ### Claim 2 (depends on 1) The method according to claim 1, wherein the control device configures the internal combustion engine in overrun such that the intake valves and exhaust valves deliver a predefined air flow into the exhaust system of the motor vehicle. ### Claim 3 (depends on 2) The method according to claim 2, wherein the control device controls a fuel injection device for the selective injection of fuel into one or more cylinders of the internal combustion engine in overrun. ### Claim 4 (depends on 1) The method according to claim 1, wherein the drivetrain generator is adapted to be mechanically coupled to the output of the hybrid drive system through a second clutch, and wherein the control device engages the second clutch to operate the drivetrain generator in a recuperation mode for braking the motor vehicle. ### Claim 5 (depends on 4) The method according to claim 4, wherein the second clutch is engaged before the first clutch for braking the motor vehicle. ### Claim 6 (depends on 1) The method according to claim 1, wherein the first clutch is disengaged again when the motor vehicle reaches a second speed, and wherein the second speed is lower than the first speed. ### Claim 7 (depends on 1) The method according to claim 1, wherein the configuring of the internal combustion engine by the control device includes a switching of a camshaft to null cams. ### Claim 8 (depends on 1) The method according to claim 1, wherein air is evacuated from the exhaust system with an evacuation device of the hybrid drive system and/or wherein an oxygen-free or oxygen-reduced gas is introduced into the exhaust system by a gas supply device of the hybrid drive system to displace the oxygen located in the exhaust system. ### Claim 9 (depends on 1) A hybrid drive system for a motor vehicle, the system comprising: an internal combustion engine with a belt-driven starter generator coupled thereto; a transmission; a drivetrain generator; an exhaust system for the internal combustion engine; a control device; and a first clutch arranged between the internal combustion engine and an output of the hybrid drive system, wherein the hybrid drive system is designed to carry out the method according to claim 1. ### Claim 10 (depends on 9) A motor vehicle comprising a hybrid drive system according to claim 9.