# US 10,480,389 B2 · Coolant circuit for a liquid-cooled transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,389 B2 - Document ID: US10480389B2 - Status: Granted - Kind: B2 - Application number: 15/796,922 - Filed: 2017-10-30 - Published: 2018-03-08 - Granted: 2019-11-19 - Earliest claimed: 2015-07-08 - Assignees: Bayerische Motoren Werke Aktiengesellschaft - Applicants: Bayerische Motoren Werke Aktiengesellschaft - Inventors: Norbert Amann - Web page: https://patentgrep.com/patent/US10480389B2 ## CPC - F01P 3/20: Cooling circuits not specific to a single part of engine or machine (F01P3/22 takes precedence) - F01P 3/06: Arrangements for cooling pistons - F01P 3/12: Arrangements for cooling other engine or machine parts - F01P 7/14: the coolant being liquid - F01P 2003/027: {Cooling cylinders and cylinder heads in parallel} - F01P 2007/146: {using valves} - F01P 2025/62: Load - F01P 2025/64: Number of revolutions - F01P 2060/045: for transmissions - F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28) ## Abstract A coolant circuit has an engine cooling circuit in which coolant can be circulated in order to cool an internal combustion engine via a cylinder head cooling circuit and a crankcase cooling circuit separated from the cylinder head cooling circuit. The coolant circuit includes a transmission cooling circuit for cooling a transmission, the transmission cooling circuit branching off from the engine cooling circuit. A valve is arranged in the transmission cooling circuit. A controller is designed to open and close the valve depending on an operating state of the internal combustion engine and/or the transmission. In particular, the transmission cooling circuit branches off from the crankcase cooling circuit to a section along which the crankcase cooling circuit is separated from the cylinder head cooling circuit. ## Claims ### Claim 1 A coolant circuit, comprising: an engine cooling circuit in which coolant is circulated in order to cool an internal combustion engine, the engine cooling circuit branching into a cylinder head cooling circuit and a crank housing cooling circuit at a bifurcation; a transmission cooling circuit for cooling a transmission, which transmission cooling circuit branches off from the crank housing cooling circuit upstream of a merging point between the branched cylinder head cooling circuit and crank housing cooling circuit; a valve which is arranged in the transmission cooling circuit; and a control which is adapted to open and close the valve in accordance with an operating state of the internal combustion engine and/or the transmission. ### Claim 2 (depends on 1) The coolant circuit as claimed in claim 1, wherein the crank housing cooling circuit has a crank housing water jacket which is guided around cylinder bores, and the transmission cooling circuit opens in the crank housing water jacket downstream of a device for absorbing heat from the transmission. ### Claim 3 (depends on 2) The coolant circuit as claimed in claim 2, wherein the valve is located downstream of the crank housing water jacket. ### Claim 4 (depends on 3) The coolant circuit as claimed in claim 3, wherein downstream of the valve, the cylinder head cooling circuit and the crank housing cooling circuit are merged together. ### Claim 5 (depends on 1) The coolant circuit as claimed in claim 1, wherein the transmission cooling circuit branches off from the crank housing cooling circuit downstream of the bifurcation and upstream of a crank housing water jacket of the crank housing cooling circuit. ### Claim 6 (depends on 5) The coolant circuit as claimed in claim 5, wherein the crank housing cooling circuit branches off downstream of the bifurcation into a crank housing water jacket and an engine oil cooling circuit which is adapted to cool an engine oil via a heat exchanger, and the transmission cooling circuit branches off from the engine oil cooling circuit. ### Claim 7 (depends on 1) The coolant circuit as claimed in claim 1, wherein the crank housing cooling circuit branches off downstream of the bifurcation into a crank housing water jacket and an engine oil cooling circuit which is adapted to cool an engine oil via a heat exchanger, and the transmission cooling circuit branches off from the engine oil cooling circuit. ### Claim 8 (depends on 1) The coolant circuit as claimed in claim 1, wherein a non-return valve is provided in the transmission cooling circuit. ### Claim 9 (depends on 1) The coolant circuit as claimed in claim 1, wherein the bifurcation is formed by a coolant pump. ### Claim 10 (depends on 5) The coolant circuit as claimed in claim 5, wherein the bifurcation is formed by a coolant pump. ### Claim 11 (depends on 1) The coolant circuit as claimed in claim 1, wherein the control is adapted to open and close the valve in accordance with an engine speed and/or an engine torque. ### Claim 12 (depends on 11) The coolant circuit as claimed in claim 11, wherein the control is adapted to open the valve only above a specific threshold value of the engine speed and/or the engine torque. ### Claim 13 (depends on 1) A motor vehicle comprising a coolant circuit as claimed in claim 1.