# US 2020/0400082 A1 · Variable compression device and engine system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0400082 A1 - Document ID: US20200400082A1 - Status: Published application - Kind: A1 - Application number: 17/013,409 - Filed: 2020-09-04 - Published: 2020-12-24 - Earliest claimed: 2018-04-06 - Assignees: IHI Corporation - Applicants: Ihi Corporation - Inventors: Yutaka Masuda; Yoshiyuki Yoshiyuki - Web page: https://patentgrep.com/patent/US20200400082A1 ## CPC - F02B 75/044: {by means of an adjustable piston length} - F02D 15/02: by alteration or displacement of piston stroke - F01B 31/14: Changing of compression ratio - F02B 75/32: Engines characterised by connections between pistons and main shafts and not specific to preceding main groups - F02B 75/045: {by means of a variable connecting rod length} - F02D 15/04: by alteration of volume of compression space without changing piston stroke - F02D 2041/001: {for engines with variable valve actuation} - F02D 2700/03: Controlling by changing the compression ratio - Y02T 10/30: Use of alternative fuels, e.g. biofuels - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F01B: MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES (of rotary-piston or oscillating-piston type F01C; of non-positive-displacement type F01D; internal-combustion engines F02B; combustion-product engine plants F02G; machines or engines, other than of positive-displacement type, for liquids F03B; positive-displacement engines driven by liquids F03C; wind motors F03D; positive-displacement machines for liquids F04B; rotary-piston, or oscillating-piston, positive-displacement machines for liquids F04C) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A variable compression device includes a piston rod, a first fluid chamber configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto, a regulation member configured to regulate movement of the piston rod in a direction in which a compression ratio is increased, a second fluid chamber provided between the piston rod and the regulation member and configured to store the working fluid, a supply flow path configured to guide the working fluid supplied to the second fluid chamber, a discharge flow path configured to guide the working fluid discharged from the second fluid chamber, and a flow rate regulation unit provided in the discharge flow path and configured to regulate a flow of the working fluid when the piston rod approaches the regulation member. ## Claims ### Claim 1 A variable compression device that is configured to change a compression ratio in a combustion chamber of an engine, the variable compression device comprising: a piston rod; a first fluid chamber which is configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto; a regulation member which is configured to regulate movement of the piston rod in a direction in which a compression ratio is increased; a second fluid chamber which is provided between the piston rod and the regulation member and is configured to store the working fluid; a supply flow path which is configured to guide the working fluid supplied to the second fluid chamber; a discharge flow path which is configured to guide the working fluid discharged from the second fluid chamber; and a flow rate regulation unit which is provided in the discharge flow path and is configured to regulate a flow of the working fluid when the piston rod approaches the regulation member. ### Claim 2 (depends on 1) The variable compression device according to claim 1, wherein the flow rate regulation unit includes a weight member which is movable together with the piston rod, and a valve which is moved in a valve closing direction by movement of the weight member. ### Claim 3 (depends on 2) The variable compression device according to claim 2, wherein the flow rate regulation unit includes a biasing member that is configured to bias the weight member in a valve opening direction. ### Claim 4 (depends on 1) The variable compression device according to claim 1, wherein a portion of the working fluid supplied to the first fluid chamber is supplied to the second fluid chamber. ### Claim 5 (depends on 1) The variable compression device according to claim 1, further comprising: a fluid chamber forming member which forms a portion of the first fluid chamber; and an absorption member which is fixed to the regulation member or the piston rod, and is configured to absorb collision energy between the regulation member and the piston rod by elastic deformation. ### Claim 6 (depends on 5) The variable compression device according to claim 5, further comprising: a fixing member which is configured to fix the regulation member to the fluid chamber forming member, wherein the fixing member includes a shaft portion which is inserted into the regulation member and the fluid chamber forming member, and a head portion which is fixed to the shaft portion and is disposed separately from the regulation member, and the absorption member is provided between the regulation member and the head portion. ### Claim 7 (depends on 5) The variable compression device according to claim 5, wherein the absorption member is provided between the regulation member and the piston rod. ### Claim 8 (depends on 7) The variable compression device according to claim 7, wherein the regulation member includes a concave portion to which the absorption member is fitted. ### Claim 9 (depends on 1) An engine system comprising the variable compression device according to claim 1.