# US 2018/0023486 A1 · Control device for 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 2018/0023486 A1 - Document ID: US20180023486A1 - Status: Published application - Kind: A1 - Application number: 15/654,285 - Filed: 2017-07-19 - Published: 2018-01-25 - Earliest claimed: 2016-07-21 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Toyota Jidosha Kabushiki Kaisha - Inventors: Yoshiyuki YAMASHITA - Web page: https://patentgrep.com/patent/US20180023486A1 ## CPC - F02D 15/04: by alteration of volume of compression space without changing piston stroke - F02B 75/041: {by means of cylinder or cylinderhead positioning} - F02D 13/0238: {by shifting the phase, i.e. the opening periods of the valves are constant} - F02D 13/0269: {Controlling the valves to perform a Miller-Atkinson cycle} - F02D 41/2422: {Selective use of one or more tables} - F02D 2041/001: {for engines with variable valve actuation} - F02D 2200/0625: Fuel consumption, e.g. measured in fuel liters per 100 kms or miles per gallon - F02D 2200/101: Engine speed - F02D 2200/1015: Engines misfires - Y02T 10/12: Improving ICE efficiencies - 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) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A control device of an internal combustion engine 100 provided with a compression ratio control part controlling a mechanical compression ratio to a target compression ratio. The compression ratio control part is configured provided with an optimum compression ratio calculating part calculating an optimum compression ratio in an engine operating state based on the engine operating state, a permittable changed compression ratio calculating part calculating a permittable changed compression ratio giving an effect of improvement of the fuel efficiency even considering the amount of fuel consumed by driving a motor when the optimum compression ratio is higher than a target compression ratio, and a target compression ratio changing part changing the target compression ratio to the permittable changed compression ratio if the optimum compression ratio is higher than the target compression ratio and the optimum compression ratio becomes the permittable changed compression ratio or more. ## Claims ### Claim 1 A control device for an internal combustion engine for controlling an internal combustion engine provided with: an engine body; and a variable compression ratio mechanism configured to drive a motor to thereby enable change of a mechanical compression ratio of the engine body, which control device comprises a compression ratio control part configured to control the mechanical compression ratio to a target compression ratio, the compression ratio control part comprising: an optimum compression ratio calculating part configured to calculate an optimum compression ratio in the engine operating state based on the engine operating state; a permittable changed compression ratio calculating part configured to calculate a permittable changed compression ratio higher than the target compression ratio giving the effect of improvement of the fuel efficiency even if considering the amount of fuel consumed by driving the motor when the optimum compression ratio is higher than the target compression ratio; and a target compression ratio changing part configured to change the target compression ratio to the permittable changed compression ratio when the optimum compression ratio is higher than the target compression ratio and the optimum compression ratio becomes the permittable changed compression ratio or more. ### Claim 2 (depends on 1) The control device for an internal combustion engine according to claim 1, wherein the permittable changed compression ratio calculating part comprises an added value calculating part configured to calculate an added value for addition to the target compression ratio to calculate the permittable changed compression ratio, and the added value calculating part is configured to increase the added value more when the target compression ratio is high compared to when it is low. ### Claim 3 (depends on 2) The control device for an internal combustion engine according to claim 2, wherein the added value calculating part is further configured to increase the added value more when the engine speed is high compared to when it is low. ### Claim 4 (depends on 1) The control device for an internal combustion engine according to claim 1, wherein the permittable changed compression ratio calculating part is provided with an added value calculating part configured to calculate an added value for addition to the target compression ratio to calculate the permittable changed compression ratio, and the added value calculating part is configured to increase the added value more when the engine speed is high compared to when it is low. ### Claim 5 (depends on 2) The control device for an internal combustion engine according to claim 2, wherein the permittable changed compression ratio calculating part further comprises: a lost fuel amount calculating part configured to calculate an amount of lost fuel excessively consumed when controlling the mechanical compression ratio to the permittable changed compression ratio to operate the engine body compared to when controlling the mechanical compression ratio to the optimum compression ratio to operate the engine body; a compression ratio changing fuel amount calculating part configured to calculate a compression ratio changing fuel amount consumed by driving the motor when changing the mechanical compression ratio from the target compression ratio to the optimum compression ratio; and an added value learning part configured to learn how to reduce the added value when the lost fuel amount becomes the compression ratio changing fuel amount or more. ### Claim 6 (depends on 1) The control device for an internal combustion engine according to claim 1, wherein the control device further comprises a motor control part configured to control a rotational speed of the motor, and the motor control part is configured to slow the rotational speed of the motor after the mechanical compression ratio rises to a speed switching compression ratio lower than the target compression ratio compared with before the mechanical compression ratio rises to the speed switching compression ratio when raising the mechanical compression ratio toward the target compression ratio. ### Claim 7 (depends on 6) The control device for an internal combustion engine according to claim 6, wherein the motor control part comprises a subtracted value calculating part configured so as to calculate a subtracted value to be subtracted from the target compression ratio to calculate the speed switching compression ratio, and the subtracted value calculating part is configured so as to increase the subtracted value more when the target compression ratio is high compared to when it is low. ### Claim 8 (depends on 7) The control device for an internal combustion engine according to claim 7, wherein the subtracted value calculating part is further configured so as to increase the subtracted value more when the engine speed is high compared to when it is low. ### Claim 9 (depends on 6) The control device for an internal combustion engine according to claim 6, wherein the motor control part comprises a subtracted value calculating part configured so as to calculate a subtracted value to be subtracted from the target compression ratio to calculate the speed switching compression ratio, and the subtracted value calculating part is configured so as to increase the subtracted value more when the engine speed is high compared to when it is low.