# US 10,480,504 B2 · Engine rotational speed control apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,504 B2 - Document ID: US10480504B2 - Status: Granted - Kind: B2 - Application number: 14/667,106 - Filed: 2015-03-24 - Published: 2015-10-15 - Granted: 2019-11-19 - Earliest claimed: 2014-04-11 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Toyota Jidosha Kabushiki Kaisha - Inventors: Hiroshi Watanabe; Yasumichi Inoue - Web page: https://patentgrep.com/patent/US10480504B2 ## CPC - F04B 49/20: by changing the driving speed - F02D 37/02: one of the functions being ignition - F02D 41/0002: {Controlling intake air} - F02D 41/083: {taking into account engine load variation, e.g. air-conditionning} - F02D 41/1401: {characterised by the control or regulation method (F02D41/1473, F02D41/1477 take precedence)} - F02D 41/1497: {With detection of the mechanical response of the engine} - F02D 41/16: for idling - F02P 5/045: {combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02)} - F02P 5/1508: {with particular means during idling} - F02D 31/003: {for idle speed control} - F02D 2200/1006: Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories - F02D 2250/18: Control of the engine output torque - F02D 2250/22: by keeping a torque reserve, i.e. with temporarily reduced drive train or engine efficiency - F04B 2201/1202: Torque on the axis - Y02T 10/40: Engine management systems - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - 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) - F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A rotational speed control apparatus for an engine is provided. The engine configured to drive a compressor that compresses a cooling medium for air conditioning. The rotational speed control apparatus includes electronic control unit. The electronic control unit is configured to: (a) correct a torque of the engine through feedback in accordance with a deviation between a rotational speed during idle operation and a target rotational speed; (b) (i) calculate a load torque of the compressor, and (ii) correct the calculated load torque through feedback in accordance with a deviation between the rotational speed of the engine and the target rotational speed and correct a required value of the torque of the engine in accordance with the corrected load torque, in a predetermined period from a start of a changeover between a driven state of the compressor and a stopped state of the compressor. ## Claims ### Claim 1 A rotational speed control apparatus for an engine, the engine configured to drive a compressor that compresses a cooling medium for air conditioning, the rotational speed control apparatus comprising: an electronic control unit configured to: (a) correct a torque of the engine through feedback in accordance with a deviation between a rotational speed during idle operation and a target rotational speed; (b) (i) calculate a load torque of the compressor, and (ii) correct the calculated load torque through feedback in accordance with a deviation between the rotational speed of the engine and the target rotational speed and correct a required value of the torque of the engine in accordance with the corrected load torque, in a predetermined period from a start of a changeover between a driven state of the compressor and a stopped state of the compressor, the start of the changeover being during idling stability of the engine; wherein a first period of the changeover from the stopped state of the compressor to the driven state of the compressor is set longer than a second period of the changeover from the driven state of the compressor to the stopped state of the compressor, the first period of changeover comprises a convergence of the load torque to a stable value through an increase from 0, the second period of changeover comprises a convergence of the load torque to 0 through a decrease, and the electronic control unit is further configured to determine if there is a possibility of a liquid pool of cooling medium in a crank chamber of the compressor based on an outside air temperature and an elapsed time from a last stoppage of the compressor, and if the electronic control unit determines that the possibility of the liquid pool of cooling medium in the crank chamber of the compressor exists, then the first period of the changeover from the stopped state of the compressor to the driven state of the compressor is longer than when the electronic control unit determines that there is no possibility of the liquid pool of cooling medium being in the crank chamber of the compressor, wherein when the outside air temperature is lower than a predetermined value and the elapsed time is longer than a predetermined value, the electronic control unit determines that the possibility of the liquid pool of cooling medium in the crank chamber of the compressor exists. ### Claim 2 (depends on 1) The rotational speed control apparatus according to claim 1, wherein the electronic control unit is configured to set a lower limit of the corrected load torque, such that the corrected load torque does not become negative. ### Claim 3 (depends on 1) The rotational speed control apparatus according to claim 1, wherein the electronic control unit is configured to correct the load torque through the feedback separately for a first required value of the load torque associated with adjustment of an intake air amount and a second required value of the load torque associated with adjustment of an ignition timing, and the electronic control unit is configured to set a correction amount through the feedback based on the first required value of the load torque such that the correction amount based on the first required value of the load torque does not exceed a value that is obtained by subtracting a predetermined reserve torque from a total correction amount of the load torque thorough the feedback. ### Claim 4 (depends on 1) The rotational speed control apparatus according to claim 1, wherein the electronic control unit is configured to calculate the load torque based on a difference between a pressure of a cooling medium upstream of the compressor and a pressure of the cooling medium downstream of the compressor. ### Claim 5 (depends on 1) The rotational speed control apparatus according to claim 1, wherein in the first period of changeover, an initial reserve torque is larger than in the second period of changeover.