# US 6,719,664 B2 · Control apparatus of lock-up clutch for vehicle and control method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,719,664 B2 - Document ID: US6719664B2 - Status: Granted - Kind: B2 - Application number: 10/230,255 - Filed: 2002-08-29 - Published: 2003-03-06 - Granted: 2004-04-13 - Earliest claimed: 2001-08-30 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Takuya Ito; Hiroaki Takeuchi - Web page: https://patentgrep.com/patent/US6719664B2 ## CPC - B60W 10/06: including control of combustion engines - B60W 10/04: including control of propulsion units - B60W 10/11: Stepped gearings - B60W 10/115: with planetary gears - B60W 30/18: Propelling the vehicle - B60W 30/1819: {Propulsion control with control means using analogue circuits, relays or mechanical links} - F16H 61/143: {using electric control means} - B60K 31/185: {connected to the speedometer display, e.g. by sensors or switches responsive to the position of the indicator needle} - B60W 2710/0616: Position of fuel or air injector - B60W 2710/0644: Engine speed - F16H 2061/0425: {Bridging torque interruption} - 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 - F16H: GEARING - 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 ## Abstract When a deceleration slip executing minimum gear stage is not established in a state of continuously executing a deceleration slip control at a target slip amount, it is judged whether or not an input shaft rotational speed of a transmission becomes a down shift judging rotational speed. When it becomes equal to or less than a predetermined down shift judging rotational speed, a down shift is executed, and a clutch pressure is controlled such that an engine rotational speed becomes a target engine rotational speed. ## Claims ### Claim 1 A control apparatus of a lock-up clutch for a vehicle having a hydraulic power transmission with a lock-up clutch which directly connects between an engine and an automatic transmission, the control apparatus comprising: a fuel-cut control portion stopping supplying a fuel to the engine at a time when the vehicle is decelerated, and restarting supplying the fuel to the engine at a time of judging that a rotational speed of the engine becomes a predetermined fuel-cut end rotational speed; a slip control portion which executes a slip control of the lock-up clutch at the time when the vehicle is decelerated; and a shift transmission control portion which performs a down shift of the automatic transmission at a time of judging that at least any one of the rotational speed of the engine and an input shaft rotational speed of the automatic transmission becomes a down shift rotational speed which is higher than the fuel-cut end rotational speed by a predetermined amount, during an execution of the slip control by the slip control portion. ### Claim 2 (depends on 1) A control apparatus according to claim 1, wherein the slip control portion changes a slip amount of the lock-up clutch so as to restrict the increase of the rotational speed of the engine in accordance with the down shift of the automatic transmission. ### Claim 3 (depends on 2) A control apparatus according to claim 2, wherein the slip control portion slips the lock-up clutch so as to prevent the rotational speed of the engine from being increased in accordance with the down shift of the automatic transmission. ### Claim 4 (depends on 3) A control apparatus according to claim 3, wherein the slip control portion slips the lock-up clutch so as to keep the rotational speed of the engine during a period after the automatic transmission has performed the down shift and until an input shaft rotational speed of the automatic transmission reaches a predetermined rotational speed relative to an engine rotational speed immediately before the automatic transmission performs the down shift. ### Claim 5 (depends on 2) A control apparatus according to claim 2, wherein the slip control portion adjusts an engagement pressure of the lock-up clutch such that the rotational speed of the engine becomes an target engine rotational speed, thereby changing the slip amount. ### Claim 6 (depends on 5) A control apparatus according to claim 5, wherein the target engine rotational speed is set to the engine rotational speed immediately before the down shift of the automatic transmission. ### Claim 7 (depends on 1) A control apparatus according to claim 1, wherein, the shift transmission control portion repeats the down shift of the automatic transmission from a gear stage of the automatic transmission being capable of executing the slip control until a gear stage being uncapable of executing the slip control, thereby increasing a time required until the rotational speed of the engine becomes the fuel-cut end rotational speed. ### Claim 8 (depends on 7) A control apparatus according to claim 7, wherein, the shift transmission control portion shifts down the automatic transmission at a time of judging that at least any one of the rotational speed of the engine and the input shaft rotational speed of the automatic transmission becomes the down shift rotational speed, during a deceleration of the rotational speed of the engine and the execution of the slip control by the slip control portion, and after the down shift, the slip control portion adjusts a slip amount of the lock-up clutch so as to restrict the increase of the rotational speed of the engine, and the shift transmission control portion judges whether the input shaft rotational speed of the automatic transmission becomes the down shift rotational speed, at a time of judging that the input shaft rotational speed of the automatic transmission becomes the down shift rotational speed, the shift transmission control portion performs next down shift. ### Claim 9 A control apparatus of a lock-up clutch for a vehicle having a lock-up clutch which directly connects between an engine and an automatic transmission, the control apparatus comprising: a slip control portion increasing a fuel-cut time required from a start of a fuel-cut at which a fuel supply to the engine is stopped and until an engine rotational speed reaches a fuel-cut end rotational speed, by slip controlling the lock-up clutch at a deceleration of the vehicle; and a shift transmission control portion which increases the fuel-cut time by shifting down the automatic transmission immediately before the engine rotational speed reaches the fuel-cut end rotational speed. ### Claim 10 A control method of a lock-up clutch for a vehicle having a hydraulic power transmission with a lock-up clutch which directly connects between an engine and an automatic transmission, comprising: a step of stopping supplying a fuel to the engine at a deceleration of the vehicle, and restarting supplying the fuel to the engine at a time of judging that a rotational speed of the engine becomes a predetermined fuel-cut end rotational speed; a step of executing a slip control of the lock-up clutch at the deceleration of the vehicle; and a step of shifting down the automatic transmission at a time of judging that at least any one of the rotational speed of the engine and an input shaft rotational speed of the automatic transmission becomes a down shift rotational speed which is higher than the fuel-cut end rotational speed by a predetermined amount, during an execution of the slip control. ### Claim 11 (depends on 10) A control method according to claim 10, wherein a slip amount of the lock-up clutch is adjusted so as to restrict the increase of the rotational speed of the engine in accordance with the down shift of the automatic transmission, in the slip control. ### Claim 12 (depends on 11) A control method according to claim 11, wherein the lock-up clutch is slipped such that the rotational speed of the engine is not increased in accordance with the down shift of the automatic transmission, in the slip control. ### Claim 13 (depends on 12) A control method according to claim 12, wherein the lock-up clutch is slipped so as to keep the rotational speed of the engine during a period after the automatic transmission has performed the down shift and until the input shaft rotational speed of the automatic transmission reaches a predetermined rotational speed relative to an engine rotational speed immediately before the automatic transmission performs the down shift, in the slip control. ### Claim 14 A control method of a lock-up clutch for a vehicle having a lock-up clutch which directly connects between an engine and an automatic transmission, comprising: a step of increasing a fuel-cut time required from a start of a fuel-cut at which a fuel supply to the engine is stopped and until an engine rotational speed reaches a fuel-cut end rotational speed, by slip controlling the lock-up clutch at a deceleration of the vehicle; and a step of increasing the fuel-cut time by shifting down the automatic transmission immediately before the engine rotational speed reaches the fuel-cut end rotational speed.