Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
  • B60W10/02—Conjoint control of vehicle sub-units of different type or different function including control of driveline clutches
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
  • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
  • B60W10/06—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of combustion engines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
  • B60W30/18—Propelling the vehicle
  • B60W30/18009—Propelling the vehicle related to particular drive situations
  • B60W30/18072—Coasting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W2510/00—Input parameters relating to a particular sub-units
  • B60W2510/02—Clutches
  • B60W2510/0291—Clutch temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W2510/00—Input parameters relating to a particular sub-units
  • B60W2510/10—Change speed gearings
  • B60W2510/107—Temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W2540/00—Input parameters relating to occupants
  • B60W2540/10—Accelerator pedal position
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • 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
  • B60W2555/00—Input parameters relating to exterior conditions, not covered by groups B60W2552/00, B60W2554/00
  • B60W2555/20—Ambient conditions, e.g. wind or rain
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/60—Other road transportation technologies with climate change mitigation effect

Definitions

• the invention relates to a drive control device and drive control method for a vehicle that is able to coast in a state where an engine is disconnected from a wheel and, more particularly, to a technique for executing any type of coasting when a condition for starting a coasting is not satisfied.
• JP 2002-227885 A suggests a control device for a vehicle, which causes the vehicle to travel in the neutral coasting by releasing a clutch when conditions relating to artificial operation, such as accelerator return operation, and a vehicle state, such as a vehicle speed and a gear position of a transmission, are satisfied during traveling.
• an artificial condition relating to the artificial operation and a vehicle condition relating to the vehicle state are set for a start condition for starting the neutral coasting, it is assumed that, for example, even when the artificial condition is satisfied, the vehicle condition may not be satisfied. Therefore, although, a driver (user) expects that the neutral coasting is executed because of the fact that the driver has conducted user operation that satisfies the artificial condition, the neutral coasting may not be executed ' depending on the vehicle state. As a result, improvement in fuel economy and a gliding feel are not obtained due to substantially non-application of engine braking force, and the driver may experience a feeling of strangeness.
• the neutral coasting is executed or not executed, so the driver may experience a feeling of strangeness.
• the above-described inconveniences are not in public domain, and it has not been suggested yet that, when the neutral coasting cannot be executed because a start condition other than the condition relating to user operation is not satisfied, another type of coasting close to the characteristic of the neutral coasting as much as possible is executed.
• the invention provides a drive control device and drive control method for a vehicle, which suppresses a feeling of strangeness experienced by a driver even when neutral coasting cannot be executed when an artificial condition is satisfied.
• a first aspect of the invention provides a drive control device for a vehicle including an engine having a plurality of cylinders and a separating device configured to disconnect the engine from a wheel or connect the engine to the wheel.
• the drive control device includes a controller configured to cause the vehicle to coast in a state where the engine is disconnected from the wheel when a predetermined start condition is satisfied during normal traveling in which the vehicle travels in a state where the engine is connected to the wheel, the predetermined start condition including an artificial condition relating to artificial operation and a vehicle condition relating to a vehicle state, and the controller being configured to cause the vehicle to coast while operation in at least part of the cylinders of the engine is stopped in a state where the engine is connected to the wheel when the artificial condition is satisfied and the vehicle condition is unsatisfied during the normal traveling.
• the separating device may be a hydraulic clutch
• the vehicle condition may include at least one of a condition that a temperature of hydraulic fluid for actuating the hydraulic clutch is higher than a predetermined fluid temperature and a condition that an ambient temperature is higher than a predetermined ambient temperature.
• the clutch In the neutral coasting, the clutch is released or engaged at the time of executing the neutral coasting or cancelling the neutral coasting (returning to the normal traveling), so engagement shock easily occurs when the controllability of the clutch deteriorates at the time of returning to the normal traveling. Therefore, the vehicle condition includes the hydraulic fluid temperature and the ambient temperature, and, when the hydraulic fluid temperature is low or when the ambient temperature is low, the neutral coasting is not executed. In contrast to this, the coasting is the cylinder stop coasting in which the clutch remains engaged, it is not required to consider engagement shock, so it is possible to select the cylinder stop coasting when the fluid temperature is low or when the ambient temperature is low.
• the controller may be configured to cause the vehicle to coast while supply of fuel to the engine is stopped in a state where the engine is connected to the wheel and operation of at least one of a piston and intake and exhaust valves of the at least part of the cylinders of the engine is stopped when the artificial condition is satisfied and the vehicle condition is not satisfied during the normal traveling.
• the cylinder stop coasting is appropriately executed in a state where engine braking force is decreased as compared to that in the engine braking traveling.
• the controller may be configured to cause the vehicle to coast by stopping the piston of the at least part of the cylinders of the engine in a state where the piston is disconnected from a crankshaft of the engine.
• the cylinder stop coasting is appropriately executed in a state where engine braking force is decreased as compared to that in the engine braking traveling.
• the controller may be configured to cause the vehicle to coast by stopping rotation of the engine through stopping supply of fuel to the engine in a state where the engine is disconnected from the wheel when the predetermined start condition, including the artificial condition relating to the artificial operation and the vehicle condition relating to the vehicle state, is satisfied during the normal traveling.
• the neutral coasting is appropriately executed in a state where engine braking force is not substantially applied.
• the controller may be configured to cause the vehicle to coast while the engine is operated by supplying fuel to the engine in a state where the engine is disconnected from the wheel when the predetermined start condition, including the artificial condition relating to the artificial operation and the vehicle condition relating to the vehicle state, is satisfied during the normal traveling.
• the neutral coasting is appropriately executed in a state where engine braking force is not substantially applied.
• the controller may be configured to cause the vehicle to coast while the engine is operated in an idling state by supplying fuel to the engine. With this configuration, irrespective of whether fuel is supplied to the engine, the neutral coasting is appropriately executed in a state where engine braking force is not substantially applied.
• a second aspect of the invention provides a drive control method for a vehicle including an engine having a plurality of cylinders and a separating device configured to disconnect the engine from a wheel or connect the engine to the wheel.
• the drive control method includes: coasting the vehicle in a state where the engine is disconnected from the wheel when a predetermined start condition, including an artificial condition relating to artificial operation and a vehicle condition relating to a vehicle state, is satisfied during normal traveling in which the vehicle travels in a state where the engine is connected to the wheel; and coasting the vehicle while operation in at least part of the cylinders of the engine is stopped in a state where the engine is connected to the wheel when the artificial condition is satisfied and the vehicle condition is unsatisfied during the normal traveling.
• FIG. 1 is a view that illustrates the schematic configuration of a drive device included in a vehicle according to an embodiment of the invention, and is a view that illustrates a relevant portion of control systems in the vehicle;
• FIG. 2 is a flowchart that illustrates a relevant portion of control operations of an electronic control unit, that is, control operations for making a driver hard to experience a feeling of strangeness even when the neutral coasting cannot be executed at the time when an artificial condition is satisfied; ,
• FIG. 3 is a flowchart that illustrates part or all of control operations for determining whether a vehicle condition is satisfied, which are executed in step S30 in the flowchart of FIG. 2;
• FIG. 4 shows time charts in the case where the control operations shown in the flowchart of FIG. 2 are executed.
• a vehicle includes a transmission that transmits power of an engine to a wheel side.
• the transmission is, for example, formed of an automatic transmission alone or an automatic transmission having a fluid transmission device.
• the automatic transmission is formed of a known planetary gear-type automatic transmission, a known synchromesh parallel-two-shaft transmission, that is, a synchromesh parallel-two-shaft automatic transmission in which a gear position is automatically shifted by a hydraulic actuator, a synchromesh parallel-two-shaft automatic transmission, that is, a so-called dual clutch transmission (DCT) of a type having two-line input shafts, a known belt-type continuously variable transmission, a known toroidal-type continuously variable transmission, or the like.
• DCT dual clutch transmission
• a clutch is used as a separating device.
• various separating devices which are able to allow or interrupt power transmission by electrically controlling reaction force, may be employed.
• an automatic transmission that is able to set a neutral mode may be utilized.
• the clutch may be any engagement device that is able to disconnect the engine from a wheel, and also includes a brake in a broad sense.
• a hydraulic friction engagement device that constitutes part of the automatic transmission that is able to set a neutral mode may be used as the clutch.
• the engine is, for example, an internal combustion engine, such as a gasoline engine and a diesel engine, which generates power by burning fuel.
• the vehicle just needs to include at least the engine as a driving force source; however, the vehicle is not limited to this configuration.
• the vehicle may further include another driving force source, such as an electric motor, in addition to the engine.
• normal traveling includes normal acceleration traveling in which the vehicle travels using the power of the engine in a state where the engine is connected to the wheel and normal deceleration traveling (engine braking traveling) in which the vehicle travels while engine braking is applied through driven rotation of the engine in a state where the engine is connected to the wheel.
• engine braking traveling engine braking force is generated by rotational resistance, such as pumping loss and friction torque, through driven rotation of the engine.
• the engine may be in a fuel cut (F/C) state where supply of fuel is stopped or may be in an operated state where fuel in a predetermined amount is supplied as in the case of an idling state, or the like. Even when fuel is supplied, engine braking force is generated through driven rotation of the engine at a rotation speed corresponding to a vehicle speed, or the like.
• F/C fuel cut
• a stop of a piston or intake and exhaust valves in cylinder stop coasting may be mechanically carried out by disengaging a clutch mechanism arranged, for example, between the piston or the intake and exhaust valves and a crankshaft.
• a clutch mechanism arranged, for example, between the piston or the intake and exhaust valves and a crankshaft.
• the intake and " exhaust valves are, for example, electromagnetic intake and exhaust valves that are able to undergo open/close control independently of rotation of the crankshaft, the operation of the intake and exhaust valves just needs to be stopped.
• a stop position of the intake and exhaust valves is, for example, adequately a compression stroke in which both valves are in a closed state; however, the stop position is not limited to this configuration. The stop position may be set as needed.
• both the intake and exhaust valves are stopped at a position at which both valves are in an open state.
• pistons and intake and exhaust valves in the remaining cylinders are operated in synchronization with rotation of the crankshaft.
• it may be configured such that only the half four cylinders are stopped and the remaining four cylinders are operated or only the six cylinders are stopped and the remaining two cylinders are operated.
• FIG. 1 is a view that illustrates the schematic configuration of a drive device 12 included in a vehicle 10 to which the invention is applied, and is a view that illustrates a relevant portion of various control systems in the vehicle 10.
• the drive device 12 includes an engine 14 and an automatic transmission 1.6.
• the engine 14 has a plurality of cylinders.
• the power of the engine 14 that serves as a driving force source is transmitted from the automatic transmission 16 to right and left wheels 20 via a differential gear unit 18.
• a damper device and a power transmission device such as a torque converter, are provided between the engine 14 and the automatic transmission 16.
• a motor generator that functions as a driving force source may be arranged between the engine 14 and the automatic transmission 16.
• the engine 14 includes an engine control device 30.
• the engine control device 30 includes various devices, a cylinder stop device, and the like.
• the various devices are, for example, an electronic throttle valve, a fuel injection device and an ignition device, required for controlling the output of the engine 14.
• the electronic throttle valve controls an intake air amount.
• the fuel injection device controls the amount of fuel supplied.
• the ignition device controls ignition timing.
• the electronic throttle valve, the fuel injection device and the ignition device are basically controlled on the basis of an operation amount of an accelerator pedal (accelerator operation amount) Gacc corresponding to a driver's drive request amount to the vehicle 10.
• the fuel injection device is able to stop supply of fuel (fuel cut (F/C)), for example, when the accelerator is released in which it is determined that the accelerator operation amount Oacc is zero even while the vehicle is traveling.
• the cylinder stop device is, for example, able to stop intake and exhaust valves of part or all of the plurality of cylinders, such as eight cylinders, by mechanically disconnecting the intake and exhaust valves from a crankshaft with the use of a clutch device, or the like.
• the cylinder stop device stops the intake and exhaust valves in a compression stroke in which both valves are in a closed state.
• a mode in which both the intake and exhaust valves are stopped in an open state may be employed or a mode in which a piston is disconnected from the crankshaft and stopped may be employed instead of or in addition to the mode in which the intake and exhaust valves are stopped.
• the automatic transmission 16 is, for example, a step-shift automatic transmission, such as a planetary gear type, in which a plurality of gear positions having different speed ratios E are established by engaged and/or released states of a plurality of hydraulic friction engagement devices (clutches and, brakes).
• the hydraulic friction engagement devices each undergo engaging control and/or releasing control by electromagnetic hydraulic control valves, selector valves, and the like, provided in a hydraulic control device 32.
• a predetermined gear position is established on the basis of driver's accelerator operation, a vehicle speed V, and the like.
• a clutch CI functions as an input clutch of the automatic transmission 16, and is similarly a hydraulic friction engagement device that undergoes engaging control and/or releasing control by the hydraulic control device 32.
• the clutch CI corresponds to a separating device (clutch) that connects the engine 14 to the wheels 20 or disconnects the engine 14 from the wheels 20.
• a belt-type continuously variable transmission may be used as the automatic transmission 16 instead of the step-shift transmission.
• the vehicle 10 includes an electronic control unit 70 (can be regarded as a controller) that executes drive control over the vehicle 10 relating to, for example, engaging control and/or releasing control over the clutch CI.
• the electronic control unit 70 is, for example, configured to include a so-called microcomputer that includes a CPU, a ROM, a RAM, an input/output interface, and the like.
• the CPU executes various controls over the vehicle 10 by carrying out signal processing in accordance with programs prestored in the ROM while utilizing a temporary storage function of the RAM.
• the electronic control unit 70 is configured to execute output control over the engine 14, shift control over the automatic transmission 16, torque capacity control over the clutch CI, and the like, and is, where necessary, divided into an engine control electronic control unit, a hydraulic control electronic control unit, and the like.
• Various signals based on detected values of various sensors are supplied to the electronic control unit 70.
• the various sensors include an engine rotation speed sensor 50, a turbine rotation speed sensor 52, an input rotation speed sensor 54, an output rotation speed sensor 56, an accelerator operation amount sensor 58, a hydraulic fluid temperature sensor 60, an ambient temperature sensor 62, and the like.
• the various signals include an engine rotation speed Ne that is the rotation speed of the engine 14, a turbine rotation speed Nt that is the rotation speed of a turbine shaft of the torque converter, a transmission input rotation speed Nin that is the input rotation speed of the automatic transmission 16, a transmission output rotation speed Nout that is the output rotation speed of the automatic transmission 16 and corresponds to the vehicle speed V, the accelerator operation amount Oacc, a hydraulic fluid temperature THoil that is the temperature of hydraulic fluid that operates the clutch CI, that is, hydraulic fluid (for example, known automatic transmission fluid (ATF) (trademark)), an ambient temperature THair, and the like.
• the hydraulic fluid is used to operate the automatic transmission 16 or, for example, lubricate and cool portions of the drive device 12.
• an engine output control command signal Se for output control over the engine 14 a hydraulic command signal Sp for engaging control over the clutch CI or shift control over the automatic transmission 16, and the like, are output from the electronic control unit 70 to the engine control device 30, the hydraulic control device 32, and the like.
• the electronic control unit 70 functionally includes an engine output control unit 72, a shift control unit 74, a neutral coasting unit 76, a cylinder stop coasting unit 78 and a drive mode determination unit 80.
• the engine output control unit 72 outputs the engine output control command signal Se to the engine control device 30 such that an engine torque Te required (hereinafter, required engine torque Tedem) is obtained.
• the engine output control command signal Se includes a signal for controlling open/close state of the electronic throttle valve, a signal for controlling a fuel injection amount injected by the fuel injection device and a signal for controlling ignition timing of the ignition device.
• the engine output control unit 72 calculates a required driving force Fdem as a. drive request amount on the basis of an actual accelerator operation amount Oacc and a vehicle speed V by consulting a prestored correlation (driving force map) (not shown) between a vehicle speed V and a required driving force Fdem using the accelerator operation amount Oacc as a parameter.
• the engine output control unit 72 calculates the required engine torque Tedem on the basis of, for example, the speed ratio E at the current gear position of the automatic transmission 16.
• the calculated required driving force Fdem is obtained by the required engine torque Tedem.
• a required driving torque Touttgt [Nm] in the wheels 20 a required driving power [W] in the wheels 20, a required transmission output torque in the automatic transmission 16, a required transmission input torque in the automatic transmission 16, the required engine torque Tedem, or the like, may be used as the drive request amount.
• the accelerator operation amount Oacc [%], a throttle valve opening degree [%], the intake air amount [g/sec] of the engine 14, or the like may be simply used as the drive request amount.
• the shift control unit 74 executes shift control over the automatic transmission 16. Specifically, the shift control unit 74 carries out shift determination on the basis of a vehicle state indicated by an actual vehicle speed V and an actual drive request amount by consulting a prestored correlation (shift map, shift line map) set using the vehicle speed V and the drive request amount as variables. When the shift control unit 74 has determined to shift the automatic transmission 16, the shift control unit 74 outputs the hydraulic command signal Sp for engaging and/or releasing the hydraulic friction engagement devices associated with the shift of the automatic transmission 16 to the hydraulic control device 32 such that the determined gear position is achieved.
• a prestored correlation shift map, shift line map
• the engine output control unit 72, shift control unit 74, neutral coasting unit 76 and cylinder stop coasting unit 78 of the electronic control unit 70 execute two types of drive modes, that is, normal traveling and coasting, shown in Table 1.
• the normal traveling is a drive mode in which the vehicle travels in a state where the engine 14 is connected to the wheels 20 (that is, in a state where the clutch CI is engaged).
• the normal traveling includes normal acceleration traveling in which the vehicle 10 is in a driving state and normal deceleration traveling (engine braking traveling) in which the vehicle 10 is in a driven state.
• the coasting is a drive mode in which the vehicle travels in a state where engine braking force is decreased as compared to that in the engine braking traveling.
• the coasting includes neutral coasting (also referred to as N coasting) and cylinder stop coasting (also referred to as cylinder stop coasting).
• the engine output control unit 72 and the shift control unit 74 execute the normal acceleration traveling in which the vehicle travels using the power of the engine 14 while the engine 14 is connected to the wheels 20. Specifically, the engine output control unit 72 executes output control over the engine 14 such that the drive request amount is obtained as described above. Together with this, the shift control unit 74 executes shift control over the automatic transmission 16, including engagement of the clutch CI , on the basis of the vehicle state indicated by the actual vehicle speed V and the actual drive request amount by consulting the shift map.
• the engine output control unit 72 and the shift control unit 74 execute engine braking traveling in which the vehicle travels while applying engine braking through driven rotation of the engine 14 in a state where the engine 14 is coupled to the wheels 20.
• the engine braking traveling for example, the vehicle travels while the connected , state between the engine 14 and the wheels 20 is kept when the accelerator is not operated.
• engine braking occurs due to pumping loss, friction torque, or the like, through driven rotation of the engine 14.
• the engine 14 may be in a state where fuel in a minimum amount is supplied as in the case of the idling state when the accelerator is not operated, and may also be controlled to a fuel cut state where supply of fuel to the engine 14 is stopped.
• the automatic transmission 16 is caused to establish a predetermined gear position on the basis of the vehicle speed V, and the like, and the clutch CI is held in an engaged state.
• the engine 14 is driven at a predetermined rotation speed that is determined on the basis of the vehicle speed V and the speed ratio E, and engine braking force having a magnitude corresponding to the rotation speed is generated.
• the neutral coasting unit 76 executes the neutral coasting in which the vehicle coasts in a state where the engine 14 is disconnected from the wheels 20. (that is, in a state where the clutch CI is released).
• rotation of the engine may be stopped by stopping supply of fuel to the engine 14 or the engine may be operated by supplying fuel to the engine 14. That is, the engine 14 may be placed in a state where rotation of the engine is stopped by carrying out fuel cut (F/C) or may be placed in an idling state where the engine is autonomously operated.
• F/C fuel cut
• engine braking force becomes substantially 0 because the clutch CI is released, so.
• the cylinder stop coasting unit 78 executes the cylinder stop coasting in which the vehicle coasts while the operation in at least part of the cylinders of the engine 14 is stopped in a state where the engine 14 is connected to the wheels 20.
• the cylinder stop coasting in a state where the engine 14 is connected to the wheels 20 by keeping the engaged state of the clutch CI, supply of fuel to the engine 14 is stopped (fuel cut (F/C)), and the intake and exhaust valves of at least part of the cylinders of the engine 14 are stopped at a position at which both the valves are in a closed state by the cylinder stop device of the engine control device 30.
• the crankshaft is driven on the basis of the vehicle speed V and the gear position of the automatic transmission 16.
• the drive mode determination unit 80 determines whether the vehicle travels in any one of the two drive modes, that is, the normal traveling and the coasting, and switches into the determined drive mode. Specifically, the drive mode determination unit 80 determines to execute the coasting when a predetermined start condition including an artificial condition relating to artificial operation and a vehicle condition relating to a vehicle state is satisfied during the normal traveling.
• the coasting is basically executed in the neutral coasting. In the neutral coasting, it may be basically predetermined such that fuel cut (F/C) having a high fuel economy improving effect is carried out.
• the neutral coasting when warm-up of the engine 14 is required, when charging of a battery by the power of the engine 14 is required, or when driving of a mechanical pump by the power of the engine 14 is required, it may be predetermined such that the engine 14 is placed in the idling state.
• the artificial condition is a driver condition relating to user operation.
• the vehicle condition is a condition relating to the state of the traveling vehicle 11 , a travel environment, and the like, not directly associated with user operation.
• the artificial condition is, for example, a condition that a period of time during which the accelerator is not operated continuously is longer than or equal to a predetermined period of time and brake operation force is smaller than a predetermined brake operation force.
• the vehicle condition is, for example, a condition that the hydraulic fluid temperature THoil is higher than a predetermined fluid temperature, the ambient temperature THair is higher than a predetermined ambient temperature, a travel road is a flat road or a downhill road having a predetermined gradient or smaller and there is no other vehicle ahead or a distance to a vehicle ahead is longer than or equal to a predetermined distance.
• Each of the predetermined values is a threshold predetermined as a condition for allowing the neutral coasting to be executed.
• the vehicle condition includes the condition of the hydraulic fluid temperature THoil and the condition of the ambient temperature THair, and, when the hydraulic fluid temperature THoil is low or when the ambient temperature THair is low, the neutral coasting is not executed.
• the predetermined fluid temperature is a predetermined determination threshold for determining that the hydraulic fluid temperature THoil is low where the controllability of the clutch CI easily deteriorates.
• the predetermined ambient temperature is a predetermined determination threshold for determining that the ambient temperature THair is low where the hydraulic fluid temperature THoil is easily decreased.
• the drive mode determination unit 80 determines to execute the normal traveling when the artificial condition is not satisfied.
• the drive mode determination unit 80 basically determines to execute the normal acceleration traveling when the artificial condition is not satisfied due to the fact that the accelerator is operated where it is not determined that the accelerator operation amount Oacc is zero.
• the drive mode determination unit 80 basically determines to execute the engine braking traveling when the artificial condition is not satisfied due to the fact that the brake operation force is larger than or equal to the predetermined brake operation force.
• the cylinder stop coasting is possible other than the neutral coasting.
• the cylinder stop coasting is able to implement coasting close to the characteristic of the neutral coasting and having a smaller engine braking force than the engine braking traveling.
• the drive mode determination unit 80 determines to execute the cylinder stop coasting when the artificial condition is satisfied and the vehicle condition is not satisfied during traveling. However, the drive mode determination unit 80 does not always execute the cylinder stop coasting when the artificial condition is satisfied and the vehicle condition is not satisfied. That is, there is a vehicle condition that is hard to cause an inconvenience when the cylinder stop coasting is executed even when the vehicle condition should be satisfied when the neutral coasting is executed. For example, as described above, when the neutral coasting is executed, the vehicle condition includes the condition of the hydraulic fluid temperature THoil and the condition of the ambient temperature THair because the controllability of the clutch CI may be deteriorated.
• the drive mode determination unit 80 determines to execute the cylinder stop coasting when the artificial condition is satisfied and when the vehicle condition is not satisfied due to the fact that the condition that the hydraulic fluid temperature THoil is higher than the predetermined fluid temperature is not satisfied or the condition that the ambient temperature THair is higher than the predetermined ambient temperature is not satisfied during traveling.
• FIG. 2 is a flowchart that illustrates a relevant portion of control operations of the electronic control unit 70, that is, control operations for making it hard for the driver to experience a feeling of strangeness even when the neutral coasting cannot be executed when the artificial condition is satisfied, and is, for example, repeatedly executed in an extremely short cycle time of about several milliseconds to several tens of milliseconds.
• FIG. 3 is a flowchart that illustrates part or all of control operations for determining whether the vehicle condition is satisfied, which are executed in the determination step S30 in the flowchart of FIG. 2.
• FIG. 4 shows time charts in the case where the control operations shown in the flowchart of FIG. 2 are executed.
• step (hereinafter, step is omitted) S10 corresponding to the drive mode determination unit 80 for example, it is determined whether the artificial condition (that is, a driver condition for allowing the neutral coasting) is satisfied.
• the process proceeds to S2Q.
• S20 corresponds to the drive mode determination unit 80, the engine output control unit 72 and the shift control unit 74. In S20, it is determined to execute the normal traveling, and the normal traveling is executed.
• S10 when affirmative determination is made in S10, the process proceeds to S30 corresponding to the drive mode determination unit 80.
• S30 for example, it is determined whether the vehicle condition (that is, the vehicle condition for allowing the neutral coasting) is satisfied.
• the flowchart shown in FIG. 3 is executed as part or all of the control operations for determining whether the vehicle condition is satisfied.
• the vehicle condition within the start condition for executing the neutral coasting includes a condition that the hydraulic fluid temperature THoil is higher than the predetermined fluid temperature and a condition that the ambient temperature THair is higher than the predetermined ambient temperature.
• the vehicle in the neutral coasting, the vehicle is caused to coast while rotation of the engine is stopped by stopping supply of fuel to the engine 14 in a state where the engine 14 is disconnected from the wheels 20 or the vehicle is caused to coast while the engine is operated by supplying fuel to the engine 14 in a state where the engine 14 is disconnected from the wheels 20.
• the neutral coasting is appropriately executed in a state where engine braking force is not substantially applied.
• the vehicle condition for executing the neutral coasting includes both two conditions, that is, the condition that the hydraulic fluid temperature THoil is higher than the predetermined fluid temperature and the condition that the ambient temperature THair is higher than the predetermined ambient temperature; however, the vehicle condition is not limited to this configuration.
• the vehicle condition may include at least one of the above two conditions.
• the vehicle condition does not include the condition of the ambient temperature THair
• engine braking force may be changed irrespective of a driver's intention, and the driver may experience a feeling of strangeness.
• the vehicle condition includes both the above two conditions, if the ambient temperature THair is lower than the predetermined ambient temperature even when the hydraulic fluid temperature THoil is higher than the predetermined fluid temperature, the neutral coasting is originally not executed, so it is possible to avoid occurrence of the above-described feeling of strangeness.
• the cylinder stop coasting is executed in S50; however,. the control operations are not limited to this configuration. For example, even when the other vehicle condition is not satisfied but the other vehicle condition is satisfied if loosened more than the condition for determining whether to execute the neutral coasting, the cylinder stop coasting may be executed.
• a travel road is a downhill road having a predetermined gradient or above or a distance to a vehicle ahead is shorter than a predetermined distance
• the vehicle condition for the neutral coasting is not satisfied; however, it may be determined whether the vehicle condition for the cylinder sto coasting is satisfied using the predetermined gradient or the predetermined distance changed to a threshold that is obtained by loosening fulfillment of the condition.
• the cylinder stop coasting is not always executed when the artificial condition is satisfied and the vehicle condition is not satisfied; instead, the cylinder stop coasting may always be executed in this case.
• the cylinder stop coasting may be executed also when the artificial condition is not satisfied.
• the artificial condition is not satisfied if brake operation force is larger than or equal to the predetermined brake operation force; however, the cylinder stop coasting may be executed in such a case.
• the parameters (the accelerator operation amount Oacc, the hydraulic fluid temperature THoil, the road surface gradient, and the like) used in the start condition (the artificial condition, the vehicle condition) and the determination thresholds (the predetermined values, such as the predetermined period of time, the predetermined fluid temperature and the predetermined gradient) for the parameters are only illustrative, and are not limited to those values.
• the clutch CI that constitutes part of the automatic transmission 16 is illustrated as the separating device that disconnects the engine 14 from the wheels 20; however, the clutch CI is not limited to this configuration.
• the clutch CI may be provided independently of the automatic transmission 16.
• the clutch CI is provided independently of the continuously variable transmission, and a known forward/reverse switching device included in ' the vehicle together with the belt-type continuously variable transmission or an engagement device included in the forward/reverse switching device may be used as the separating device.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Automation & Control Theory (AREA)
• Control Of Driving Devices And Active Controlling Of Vehicle (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
• Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)

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Citations (7)

• 2012
  • 2012-10-30 JP JP2012239464A patent/JP2014088825A/ja not_active Withdrawn
• 2013
  • 2013-10-24 WO PCT/IB2013/002669 patent/WO2014068399A1/en active Application Filing

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