JP2012072875A - Engine start control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine start control apparatus that both improves fuel consumption by stopping an engine in driving a vehicle and secures startability in restarting after a stop of the engine.SOLUTION: A start control apparatus 70 of the engine 4 controls a restart of the engine 4 after the stop of the engine 4 when the vehicle 1 is driven. The apparatus includes: a startability determination unit 88 for determining the startability of the engine 4, the engine being a power source when vehicle 1 traveling; and a shift control unit 92 being an engaging force controller that is disposed to control engaging force of a friction engagement element 22 which engages when power generated in the engine 4 is transferred to a driving wheel 28 side, and that adjusts the engaging force of the friction engagement element 22, when the engine 4 is started, on the basis of the startability of the engine 4 determined by the startability determination unit 88.

Description

  The present invention relates to an engine start control device.

  In recent vehicles, for the purpose of improving fuel efficiency and reducing exhaust gas emissions, when there is no torque request from the driver when the vehicle is running, the engine is stopped and the vehicle is driven inertially. Control technology that stops the engine when it is temporarily stopped has been developed. For example, in the control device for restarting the engine of a vehicle described in Patent Document 1, when a predetermined condition such as setting the shift position to the non-drive position is satisfied, the engine is stopped and the shift position is set to the drive position again. The engine is restarted when a predetermined condition such as is satisfied.

  In addition, when the transmission mounted on the vehicle is an automatic transmission that performs a shift by switching engagement and release of a clutch and brake controlled by hydraulic pressure, when the engine is stopped, the clutch of the automatic transmission, etc. The oil pump that generates hydraulic pressure for operation is also stopped. For this reason, when the engine is stopped, the engaging force of the clutch or the like of the automatic transmission may be reduced. Therefore, in the control device described in Patent Document 1, in order to immediately generate the driving force when the engine is restarted, control is performed to rapidly increase the hydraulic pressure for increasing the engagement force of the clutch of the automatic transmission. ing.

JP-A-11-351371

  However, the engine is a battery that drives a starter used to start the engine, such as the deposit state that is a deposit when fuel burns in the combustion chamber, the current temperature of the engine, the variation of the individual engine, etc. The startability may change depending on various states related to engine start such as deterioration of engine. If the engine startability has changed in this way when the engine is restarted after stopping the engine for the purpose of improving the fuel efficiency, etc., the engine start and the clutch engagement force There may be a deviation in the synchronization timing. As a result, it may not be possible to ensure an increase in the engine rotational speed. In this case, the engine startability may deteriorate, or a shock may occur when the clutch is engaged.

  The present invention has been made in view of the above circumstances, and achieves both improvement in fuel consumption by stopping the engine during driving of the vehicle and ensuring startability at restart after stopping the engine. It is an object of the present invention to provide an engine start control device capable of performing the above.

  In order to solve the above-described problems and achieve the object, an engine start control device according to the present invention includes startability determination means for determining startability of an engine that is a power source when a vehicle travels, and generated by the engine. The engagement force of the friction engagement element that is engaged when transmitting the motive power to the drive wheel side is controllable, and based on the startability of the engine determined by the startability determination means when the engine is started Engagement force control means for adjusting the engagement force of the friction engagement element.

  Further, in the engine start control device, the startability determining means determines a change in the engine startability based on an amount of change in the rotational speed of the engine, and the engagement force control means is the startability determination means. It is preferable that the engagement force of the friction engagement element is adjusted based on the amount of change in the rotational speed of the engine determined in (1).

  In the engine start control device, it is preferable that the engagement force control means adjusts the timing at which the engagement force of the friction engagement element is increased at the start of the engine based on the startability of the engine.

  In the engine start control device, it is preferable that the engagement force control means adjusts the magnitude of the engagement force of the friction engagement element when the engine is started based on the startability of the engine.

  The engine start control device according to the present invention adjusts the engagement force of the friction engagement element based on the startability of the engine determined by the startability determination means when starting the engine. When the engine is restarted after the engine is stopped, the engagement timing and the engagement force of the friction engagement element can be matched to the engine startability. As a result, it is possible to secure an increase in the rotational speed of the engine when the engine is started, improve fuel efficiency by stopping the engine when the vehicle is operating, and ensure startability when restarting after the engine is stopped. It is possible to achieve both of these.

FIG. 1 is a schematic diagram of a vehicle including an engine start control device according to an embodiment. FIG. 2 is an explanatory diagram of precharging of the friction engagement element during automatic start. FIG. 3 is an explanatory diagram in the case of adjusting the engagement timing of the friction engagement element in accordance with the startability of the engine. FIG. 4 is an explanatory diagram when the engagement force of the friction engagement element is adjusted in accordance with the startability of the engine. FIG. 5 is an explanatory diagram in a case where the automatic start is performed immediately after the automatic stop of the engine. FIG. 6 is an explanatory diagram in the case where the engagement timing and the engagement force of the friction engagement element are corrected according to the startability of the engine.

  Hereinafter, an embodiment of an engine start control device according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

Embodiment
FIG. 1 is a schematic diagram of a vehicle including an engine start control device according to an embodiment. The vehicle 1 including the start control device 70 according to the present embodiment shown in FIG. 1 is provided with an engine 4 that is an internal combustion engine as a power source during traveling. The engine 4 is an automatic transmission that is an example of a transmission. It is connected to the machine 20. The automatic transmission 20 is connected to a final speed reducer 26 via a power transmission path, and the final speed reducer 26 is connected to drive wheels 28 via a drive shaft.

  Thus, the automatic transmission 20 interposed between the engine 4 and the final reduction gear 26 is a combination of a planetary gear mechanism, which is a plurality of transmission elements, and a plurality of friction engagement elements 22 such as clutches and brakes. The present invention is provided as a multistage transmission including a transmission mechanism configured and a torque converter that transmits torque via a fluid. Among these, the clutch is a friction engagement element 22 that rotates together with the gears of the planetary gear mechanism when the engagement elements are engaged with each other, and the brake is rotated when the engagement elements are engaged with each other. The friction engagement element 22 stops. Thus, the automatic transmission 20 provided with the plurality of friction engagement elements 22 and the planetary gear mechanism changes the combination of engagement of the friction engagement elements 22, thereby changing the engine 4 and the final reduction gear 26. It is possible to switch the gear ratio between the two. That is, the automatic transmission 20 can switch the gear position by changing the combination of engagement of the friction engagement elements 22.

  Further, the friction engagement element 22 provided in the automatic transmission 20 is provided so as to be operable by applying hydraulic pressure, and the engine 4 can generate hydraulic pressure to be applied to the friction engagement element 22. A possible oil pump 30 is connected. The oil pump 30 is operated by power generated by the engine 4 so as to generate hydraulic pressure.

  Further, the engine 4 is provided with an engine speed sensor 8 which is a rotational speed detecting means for detecting the rotational speed of the crankshaft 6, and detects the rotational speed during operation of the engine 4, that is, the engine speed. It is possible. Further, the automatic transmission 20 is provided with a vehicle speed sensor 24 which is a vehicle speed detecting means for detecting the vehicle speed by detecting the rotational speed of the output side rotating body such as the output shaft.

  Further, in the vicinity of the engine 4, various auxiliary machines 32 such as a power steering pump and an air conditioner compressor, and a motor generator (hereinafter referred to as "MG") 40 having functions of an electric motor and a generator are arranged. Has been. Among these, the MG 40 is used as a power source for driving the MG 40, and when the MG 40 functions as a generator (alternator), the MG 40 is connected to a high voltage battery 46 that stores the generated power via an inverter 44. Connected. The inverter 44 and the high voltage battery 46 are both connected to a DC / DC converter 48, and the DC / DC converter 48 further supplies power to various electric components and electric devices mounted on the vehicle 1. Is connected to a battery 50 used as a power source for supplying the power. The DC / DC converter 48 connected to the inverter 44 and the high voltage battery 46 steps down the voltage of the high voltage battery 46 and the voltage of the electric power generated by the MG 40 so that the battery 50 can be charged. It has been.

  In the present embodiment, the electric devices and the like mounted on the vehicle 1 are provided so as to supply electric power from the battery 50. However, the battery 50 is omitted and the electric devices and the like are omitted. On the other hand, the step-down power may be directly supplied via the DC / DC converter 48.

  In addition, a crank damper 10 having a pulley 12 is attached via an electromagnetic clutch 14 to a crankshaft 6 which is a rotating shaft provided so that power can be output to the outside by rotating when the engine 4 is operated. Further, pulleys 34 and 42 are attached to the auxiliary machines 32 and MG 40 so as to be integrally rotatable, and a transmission belt 52 is hung on the pulleys 34 and 42 and the pulley 12 of the crank damper 10. ing.

  Further, in the vicinity of the driver's seat of the vehicle 1, an accelerator pedal 56 capable of adjusting power generated by the engine 4 and a brake pedal capable of adjusting braking force generated by a brake device (not shown) included in the vehicle 1. 60 is provided. Further, a shift lever 64 that can switch the range of the automatic transmission 20 is provided in the vicinity of the driver's seat. As the shift range of the automatic transmission 20, for example, P (parking), R (reverse), N (neutral), D (drive), 2nd speed, 1st speed, etc. are set. The shift range can be switched by selecting the range.

  The operation states of the pedals and the shift lever 64 provided as described above are provided so as to be detected by the driving operation detection means. Specifically, the operation state of the accelerator pedal 56 can be detected by the accelerator sensor 58, and the operation state of the brake pedal 60 can be detected by the brake sensor 62. Similarly, the shift lever 64 is provided so that the shift sensor 66 can detect the operation state of the shift lever 64, that is, the selection state of the shift range of the automatic transmission 20 selected by the shift lever 64.

  Engines such as the engine 4 and devices such as the inverter 44 provided as described above are mounted on the vehicle 1 and connected to an ECU (Electronic Control Unit) 80 that controls each part of the vehicle 1. Similarly, sensors such as the engine speed sensor 8, the vehicle speed sensor 24, the accelerator sensor 58, the brake sensor 62, and the shift sensor 66 are also connected to the ECU 80. Thereby, each part of the vehicle 1 is controlled and operated by the ECU 80 based on the detection results of the sensors. For example, the engine 4 has an intake air amount, a fuel injection amount by an injector (not shown), an ignition timing, an opening degree of an accelerator pedal 56 detected by an accelerator sensor 58, an engine speed detected by an engine speed sensor 8, It operates by being controlled according to the engine coolant temperature and the like.

  The MG 40 is provided so as to be controllable through the control of the inverter 44, and the MG 40 is operated by the electric power of the high voltage battery 46 by controlling the inverter 44, and generates electric power by the power of the engine 4. .

  Further, the vehicle 1 can automatically stop the operation of the engine 4 when the vehicle 1 is temporarily stopped, such as waiting for a signal while the vehicle 1 is driving, that is, the vehicle 1 can be automatically stopped. It is possible. Further, when the engine 4 is automatically stopped, the engine 4 can be automatically restarted in response to the driver's start request, that is, the automatic start can be performed. These automatic stop and automatic start are made possible by controlling the engine 4 and the MG 40 with the ECU 80. For this reason, the ECU 80 is provided as a stop control device for controlling the automatic stop of the engine 4, It is also provided as a start control device 70 that controls the automatic start of the engine 4.

  Further, the ECU 80 can exchange information and signals with each device connected to the ECU 80, and the hardware configuration of the ECU 80 includes a processing unit having a CPU (Central Processing Unit), Since it is a known configuration including a storage unit such as a RAM (Random Access Memory), the description thereof is omitted.

  The processing unit of the ECU 80 provided in this way includes sensors for detecting the state of the operating means of the vehicle 1 such as the accelerator sensor 58, the brake sensor 62, and the shift sensor 66, the engine speed sensor 8 and the vehicle speed sensor 24. A driving state acquisition unit 82 that is a driving state acquisition unit that acquires the driving operation state of the driver 100 and the driving state of the vehicle 1 based on the detection results of the sensors that detect the driving state of the vehicle 1, etc. A travel control unit 84 that is a travel control unit that performs travel control of the vehicle 1 such as control of the engine 4, and an automatic control determination unit 86 that is an automatic control determination unit that determines whether to automatically stop or start the engine 4. And a startability determination unit 88 that is a startability determination means for determining the startability of the engine 4 and an MG control unit that controls the operation of the MG 40 through controlling the inverter 44. The MG control unit 90 and the friction engagement element 22 included in the automatic transmission 20 are controlled to be engaged and disengaged, and provided as a shift control means for controlling the shift of the automatic transmission 20. A shift control unit 92 provided also as an engagement force control means provided so as to be able to control the engagement force of the friction engagement element 22 that is engaged when the generated power is transmitted to the drive wheel 28 side.

  The start control device 70 according to this embodiment is configured as described above, and the operation thereof will be described below. When the vehicle 1 travels, the accelerator opening, which is the operation amount of the accelerator pedal 56 operated by the driver 100, is detected by the accelerator sensor 58, and the detection result is acquired by the driving state acquisition unit 82 of the ECU 80. The accelerator opening degree acquired by the driving state acquisition unit 82 is transmitted to the travel control unit 84 of the ECU 80.

  The traveling control unit 84 controls the engine 4 based on the accelerator opening acquired by the driving state acquisition unit 82 and the traveling state of the vehicle 1 acquired by other sensors, so that the power requested by the driver 100 is obtained. Generated by the engine 4. At that time, the traveling control unit 84 controls the operation while detecting the operation state of the engine 4 based on the detection result of the engine speed sensor 8 and the like. The power generated by the engine 4 is transmitted to the drive wheels 28 via the automatic transmission 20 and the final reduction gear 26, thereby generating a drive force on the drive wheels 28.

  Further, when the vehicle 1 is traveling, the driver 100 operates the shift lever 64 to select the shift range of the automatic transmission 20. The operation state of the shift lever 64 is detected by the shift sensor 66 and acquired by the driving state acquisition unit 82 of the ECU 80. The operation state of the shift lever 64 is transmitted to the shift control unit 92 of the ECU 80, and the shift control unit 92 performs the vehicle 1 according to the operation state of the shift lever 64, that is, according to the selected shift range. The shift control of the automatic transmission 20 is performed based on the driving state during the driving. As described above, by performing the operation control of the engine 4 and the shift control of the automatic transmission 20, the vehicle 1 travels while generating the driving force required by the driver 100.

  Further, the vehicle 1 stops the operation of the engine 4 when the automatic stop condition is satisfied. Conditions for this automatic stop include, for example, “the rotational speed of the engine 4 is equal to or lower than the idle rotational speed”, “the vehicle speed is 0”, “no depression of the accelerator pedal 56”, “ The shift range of the automatic transmission 20 is either D, 2nd speed, or 1st speed ".

  The determination as to whether or not the automatic stop condition is satisfied is based on the driving operation state of the driver 100 and the detection result of the driving state in the driving state acquisition unit 82 that acquires the driving state of the vehicle 1. This is performed by an automatic control determination unit 86 included in the ECU 80. If it is determined by the automatic control determination unit 86 that the automatic stop condition is satisfied, the travel control unit 84 performs control such as fuel cut of the engine 4 to stop the engine 4. By performing the control, the engine 4 is automatically stopped.

  When the engine 4 is automatically stopped, the electromagnetic clutch 14 is released together with the stop control of the engine 4, and the MG control unit 90 controls the inverter 44 to operate the MG 40. That is, power is generated in the MG 40 by the power of the high voltage battery 46. The power generated in the MG 40 is transmitted from the pulley 42 attached to the MG 40 to the pulley 34 attached to the auxiliary machine 32 via the transmission belt 52. As a result, the auxiliary machine 32 is operated by the power generated by the MG 40 even when the engine 4 is stopped, and even when the auxiliary machine 32 uses, for example, a power steering pump or an air conditioner compressor. Can be operated while the engine 4 is stopped.

  In this case, since the electromagnetic clutch 14 is in a released state, the pulley 12 of the crank damper 10 is idled on the crankshaft 6. For this reason, the power generated by the MG 40 is not transmitted to the crankshaft 6.

  When the vehicle 1 satisfies the automatic stop condition, the engine 4 is stopped in this manner, thereby reducing fuel consumption and exhaust gas emission, but the engine 4 is stopped. In the state, when the driving operation that can determine that the driver 100 is requesting the driving force is performed, the engine 4 is restarted. For example, when the driver 100 depresses the accelerator pedal 56, the engine 4 is restarted, that is, the engine 4 is automatically started. Specifically, even when the engine 4 is stopped, the driving state of the vehicle 1 is continuously acquired by the driving state acquisition unit 82. Therefore, the operation state of the accelerator pedal 56 and the like acquired by the driving state acquisition unit 82 is changed. On the basis of this, when it can be determined that the driver 100 is requesting the driving force, the automatic control determination unit 86 determines that the engine 4 is automatically started.

  As described above, when the automatic control determination unit 86 determines that the engine 4 is automatically started, the traveling control unit 84 engages the electromagnetic clutch 14 and the MG control unit 90 controls the MG 40. The MG 40 generates power that can start the engine 4. That is, in the case of performing automatic start, the MG 40 is used as a starter that is engine start means when starting the engine 4. When the engine 4 is automatically started and the MG 40 is operated using the MG 40 as a starter, the power generated in the MG 40 is transmitted from the pulley 42 of the MG 40 to the pulley 12 of the crank damper 10 via the transmission belt 52. Further, the power generated by the MG 40 is transmitted from the crank damper 10 to the crankshaft 6 of the engine 4 via the electromagnetic clutch 14 in the engaged state. As a result, the crankshaft 6 rotates, and the engine 4 is automatically started by performing fuel supply control and ignition control of the engine 4 simultaneously with these controls.

  Here, when the engine 4 is stopped in a state where the shift range of the automatic transmission 20 is selected from D, 2nd speed, and 1st speed, the engine 4 and the drive wheels 28 can transmit power. It is in a state. For this reason, when the engine 4 is automatically started, the automatic transmission 20 is also controlled in parallel with the control for starting the engine 4.

  Specifically, the automatic transmission 20 is switched to a gear stage used during low-speed traveling among a plurality of gear stages immediately before the vehicle 1 stops. Therefore, the friction engagement element 22 is The friction engagement element 22 for switching to the gear position is engaged. Further, the gear stage in this case is a gear stage suitable for starting the stopped vehicle 1 as well. However, when the predetermined shift speed is selected and power can be transmitted between the engine 4 and the drive wheels 28, the engine 4 is started by the power generated by the MG 40. In addition, the power generated by the MG 40 is transmitted not only to the engine 4 but also to the drive wheels 28.

  In this case, the engine 4 is difficult to start. Thus, when the engine 4 is started in a state where the predetermined shift stage of the automatic transmission 20 is selected, the engine 4 is engaged when switching to this shift stage. After the engagement force of the friction engagement element 22 to be lowered is once reduced, the friction engagement element 22 is engaged again. For example, when the friction engagement element 22 to be engaged when switching to this shift stage is the clutch C1 among the plurality of friction engagement elements 22 included in the automatic transmission 20, the control is performed in parallel with the control for starting the engine 4. Then, the clutch control unit 92 controls the clutch C1, and once the engagement force of the clutch C1 is reduced, it is increased again.

  FIG. 2 is an explanatory diagram of precharging of the friction engagement element during automatic start. When the engine 4 is automatically started, the engagement force of the clutch C1 is controlled as described above. When the driver 100 requests driving force when the engine 4 is stopped, the driver 100 drives immediately. May require power. In this case, in order to increase the acceleration response according to the driving force requested by the driver 100, the engagement force of the clutch C1 controlled during the start of the engine 4 is increased according to the requested driving force. That is, when the engine 4 is automatically started, the starting force of the starting clutch that is engaged when starting the clutch C1 or the like is controlled while the starting control of the engine 4 is performed according to the driving force required by the driver 100. Precharge, which is a control to be increased before the start-up, is completed.

  The precharge during the automatic start of the engine 4 will be described. When the automatic control determination unit 86 determines that the engine 4 is to be automatically started, first, the shift control unit 92 controls the automatic transmission 20 to When the engagement force is generated in the clutch C1, the C1 pressure 110, which is the hydraulic pressure applied to the clutch C1, is reduced. Specifically, the clutch C1 is not released completely, and the C1 pressure 110 is reduced within a range where force can be transmitted by the clutch C1 in a state where the transmission rate is reduced.

  Simultaneously with the control of the C1 pressure 110, the starter signal 130, which is a signal output from the travel control unit 84 when the MG 40 is used as a starter, is turned on from the OFF state. Thereby, MG40 is operated and the crankshaft 6 is rotated. Thus, the engine speed 150 increases as the crankshaft 6 is rotated by the power of the MG 40. In this case, since the C1 pressure 110 is a pressure within a range where the force can be transmitted by the clutch C1, a part of the MG 40 power transmitted to the automatic transmission 20 through the rotation of the crankshaft 6 is Is transmitted to the drive wheel 28. That is, since the C1 pressure 110 is in a precharged state, a part of the force input from the engine 4 side to the automatic transmission 20 is output to the drive wheel 28 side. As a result, the vehicle 1 starts accelerating, and the acceleration 160 starts to increase immediately after the start of the automatic start control of the engine 4.

  Further, in this state, the traveling control unit 84 controls the engine 4 to turn on the engine ignition signal 140 from the OFF state while injecting fuel from the injector. As a result, the combustion of fuel starts in the combustion chamber (not shown) of the engine 4, so that the engine speed 150 increases due to the energy during the combustion, and the acceleration 160 also increases accordingly. In this way, the engine 4 is operated by the energy at the time of combustion of the fuel, and the engine speed 150 becomes equal to or higher than a predetermined speed at which the engine 4 can be stably operated without applying force from the outside. If this happens, the starter signal 130 is turned off and the input of power from the MG 40 to the engine 4 is stopped.

  Further, in this way, when the engine speed 150 becomes equal to or higher than the predetermined speed and the operating state of the engine 4 becomes stable, the C1 pressure 110 is increased and the engagement force of the clutch C1 is increased. . For this reason, the transmission rate at which the power generated in the engine 4 is transmitted to the drive wheels 28 also increases, so that the acceleration 160 also increases.

  When the engine 4 is automatically started, the acceleration 160 increases immediately after the start of the automatic start control by precharging the friction engagement element 22 of the automatic transmission 20 in this way. Thereby, it accelerates in the state with the high responsiveness in accelerating according to the driving force which the driver | operator 100 requests | requires.

  When the driver 100 requests driving force while the engine 4 is stopped by the automatic stop control, the engine 4 is controlled to start automatically. The startability may change depending on the state when starting the engine 4. For example, the amount of deposits in the engine 4, the temperature of the lubricating oil in the engine 4, the state of the engine 4, such as variations in the individual pieces of the engine 4, and the start and operation of the engine 4 such as the high voltage battery 46 and the battery 50. The startability of the engine 4 may change depending on the state of the equipment. Therefore, when the engine 4 is automatically started, the startability of the engine 4 is determined, and when the startability of the engine 4 is poor, control according to the startability is performed.

  FIG. 3 is an explanatory diagram in the case of adjusting the engagement timing of the friction engagement element in accordance with the startability of the engine. The startability of the engine 4 is determined by a startability determination unit 88 of the ECU 80 according to detection results detected by various sensors provided in each engine or device of the vehicle 1. For example, after the startability determination unit 88 issues a starter start instruction, the startability determination unit 88 determines deterioration of the high voltage battery 46 based on the actual start timing of the MG 40 used as the starter, or issues an ignition instruction of the engine 4 The deterioration of the battery 50 is determined based on the delay in the increase in the engine speed.

  Further, when the depositability of the engine 4 is determined by the startability determination unit 88, the amount of change in the engine speed when the engine 4 is started, or when the engine 4 is stopped and the clutch C1 is released. The determination is based on the amount of change in the engine speed or the deviation from the reference deceleration during fuel cut. The startability determination unit 88 determines that the startability of the engine 4 is poor when it is determined that the high voltage battery 46 or the battery 50 is deteriorated or when it is determined that the amount of deposit of the engine 4 is large. .

  In addition, when the temperature of the lubricating oil that lubricates each part of the engine 4 is low, the viscosity of the lubricating oil increases and resistance during operation of the engine 4 increases, so the startability determining unit 88 also determines the temperature of this lubricating oil. It is used to determine the startability of the engine 4 and when the oil temperature is low, it is determined that the startability is poor.

  When the automatic start control of the engine 4 is performed, the control at the start of the engine 4 is made different according to the startability of the engine 4 determined by the startability determination unit 88 as described above. Specifically, the shift control unit 92 adjusts the engagement force of the clutch C1 of the automatic transmission 20 based on the startability of the engine 4 determined by the startability determination unit 88, and adjusts the engagement force of the clutch C1. For example, the timing of engagement of the clutch C1 is adjusted. As described above, the control for adjusting the engagement timing of the clutch C1 based on the startability of the engine 4 will be described. When the engine 4 is automatically started, the shift control unit 92 first performs automatic shift. The machine 20 is controlled, and the C1 pressure 110 is reduced within a range in which force can be transmitted by the clutch C1 in a state where the transmission rate by the clutch C1 is reduced.

  Simultaneously with the control of the C1 pressure 110, the starter signal 130 is turned ON by the travel control unit 84. Thus, when the starter signal 130 is turned on, the MG 40 normally starts immediately according to the starter signal 130 and generates power for starting the engine 4. However, when the high voltage battery 46 is deteriorated, the electric power supplied from the high voltage battery 46 to the MG 40 is reduced, so that the MG 40 is difficult to start. For this reason, the starter actual operation state 132 indicating a state in which the MG 40 activated by the starter signal 130 is actually operating causes a delay with respect to the starter signal 130.

  When the engine 4 is started, the engine ignition signal 140 is switched from the OFF state to the ON state, so that the fuel is ignited in the combustion chamber of the engine 4 to burn the fuel. Boosts the electric power of the battery 50 by an ignition circuit (not shown), and generates the electric power from the ignition plug (not shown) by the boosted electric power. However, when the battery 50 is deteriorated, the electric power supplied from the battery 50 to the ignition circuit is reduced, so that it is difficult for a spark to be generated by the spark plug and it is difficult to ignite the fuel in the combustion chamber. Therefore, in this case, the engine actual ignition state 142 indicating the actual spark ignition state in the combustion chamber generated by the engine ignition signal 140 is delayed with respect to the engine ignition signal 140.

  When combustion of fuel starts in the combustion chamber of the engine 4, the engine speed 150 increases due to the energy at the time of combustion of the fuel, but the starter actual operation state 132 is delayed with respect to the starter signal 130, or the actual engine ignition is performed. When the state 142 is delayed with respect to the engine ignition signal 140, the engine speed also increases later than the engine speed 150 at the normal time. That is, the engine speed increases after the spark ignition is actually performed and the combustion of the fuel starts, and thus the engine speed when the actual operation of each part with respect to the control signal is delayed as described above. The engine speed 152 at the time of operation delay increases with a delay from the engine speed 150 at the normal time.

  In addition, when the engine 4 is automatically started, a precharge is performed to increase the engagement force of the clutch C1 or the like before the start of the engine 4 is completed. If the startability of the engine 4 is poor, this precharge is performed. This timing is also changed from when the engine 4 has good startability. That is, as described above, the startability of the engine 4 is determined by the startability determination unit 88 based on the deterioration of the high voltage battery 46 and the battery 50, the deposit amount of the engine 4, the oil temperature, and the like. When the startability of the engine 4 is poor due to deterioration of the engine 4 or the like, as described above, the increase in the engine speed at the start of the engine 4 is delayed.

  For this reason, when the startability determination unit 88 determines that the startability of the engine 4 is poor, the precharge timing is also delayed. In other words, due to the poor startability of the engine 4, an operation delay time C1 which is the hydraulic pressure applied to the clutch C1 when a delay occurs in the actual operation of each part with respect to the control signal when the engine 4 is started. The pressure 112 is increased with a delay from the normal C1 pressure 110.

  When the engine 4 is automatically started, the engine speed 152 at the time of operation delay, which is the engine speed when the startability of the engine 4 is poor, rises later than the engine speed 150 when the startability is good. In this case, however, the transmission rate of the force transmitted from the engine 4 to the drive wheel 28 side is delayed by increasing the operation delay C1 pressure 112 with a delay relative to the normal C1 pressure 110 in this way. Rise.

  That is, when the transmission rate of the force from the engine 4 to the drive wheels 28 increases, the load on the engine 4 increases when viewed from the engine 4, but when the startability of the engine 4 is poor, As the transmission rate of the force to the drive wheels 28 increases with a delay, the increase in the load of the engine 4 is also delayed. For this reason, even if the startability of the engine 4 is poor, the state in which the load increases is delayed, so that the state in which the load is low is maintained for a long time. Before the load increases, the engine speed increases to a predetermined level. The engine speed becomes equal to or greater than the rotational speed, and the operating state of the engine 4 becomes stable.

  When the engine 4 is automatically started when it is determined that the startability of the engine 4 is poor, the timing for increasing the C1 pressure is delayed in this way, and the timing for increasing the engagement force of the clutch C1 is delayed, thereby starting the engine 4 Ensure sex. Thereby, the vehicle 1 is accelerated in a state where the responsiveness when accelerating according to the driving force requested by the driver 100 is high.

  FIG. 4 is an explanatory diagram when the engagement force of the friction engagement element is adjusted in accordance with the startability of the engine. During the automatic start of the engine 4 when the startability of the engine 4 is poor, the startability of the engine 4 is ensured by delaying the timing for increasing the engagement force of the clutch C1, but only by delaying the engagement force of the clutch C1, It may be difficult to ensure the startability of the engine 4. In such a case, the startability of the engine 4 is ensured by adjusting the magnitude of the engagement force of the clutch C1 when the engine 4 is automatically started.

  The control in this case will be described. When the MG 40 cannot generate a predetermined amount of power, the amount of deposit of the engine 4 is large, or the oil temperature is low due to deterioration of the high voltage battery 46, the engine 4 It becomes difficult to increase the rotation speed. That is, when the engine 4 is automatically started, if the startability of the engine 4 is poor due to these causes, the engine speed 154 when the engine startability is poor in this case is the startability of the engine 4. However, the overall engine speed is lower than the normal engine speed of 150. For this reason, it is difficult for the engine speed 154 when the startability is poor to reach a predetermined speed at which the operating state of the engine 4 becomes stable. For this reason, in such a case, the engaging force of the clutch C1 for precharging is reduced. In other words, the poor startability of the engine 4 causes the C1 pressure 114 at the time of poor startability, which is the hydraulic pressure to be applied to the clutch C1, when the rotational speed of the engine 4 is difficult to increase, to be higher than the normal C1 pressure 110 make low.

  Thus, when the C1 pressure 114 at the time of poor startability is made lower than the C1 pressure 110 at the normal time, the engagement force of the clutch C1 is the engagement force at the time of normal precharge with good startability of the engine 4 Smaller than. Thus, when the engagement force of the clutch C1 at the time of precharging is reduced, the transmission rate of the force transmitted from the engine 4 to the drive wheel 28 side is also reduced. For this reason, in this case, the load on the engine 4 when precharging is performed is lower than that during normal precharging. Therefore, even when the startability of the engine 4 is poor and the rotation speed of the engine 4 is difficult to increase, the load of the engine 4 when the clutch C1 is precharged is lower than the load when the startability is good. The rotational speed of 4 tends to increase. As a result, the engine speed increases to a predetermined speed or higher, and the operating state of the engine 4 becomes stable.

  When it is determined that the startability of the engine 4 is poor and it is difficult for the engine 4 to increase in rotational speed, the startability of the engine 4 can be ensured only by delaying the engagement force of the clutch C1 during the automatic start of the engine 4. When it is difficult, the C1 pressure is lowered as compared with the normal precharge. That is, when the startability of the engine 4 is worse than the startability when the startability can be ensured by delaying the engagement force of the clutch C1, the engagement force of the clutch C1 is set to be greater than the engagement force at the time of normal precharging. Also, the amount of increase in the engine speed is ensured by making it smaller. Thereby, even when the startability of the engine 4 is worse, the startability at the time of automatic start is ensured, so that the vehicle 1 has a high responsiveness when accelerating according to the driving force requested by the driver 100. Accelerate with.

  FIG. 5 is an explanatory diagram in a case where the automatic start is performed immediately after the automatic stop of the engine. In the start control device 70 according to the present embodiment, it is possible to control automatic stop and automatic start of the engine 4, but depending on the traveling state of the vehicle 1, it may be performed immediately after the automatic stop. is there. During normal travel of the vehicle 1, the friction engagement element 22 that is engaged during the travel of the vehicle 1 is engaged with a large engagement force among the friction engagement elements 22. The hydraulic pressure applied to the element 22 is a large pressure. Therefore, immediately after the automatic stop of the engine 4, the hydraulic pressure applied to the friction engagement element 22 is high. For example, when the friction engagement element 22 is the clutch C1, the engine 4 Immediately after the automatic stop, the C1 pressure 110, which is the hydraulic pressure applied to the clutch C1, is high.

  On the other hand, when the engine 4 is automatically started, the rotational speed of the stopped engine 4 is increased to a predetermined rotational speed at which the operation of the engine 4 is stabilized. In this case, the frictional force of the automatic transmission 20 is increased. When the coupling element 22 is engaged with a large engagement force, the load on the engine 4 increases, and the engagement force is reduced. Specifically, a hydraulic pressure that can cause the friction engagement element 22 to generate an engagement force that can ensure both startability of the engine 4 and acceleration acceleration of the vehicle 1 is set as the target hydraulic pressure. For example, when the friction engagement element 22 is the clutch C1, a target C1 pressure 118, which is a target hydraulic pressure when the clutch C1 generates an engagement force for achieving both of them, is set.

  However, immediately after the engine 4 is automatically stopped, the C1 pressure 110 is high. Therefore, an automatic control signal 170 from the automatic control determination unit 86 is used as an automatic control signal 170 that is a control signal for automatic stop or automatic start of the engine 4. When the automatic control signal 170 is switched to automatic start immediately after that, the C1 pressure 110 is high.

  That is, when an automatic stop signal is output as the automatic control signal 170, the shift control unit 92 reduces the C1 pressure 110 and the travel control unit 84 performs stop control of the engine 4 in order to reduce the engagement force of the clutch C1. As a result, the engine speed 150 also decreases. However, immediately after that, when an automatic start signal is output as the automatic control signal 170, the shift control unit 92 controls the target C1 pressure 118 as a target value when controlling the hydraulic pressure applied to the clutch C1, The actual C1 pressure 116, which is the hydraulic pressure actually applied to the clutch C1, is larger than the target C1 pressure 118.

  For this reason, since the hydraulic pressure applied to the clutch C1 is excessively applied to the target hydraulic pressure, the shift control unit 92 in this case sets the hydraulic pressure applied to the clutch C1. The target value at the time of control is corrected. That is, a correction C1 pressure 120 lower than the target C1 pressure 118 is newly set as a target value of the hydraulic pressure, and the hydraulic pressure applied to the clutch C1 is controlled. As a result, the actual C1 pressure 116 is more likely to decrease, and thus approaches the target C1 pressure 118 in a shorter time.

  The above start control device 70 adjusts the engagement force of the clutch C1 that is engaged when the vehicle 1 starts based on the startability of the engine 4 determined by the startability determination unit 88 when the engine 4 is started by automatic start control. Therefore, when the engine 4 is restarted after the engine 4 is stopped for the purpose of improving fuel consumption, the engagement timing and the engagement force of the clutch C1 can be matched to the startability of the engine 4. Thereby, the load on the engine 4 at the time of starting the engine 4 can be adjusted so that the rotational speed of the engine 4 can be appropriately increased, and the amount of increase in the rotational speed of the engine 4 at the time of starting is ensured. be able to. As a result, it is possible to achieve both improvement in fuel consumption by stopping the engine 4 during operation of the vehicle 1 and securing startability when restarting after the engine 4 is stopped.

  Moreover, since the startability at the time of restart after the stop of the engine 4 can be ensured in this way, the required driving force when the driver 100 requests the driving force with the engine 4 stopped is more reliably determined. Moreover, it can be generated in a short time. As a result, the acceleration responsiveness when the engine 4 is restarted can be improved more reliably.

  Further, when the engine 4 is restarted, the engagement timing and the engagement force of the clutch C1 can be matched to the startability of the engine 4, so that the clutch C1 is not synchronized with the operating state of the engine 4. It can suppress that a shock generate | occur | produces at the time of engagement resulting from engaging. As a result, the riding comfort when the engine 4 is restarted can be ensured.

  Further, since the timing for increasing the engagement force of the clutch C1 at the start of the engine 4 is adjusted based on the startability of the engine 4, the timing for increasing the load of the engine 4 is set according to the startability of the engine 4. Can be adjusted. As a result, the amount of increase in the rotational speed of the engine 4 at the start of the engine 4 can be ensured more reliably, fuel efficiency can be improved by stopping the engine 4 during operation of the vehicle 1, and after the engine 4 is stopped It is possible to more surely ensure startability at the time of restart.

  Further, since the magnitude of the engagement force of the clutch C1 at the start of the engine 4 is adjusted based on the startability of the engine 4, the load on the engine 4 is adjusted according to the startability of the engine 4. can do. As a result, the amount of increase in the rotational speed of the engine 4 at the start of the engine 4 can be ensured more reliably, fuel efficiency can be improved by stopping the engine 4 during operation of the vehicle 1, and after the engine 4 is stopped It is possible to more surely ensure startability at the time of restart.

  FIG. 6 is an explanatory diagram in the case where the engagement timing and the engagement force of the friction engagement element are corrected according to the startability of the engine. In the above-described start control device 70, when the engine 4 is automatically started when the startability of the engine 4 is poor, the startability of the engine 4 is adjusted by adjusting the timing of increasing the engagement force of the clutch C1 and the engagement force. However, the startability of the engine 4 is not uniform, and the startability may vary. For this reason, when the startability varies as described above, it is preferable to correct the control of the engagement force of the clutch C1 during the automatic start of the engine 4 according to the startability of the engine 4.

  The control for correcting the engagement control of the clutch C1 will be described. In this case, the startability determination unit 88 is the engine speed sensor 8 obtained by the operating state acquisition unit 82 for the rotational speed of the engine 4 at the time of automatic start. The startability of the engine 4 is determined on the basis of the obtained change amount of the rotational speed of the engine 4. Thus, the engine speed 156 at the time of startability determination, which is the rotation speed of the engine 4 acquired when determining the startability of the engine 4, is lower than the normal engine speed 150 when the startability is good. When the startability determining unit 88 determines that the startability has deteriorated, the hydraulic pressure applied to the clutch C1 controlled by the shift control unit 92 is corrected.

  Specifically, when the startability determination unit 88 determines that the startability of the engine 4 has deteriorated, the correction-time C1 pressure 122, which is the hydraulic pressure applied to the clutch C1 when correcting the hydraulic pressure, The pressure is lower than the C1 pressure 110 during normal precharge. Thereby, the load on the engine 4 from the automatic transmission 20 side is reduced, and the increase amount of the engine speed is ensured.

  Further, the startability determination unit 88 continuously acquires the rotation speed of the engine 4, but when the load of the engine 4 is reduced, the engine rotation speed 156 at the time of startability determination is increased and the normal engine rotation speed 150 is increased. If it is determined that the pressure exceeds the value, the correction C1 pressure 122 is made higher than the C1 pressure 110 during normal precharge. Thereby, the engagement force of the clutch C1 at the time of precharging is increased, and the transmission rate of the force transmitted from the engine 4 to the drive wheel 28 side is increased. Therefore, the ratio of using the power of the engine 4 increased as the rotational speed of the engine 4 as a driving force is increased, the driving force required by the driver 100 is secured, and the load of the engine 4 is increased. As a result, the engine 4 is prevented from excessively increasing and desired control is performed.

  As described above, the shift control unit 92 adjusts the engagement force of the clutch C1 based on the amount of change in the rotational speed of the engine 4 determined by the startability determination unit 88, so that the startability of the engine 4 at the time of automatic start can be improved. Since the dynamic change is determined and the engagement force is adjusted based on the determination result, the engagement force of the clutch C1 can be set to an appropriate magnitude at a more appropriate timing. Thereby, the load with respect to the engine 4 at the time of the automatic start of the engine 4 can be adjusted to an appropriate magnitude at an appropriate timing according to the startability of the engine 4. As a result, the amount of increase in the rotational speed of the engine 4 at the start of the engine 4 can be ensured more reliably, fuel efficiency can be improved by stopping the engine 4 during operation of the vehicle 1, and after the engine 4 is stopped It is possible to more surely ensure startability at the time of restart.

  Further, in the above-described start control device 70, the conditions for the automatic stop of the engine 4 are “the rotational speed of the engine 4 is equal to or lower than the idle rotational speed”, “the vehicle speed is 0”, “depressing the accelerator pedal 56”. "The shift range of the automatic transmission 20 is either D, 2nd speed, or 1st speed" as an example, but the conditions for the automatic stop of the engine 4 are not limited to this. Good. For example, the condition may be that “the shift range of the automatic transmission 20 is N or P”. When the shift range of the automatic transmission 20 is N or P, it is clear that the driver 100 does not request driving force. In this case, the engine 4 is automatically stopped by stopping the engine 4. The control to stop and the intention of the driver 100 can be matched more reliably.

  In this way, when it is determined whether or not the condition for automatic stop of the engine 4 is satisfied including that the shift range is N or P, whether or not the condition is satisfied for a predetermined time. In addition, it is preferable to make a judgment including it. For example, the shift lever 64 may pass through other ranges that are not selected when performing a shift range switching selection operation. Even when the shift range is not selected, the shift lever 64 may be operated when the shift lever 64 is operated. May pass the shift range. For this reason, when it is determined whether or not a shift range that is a condition for automatic stop is selected, it is preferable to determine whether or not the selected state is maintained for a predetermined time.

  Further, in the above description, the case where the automatic stop of the engine 4 is performed when the vehicle 1 is stopped is described. However, the automatic stop of the engine 4 may be performed other than when the vehicle 1 is stopped. Good. For example, when the driver 100 does not request driving force while the vehicle 1 is traveling, the engine 4 may be automatically stopped and the vehicle 1 may travel with inertia. In this case, when the driver 100 requests the generation of driving force while traveling due to inertia, the engine 4 is automatically started. At that time, the speed of the automatic transmission 20 is set to a speed suitable for the vehicle speed at the time of automatic start so that the power of the engine 4 is transmitted to the drive wheels 28. The magnitude and timing of the engagement force of the friction engagement elements 22 to be combined are adjusted based on the startability of the engine 4.

  As a result, when the engine 4 is stopped for the purpose of improving the fuel consumption during the traveling of the vehicle 1 and the inertial traveling is performed, the load on the engine 4 when the engine 4 is restarted is set to the appropriate engine speed. It can be adjusted to a size that can be raised. As a result, the amount of increase in the rotational speed of the engine 4 when returning from inertial running can be ensured, fuel efficiency can be improved by stopping the engine 4 during operation of the vehicle 1, and restart after the engine 4 is stopped. It is possible to ensure both startability and time.

  In the above description, the clutch C1 is used as an example of the friction engagement element 22 that adjusts the engagement force when the engine 4 is automatically started, that is, when the engine 4 is stopped. However, the friction engagement element 22 that adjusts the engagement force when the engine 4 is restarted may be other than the clutch C1. The frictional engagement element 22 that adjusts the engagement force when the engine 4 is restarted is engaged when the shift stage of the automatic transmission 20 is changed to a shift stage suitable for the vehicle speed and required driving force when the engine 4 is restarted. As long as it is the friction engagement element 22 which does, other than the clutch C1, such as a brake, may be used.

  Further, in the vehicle 1 described above, the oil pump 30 is provided so as to be operated by the power generated by the engine 4 and generate hydraulic pressure, but the oil pump 30 is similar to the auxiliary machine 32 in the MG 40. It may be provided so as to be operable by the power generated in the above. As a result, the oil pump 30 can generate hydraulic pressure even when the engine 4 is stopped. When the engine 4 is automatically started, the friction of the automatic transmission 20 does not matter regardless of the operating state of the engine 4. A hydraulic pressure for generating an engagement force can be applied to the engagement element 22. Therefore, when controlling the engagement force of the friction engagement element 22 at the time of automatic start of the engine 4, desired control can be performed more reliably, and startability at the time of start of the engine 4 can be ensured more reliably. be able to.

  In addition, the transmission that shifts the power generated by the engine 4 and transmits it to the drive wheel 28 side is not a transmission that has a torque converter or a planetary gear mechanism, and the gear ratio is changed by changing the combination of gears during power transmission. A transmission including a stepped transmission mechanism to be changed and a friction engagement element that transmits power generated by the engine 4 to the stepped transmission mechanism may be used. Alternatively, by using a belt and a pulley, etc., a continuously variable transmission mechanism that can switch the gear ratio steplessly, and a friction engagement element that transmits the power generated by the engine 4 to the continuously variable transmission mechanism, A transmission provided may be used. In these cases, when the engine 4 is restarted by automatic start after the automatic stop, the friction engagement located between the engine 4 and the stepped transmission mechanism or the continuously variable transmission mechanism based on the startability of the engine 4. By adjusting the engagement force of the elements, startability when the engine 4 is started is ensured.

  As described above, the friction engagement element that adjusts the engagement force when the engine 4 is restarted may be other than the clutch C1 included in the automatic transmission 20, and may be a friction engagement element that is engaged when the engine 4 is restarted. For example, the type is not limited.

  In addition, the vehicle 1 including the start control device 70 according to the embodiment uses the MG 40 that is also used as a generator as a starter that transmits the power of the engine 4 when the engine 4 is started. The starter used sometimes may use a dedicated electric motor for starting. Further, the drive and power generation configuration of the MG 40 may be other than the configuration in the vehicle 1 described above. For example, the starter may be provided so as to be operable by the power supplied from the battery in the same manner as other electric devices.

  As described above, the engine start control device according to the present invention is useful for a vehicle that automatically stops and starts an engine as needed without a driver's operation. It is suitable for a vehicle having a clutch that engages when the power of the engine is transmitted to the drive wheels in the power transmission path between the two.

DESCRIPTION OF SYMBOLS 1 Vehicle 4 Engine 8 Engine speed sensor 20 Automatic transmission 22 Friction engagement element 24 Vehicle speed sensor 28 Drive wheel 40 MG
46 High Voltage Battery 50 Battery 56 Accelerator Pedal 60 Brake Pedal 64 Shift Lever 70 Start Control Device 80 ECU
82 Driving state acquisition unit 84 Travel control unit 86 Automatic control determination unit 88 Startability determination unit 90 MG control unit 92 Shift control unit

Claims (4)

Startability determining means for determining startability of an engine which is a power source when the vehicle is running;
An engagement force of a friction engagement element that is engaged when transmitting the power generated in the engine to the drive wheel side is provided so as to be controllable, and when the engine is started, the startability determination means determines the engine Engagement force control means for adjusting the engagement force of the friction engagement element based on startability;
An engine start control device comprising: The startability determining means determines a change in startability of the engine based on an amount of change in the rotational speed of the engine,
2. The engine start according to claim 1, wherein the engagement force control unit adjusts the engagement force of the friction engagement element based on a change amount of the rotation speed of the engine determined by the startability determination unit. Control device.   3. The engine according to claim 1, wherein the engagement force control unit adjusts a timing at which the engagement force of the friction engagement element is increased when the engine is started based on startability of the engine. Start control device.   3. The engine according to claim 1, wherein the engagement force control unit adjusts the magnitude of the engagement force of the friction engagement element when the engine is started based on startability of the engine. Start control device.

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