JP4857685B2 - Engine starting method and engine starting device - Google Patents

Description

  The present invention relates to an engine starting device that starts an engine (an internal combustion engine) using an electric motor (hereinafter simply referred to as a motor) connected to an output shaft thereof.

  As an idle stop device for improving fuel efficiency, the engine is automatically stopped when a predetermined idle stop condition (stop condition) is satisfied, and then the engine is stopped when a predetermined idle stop release condition (start condition) is satisfied. Is automatically started, and a motor connected to the output shaft of the engine is used at the time of starting.

As an engine starting method in this case, as described in Patent Document 1, an engine stopped by a motor (motor operation of a generator) is approximately equal to a predetermined idle rotation speed unique to the engine. Rotate to the rotational speed, and start the fuel supply and ignition operation to the engine after the engine rotational speed almost reaches the idle rotational speed, and then release the operation of the motor (operation as a generator motor) Has been proposed.
Japanese Patent Laid-Open No. 9-1117012

  By the way, there is a limit to the amount of electric power that can be continuously output from the battery for battery protection, and if a large amount of power is supplied to the motor when the engine is started by the motor, the amount of electric power is limited by the limit, causing a problem in starting the engine. May occur.

  This will be described with reference to FIGS. 7 and 8. FIG. 7 shows the relationship between the intake valve closing timing IVC and the cranking rotational speed necessary for starting the engine, and FIG. 8 shows the cranking. The characteristic of the cranking retention time from the rotation speed and the battery capacity is shown. In FIG. 7, in an engine having a slow characteristic in which the intake valve closing timing IVC is, for example, A (a timing within the compression stroke after the bottom dead center), a high crankkind rotational speed such as C is required because the actual compression pressure is low. . From the characteristics shown in FIG. 8, it can be seen that the cranking retention time from the battery capacity is shortened at a high cranking rotation speed. Note that A shown in FIG. 7 and A shown in FIG. 8 are irrelevant.

  Here, the cranking holding time is determined by the amount of power that can be output from the battery, and the cranking holding time becomes shorter as the amount of power that can be output from the battery is smaller. Therefore, in an engine with a low intake valve closing timing IVC and a small actual compression ratio, when the amount of electric power that can be output from the battery is small without sufficiently charging the battery, the cranking holding time is shortened and the engine is started. There is a situation that cannot be made.

  In this case, if the engine has an intake valve timing variable mechanism that can advance at least the intake valve close timing, the intake valve close timing IVC is set by operating the intake valve timing variable mechanism at the start of cranking, for example. In FIG. 7, since the actual compression pressure is improved by accelerating from A to B (a time near the bottom dead center), the cranking rotational speed necessary for starting the engine is shifted to a lower side from C to D. And the power consumption of the battery can be suppressed by the decrease in the cranking rotation speed.

  However, when the intake valve timing variable mechanism is hydraulically driven, a response delay until the intake valve timing variable mechanism actually operates becomes a problem. That is, in the hydraulically driven intake valve timing variable mechanism, the hydraulic pressure of the oil pumped by the engine drive pump is used as the drive source, and the hydraulic pressure rise time from the start of cranking until the hydraulic pressure of the oil pumped by the pump rises The intake valve closing timing is actually advanced after the hydraulic pressure rising time has elapsed. Therefore, when an engine equipped with a hydraulically driven intake valve timing variable mechanism is left for a long period of time, the oil in the oil gallery has fallen, and the oil pressure does not rise immediately after cranking is started. It takes a predetermined time to reach the operation start pressure of the variable valve timing mechanism. Especially under low temperature conditions, oil is highly viscous and it takes time to increase the oil pressure.

  Therefore, even if the intake valve timing variable mechanism is instructed to advance the intake valve closing timing at the start of cranking, the intake valve closing timing is actually advanced after the hydraulic pressure rise time. At the same time as the start of ranking, setting the cranking speed for the engine state after the intake valve closing timing has actually advanced has been set because the intake valve closing timing does not advance during the hydraulic pressure rise time. The cranking rotation speed will be too low to complete the explosion. Therefore, in order to start an engine having a hydraulically driven intake valve timing varying mechanism, it is necessary to set the cranking rotation speed while observing the hydraulic pressure state from the start of cranking.

  However, the above-mentioned Patent Document 1 does not describe any engine starting method including a hydraulically driven intake valve timing varying mechanism.

  Therefore, an object of the present invention is to ensure that the engine can be started while suppressing power consumption of the battery even in an engine having a hydraulically driven intake valve timing varying mechanism.

In the present invention, in the engine starting method that starts by cranking the crankshaft of the engine by the motor, or in the engine starting device that starts by cranking the crankshaft of the engine by the motor, the rotational force of the crankshaft A pump that pumps oil using as a drive source, and an intake valve timing variable mechanism that uses the hydraulic pressure of the oil pumped by the pump as a drive source. During the cranking , the intake valve timing variable mechanism performs actual compression. The intake valve closing timing is moved so that the ratio becomes high, and during the cranking, the oil pressure of the oil pumped by the pump from the start of cranking is pumped by the pump before rising or reaching a predetermined oil pressure. The oil pressure of the oil The motor rotation speed at the time of cranking is controlled at a lower rotation speed after reaching a predetermined hydraulic pressure, or during the cranking, the intake valve timing variable mechanism is used to increase the actual compression ratio. The valve closing time is moved, and during the cranking, the oil pressure of the oil pumped by the pump rises before the oil pressure of the oil pumped by the pump rises from the start of cranking or before reaching the predetermined oil pressure. The motor supply power at the time of cranking is controlled with a smaller motor supply power after or after reaching a predetermined oil pressure .

According to the present invention, the pump includes a pump that pumps oil using the rotational force of the crankshaft as a drive source, and an intake valve timing variable mechanism that uses the oil pressure of the oil pumped by the pump as a drive source, and during the cranking The intake valve closing timing is moved by the intake valve timing variable mechanism so as to increase the actual compression ratio, and during the cranking, before the hydraulic pressure of the oil pumped by the pump rises from the start of cranking or a predetermined hydraulic pressure Before reaching the oil pressure of the oil pumped by the pump, or control the motor rotation speed at the time of cranking at a lower rotation speed after reaching a predetermined oil pressure, or during the cranking, By the intake valve timing variable mechanism, the intake valve closing timing is moved so as to increase the actual compression ratio, During ranking, before the hydraulic pressure of oil pumped by the pump rises from the start of cranking or before reaching the predetermined hydraulic pressure, the hydraulic pressure of oil pumped by the pump rises or reaches the predetermined hydraulic pressure Since the motor supply power during cranking is controlled with a smaller motor supply power, the engine can be started reliably while suppressing power consumption of the battery, even for an engine with a hydraulically driven intake valve opening / closing timing variable mechanism. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration in which an engine starter directly used for carrying out an engine start method is applied to an idle stop vehicle.

  The rotating shaft of a motor (motor generator) 2 is directly connected to the output shaft of the engine 1. Thus, the automatic transmission 4 with the torque converter 3 is connected to the output side of the engine 1 via the motor 2, and the drive wheels 7 and 8 are driven via the differential gear 6 by the output shaft 5 of the transmission 4. It is like that.

  The motor 2 is connected to the high voltage battery 9 via the inverter 10 and receives power supply from the high voltage battery 9 at the start (when starting with the engine key switch and when starting after the idle stop). The battery 9 is charged as a generator except during starting. Thus, the motor 2 is mainly used for starting the idle stop device, so that the battery 9 can be downsized.

  The engine 1 is interposed between the cam sprocket 1d and the intake valve camshaft 1e, and an intake valve timing control mechanism (hereinafter referred to as "VTC mechanism") that can continuously control the phase of the intake valve cam with a constant operating angle. .) 11 is provided. Here, a timing chain 1c is wound around the cam sprocket 1d and the crank sprocket 1a so that the power of the crankshaft 1a is transmitted to the intake valve camshaft 1e.

  The VTC mechanism 11 (intake valve timing variable mechanism) is hydraulically driven. The operation of the hydraulic drive type VTC mechanism 11 will be briefly described. The VTC mechanism 11 rotates integrally with the intake valve camshaft 1e and can open and close the intake valve that can rotate relative to the cam sprocket 1d. A timing controller 12, an electromagnetic control valve 13 for duty-controlling the hydraulic pressure to the intake valve opening / closing timing controller 12, and an oil supply device for supplying oil having pressure to the intake valve opening / closing timing controller 12. Yes. The electromagnetic control valve 13 receives a signal from the integrated controller 31 and controls the relative position (phase) of the intake valve opening / closing timing controller 12 with respect to the cam sprocket 1d.

  In an initial state such as when the engine is started, the vane 12a and the cam sprocket 1d of the intake valve opening timing controller 12 are in the most retarded state by an internal lock pin (not shown) that receives a spring reaction force. Now, when the electromagnetic control valve 13 is switched to the retard side while the VTC mechanism 11 is being controlled, the oil flows into the oil supply passage 27 as shown on the right side of FIG. The vane 13a of the controller 12 is rotated counterclockwise by the hydraulic pressure (see the left side in FIG. 2), and the intake valve camshaft 1e rotates to the retard side. On the other hand, when the electromagnetic control valve 13 is switched to the advance side, as shown on the right side of FIG. 3, the oil flows into the oil supply passage 28, contrary to the retard side, and the vane of the intake valve opening / closing timing controller 12. 12a is rotated clockwise by hydraulic pressure (see the left side of FIG. 3), and the intake valve camshaft 1e is rotated to the advance side.

  When the target valve timing (intake valve opening timing and intake valve closing timing) is reached, the electromagnetic control valve 13 shuts off both the oil passages 27 and 28 as shown in FIG. 4 as long as it does not change according to the operating conditions. Then, the phase of the camshaft 1e is held at that position.

  Actually, the cam position for the intake valve (the position of the camshaft 1e) is detected by the camshaft position sensor 33 at the rear of the cylinder head so that the actual intake valve cam position becomes the optimum target intake valve timing according to the operating conditions. The duty value given to the electromagnetic control valve 13 is feedback controlled.

  The oil supply device to the intake valve opening / closing timing controller 12 includes an oil tank 21, an oil pump 22, an oil supply passage, and the like. The oil pumped by the oil pump 22 passes through an oil filter 23 and an oil cooler 24 once to main. The oil is stored in the gallery 25 and is supplied to the intake valve opening timing controller 12 via the electromagnetic control valve valve 13 and the oil supply passages 27 and 28 through the oil supply passage 26 branched from the main gallery 25. Reference numeral 29 denotes a drain passage to the oil tank 21.

  Here, the oil pump 22 has an oil pump sprocket (not shown), and the timing chain 1c is also wound around this sprocket. Therefore, the oil pump 22 uses the rotational force of the crankshaft 1a as a drive source to drive oil. Pump.

  The integrated control unit 31 controls the operation of the VTC mechanism 11 in addition to the operation of the engine 1 (specifically, the fuel supply device 25, the ignition device 26 and the throttle device 27), the motor 2 and the automatic transmission 4. An engine key switch 34, a crankshaft position sensor 32, a camshaft position sensor 33, an accelerator pedal sensor 35 for detecting the depression amount of an accelerator pedal, a throttle sensor 36 for detecting the opening of a throttle valve (a part of the throttle device 27), Signals are input from an idle switch 37 that is turned on when the accelerator pedal is not depressed or the throttle valve is fully closed, a brake switch 38 that is turned on when the brake pedal is depressed, a vehicle speed sensor 39 that detects the vehicle speed, and the like. Here, the engine rotation speed (motor rotation speed) Ne is calculated based on signals from the crankshaft position sensor 32 and the camshaft position sensor 33.

  FIG. 5 is a flowchart for executing engine start control, and shows a flow of control over time. It is not executed at regular intervals. This will be described with reference to the time chart from the start in FIG.

  Here, in FIG. 6, changes from the start of cranking of the actual engine rotation speed, the hydraulic pressure in the main gallery 25, the power supplied to the motor 2, and the VTC operating angle (rotation angle of the camshaft 1 e) are modeled from above. Show.

  In the uppermost stage, the case of the conventional apparatus is indicated by a one-dot chain line. Here, the conventional apparatus has a high cranking rotation speed that can obtain a complete explosion even when the VTC mechanism 11 is not operated. When the cranking rotation speed is set higher than the initial cranking speed, the battery power consumption increases. In the example shown in the figure, the power limit for battery protection is caught before the timing t1, The engine cannot be started.

  In step 1 in FIG. 5, it is checked whether or not the activation request flag = 1 (there is an activation request). This start request flag is used when the engine is automatically started under the idle stop release condition after the engine is automatically stopped under the idle stop condition in addition to the normal engine start by the engine key switch 34 (start switch). It is set to 1 by another routine.

  Here, the idle stop condition is, for example, when the idle switch 37 is ON, the engine rotational speed Ne is in the vicinity of the idle rotational speed, the vehicle speed is 0, and the brake switch 38 is ON. . The idle stop release condition is, for example, when the idle switch 37 is OFF (accelerator pedal depression) and the brake switch 38 is OFF after the idle stop.

  When the activation request flag = 1 (there is an activation request), the process proceeds to steps 2, 3, and 4 and the operations of steps 2, 3, and 4 are performed simultaneously.

  In step 2, the VTC mechanism 11 is instructed to advance the intake valve closing timing IVC by a predetermined amount (duty control of the electromagnetic control valve 13).

  The reason for advancing the intake valve closing timing IVC at the start of cranking is that the actual compression ratio is increased by the advance angle of the intake valve closing timing, and the cranking rotation necessary for starting the engine by the increased actual compression ratio. This is because the speed can be reduced. That is, there is a correlation shown in FIG. 7 between the intake valve closing timing IVC and the cranking rotational speed necessary for starting the engine, and the intake valve closing timing IVC is, for example, A (within the compression stroke past the bottom dead center). In the engine having a slow characteristic at the time of (1), a high crankkink rotational speed such as C is required because the actual compression pressure is low. In this case, if the engine is provided with the VTC mechanism 11, the intake valve closing timing IVC is advanced from, for example, A to B (timing near the bottom dead center) by operating the VTC mechanism 11 at the start of cranking. Since the actual compression pressure improves, the cranking rotational speed necessary for starting the engine can be shifted to a lower side from C to D, and the power consumption of the battery is suppressed by the decrease in the cranking rotational speed. it can. In FIG. 7, the intake valve closing timing A is a value inherent to the engine, and differs depending on the specifications of the oil pump 22 and the engine.

  In FIG. 7, the advance amount ADV of the intake valve closing timing from A (the timing in the compression stroke past the bottom dead center) to B (the timing in the vicinity of the bottom dead center), that is, the predetermined advance amount shown in the lowermost stage of FIG. The ADV may be a constant value simply, but is preferably set according to the engine temperature (for example, the cooling water temperature Tw) and the battery charge amount. For example, the advance amount ADV at the intake valve closing timing is increased as the engine temperature is lower. This is because the engine friction increases as the engine temperature decreases, and therefore the engine needs to be advanced to the torque output side.

  Further, the advance amount ADV of the intake valve closing timing is increased as the battery storage amount is smaller. The reason is that it is desired to lower the cranking rotation speed in order to suppress the battery power consumption as the battery storage amount is smaller. Here, the battery charge amount is the amount of power that can be continuously output from the battery 9.

  However, as shown in the lowermost stage in FIG. 6, even if the duty command value is given from the integrated controller 31 to the electromagnetic control valve 13 simultaneously with the start of cranking (see the broken line in the lowermost stage in FIG. 6), the intake valve is actually closed. The timing IVC starts to advance at the timing t2 when the main gallery hydraulic pressure coincides with the operation start pressure P1 of the VTC mechanism 11, and the timing at which the intake valve closing timing is completed is further delayed at timing t3. It is.

  In step 3, the power control of the motor 2 is performed via the inverter 10, so that the power supplied to the motor 2 becomes the first target power Pw1 [kW] as shown in the third stage of FIG. At this time, the cranking rotational speed (motor rotational speed) settles in the vicinity of the first rotational speed N1, which is considerably lower than in the case of the conventional device (see the one-dot chain line) as shown in the uppermost part of FIG.

  The reason why the cranking rotational speed is set to a low value such as the first rotational speed N1 at the beginning of cranking is as follows. That is, in the hydraulic drive type VTC mechanism 11, since the oil pump 22 is driven by the crankshaft 1a of the engine, if the engine is not driven, the oil pump 22 is not driven and the oil pump 22 is driven. First of all, since it is necessary to fill the oil supply passage with oil, the hydraulic pressure does not rise immediately, and a certain delay (hydraulic rise time) occurs. For this reason, in the engine after being left for a long time, there is no oil in the oil gallery 25 and the oil pump 22, and the hydraulic pressure in the main gallery 25 after the cranking starts as shown in the second stage of FIG. It takes time to increase to the operation start hydraulic pressure P1. Especially under low temperature conditions, oil is highly viscous and it takes time to increase the oil pressure.

  In this case, the oil pressure rise time shown in the second stage of FIG. 6 (the time from the start of cranking to the time when the oil pressure rises from zero) is the same even if the cranking rotational speed is increased as shown in FIG. It is not shortened enough to meet the increase in rotational speed. On the other hand, since the power required for cranking increases as the cranking rotation speed increases, the cranking retention time decreases as the cranking rotation speed increases (see FIG. 8). Therefore, even if the cranking rotation speed is increased unnecessarily, it will only invite useless power consumption of the battery 9, and there is a possibility of starting failure due to power shortage of the battery 9 before starting the engine (the uppermost stage in FIG. 6). (Refer to the conventional device).

  Therefore, in the present embodiment, the cranking rotation speed is set stepwise, and the cranking rotation speed necessary only for the increase of the hydraulic pressure is set during the oil pressure rise time (Cranking rotation speed A shown in FIG. 8). , Preventing excessive power consumption of the battery 9. Then, as will be described later, after the hydraulic pressure rise time has elapsed, the cranking rotational speed (D cranking rotational speed D shown in FIG. 7) required to start the engine is increased. By such a series of operations, the engine is reliably started while suppressing excessive power consumption of the battery 9.

  The first rotation speed N1 is a variable value. That is, when the engine speed reference value and the battery charge amount reference value are the first rotation speed N1base, and the engine temperature and the battery charge amount deviate from the engine temperature reference value and the battery charge amount reference value, A value obtained by correcting the basic first rotation speed N1base according to the engine temperature or the battery storage amount is set as the first rotation speed. For example, the correction is made such that the lower the engine temperature, the lower the first rotation speed N1. The smaller the battery charge amount, the lower the first rotation speed N1 is corrected. The first target power Pw1 to be given to the motor 2 is set according to the first rotation speed N1 determined in this way.

  In step 4, the engine 1 is started. Specifically, fuel supply to the engine 1 is started via the fuel supply device 25 and ignition is started via the ignition device 26. Each control of such fuel supply and ignition is the same as before. Here, the fuel supply device 25 is considered to be provided with a fuel injection valve facing the intake port. Further, at the time of start-up, the fuel injection amount to be supplied by the fuel injection valve is set with the stoichiometric air-fuel ratio as the target air-fuel ratio.

  However, even if combustion occurs in the combustion chamber due to fuel supply and ignition during the hydraulic pressure rise time, the cranking rotational speed is in the vicinity of the first rotational speed N1, which is low, and the intake valve closing timing is not advanced. Since the actual compression ratio remains small, no complete explosion occurs.

  In step 5, it is checked whether or not the hydraulic pressure in the main gallery 25 has risen due to the start of the pumping of the oil pump 21. As a method for determining the hydraulic pressure, for example, a hydraulic sensor 40 is provided in the main gallery 25, and it is determined that the hydraulic pressure in the main gallery 25 has risen when the hydraulic pressure detected by the hydraulic sensor 40 exceeds a predetermined value. That's fine. Or, more simply, the hydraulic pressure rise time can be obtained in advance by adaptation, and it can be determined that the hydraulic pressure in the main gallery 25 has risen when the adaptive value of the hydraulic pressure rise time has elapsed since the start. If the hydraulic pressure in the main gallery 25 has not risen, the system waits as it is.

  On the other hand, when the hydraulic pressure in the main gallery 25 rises, the process proceeds to step 6 to perform power control of the motor 2 and the power supplied to the motor 2 is higher than the first target power Pw1 as shown in the third stage of FIG. The second target power Pw2 [kW] is set. At this time, the cranking rotation speed (motor rotation speed) is higher than the first rotation speed N1 as shown in the uppermost part of FIG. 6, and is slightly near the second rotation speed N2 that is slightly lower than the rotation speed set in the conventional apparatus. Calm down.

  Here, as a method for setting the second target power Pw2, a table of cranking rotation speeds having the contents shown in FIG. 7 is prepared in advance, and is set in the above step 2 from the most retarded position of the VTC mechanism 11. The position advanced by the advance amount ADV of the intake valve closing timing is calculated as the intake valve closing timing IVC, and a table of the cranking rotational speed prepared in advance is searched from the calculated intake valve closing timing IVC. Thus, the cranking rotation speed (= second rotation speed N2) is obtained, and the second target power Pw2 may be determined according to the second rotation speed N2.

  In FIG. 6, when the hydraulic pressure in the main gallery 25 rises at the timing of t1, the hydraulic pressure reaches the operation start hydraulic pressure P1 of the VTC mechanism 11 at the timing of t2 after the elapse of a predetermined response delay period from this timing. The operating angle (the rotation angle of the camshaft 1e) increases (the intake valve closing timing IVC actually goes to the advance side). As the intake valve closing timing IVC moves toward the advance side, the amount of air trapped in the combustion chamber increases and the actual compression ratio increases. Then, the actual compression ratio that satisfies the complete explosion condition is reached at the timing of t3 when the intake valve closing timing reaches the predetermined advance angle ADV, the complete explosion occurs, the engine speed rapidly rises, and the engine starts. To do.

  In order to determine whether or not this complete explosion has occurred, in step 7, it is determined whether or not the engine 1 has generated torque. This complete explosion determination method is performed based on regenerative electric power generated by the regenerative torque of the motor 2. That is, it is determined that a complete explosion has occurred when the torque of the motor 2 is reversed from positive to negative. In brief, it is only necessary to determine that a complete explosion has occurred when the actual engine rotational speed is equal to or higher than the complete explosion rotational speed by comparing the actual engine rotational speed with the complete explosion rotational speed (see the uppermost stage in FIG. 6).

  If it is determined in step 7 that the engine 1 has generated torque, the process proceeds to step 8 to cancel the power control of the motor 2. In FIG. 6, the release timing of the power control of the motor 2 is t4 immediately after the complete explosion determination of the engine 1 (see the third stage in FIG. 6). In this way, after determining that the engine has generated torque, by canceling the power control of the motor 2, it is possible to prevent rotational fluctuations when the independence of the engine 1 varies. Note that the power control release timing of the motor 2 need not be immediately after the complete explosion determination of the engine 1, and may be any time after t4.

  Finally, in step 9, the activation request flag is reset to 0, and this flow ends.

Thus, according to the present embodiment (the invention described in claims 1 and 14 ), the pump 22 that pumps oil using the rotational force of the crankshaft 1a as a drive source is provided, and the hydraulic pressure of the oil pumped by the pump 22 is provided. Therefore, even if the engine is equipped with a hydraulic drive type VTC mechanism 11 (intake valve opening / closing timing variable mechanism), the engine is controlled while suppressing the power consumption of the battery 9. It can start reliably.

According to the present embodiment (the invention described in claims 1 and 14 ), before the hydraulic pressure of the oil pumped by the pump 22 rises from the start of cranking, the rotational speed is lower than that after the rise (first rotational speed N1). When controlling the motor rotation speed during cranking, or before cranking, the oil pressure pumped by the pump 22 rises before the oil pressure rises, and when cranking with a smaller motor supply power (first target power Pw1) Therefore, before the hydraulic pressure of the oil pumped by the pump 22 rises from the start of cranking, the same rotational speed (second rotational speed N2) as that after the hydraulic pressure of the oil pumped by the pump 22 rises is controlled. ) To control the motor rotation speed at the time of cranking or from the start of cranking to the pump 22 In the case where the motor supply power at the time of cranking is controlled with the same motor supply power (second target power Pw2) as that after the oil pressure of the oil pumped by the pump 22 rises before the oil pressure of the oil being pumped rises. Thus, the power consumption of the battery 9 can be reduced (the power consumption is almost halved).

According to the present type condition, a pump 22 for pumping oil rotational force of the crankshaft 1a as a drive source, as well as the hydraulic pressure of the oil pumped by the pump 22 as a drive source, the pump from the start of cranking 22 And a VTC mechanism 11 (intake valve timing variable mechanism) for actually advancing at least the intake valve closing timing IVC after the oil pressure rise time has elapsed. At the start of cranking, this VTC mechanism 11 is instructed to advance the intake valve closing timing from the time in the compression stroke that is too low to the bottom dead center (step 2 in FIG. 5). Based on the intake valve closing timing advance instruction at the start of ranking and the actual advance angle of the intake valve closing timing, the motor rotation speed at the time of cranking is controlled (Fig. Step 3, 5, 6) so the even engines with VTC mechanism 11 of the hydraulically-driven, can be reliably start the engine while suppressing the power consumption of the battery 9.

According to the present type state, after the intake valve closing timing advance instructions at cranking start, before the intake valve closing timing is actually advanced is less than the subsequent rotational speed (second rotational speed N2) Rotation Since the motor rotation speed at the time of cranking is controlled by the speed (first rotation speed N1), after the intake valve closing timing advance instruction at the start of cranking, before the intake valve closing timing actually advances, The power consumption of the battery 9 can be reduced as compared with the case where the motor rotation speed at the time of cranking is controlled at the same rotation speed as the rotation speed (second rotation speed N2).

According to the present embodiment (the inventions described in claims 6 and 19 ), the low rotational speed (first rotational speed N1) is corrected according to the engine temperature or the battery charge amount, and therefore the engine temperature and the battery charge amount are different. Even so, a low rotational speed can be appropriately provided.

According to the present embodiment (the invention described in claims 10 and 23 ), the advance amount ADV of the intake valve closing timing is set according to the engine temperature or the battery storage amount, and therefore the engine temperature and the battery storage amount are different. However, the advance amount ADV of the intake valve closing timing can be appropriately given.

In the embodiment, before the hydraulic pressure of the oil pumped by the pump from the start of cranking rises, the motor rotational speed at the time of cranking is controlled at a lower rotational speed after the rise or pumped from the cranking start by the pump. The case where the motor supply power at the time of cranking is controlled by a smaller motor supply power after the oil pressure has risen before the oil pressure rises has been described. However, the oil pressure of the oil pumped by the pump from the start of cranking is predetermined. Before reaching the oil pressure, control the motor rotation speed during cranking at a lower rotation speed after reaching the oil pressure, or reach the oil pressure pumped by the pump from the start of cranking before reaching the predetermined oil pressure. Control the motor supply power during cranking with a smaller motor supply power after Unishi and may be. In this case, as the predetermined hydraulic pressure, for example, a positive value close to zero can be used (the invention according to claims 1 and 14 ).

In the embodiment, the case where ignition is performed before the hydraulic pressure of the oil pumped by the pump 22 rises (or before reaching a predetermined hydraulic pressure) has been described (the invention according to claims 3 and 16 ). The ignition may not be executed before the hydraulic pressure of the oil pumped by 22 rises (or before the predetermined hydraulic pressure is reached) (inventions according to claims 4 and 17 ).

In the embodiment, after the intake valve closing timing advance instruction at the start of cranking, the ignition is executed before the intake valve closing timing actually advances, the intake valve closing at the start of cranking has been described. after timing advance instructions, before the intake valve closing timing is actually advanced Ru can avoid running ignition.

  In the embodiment, the case where the present invention is applied to an idle stop vehicle has been described. However, the present invention is not limited to this, and the motor includes a starter. Accordingly, the present invention can be applied to an engine that is started by cranking the crankshaft of an engine with a starter.

  The motor rotation speed control processing procedure according to claim 1 is performed by steps 3, 5, and 6 in FIG.

The function of the motor rotation speed control means according to the fourteenth aspect is fulfilled by steps 3, 5, and 6 in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which applied the starting device of the engine of 1st Embodiment of this invention to the idle stop vehicle. The schematic block diagram for demonstrating the action | operation at the time of advance of a VTC mechanism. The schematic block diagram for demonstrating the action | operation at the time of retardation of a VTC mechanism. The schematic block diagram for demonstrating the action | operation in the holding | maintenance state of a VTC mechanism. The flowchart for demonstrating engine starting. Time chart from engine start. The characteristic view which shows the relationship between intake valve closing timing IVC and cranking rotation speed. Each characteristic diagram of oil pressure rise time and cranking retention time with respect to cranking rotation speed.

Explanation of symbols

1 Engine 2 Motor 9 Battery 11 VTC mechanism (Intake valve timing variable mechanism)
31 Integrated controller

Claims (26)

In a starting method of an engine that starts by cranking an engine crankshaft by a motor,
A pump that pumps oil using the rotational force of the crankshaft as a drive source;
An intake valve timing variable mechanism that uses the hydraulic pressure of oil pumped by this pump as a drive source,
During the cranking, the intake valve closing timing is moved by the intake valve timing variable mechanism so that the actual compression ratio becomes high,
During the cranking, before the hydraulic pressure of the oil pumped by the pump rises from the start of cranking or before reaching the predetermined hydraulic pressure, the hydraulic pressure of the oil pumped by the pump rises or reaches the predetermined hydraulic pressure. A method for starting an engine, comprising: controlling a motor rotation speed during cranking at a lower rotation speed after reaching the engine. In a starting method of an engine that starts by cranking an engine crankshaft by a motor,
A pump that pumps oil using the rotational force of the crankshaft as a drive source;
An intake valve timing variable mechanism that uses the hydraulic pressure of oil pumped by this pump as a drive source,
During the cranking, the intake valve closing timing is moved by the intake valve timing variable mechanism so that the actual compression ratio becomes high,
During the cranking, before the hydraulic pressure of the oil pumped by the pump rises from the start of cranking or before reaching the predetermined hydraulic pressure, the hydraulic pressure of the oil pumped by the pump rises or reaches the predetermined hydraulic pressure. A method for starting an engine, comprising: controlling motor supply power during cranking with lower motor supply power after reaching the motor.   3. The engine starting method according to claim 1, wherein ignition is not performed before the hydraulic pressure of oil pumped by the pump rises or reaches a predetermined hydraulic pressure. 4.   3. The engine starting method according to claim 1, wherein ignition is performed even before the hydraulic pressure of the oil pumped by the pump rises or reaches a predetermined hydraulic pressure. 4.   The intake valve closing timing is instructed to the intake valve timing variable mechanism at the start of cranking from the timing in the compression stroke after the bottom dead center to the timing in the vicinity of the bottom dead center. The engine start method according to 1 or 2. The engine starting method according to claim 1, wherein the low rotational speed is corrected according to an engine temperature. The engine starting method according to claim 1, wherein the low rotation speed is corrected according to a battery storage amount.   The engine starting method according to claim 6, wherein the lower rotational speed is corrected to be lower as the engine temperature is lower.   The engine starting method according to claim 7, wherein the correction is made such that the lower the rotation speed becomes lower as the battery charge amount is smaller.   6. The engine start according to claim 5, wherein an advance amount of the intake valve closing timing from a time in the compression stroke past the bottom dead center to a time in the vicinity of the bottom dead center is set according to the engine temperature. Method.   6. The engine according to claim 5, wherein an advance amount of the intake valve closing timing from a time in the compression stroke past the bottom dead center to a time in the vicinity of the bottom dead center is set in accordance with a battery charge amount. How to start.   11. The engine starting method according to claim 10, wherein the setting is made such that the advance amount of the intake valve closing timing increases as the engine temperature decreases.   12. The engine starting method according to claim 11, wherein the amount of advance of the intake valve closing timing is set larger as the battery storage amount is smaller. In an engine starter that starts by cranking the crankshaft of an engine with a motor,
A pump that pumps oil using the rotational force of the crankshaft as a drive source;
An intake valve timing variable mechanism that uses the hydraulic pressure of oil pumped by this pump as a drive source,
During the cranking, the intake valve closing timing is moved by the intake valve timing variable mechanism so that the actual compression ratio becomes high,
During the cranking, before the hydraulic pressure of the oil pumped by the pump rises from the start of cranking or before reaching the predetermined hydraulic pressure, the hydraulic pressure of the oil pumped by the pump rises or reaches the predetermined hydraulic pressure. An engine starter that controls a motor rotation speed during cranking at a lower rotation speed after reaching the engine. In an engine starter that starts by cranking the crankshaft of an engine with a motor,
A pump that pumps oil using the rotational force of the crankshaft as a drive source;
An intake valve timing variable mechanism that uses the hydraulic pressure of oil pumped by this pump as a drive source,
During the cranking, the intake valve closing timing is moved by the intake valve timing variable mechanism so that the actual compression ratio becomes high,
During the cranking, before the hydraulic pressure of the oil pumped by the pump rises from the start of cranking or before reaching the predetermined hydraulic pressure, the hydraulic pressure of the oil pumped by the pump rises or reaches the predetermined hydraulic pressure. An engine starter that controls motor supply power during cranking with lower motor supply power after reaching the engine.   The engine starter according to claim 14 or 15, wherein ignition is not performed before the hydraulic pressure of the oil pumped by the pump rises or reaches a predetermined hydraulic pressure.   The engine starter according to claim 14 or 15, wherein ignition is performed even before the hydraulic pressure of the oil pumped by the pump rises or reaches a predetermined hydraulic pressure.   The intake valve closing timing is instructed to the intake valve timing variable mechanism at the start of cranking from the timing in the compression stroke after the bottom dead center to the timing in the vicinity of the bottom dead center. The engine starting device according to 14 or 15. Engine starting system according to claim 1 4, characterized in that to correct the low rotational speed in accordance with engine temperature. Engine starting system according to claim 1 4, characterized in that to correct the low rotational speed in accordance with the battery storage amount.   20. The engine starter according to claim 19, wherein the lower the engine temperature, the lower the rotational speed is corrected.   21. The engine starting device according to claim 20, wherein the lower the rotation speed is corrected, the smaller the battery storage amount is.   19. The engine start according to claim 18, wherein an advance amount of the intake valve closing timing from a time in the compression stroke past the bottom dead center to a time in the vicinity of the bottom dead center is set according to the engine temperature. apparatus.   19. The engine advancement amount according to claim 18, wherein an advance amount of the intake valve closing timing from a time in the compression stroke past the bottom dead center to a time in the vicinity of the bottom dead center is set according to a battery charge amount. Starter.   24. The engine starter according to claim 23, wherein the engine start device is set such that the advance amount of the intake valve closing timing increases as the engine temperature decreases.   25. The engine starter according to claim 24, wherein the starting amount of the engine is set such that the advance amount of the intake valve closing timing increases as the battery storage amount decreases.

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