JP3555516B2 - Automatic stop / restart system for engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic engine stop / restart device that automatically stops an engine when a vehicle stops and automatically restarts the engine when the vehicle starts.
[0002]
[Conventional technology and problems to be solved]
As an automatic engine stop / restart device for a vehicle equipped with an automatic transmission, for example, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 8-291725. In this device, the engine is automatically stopped and restarted as follows. That is, a select position sensor that detects the position of the select lever, a vehicle speed sensor that detects the vehicle speed, a rotational speed sensor that detects the rotational speed of the engine, a brake sensor that detects whether the brake pedal is depressed, and the like are provided. The engine is temporarily stopped when it is detected that the lever is in the neutral range, the vehicle speed is zero, the engine speed is the idle speed, and the brake pedal is depressed. Also, in this stop state, when it is detected that the select lever is in the drive range, the vehicle speed is zero, the engine speed is zero, and the brake pedal is not depressed, the automatic shift is performed. The engine is electrically held in the neutral range and the engine is restarted. When the engine reaches the idling speed, the neutral range is released.
[0003]
By the way, immediately after the restart of the engine, the intake pipe negative pressure has not developed and the amount of air taken into the cylinder is large. Therefore, the generated engine torque becomes larger than when the accelerator pedal is depressed from the idling state. Therefore, if the accelerator is depressed before or after the release of the brake, the engine torque becomes too large, and if this is transmitted to the drive system, a shock is generated, which is not preferable. In addition, the same acceleration force cannot be obtained when the engine is started from an idle state where the engine is not stopped, and when the engine is restarted from the stopped state of the engine, giving the occupant a sense of discomfort.
[0004]
In response to such a problem, excess torque may be absorbed by controlling the torque of the motor generator to the absorption side (power generation control) in synchronization with the generation of engine torque, but depending on the type of battery, Cannot fully absorb the excess torque generated when the engine is restarted, and the voltage of the battery rapidly increases, which may affect peripheral devices or generate heat to accelerate deterioration. If the opportunity for restarting the engine, that is, the number of times of idle stop is limited to avoid this, the fuel efficiency improvement effect will be impaired accordingly. In addition, it is conceivable to reduce the torque by retarding the ignition timing or making the air-fuel ratio lean, but in that case, the combustion may become unstable.
[0005]
The present invention has been made in view of such a problem, and avoids excessive power generation by a motor generator by temporarily suppressing an increase in engine output when an accelerator pedal is depressed during restart. It is aimed at.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, according to the invention of claim 1, a motor generator is connected to an engine, and a torque converter or an automatic transmission with a starting clutch is interposed between the motor generator and a wheel drive shaft. The engine is automatically stopped when stopped, and the engine can be restarted by the motor generator in a state where the engine torque or engine shaft output is transmitted to the wheel drive shaft when starting, and the engine shaft output and the inertia force during vehicle braking can be reduced. In a vehicle engine in which the motor generator is capable of generating regenerative power, a rotation speed detecting means for detecting a rotation speed of the engine or the motor generator, a means for detecting an operation amount of an accelerator pedal, and Performs motor generator speed control using the idle speed as the target speed When the accelerator is turned on when the engine is restarted, the regenerative torque of the motor generator is maintained while the target speed in the motor speed control is kept at or near the idle speed. A regenerative torque limiter setting means for setting a regenerative torque limiter and an output control device for controlling the engine output in response to the accelerator operation, the operation being delayed with respect to the accelerator on operation when the engine is restarted. Means.
[0007]
According to a second aspect of the present invention, the delay means according to the first aspect of the present invention is set so that the delay period becomes longer as the accelerator opening is smaller.
[0008]
According to a third aspect of the present invention, the delay unit according to the first or second aspect is set to have a characteristic that the longer the limiter torque initial value set by the regenerative torque limiter setting unit is, the longer the delay period is. And
[0009]
[Action / Effect]
In each of the above inventions, when the engine generates combustion torque as the accelerator pedal is depressed (accelerator-on) at the time of restarting the engine, the motor speed is controlled by the motor generator with the idle speed as the target speed. The generator changes its operation from the drive side to the regenerative side to absorb the torque, and the regenerative torque limiter limits the absorption of the torque, so that only the excessively generated torque is absorbed. Therefore, the engine speed smoothly increases to the target speed and engine stall is prevented. Therefore, the driving force can be smoothly raised by depressing the accelerator pedal, and the same acceleration force is obtained when the engine is started from an idle state where the engine is not stopped and when the engine is started and started when the engine is stopped. , A feeling of acceleration can be obtained, and drivability can be improved.
[0010]
However, in the present invention, the engine output rises after a predetermined delay period has elapsed with respect to the depression operation of the accelerator pedal. That is, the operation of an engine output control device such as a throttle valve of a gasoline engine or a fuel injection control lever of a diesel engine is delayed with respect to the operation of an accelerator pedal. For this reason, the amount of torque absorption by the regenerative torque limiter at the time of engine restart can be reduced accordingly, and the charging load is reduced, so that deterioration of the battery can be prevented and its durability can be further improved.
[0011]
Further, since the absolute amount of the torque to be absorbed is reduced, even if an error occurs in the set value of the regenerative torque limiter, the influence is small, so that smoother driving force characteristics and drivability can be obtained.
[0012]
Further, as the opening degree of the accelerator pedal is smaller as in the invention of claim 2, or as the limiter torque initial value set by the regenerative torque limiter is larger as in the invention of claim 3, the output control device is increased. By increasing the delay period, the engine output can be started at a more appropriate timing in accordance with the actual change in the engine intake air amount, so that better driving performance can be obtained.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an automatic stop / restart device for absorbing regenerative torque at the time of restart by a torque limiter, which is a premise of the present invention, will be described.
[0014]
As shown in FIG. 1, a motor generator 2 having both functions of a generator and an electric motor is provided between the engine 1 and the continuously variable automatic transmission 3.
[0015]
Motor generator 2 is directly connected to the crankshaft of engine 1. The continuously variable automatic transmission 3 includes a torque converter 4, a forward / reverse switching clutch 5, and a belt-type continuously variable transmission 6. The drive torque of the engine 1 is transmitted to the drive shaft 7 and the tire 8 via these components. Tell
[0016]
The motor generator 2 is functionally equivalent even when connected to the crankshaft of the engine 1 via a belt or a chain. Further, a configuration using a stepped automatic transmission instead of the continuously variable automatic transmission 3 may be adopted. Further, instead of the torque converter 4, a start clutch for transmitting the torque of the engine 1 when the engine 1 is restarted may be provided.
[0017]
The electric power control unit 12 drives and drives the motor generator 2, and the electric power is supplied from or charged to the battery 13.
[0018]
Reference numeral 9 denotes a rotation speed sensor for detecting the rotation speeds of the engine 1 and the motor generator 2 and a crank angle of the engine 1, reference numeral 11 denotes a brake sensor for detecting a depression amount of a brake pedal 16 (see FIG. 2) of the vehicle, and reference numeral 15 denotes an accelerator pedal. 17 shows an accelerator sensor that detects an operation amount of the engine 17 (see FIG. 2).
[0019]
The start control unit 10 outputs a target torque and a target rotation speed of the motor generator 2 to the power control unit 12 based on these sensor signals and a signal from an engine control unit 20 (see FIG. 2) described later. The control of the motor generator 2 is performed via the control unit 12.
[0020]
The start control unit 10 is provided in the engine control unit 20, but may be provided in an integrated controller (not shown) that controls the entire power train of the vehicle.
[0021]
FIG. 2 shows an engine control system, in which 11 is a brake sensor, 15 is an accelerator sensor, 9 is a rotational speed sensor, 21 is a water temperature sensor for detecting the cooling water temperature of the engine, and 22 is a select lever of the automatic transmission 3. Is a select position sensor for detecting the position of the vehicle, and 23 is a vehicle speed sensor for detecting the vehicle speed.
[0022]
The engine control unit 20 controls automatic stop (idle stop) and start (restart) of the engine 1 based on these sensor signals. Further, based on the intake air amount of the engine 1 measured by the air flow meter 24 and the engine speed and the phase (crank angle) of the engine rotation measured by the rotation speed sensor 9, a fuel amount corresponding to the intake air amount is obtained. An ignition timing corresponding to the engine load and the engine speed is calculated, a fuel injector 25 provided at an intake port of each cylinder is driven to supply the calculated fuel amount, and each cylinder is adjusted in accordance with the calculated ignition timing. The ignition of the ignition plug 26 is controlled.
[0023]
The intake system is provided with an electronically controlled throttle valve 27 whose opening can be electronically controlled, and controls the intake air amount of the engine 1 according to a target engine torque input from an integrated controller (not shown).
[0024]
Although the engine 1 is a gasoline engine, a configuration using a diesel engine is also possible. In this case, the torque is controlled by controlling the fuel injection amount according to the control lever opening of the fuel injection pump. Is done.
[0025]
Next, the contents of the automatic stop and restart control of the engine will be described based on the flowcharts of FIGS.
[0026]
As shown in FIG. 3, in steps 1 to 5, the warm-up operation is completed, the brake pedal 16 is depressed (ON), the vehicle speed is approximately 0 km / h, and the accelerator pedal 17 is It is determined that the driver is not depressed (off) and that the rotation speed of the engine 1 is equal to or lower than an idle rotation speed (for example, 800 rpm).
[0027]
In step 6, it is determined whether or not all of these conditions are satisfied for the first time (flag FCOND = 0). If it is the first time, in step 7, the delay time and the flag FCOND = 1 are set.
[0028]
In step 8, the position of the select lever is checked. If it is not in the reverse range, the process proceeds to step 9 and subsequent steps.
[0029]
In the reverse range, the engine 1 is not automatically stopped, and if the engine 1 is stopped, the process proceeds from step 29 to step 32 to step 22 and restarts the engine 1 (described later).
[0030]
When the vehicle is not in the reverse range, that is, when the vehicle is in the drive range, the neutral range, or the parking range, a flag FRFST = 0 indicating that the vehicle is not in the reverse range is set in step 9 and whether or not the engine 1 is stopped in step 10. to see.
[0031]
If the engine 1 is not stopped, the engine stop mode of steps 12 to 17 is entered when the delay time set in steps 11 to 7 has elapsed.
[0032]
In steps 12 to 14, the motor torque of the motor generator 2 is set to 0, and the fuel injection of the engine 1 is stopped. In steps 15 to 17, it is determined whether or not the engine stop sequence is the first time (flag FISTPFST = 0). If it is the first time, the engine 1 is stopped after the idle stop (I / S) permission time and the flag FISTPFST = 1 are set. FENGSTRT = 0 is set.
[0033]
As described above, when the vehicle is temporarily stopped, the engine 1 is temporarily automatically stopped. The automatic stop of the engine 1 may be performed only when the engine is in the drive range.
[0034]
On the other hand, if the conditions of Steps 1 to 4 are not satisfied, that is, if the engine is being stopped automatically, when the brake pedal 16 is released (OFF) or the accelerator pedal 17 is depressed (ON), the process proceeds to Step 18. Clears the flag FCOND (= 0) and enters the engine restart mode from step 19 to step 22 and subsequent steps.
[0035]
In steps 22 to 24, a target start torque is given to the start control unit 10 to start driving the motor generator 2, and first, a delay time corresponding to a development time of the intake pipe negative pressure (Boost) and a delay time of the engine 1. A flag FENGSTRT = 1 indicating start is set.
[0036]
The delay time corresponding to the Boost development time is a time from the start of the engine 1 (atmospheric pressure state) until the boost becomes equivalent to minus 500 mmHg with the accelerator turned off, and is set to, for example, about 1.5 seconds.
[0037]
In step 25, it is determined whether or not the accelerator pedal 17 is depressed. When the accelerator pedal 17 is not depressed, the start control unit 10 sets the idling speed to the target speed in steps 26 to 28 and shifts to the speed control of the motor generator 2. After the elapse of the delay time corresponding to the set Boost development time, fuel injection is started. When the engine 1 has completely exploded, the torque control of the motor generator 2 is started at 0, and the restart control ends.
[0038]
When the accelerator pedal 17 is depressed, the idling speed is set to the target speed in the start control unit 10 in steps 33 to 35, and the process proceeds to the speed control of the motor generator 2 (the speed in step 26). After entering the control, the operation is continued when the accelerator pedal 17 is depressed), and the fuel injection is started. When the engine 1 has completely exploded, the regenerative torque limiter described below is released, and at step 36, the torque control of the motor generator 2 is started at 0, and the restart control is terminated.
[0039]
When the engine 1 is restarted, regenerative torque limiter control (setting of the regenerative torque limiter) for limiting the regenerative torque of the motor generator 2 is performed in parallel with the restart control.
[0040]
As shown in FIG. 4, in step 101, the flag FCYLBRN is checked to determine whether or not the cylinder whose ignition timing comes next will burn. As long as a flag described later is not set, the process proceeds to step 109 by the flag FCYLBRN = 0.
[0041]
In step 109, based on the crank angle of the engine 1, a flag CYLCS indicating which cylinder is in the compression stroke of the current crank angle position, and a flag FHINJEX (CYLCS) indicating whether fuel has been injected into the cylinder. Thus, it is determined whether fuel has been injected into the cylinder at the next ignition timing (flag FHINJEX (CYLCS) = 1).
[0042]
When the fuel is not injected, a predetermined delay time TFCBNDEC is set in step 110, and the calculation (update) of the initial value of the regenerative torque limiter TRQLMTST is performed in step 111 every execution cycle (10 ms) of the flow. repeat.
[0043]
When the fuel is injected, a flag FCYLBRN is set (= 1) at step 102 to estimate that the cylinder whose ignition timing will come next will burn. Thereafter, the same routine is performed from step 101.
[0044]
In step 103, it is determined whether or not the delay time TFCBNDEC set in step 110 has become 0. If not, the initial value of the regenerative torque limiter TRQLMTST is calculated (step 112) every step (10 ms) of the flow. Update) is repeated, and in step 113, the delay time TFCBNDEC is subtracted.
[0045]
The initial value of the regenerative torque limiter TRQLMTST is given by a function of the engine stop time (time from the start of fuel cut) TISTPON and the elapsed time after the engine is started TISTPOF, and based on these, the characteristics are set as shown in FIG. Search and ask for the map. FIG. 6 shows an example of the map.
[0046]
Immediately after the start of the engine, the boost is not developed, and the engine torque generated increases as much as the excess air is sucked in. As time elapses, the boost develops and the excess air disappears. In addition, if the time until the engine is started after the engine is stopped is long, the boost before the stop is eliminated and the pressure becomes the atmospheric pressure, but the shorter the time, the more the boost remains. Therefore, the initial value of the regenerative torque limiter TRQLMTST is set to a larger value so as to absorb a torque corresponding to a larger excess air as the engine stop time TISTPON is longer and the elapsed time TISTPOF after the engine is started is shorter. The initial value of the regenerative torque limiter TRQLMTST is set to be smaller as the engine stop time TISTPON is shorter and the elapsed time TISTPOF after the start of the engine is longer.
[0047]
FIG. 7 shows the case where the accelerator is depressed almost simultaneously with the start of the engine (the elapsed time TISTPOF after the start of the engine is almost 0 seconds), and the case where the accelerator is depressed after elapse of, for example, 0.8 seconds after the start of the engine. The characteristics of the excess air from the accelerator depression and the required torque value to be absorbed are shown. When the accelerator is depressed almost simultaneously with the start of the engine, the excess air is large, and the torque to be absorbed is large, and the excess air decreases with time. For example, after 0.7 seconds (depending on the engine load), the torque is reduced. No absorption is required. Further, when the accelerator is depressed, for example, 0.8 seconds after the start of the engine, there is almost no surplus air, and the torque to be absorbed becomes extremely small. However, in FIG. 7, the intake pipe pressure at the time of startup is the atmospheric pressure.
[0048]
Note that the initial value of the regenerative torque limiter TRQLMTST may be given as a function of only the elapsed time TISTPOF after the start of the engine.
[0049]
If it is determined in step 103 that the delay time TFCBNDEC set in step 110 has become 0, the process proceeds to step 104 and subsequent steps.
[0050]
The delay time TFCBNDEC is set to the time from the compression stroke to the ignition timing of the cylinder where the compression stroke comes next. Therefore, when the engine generates the combustion torque, the process is started after step 104. The delay time TFCBNDEC may be longer than the ignition timing by a predetermined time so as to match the peak of combustion.
[0051]
In step 104, it is determined whether the state where the torque (regeneration torque) of the motor generator 2 is equal to or less than a predetermined value (0 or near 0) has been continued for a predetermined time.
[0052]
When the regenerative torque of the motor generator 2 is not less than the predetermined value (when the torque to be absorbed is large), the regenerative torque limiter TRQLMTST (initial value) is subtracted in step 106. This is done by subtracting the predetermined value DTTRQLMT from the previous value within a range not falling below the target value TGTRQLMT (0 or near 0) every execution cycle (10 ms) of the flow.
[0053]
If the regenerative torque of the motor generator 2 is kept at or below a predetermined value (0 or near 0) for a predetermined time, it is determined that the engine has completely exploded, and the flag fKANBAKU = 1 is set at step 107 and at step 108 The regenerative torque limiter TRQLMTST is added (released). This means that the predetermined value DLTLMTP is added to the previous value within a range that does not exceed the maximum value TGTRQMAX at every execution cycle (10 ms) of the flow.
[0054]
That is, as shown in FIG. 8, the operation of the initial value of the regenerative torque limiter TRQLMTST is started simultaneously with the start of the engine, and the regenerative torque limiter TRQLMTST is set to a predetermined slope (predetermined value DLTLMTP) starting from the timing at which the engine generates combustion torque. / 10 ms), and subtracts to or near zero. After the complete explosion, the regenerative torque limiter TRQLMTST is added so as to be released.
[0055]
The calculated value of the initial value of the regenerative torque limiter TRQLMTST in steps 111 and 112 and the subtraction value and the added value of the regenerative torque limiter TRQLMTST in steps 106 and 108 are calculated when the accelerator pedal 17 is depressed for each calculation. Only the start control signal is transmitted to the start control unit 10.
[0056]
Although these calculations are performed with positive values for simplicity, the regenerative torque is a negative value, so the regenerative torque limiter TRQLMTST converts the value to a negative value and transmits the converted value.
[0057]
With this configuration, when the brake pedal 16 is released from the state where the engine 1 is automatically stopped (when the accelerator pedal 17 is not depressed), the motor generator 2 is driven and the engine 1 is restarted.
[0058]
The rotation speed control of the motor generator 2 is performed with the idling rotation speed as the target rotation speed, and after a delay time corresponding to the Boost development time has elapsed (the idling rotation speed has been reached), the fuel injection is started, and the engine torque is reduced. When this occurs, the torque of the motor generator 2 is reduced and regenerated by the rotation speed control.
[0059]
Therefore, as shown in FIG. 9, the engine speed is started up smoothly and is maintained at the idle speed.
[0060]
If the state where the torque of the motor generator 2 is equal to or less than the predetermined value continues for a predetermined time, it is determined that the explosion is complete, and the restart is terminated. However, if the engine torque is not generated due to smoldering, misfire, etc., the motor generator 2 2 is driven. Therefore, even if the generation of the engine torque is delayed, the engine will not stall, and the creep torque is reliably maintained.
[0061]
On the other hand, when the brake pedal 16 is released from the state where the engine 1 is automatically stopped and the accelerator pedal 17 is depressed, the motor generator 2 is driven, and the idling speed is set as the target speed to control the speed of the motor generator 2. Is performed, fuel injection is started simultaneously with depression of the accelerator pedal 17, and the regenerative torque limiter of the motor generator 2 is set.
[0062]
The regenerative torque limiter is based on the engine stop time and the elapsed time after the engine is started, so that as the stop time is longer and the elapsed time after the start is shorter, the engine torque generated excessively is absorbed. The value is calculated and set. As the stop time is longer and the elapsed time after startup is shorter, that is, when the brake pedal 16 is released and the accelerator pedal 17 is immediately depressed, the boost is not developed, the excess air is large, and excessive engine torque is generated. However, an initial value is calculated and set so as to absorb the excessive engine torque.
[0063]
That is, when the fuel injection is started by depressing the accelerator pedal 17 and the engine generates combustion torque, the motor generator 2 is driven as shown in FIG. The operation is changed from the side to the regeneration side to absorb the torque, and the absorption of the torque is limited to a set value (initial value) by the regeneration torque limiter.
[0064]
In this case, before the engine generates the combustion torque, the motor generator 2 is driven by power without driving the torque to the regenerative torque limiter. However, when the engine generates the combustion torque, the motor generator 2 transmits the torque to the regenerative torque limiter. The regenerative operation is performed in which the regenerative torque of the motor generator 2 matches the regenerative torque limiter.
[0065]
Then, after setting the initial value, the regenerative torque limiter is controlled so as to subtract 0 or near 0 with a predetermined gradient, that is, to reduce the absorption of torque by the motor generator 2 as shown in FIG.
[0066]
If there is no regenerative torque limiter, the motor generator 2 operates so as to absorb all torques other than the combustion torque for maintaining the idling rotation speed, but the excess amount is set by the initial setting and the subtraction setting of the regenerative torque limiter. Only torque is absorbed.
[0067]
The torque of the motor generator 2 remains stuck to the regenerative torque limiter. Therefore, the engine speed is changed from the idle speed to the target speed while the speed control of the motor generator 2 is performed with the idle speed as the target speed. It is raised smoothly. Of course, the rotation speed control of the motor generator 2 prevents the engine from stalling even if the generation of the engine torque is delayed due to smoldering, misfire, or the like.
[0068]
If the state where the torque of motor generator 2 is equal to or less than a predetermined value (0 or near 0) continues for a predetermined time, it is determined that a complete explosion has occurred, and the restart is terminated. However, although not shown in FIG. 10, after the complete explosion, the regenerative torque limiter is released, and the control is shifted from the rotation speed control of the motor generator 2 to the torque control.
[0069]
As described above, the regenerative torque limiter is set to absorb the excessive engine torque based on the state of Boost development. Therefore, when the brake pedal 16 is released and the accelerator pedal 17 is depressed, the overshoot torque is accurately determined. The driving force at the time of starting the vehicle can be smoothly increased.
[0070]
Therefore, the same acceleration force and the same feeling of acceleration can be obtained in the case where the engine starts from the idle state where the engine is not stopped, and the case where the engine is started and started in the state where the engine is stopped, and the drivability can be improved.
[0071]
Although the initial value of the regenerative torque limiter is set based on the engine stop time and the elapsed time after the start of the engine, the control can be simplified by giving it as a function of only the elapsed time after the start of the engine. If an intake pressure sensor for detecting the intake pipe negative pressure is provided, and the initial value of the regenerative torque limiter is set based on the detected value, the setting can be performed more accurately.
[0072]
Further, the regenerative torque limiter is changed to 0 or near 0 at a predetermined inclination (predetermined value DTTRQLMT / 10 ms) after setting the initial value, but is variable according to the intake pipe negative pressure, that is, the intake pipe negative pressure is large. At this time, the inclination may be reduced so that the inclination increases as the inclination decreases. In this way, the excess torque can be more accurately absorbed after the engine combustion torque is generated.
[0073]
If the state in which the torque of the motor generator 2 is equal to or less than a predetermined value (0 or near 0) continues for a predetermined time, that is, if the state in which the regenerative torque limiter becomes 0 or near 0 continues for a predetermined time, it is determined that the engine has completely exploded. However, when the state in which the regenerative torque of the motor generator 2 is stuck to the regenerative torque limiter (the state in which the engine is generating the combustion torque) has continued for a predetermined time, or the combustion cycle of the engine that generates the combustion torque is in a predetermined state. When the number of cycles is reached, it may be determined that the explosion is complete.
[0074]
Further, in this example, it is also possible to make the setting of the regenerative torque limiter smaller and to make the acceleration force after the idle stop larger than in the past, and thereby to improve the starting performance. .
[0075]
By the way, as described above, when the brake pedal 16 is released at the time of restart and the accelerator pedal 17 is depressed, in order to properly absorb the overshoot torque and smoothly raise the driving force at the time of starting the vehicle. Must have sufficient battery capacity to sufficiently absorb the recovered power for the overshoot torque. Some types of batteries, such as lead-acid batteries, are not suitable for absorbing a large overshoot torque and may generate heat to cause deterioration. In such a case, it is necessary to suppress the generation of the overshoot torque to be absorbed by some method.
[0076]
On the other hand, as described with reference to FIG. 7, when the accelerator pedal is depressed with a certain time delay after the start of the engine, there is almost no excess air, and the torque to be absorbed becomes extremely small. Focusing on such points, the present invention is configured so that the actual throttle opening changes with a delay with respect to the depression operation of the accelerator pedal. Hereinafter, control contents for performing such control will be described with reference to the flowchart shown in FIG.
[0077]
This control basically controls the opening of the throttle valve 27 (see FIG. 2) in accordance with the operation amount of the accelerator pedal 17 (also referred to as the accelerator opening). It is periodically executed in parallel with the stop / restart control. At the beginning of this control, a complete explosion of the engine is determined (step 301). If the complete explosion determination is satisfied, that is, if the complete explosion has occurred, the throttle opening delay control is not performed thereafter, the delay start flag DLYSET is cleared to 0, and the target set according to the accelerator opening read from the accelerator sensor 15 is set. The throttle opening of the engine is controlled without delay so as to match the throttle opening TVO (steps 302 to 304).
[0078]
When the restart condition is not satisfied in step 301, the state of the idle switch (not shown) is detected. The idle switch is an idle detection switch that is turned on when the accelerator pedal 17 is not depressed and turned off when the accelerator pedal 17 is depressed. When it is on, it is in an idle state, and there is no need to delay control the throttle opening, so that the normal throttle opening control is performed by the processing from step 303 described above.
[0079]
On the other hand, when the idle switch is off, that is, when the accelerator pedal 17 is depressed, the opening degree read result from the accelerator sensor 15 and the target throttle opening degree TVO are set based on the result, and then the state of the delay start flag DLYSET is set. Is determined (steps 306 to 308). Since DLYSET = 0 at the beginning of this flow, the delay time T of the throttle opening control is set and DLYSET is set to 1 by the processing of the next step 309. Once DLYSET = 1 is set, the setting of the delay time T is bypassed from the next processing. That is, in this case, the amount is detected only when the accelerator pedal 17 is depressed, and the delay time T is set.
[0080]
The delay time T is set by a map search or the like so as to be longer as the accelerator opening is smaller as shown in FIG. 12 or as the initial value of the limiter torque is larger as shown in FIG. An appropriate delay time is set so as to better respond to changes in the intake air amount. Then, in the subsequent steps 310 to 312, the command of the target throttle opening TVO is delayed so that the throttle opening changes with a delay time set as described above.
[0081]
In this case, as described above, the delay time T is set according to the initial accelerator opening when the accelerator pedal 17 is depressed, but the delay time T is variably set according to the momentary change amount of the accelerator opening. It may be configured as follows.
[0082]
FIG. 13 shows a change in the amount of torque absorption during such delay control. As is clear from the comparison with FIG. 10, the amount of torque absorption when the accelerator pedal is depressed when the engine is restarted can be more sufficiently suppressed than when the delay control is not performed. As a result, the load on the battery for absorbing the torque can be reduced accordingly, so that deterioration due to heat generation and the like can be avoided and durability can be improved. In addition, under idle stop conditions, the engine can be reliably stopped automatically to improve fuel efficiency. Can be secured.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of the present invention.
FIG. 2 is a configuration diagram of an embodiment of an engine control system.
FIG. 3 is a flowchart showing basic control contents of the embodiment.
FIG. 4 is a flowchart showing basic control contents of the embodiment.
FIG. 5 is a characteristic diagram of an initial value of a regenerative torque limiter.
FIG. 6 is a map diagram of a regenerative torque limiter.
FIG. 7 is a characteristic diagram of surplus air and a required torque value to be absorbed after the accelerator is depressed.
FIG. 8 is a timing chart of a regenerative torque limiter.
FIG. 9 is a timing chart when the engine is restarted (accelerator off).
FIG. 10 is a timing chart when the engine is restarted (accelerator on / no delay control).
FIG. 11 is a flowchart showing control contents of delay control of the embodiment.
FIG. 12 is a map diagram of a delay time (delay time).
FIG. 13 is a timing chart when the engine is restarted (accelerator on / with delay control).
[Explanation of symbols]
1 engine
2 Motor generator
3 continuously variable automatic transmission
4 Torque converter
7 Drive shaft
8 tires
9. Rotation speed sensor (rotation speed detection means)
10 Start control unit (including the function of delay means)
11 Brake sensor
12 Power control unit
13 Battery
15 Accelerator sensor (means for detecting accelerator operation amount)
20 Engine control unit
21 Water temperature sensor
22 Select position sensor
23 Vehicle speed sensor
24 Air flow meter
25 Fuel injector
26 Spark plug
27 Electric throttle valve

Claims (3)

A motor generator is connected to the engine, and an automatic transmission with a torque converter or a starting clutch is interposed between the motor generator and the wheel drive shaft. The engine is automatically stopped when the vehicle stops and the engine is rotated when starting. For vehicles where the engine can be restarted by the motor generator while transmitting the power or the engine shaft output to the wheel drive shaft, and the motor generator can generate regenerative power by receiving the engine shaft output and the inertia force during vehicle braking. In the engine,
Rotation speed detection means for detecting the rotation speed of the engine or the motor generator,
Means for detecting the operation amount of the accelerator pedal,
Motor generator rotation speed control means for controlling the rotation speed of the motor generator with the idle rotation speed as the target rotation speed when the engine is restarted,
When the accelerator is turned on when the engine is restarted, a regenerative torque limiter that limits the regenerative torque of the motor generator is set while the target rotational speed in the rotational speed control of the motor generator is kept at or near the idle rotational speed. Regenerative torque limiter setting means,
Delay means for operating the output control device for controlling the engine output in accordance with the accelerator pedal operation amount with a delay with respect to the accelerator operation when the engine is restarted. Starting device. 2. The automatic stop / restart system for an engine according to claim 1, wherein the delay means is set to have a characteristic in which the smaller the accelerator opening, the longer the delay period. 3. The automatic stop of the engine according to claim 1, wherein the delay unit is set to have a characteristic that the longer the limiter torque initial value set by the regenerative torque limiter setting unit, the longer the delay period. Restart device.

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