JP3614035B2 - Engine automatic stop / restart device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of engine revolutions to a target one so as to prevent a stall by setting a regenerative torque limiter limiting regenerative torque of a motor generator, whose number of revolutions is controlled when an accelerator is turned on at an engine restart time. SOLUTION: When a brake pedal is released or an accelerator pedal is actuated while an engine is in an automatic stop condition, an engine restart mode is entered, and in this process, electric current is fed to a motor generator 2 so as to drive it via a power control unit 12 according to a target start torque from an start control unit 10. After the elapse of a predetermined delay time accompanied by increase of an intake negative pressure, fuel injection is started. Immediately after the start, shorter the elapse of time after engine start is the larger the value of regenerative torque limiter is set for absorbing engine torque equivalent to massive excessive air when an engine stop time is longer and, and the engine can be assured of smooth start up.

Description

このタイミングチャートを図１５に示す。このように、加重平均によって回生トルクリミッタの減算設定を行えば、過剰分のトルク吸収を一層的確に行える。
【０１０２】
なお、上記各形態では、回生トルクリミッタは、モータジェネレータの回生トルク（トルクそのもの）を制限する、としているが、トルクを制限する代わりに、回生出力を制限するようにしても良い。
【図面の簡単な説明】
【図１】実施の形態を示す構成図である。
【図２】エンジンの制御システムを示す構成図である。
【図３】制御内容を示すフローチャートである。
【図４】制御内容を示すフローチャートである。
【図５】回生トルクリミッタの初期値の特性図である。
【図６】回生トルクリミッタのマップ図である。
【図７】アクセル踏み込み時点からの余剰空気と吸収すべきトルク要求値の特性図である。
【図８】回生トルクリミッタのタイミングチャートである。
【図９】エンジン再始動時（アクセルオフ）のタイミングチャートである。
【図１０】エンジン再始動時（アクセルオン）のタイミングチャートである。
【図１１】第２の実施の形態の制御内容を示すフローチャートである。
【図１２】第３の実施の形態の制御内容を示すフローチャートである。
【図１３】回生トルクリミッタのタイミングチャートである。
【図１４】第４の実施の形態の制御内容を示すフローチャートである。
【図１５】回生トルクリミッタのタイミングチャートである。
【符号の説明】
１ エンジン
２ モータジェネレータ
３ 無段自動変速機
４ トルクコンバータ
７ ドライブシャフト
８ タイヤ
９ 回転数センサ
１０ 始動制御コントロールユニット
１１ ブレーキセンサ
１２ 電力コントロールユニット
１３ バッテリ
１５ アクセルセンサ
２０ エンジンコントロールユニット
２１ 水温センサ
２２ セレクト位置センサ
２３ 車速センサ
２４ エアフローメータ
２５ 燃料インジェクタ
２６ 点火プラグ
２７ 電制スロットルバルブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine automatic stop / restart apparatus that automatically stops an engine when the vehicle is stopped and automatically restarts the engine when starting.
[0002]
[Prior art]
As an engine automatic stop / restart apparatus for vehicles equipped with an automatic transmission, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 8-291725. In this apparatus, 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 rotation speed sensor that detects the engine speed, a brake sensor that detects whether the brake pedal is depressed, etc. 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. In this stopped state, automatic shift is detected 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 machine is electrically held in the neutral range, the engine is restarted, and the neutral range is released when the engine reaches idle speed.
[0003]
[Problems to be solved by the invention]
However, in such an automatic stop / restart system for an engine, in order to start the engine with the automatic transmission electrically in the neutral range, the creep force peculiar to a vehicle equipped with a conventional automatic transmission with a torque converter is reduced. Occurrence is delayed. Even if the selector lever is put in the drive range and the brake is released in anticipation of the creep force, the creep force cannot be obtained until the neutral range hold of the automatic transmission is released, so there is a sense of incongruity.
[0004]
Further, in this case, torque proportional to the square of the engine rotation is transmitted by the torque converter, so that when the neutral range of the automatic transmission is released when the engine rotation is started, a large driving force is transmitted to the wheel side. As a result, a shock occurs. In particular, when the accelerator is depressed before and after the release of the brake, the engine torque increases, so the shock increases.
[0005]
Therefore, a motor generator is connected to the engine so as to eliminate such a delay in shock and creep force, and the engine rotational force or engine shaft output is driven through an automatic transmission with a torque converter (or starting clutch). It is considered to start the engine by a motor generator in a state where it is transmitted to the shaft.
[0006]
However, even with such a starting method, the intake pipe negative pressure (Boost) is not developed immediately after the engine is started, and the generated engine torque increases as the amount of air sucked into the cylinder increases. Therefore, if the accelerator is depressed before and after the brake is released, the engine torque becomes too large, which may give a sense of discomfort.
[0007]
For example, when the engine is not stopped (idle stop) and the accelerator is depressed from the idle state, the intake pipe negative pressure is sufficiently developed, so that a predetermined engine torque can be obtained, but the engine is stopped ( In the case of idling stop), if the accelerator is depressed immediately after the engine is restarted, and in the extreme case the brake is released, the pressure in the intake pipe remains at atmospheric pressure. Excessive torque is generated.
[0008]
Therefore, when the vehicle starts from an idle state where the engine is not stopped and when the engine starts from the engine stopped state, the same acceleration force cannot be obtained, giving a sense of incongruity.
[0009]
To deal with such problems, it is conceivable to absorb excessive torque by controlling the motor generator torque to the absorption side (power generation control) in synchronization with the generation of engine torque. If the fuel is injected, the explosion does not necessarily complete, and if it does not complete the explosion, but shifts to the power generation control, the engine speed and the like are reduced. Further, if the absorption torque of the motor generator is too large, the required acceleration force cannot be obtained.
[0010]
An object of the present invention is to solve such problems.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, a motor generator is connected to the engine, a torque converter or an automatic transmission with a starting clutch is interposed between the motor generator and the wheel drive shaft, and the engine is automatically stopped when the vehicle is stopped. The engine can be restarted by the motor generator while transmitting the engine rotational force or engine shaft output to the wheel drive shaft when starting, and the motor generator can generate regenerative power by receiving the engine shaft output and the inertial force during vehicle braking. In the vehicular engine, the rotation speed detection means for detecting the rotation speed of the engine or the motor generator, the means for detecting the state of the accelerator, and the idle speed of the motor generator as the target rotation speed when the engine is restarted. Motor generator rotation speed control means for controlling the rotation speed; 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 speed in the motor generator speed control is kept at or near the idle speed. Regenerative torque limiter setting means.
[0012]
In a second aspect based on the first aspect, the regenerative torque limiter sets an initial value based on an elapsed time after starting the engine or the elapsed time and the engine stop time or the intake pipe negative pressure, and the engine is set to a combustion torque. Starting from the timing of occurrence of the error, it is changed to 0 or near 0 with a predetermined inclination.
[0013]
According to a third invention, in the first invention, the regenerative torque limiter sets an initial value based on an elapsed time after starting the engine or the elapsed time and the engine stop time or an intake pipe negative pressure, and the engine generates a combustion torque. Starting from a timing shifted by a predetermined time from the timing at which the error occurs, it is changed to 0 or near 0 with a predetermined slope.
[0014]
In a fourth aspect based on the first aspect, the regenerative torque limiter sets an initial value based on an elapsed time after starting the engine or the elapsed time and the engine stop time or the intake pipe negative pressure, and regenerates the motor generator. Starting from the timing when the torque sticks to the regenerative torque limiter, the torque is changed to 0 or near 0 with a predetermined inclination.
[0015]
According to a fifth invention, in the second and third inventions, a discriminating means for discriminating whether or not fuel is injected for each cylinder of the engine, and which cylinder the compression angle position of the current engine is in the compression stroke The timing at which the engine generates combustion torque is determined by determining whether combustion is performed at the next ignition timing based on these determinations.
[0016]
According to a sixth aspect of the present invention, in the first to fourth aspects of the present invention, when the accelerator is on, a state in which the regenerative torque of the motor generator is stuck to the regenerative torque limiter continues for a predetermined time, or the combustion cycle of the engine is a predetermined cycle. Completion determination means for determining a complete explosion when the number reaches the number, and torque control means for shifting the motor generator from rotation speed control to torque control based on the completion explosion determination.
[0017]
In a seventh aspect based on the first to fourth aspects, when the accelerator is turned on, a state in which the regenerative torque of the motor generator is stuck to the regenerative torque limiter continues for a predetermined time, or the combustion cycle of the engine is a predetermined cycle. Complete explosion determination means for determining a complete explosion when the number reaches the limit, and limiter releasing means for changing the regenerative torque limiter in a direction for releasing the regenerative torque limit after completion of the explosion determination.
[0018]
In an eighth aspect based on the second aspect, the predetermined inclination for changing the regenerative torque limiter to 0 or near 0 is variable based on the intake pipe negative pressure.
[0019]
【The invention's effect】
According to the first invention, when the accelerator is turned on when the engine is restarted and the engine generates combustion torque, the motor generator is regenerated from the drive side by the rotational speed control of the motor generator with the idle rotational speed as the target rotational speed. The torque is absorbed by changing the operation to the side, and the absorption of the torque is limited by the regenerative torque limiter, and only the torque that is excessively generated by the intake pipe negative pressure state is absorbed. Therefore, the engine speed smoothly increases to the target speed, and engine stall is prevented.
[0020]
Therefore, the driving force can be raised smoothly by turning on the accelerator, and when starting from an idle state where the engine is not stopped and when starting the engine from the engine stopped state, the same acceleration force and acceleration A feeling can be obtained and drivability can be improved.
[0021]
According to the second to fifth inventions, the regenerative torque limiter can be accurately set in accordance with the state of the intake pipe negative pressure and the generation of the combustion torque, and the excessive torque can be absorbed accurately.
[0022]
According to the sixth and seventh inventions, the complete explosion of the engine can be accurately determined, and the normal control can be quickly and satisfactorily transferred.
[0023]
According to the eighth aspect, after the combustion torque of the engine is generated, the excessive torque can be absorbed more accurately.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
As shown in FIG. 1, a motor generator 2 having both functions of a generator and an electric motor is disposed between an engine 1 and a continuously variable automatic transmission 3.
[0026]
Motor generator 2 is directly connected to a crankshaft (not shown) of engine 1 and rotates synchronously with 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. Tell.
[0027]
The motor generator 2 is functionally equivalent even if connected to the crankshaft of the engine 1 via a belt or chain. Further, a stepped automatic transmission may be used instead of the continuously variable automatic transmission 3. Further, instead of the torque converter 4, a start clutch that transmits torque on the engine 1 side when the engine 1 is restarted may be provided.
[0028]
The motor generator 2 is driven and driven by the power control unit 12, and the power is supplied from the battery 13 or charged to the battery 13.
[0029]
Reference numeral 9 denotes a rotational speed sensor for detecting the rotational speed of the engine 1 and the motor generator 2 and a crank angle of the engine 1, 11 denotes a brake sensor for detecting a depression amount of a brake pedal 16 (see FIG. 2) of the vehicle, and 15 denotes an accelerator pedal. The accelerator sensor which detects the operation amount of 17 (refer FIG. 2) is shown.
[0030]
The start control control unit 10 outputs the target torque and the 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) to be described later. The motor generator 2 is controlled via the control unit 12.
[0031]
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.
[0032]
FIG. 2 shows an engine control system, in which 11 is a brake sensor, 15 is an accelerator sensor, 9 is a rotation speed sensor, 21 is a water temperature sensor that detects the cooling water temperature of the engine, and 22 is a select lever of the automatic transmission 3. A select position sensor 23 for detecting the position of the vehicle, and a vehicle speed sensor 23 for detecting the vehicle speed.
[0033]
The engine control unit 20 controls stop (automatic 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, the engine speed and the phase (crank angle) of the engine rotation measured by the rotational speed sensor 9, the fuel amount corresponding to the intake air amount and The ignition timing commensurate with the engine load and the engine speed is calculated, the fuel injector 25 provided in the 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 spark plug 26 is controlled. The engine 1 is a so-called MPI system in which a fuel injector is provided at the intake port of each cylinder and injects fuel. However, a so-called direct injection engine in which fuel is directly injected into each cylinder may be used. .
[0034]
Further, the intake system is provided with an electrically controlled throttle valve 27 whose opening degree can be electronically controlled, and controls the intake air amount of the engine 1 in accordance with a target engine torque input from an integrated controller (not shown).
[0035]
In addition, although the engine 1 shows a gasoline engine, you may use a diesel engine. In the case of a diesel engine, the torque can be controlled by controlling the fuel injection amount.
[0036]
Next, the contents of the automatic engine stop and restart control will be described based on the flowcharts of FIGS.
[0037]
As shown in FIG. 3, in steps 1 to 5, the warm-up operation is finished, 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 engine 1 has not been depressed (off) and that the rotational speed of the engine 1 is equal to or lower than the idle rotational speed (for example, 800 rpm).
[0038]
In step 6, it is determined whether or not all of these conditions are satisfied (flag FCOND = 0) for the first time. If it is the first time, the delay time and the flag FCOND = 1 are set in step 7.
[0039]
In step 8, the position of the select lever is viewed. When not in the reverse range, the process proceeds to step 9 and thereafter.
[0040]
When in the reverse range, the engine 1 is not automatically stopped. If the engine 1 is stopped, the process proceeds from step 29 to step 32 to step 22 and subsequent steps, and the engine 1 is restarted (described later).
[0041]
When it is not in the reverse range, that is, when it is in the drive range, neutral range or parking range, a flag FRFST = 0 indicating that it 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.
[0042]
If the engine 1 is not stopped, the engine stop mode of steps 12 to 17 is entered when the delay time set in step 11 to step 7 has elapsed.
[0043]
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. The flag FENGSTRT = 0 indicating the above is set.
[0044]
Thus, when the vehicle is temporarily stopped, the engine 1 is automatically stopped temporarily. The engine 1 may be automatically stopped only when it is in the drive range.
[0045]
On the other hand, if the conditions of Steps 1 to 4 are not met, that is, if the engine is in automatic stop, when the brake pedal 16 is released (OFF) or the accelerator pedal 17 is depressed (ON), Step 18 is executed. Then, the flag FCOND is cleared (= 0), and the engine restart mode after step 22 is entered from step 19.
[0046]
In steps 22 to 24, a target starting torque is given to the start control control unit 10 to start driving the motor generator 2, and first, a delay time corresponding to the development time of the intake pipe negative pressure (Boost) and the engine 1 are set. A flag FENGSTRT = 1 indicating start is set.
[0047]
The delay time corresponding to the boost development time is the time from when the engine 1 is started (atmospheric pressure state) until the boost becomes equivalent to −500 mmHg with the accelerator off, and is set to about 1.5 seconds, for example.
[0048]
In step 25, it is determined whether or not the accelerator pedal 17 is depressed.
[0049]
When the accelerator pedal 17 is not depressed, the start control control unit 10 sets the idle rotation speed to the target rotation speed in steps 26 to 28 and shifts to the rotation speed control of the motor generator 2. After a delay time corresponding to the set boost development time has elapsed, fuel injection is started. When the engine 1 is completely detonated, the torque control of the motor generator 2 is started, and the restart control is terminated.
[0050]
When the accelerator pedal 17 is depressed, the start control control unit 10 sets the idle rotation speed to the target rotation speed in steps 33 to 35 and shifts to the rotation speed control of the motor generator 2 (the rotation speed in step 26). When the accelerator pedal 17 is depressed after the control is started, the fuel injection is started. If the engine 1 is completely detonated, a regenerative torque limiter, which will be described later, is released, and at step 36, the torque control of the motor generator 2 is entered at 0, and the restart control is terminated.
[0051]
Then, at the time of restart of the engine 1, 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.
[0052]
As shown in FIG. 4, in step 101, the flag FCYLBRN is checked to determine whether or not the cylinder that comes to the next ignition timing burns. This proceeds to step 109 because the flag FCYLBRN = 0 until the flag described later is not set.
[0053]
In step 109, based on the crank angle of the engine 1, a flag CYLCS indicating which cylinder the current crank angle position is in the compression stroke, and a flag FHINJEX (CYLCS) indicating whether fuel has been injected into the cylinder, Thus, it is determined whether or not fuel has been injected into the cylinder at the next ignition timing (flag FHINJEX (CYLCS) = 1).
[0054]
When the fuel is not injected, a predetermined delay time TFCBNDEC is set in step 110, and the initial value of the regenerative torque limiter TRQLMTST is calculated (updated) in step 111 every flow execution period (10 ms). repeat.
[0055]
When the fuel is injected, a flag FCYLBRN is set (= 1), which estimates that the cylinder whose ignition timing will come next burns in step 102. Thereafter, the same routine is advanced from step 101 as well.
[0056]
In step 103, whether or not the delay time TFCBNDEC set in step 110 has become zero is determined. If not, calculation of the initial value of the regenerative torque limiter TRQLMST in step 112 is performed at every flow execution cycle (10 ms) ( Update) is repeated, and in step 113, the delay time TFCBNDEC is subtracted.
[0057]
The initial value of the regenerative torque limiter TRQLMTS is given as a function of the engine stop time (time from the start of fuel cut) TISTPON and the engine elapsed time TISTPOF. Based on these functions, the characteristics shown in FIG. 5 are set. Find and search for the maps you have made. FIG. 6 shows an example of a map.
[0058]
Immediately after the engine is started up, the boost is not developed, and the generated engine torque is increased by the amount of intake of the surplus air. As time passes, the boost develops and the surplus air disappears. In addition, when the time until the engine is started after the engine is stopped is long, the boost before the engine stops and the atmospheric pressure is reached. Therefore, the initial value of the regenerative torque limiter TRQLMST is set to a larger value so as to absorb the torque corresponding to the larger excess air as the engine stop time TISTPON is longer and the elapsed time after engine startup TISTPOF is shorter. The initial value of the regenerative torque limiter TRQLMTS is set to be smaller as the engine stop time TISTPON is shorter and the elapsed time after engine startup TISTPOF is longer.
[0059]
FIG. 7 shows that when the accelerator is depressed almost simultaneously with the start of the engine (the elapsed time after engine startup TISTPOF is approximately 0 seconds), and when the accelerator is depressed after, for example, 0.8 seconds have elapsed after the engine is started. The characteristics of the excess air from the time when the accelerator is depressed and the required torque value to be absorbed are shown. When the accelerator is depressed almost at the same time as starting the engine, the amount of excess air is large, so 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) Absorption of is no longer necessary. Further, for example, when the accelerator is depressed after 0.8 seconds have elapsed after starting the engine, there is almost no excess air, and the torque to be absorbed is extremely small. However, in FIG. 7, the intake pipe pressure at the time of start-up is the atmospheric pressure.
[0060]
Note that the initial value of the regenerative torque limiter TRQLMTST may be given as a function of only the elapsed time TISTPOF after engine startup.
[0061]
If it is determined in step 103 that the delay time TFCBNDEC set in step 110 has become zero, step 104 and subsequent steps are entered.
[0062]
The delay time TFCBNDEC is set to the time from the compression stroke to the ignition timing of the cylinder in which the compression stroke comes next. Therefore, when the engine generates combustion torque, the routine proceeds to step 104 and after. The delay time TFCBNDEC may be longer than the ignition timing by a predetermined time so as to match the combustion peak.
[0063]
In step 104, it is determined whether or not the state where the torque (regenerative 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.
[0064]
When the regenerative torque of the motor generator 2 is not below the predetermined value (when the torque to be absorbed is large), the regenerative torque limiter TRQLMTST (initial value) is subtracted at step 106. This subtracts the predetermined value DTTRQLMT from the previous value within a range that does not fall below the target value TGTRQLMT (0 or near 0) every flow execution cycle (10 ms).
[0065]
If the state where the regenerative torque of the motor generator 2 is less than or equal to a predetermined value (0 or near 0) is continued 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 Addition (cancellation) of the regenerative torque limiter TRQLMTST is performed. This adds the predetermined value DLTLLMTP to the previous value within a range not exceeding the maximum value TGTRQMAX at each flow execution cycle (10 ms).
[0066]
That is, as shown in FIG. 8, the calculation of the initial value of the regenerative torque limiter TRQLMTST is started at the same time as the engine is started, and the regenerative torque limiter TRQLMTST is set to a predetermined inclination (predetermined value DLTLLMTP) starting from the timing at which the engine generates combustion torque. / 10 ms), and subtracts to 0 or near 0. After the complete explosion, addition is performed so as to cancel the regenerative torque limiter TRQLMTST.
[0067]
The calculated value of the initial value of the regenerative torque limiter TRQLMTS in steps 111 and 112 and the subtracted value and the added value of the regenerative torque limiter TRQLMMTST in steps 106 and 108 are obtained when the accelerator pedal 17 is depressed for each calculation. Only to the start control unit 10.
[0068]
Although these calculations are performed with a positive value for simplicity, the regenerative torque is a negative value. Therefore, the regenerative torque limiter TRQLMTS is converted into a negative value and transmitted.
[0069]
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.
[0070]
The rotational speed control of the motor generator 2 is performed with the idle rotational speed as the target rotational speed, and fuel injection is started after a delay time corresponding to the boost development time has elapsed (reaching the idle rotational speed), and the engine torque is increased. When this occurs, the torque of the motor generator 2 is reduced and regenerated by controlling the rotational speed.
[0071]
Therefore, as shown in FIG. 9, the engine speed is smoothly raised and maintained at the idle speed.
[0072]
If the torque of the motor generator 2 remains below the predetermined value for a predetermined time, it is determined that the explosion has been completed and the restart is terminated. However, if engine torque does not occur due to smoldering, misfire, etc., the motor generator 2 is driven. Therefore, even if the generation of the engine torque is delayed, the engine does not fall into the engine stall, and the creep torque is reliably maintained.
[0073]
On the other hand, when the brake pedal 16 is released from the state in which the engine 1 is automatically stopped and the accelerator pedal 17 is depressed, the motor generator 2 is driven, and the rotational speed control of the motor generator 2 is performed using the idle rotational speed as the target rotational speed. The fuel injection is started simultaneously with the depression of the accelerator pedal 17, and the regenerative torque limiter of the motor generator 2 is set.
[0074]
This regenerative torque limiter is based on the engine stop time and the elapsed time after engine start-up. The value is calculated and set. The stop time is long and the elapsed time after startup is short, that is, the boost is not developed as much as the accelerator pedal 17 is depressed immediately after releasing the brake pedal 16, the excess air is large, and the engine torque is generated excessively However, the initial value is calculated and set so as to absorb the excessive engine torque.
[0075]
That is, when 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. 10 by the rotational speed control of the motor generator 2 with the idle rotational speed as the target rotational speed. The operation is changed from the side to the regenerative side to absorb the torque, and the regenerative torque limiter limits the absorption of the torque to the set value (initial value).
[0076]
In this case, before the engine generates combustion torque, the motor generator 2 is driven by power running without the torque sticking to the regenerative torque limiter. However, when the engine generates combustion torque, the motor generator 2 causes the torque to reach the regenerative torque limiter. The regenerative operation is performed (the regenerative torque of the motor generator 2 matches the regenerative torque limiter).
[0077]
After the initial value is set, the regenerative torque limiter is controlled so as to subtract 0 or near 0 with a predetermined inclination, that is, to reduce the absorption of torque by the motor generator 2 as shown in FIG.
[0078]
When there is no regenerative torque limiter, the motor generator 2 operates so as to absorb all torque other than the combustion torque for maintaining the idle speed, but an excess amount is set by the initial setting and subtraction setting of the regenerative torque limiter. Only torque is absorbed.
[0079]
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 idling speed as the target speed. It rises smoothly. Of course, by controlling the rotational speed of the motor generator 2, even if the generation of the engine torque is delayed due to smoldering, misfire, etc., it is prevented that the engine generator 2 falls into the engine stall.
[0080]
Then, when the torque of motor generator 2 is below a predetermined value (0 or near 0) continues for a predetermined time, it is determined that complete explosion has occurred, and restart is completed. However, although not shown in FIG. 10, after the complete explosion, the regenerative torque limiter is released and the motor generator 2 is shifted from the rotational speed control to the torque control.
[0081]
As described above, since the regenerative torque limiter is set to absorb excessive engine torque based on the development state of the boost, when the brake pedal 16 is released and the accelerator pedal 17 is depressed, the overshoot torque is accurately determined. So that the driving force at the start of the vehicle can be raised smoothly.
[0082]
Therefore, when the vehicle starts from an idle state where the engine is not stopped and when the vehicle starts when the engine is stopped, the same acceleration force and feeling of acceleration can be obtained, and drivability can be improved.
[0083]
Note that the initial value of the regenerative torque limiter is set based on the engine stop time and the elapsed time after engine startup, but control can be simplified if given as a function only of the elapsed time after engine startup. Further, 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 made more accurately.
[0084]
The regenerative torque limiter is changed to 0 or near 0 with a predetermined slope (predetermined value DLTLLMTP / 10 ms) after the initial value is set, but is variable according to the intake pipe negative pressure, that is, the intake pipe negative pressure is large. In some cases, the inclination may be decreased and the inclination may be increased as the inclination decreases. In this way, after the combustion torque of the engine is generated, the excessive torque can be absorbed more accurately.
[0085]
Further, if the motor generator 2 torque is equal to or less than a predetermined value (0 or close to 0) for a predetermined time, that is, if the regenerative torque limiter is 0 or close to 0 continues for a predetermined time, it is determined that the engine has completely exploded. However, when the regenerative torque of the motor generator 2 sticks to the regenerative torque limiter (the state in which the engine generates combustion torque) continues for a predetermined time, or the combustion cycle of the engine that generates the combustion torque is predetermined. When the number of cycles is reached, a complete explosion may be determined.
[0086]
In this example, it is also possible to reduce the setting of the regenerative torque limiter and increase the acceleration force after idling stop compared to the conventional one, and in this way, the start performance can be improved. .
[0087]
11, 12 and 14 show second to fourth embodiments of the present invention. These show the subtraction flow of the regenerative torque limiter, which is performed in place of the regenerative torque limiter subtraction step (step 106) of FIG.
[0088]
In FIG. 11, in step 201, the engine load TP, that is, the intake air amount of the engine (the operation amount of the accelerator pedal 17) is read.
[0089]
In step 202, based on the engine load TP, the decay time DTDLMT until the regenerative torque limiter TRQLMTST (initial value) is subtracted from the target value TGTRQLMT (0 or near 0) is calculated. This is obtained on the basis of the engine load TP with reference to a table (see the characteristic diagram in Step 202) in which the target value TGTRQLMT is determined in advance.
[0090]
In step 203, an attenuation step amount DTTRQLMT (TRQLMTST−GTTRRQLMT / DTDLMT) is calculated from the regenerative torque limiter TRQLMTST, the target value TGTRQLMT, and the attenuation time DTDLMT.
[0091]
In step 204, the regenerative torque limiter TRQLMTST is subtracted. This subtracts the attenuation step amount DTTRQLMT × execution cycle TJOB from the previous value every flow execution cycle TJOB (10 ms).
[0092]
When the regenerative torque limiter TRQLMTST reaches the target value TGTRQLMT in steps 205 and 206, the subtraction is finished.
[0093]
In FIG. 12, the engine load TP is read in step 301.
[0094]
In step 302, the attenuation step amount DTTRQLMT is calculated based on the regenerative torque limiter TRQLMTST (initial value) and the engine load TP. This is obtained by referring to a map (see the characteristic diagram in step 302) in which the attenuation step amount DTTRQLMT is determined in advance based on the regenerative torque limiter TRQLMTST and the engine load TP.
[0095]
In step 303, the regenerative torque limiter TRQLMTST is subtracted. This subtracts the attenuation step amount DTTRQLMT from the previous value every flow execution cycle (10 ms).
[0096]
When the regenerative torque limiter TRQLMTST reaches the target value TGTRQLMT in steps 304 and 305, the subtraction is finished.
[0097]
The timing charts of FIGS. 11 and 12 are shown in FIG. Thus, if the subtraction is performed by calculating the attenuation step amount DTTRQLMT based on the engine load TP, the subtraction setting of the regenerative torque limiter can be accurately performed according to the excessive torque.
[0098]
In FIG. 14, the regenerative torque limiter is subtracted by weighted average, and the engine load TP is read in step 401.
[0099]
In step 402, a weighted average coefficient KJLMT (0 ≦ KJLMT ≦ 1) is calculated based on the engine load TP. This is obtained with reference to a table (see the characteristic diagram in step 402) in which the weighted average coefficient KJLMT is determined in advance based on the engine load TP.
[0100]
In step 403, the regenerative torque limiter TRQLMTST is subtracted from the following equation (1).
[0101]

This timing chart is shown in FIG. Thus, if the subtraction setting of the regenerative torque limiter is performed by weighted average, the excessive torque can be absorbed more accurately.
[0102]
In each of the above embodiments, the regenerative torque limiter limits the regenerative torque (torque itself) of the motor generator. However, instead of limiting the torque, the regenerative output may be limited.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating an embodiment.
FIG. 2 is a configuration diagram showing an engine control system;
FIG. 3 is a flowchart showing control contents.
FIG. 4 is a flowchart showing control contents.
FIG. 5 is a characteristic diagram of an initial value of a regenerative torque limiter.
FIG. 6 is a map of a regenerative torque limiter.
FIG. 7 is a characteristic diagram of surplus air from the time when the accelerator is depressed and a torque request value to be absorbed.
FIG. 8 is a timing chart of a regenerative torque limiter.
FIG. 9 is a timing chart when the engine is restarted (accelerator is off).
FIG. 10 is a timing chart at the time of engine restart (accelerator on).
FIG. 11 is a flowchart illustrating control contents of the second embodiment.
FIG. 12 is a flowchart showing the control contents of the third embodiment.
FIG. 13 is a timing chart of a regenerative torque limiter.
FIG. 14 is a flowchart showing control contents of the fourth embodiment;
FIG. 15 is a timing chart of a regenerative torque limiter.
[Explanation of symbols]
1 engine
2 Motor generator
3 continuously variable automatic transmission
4 Torque converter
7 Drive shaft
8 tires
9 Speed sensor
10 Start control unit
11 Brake sensor
12 Power control unit
13 battery
15 Accelerator sensor
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 (8)

A motor generator is connected to the engine, and a torque converter or an automatic transmission with a starting clutch is interposed between the motor generator and the wheel drive shaft to automatically stop the engine when the vehicle stops, and to rotate the engine when starting For vehicles in which the motor generator can be restarted by the motor generator in a state where the force or engine shaft output is transmitted to the wheel drive shaft, and the motor generator can generate regenerative power by receiving the inertia force during engine shaft output or vehicle braking In the engine
A rotational speed detecting means for detecting the rotational speed of the engine or the motor generator;
Means for detecting the state of the accelerator;
Motor generator rotation speed control means for controlling the rotation speed of the motor generator with the idle rotation speed as a 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 motor generator rotational speed control is kept at or near the idle rotational speed. An automatic engine restart / restart apparatus comprising: a regenerative torque limiter setting means. The regenerative torque limiter sets an initial value based on an elapsed time after starting the engine or the elapsed time and the engine stop time or the intake pipe negative pressure, and starts at a predetermined inclination with the timing at which the engine generates combustion torque. 2. The automatic stop / restart device for an engine according to claim 1, wherein the automatic stop / restart device is changed to zero or near zero. The regenerative torque limiter sets an initial value based on the elapsed time after engine startup or the elapsed time and engine stop time or intake pipe negative pressure, and starts at a timing shifted by a predetermined time from the timing at which the engine generates combustion torque. The automatic stop / restart apparatus for an engine according to claim 1, wherein the engine is changed to 0 or near 0 with a predetermined inclination. The regenerative torque limiter sets the initial value based on the elapsed time after engine startup or the elapsed time and engine stop time or intake pipe negative pressure, and starts from the timing when the regenerative torque of the motor generator sticks to the regenerative torque limiter. The automatic stop / restart apparatus for an engine according to claim 1, wherein the engine is changed to 0 or near 0 with a predetermined inclination. Determining means for determining whether fuel has been injected for each cylinder of the engine; and determining means for determining which cylinder is in the compression stroke of the current engine crank angle position, wherein the engine generates combustion torque The automatic stop / restart apparatus for an engine according to claim 2 or 3, wherein the timing for performing the determination is determined by determining whether combustion is performed at the next ignition timing based on these determinations. Complete explosion determination means for determining complete explosion when the accelerator generator is on when the regenerative torque of the motor generator is stuck to the regenerative torque limiter for a predetermined time or when the engine combustion cycle reaches a predetermined number of cycles. And an automatic stop / restart of the engine according to any one of claims 1 to 4, further comprising: torque control means for shifting the motor generator from rotational speed control to torque control based on a complete explosion determination. apparatus. Complete explosion determination means for determining complete explosion when the accelerator generator is on when the regenerative torque of the motor generator is stuck to the regenerative torque limiter for a predetermined time or when the engine combustion cycle reaches a predetermined number of cycles. And a limiter releasing means for changing the regenerative torque limiter in a direction to release the regenerative torque limiter after completion of the explosion determination. The automatic stop / restart apparatus for an engine according to claim 2, wherein the predetermined inclination for changing the regenerative torque limiter to 0 or near 0 is variable based on intake pipe negative pressure.

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