JP2008215230A - Engine revolution stop control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately control an engine revolution stop crank angle within a target crank angle range. <P>SOLUTION: An ECU 30 calculates a revolution behavior until engine revolution is stopped at a target stop crank angle (hereinafter referred to as "target track"), and controls a load of an alternator 33 to make engine revolution behavior correspond to the target track when engine revolution is stopped. To obtain the target track, a relationship between a crank angle up to the target stop crank angle and target engine speed is calculated at a predetermined crank angle interval and is tabulated. It is preferable to calculate the target track corresponding to reference load torque, for example which is set to be a half of a maximum load controllable by the alternator 33. To reduce a deviation between the target engine speed and actual engine speed on the basis of the reference torque, required load torque of the alternator 33 is calculated to control a load of the alternator 33. Due to this procedure, the engine revolution stop crank angle can be accurately controlled within the target crank angle range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine rotation stop control device having a function of controlling an engine rotation stop crank angle.

In recent years, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-315202), in a vehicle equipped with an automatic engine stop / start system (idle stop system), the engine is stopped in order to improve restartability. When the engine is stopped automatically for the purpose of controlling the engine rotation stop crank angle to a crank angle range suitable for starting, sometimes the target current value of the alternator is increased to an initial value set to a large value in advance. There is one that performs control to reduce.
JP-A-2005-315202 (second page, etc.)

  The engine rotation stop control device described in Patent Document 1 attempts to control the engine rotation stop crank angle to a target crank angle range by controlling the load of the alternator when the engine is automatically stopped. In actual control, when the engine rotation speed detected when the piston passes the compression top dead center is within 480 rpm to 540 rpm, the target current value of the alternator is set to the engine at that time using a preset map. Since it is only set according to the rotational speed (see paragraph [0069] of Patent Document 1), the alternator load control is rough and it is difficult to sufficiently compensate for variations in engine rotational behavior during the engine stop process. is there. For this reason, in the thing of the said patent document 1, the dispersion | variation in an engine rotation stop crank angle cannot fully be reduced, and it seems that the effect of a restart property improvement is few.

  The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to sufficiently compensate for variations in engine rotation behavior during the engine stop process, and to accurately target the engine rotation stop crank angle. It is an object of the present invention to provide an engine rotation stop control device that can be controlled within a crank angle range.

  In order to achieve the above object, an invention according to claim 1 is directed to an engine rotation stop control device that stops engine rotation by stopping ignition and / or fuel injection when an engine stop request is generated. Target trajectory calculation means for calculating rotational behavior until the stop crank angle is stopped (hereinafter referred to as “target trajectory”), and engine auxiliary load so that the engine rotational behavior matches the target trajectory when the engine rotation is stopped. It is set as the structure provided with the stop control means to control. In this configuration, when the engine rotation is stopped, the engine auxiliary load is controlled so that the engine rotation behavior matches the target trajectory, so that variations in engine rotation behavior during the engine stop process can be sufficiently compensated, The engine rotation stop crank angle can be accurately controlled within the target crank angle range.

  Further, as the target trajectory as in claim 2, a torque obtained by setting the relationship between the crank angle to the target stop crank angle and the target engine speed at a predetermined crank angle interval (for example, 30 CA interval) is used. It is preferable to calculate the target trajectory in the direction of turning the crank angle with the target stop crank angle as an initial value based on the energy conservation law considering the above. In this way, the target trajectory up to the target stop crank angle can be set with high accuracy.

  In this case, the loss torque may be switched between the low-rotation side loss torque and the high-rotation side loss torque at any engine speed (for example, 150 rpm). Thereby, the precision of loss torque can be improved.

  Further, as in claim 4, the relationship between an arbitrary crank angle (for example, TDC) during engine stop behavior that becomes the target stop crank angle and the engine rotation speed is obtained as an initial value, and an arbitrary crank angle obtained as an initial value A target trajectory may be obtained by setting a relationship between the crank angle to the engine speed and the target engine speed at a predetermined crank angle. At this time, the target trajectory may be calculated in the direction of increasing the crank angle using the initial value obtained earlier based on the energy conservation law considering the loss torque.

  Further, as in claim 5, the initial value calculation is performed by learning the relationship between the engine rotation speed and the stop crank angle at an arbitrary crank angle (for example, TDC) from the stop behavior of the engine, and at the desired crank angle. What is necessary is just to obtain | require the engine rotational speed used as an angle | corner, and let the calculated engine rotational speed and arbitrary cranks be an initial value. In this way, the initial value of the target trajectory that becomes the target stop crank angle can be set.

  In these cases, as in claim 6, the loss torque may be obtained by summing at least the pumping loss, the friction loss and the auxiliary load. Thereby, loss torque can fully be reflected in a target track.

  Further, as in claim 7, the load of the generator is controlled as an auxiliary load controlled in the process of stopping the engine rotation, and a predetermined load (hereinafter referred to as “reference load”) smaller than the maximum load controllable by the generator. It is preferable to feedback-control the load of the generator with reference to. This makes it possible to virtually control the load torque of the generator in both positive and negative directions (load torque below the reference load is virtually negative load torque, and load torque above the reference load is positive The load torque of the generator can be controlled as the load torque), and the followability of the engine rotation behavior to the target track can be improved.

  In this case, as in claim 8, the loss torque may be obtained by summing at least the pumping loss, the friction loss, and the reference load. That is, if the reference load is added as an auxiliary load to be added to the loss torque, the feedback control of the generator load can be accurately performed with reference to the reference load.

Hereinafter, an embodiment embodying the best mode for carrying out the present invention will be described.
First, the overall configuration of the engine control system will be schematically described with reference to FIG.
A throttle valve 14 is provided in the middle of the intake pipe 13 connected to the intake port 12 of the engine 11, and an opening degree (throttle opening degree) TA of the throttle valve 14 is detected by a throttle opening degree sensor 15. The intake pipe 13 is provided with a bypass passage 16 that bypasses the throttle valve 14, and an idle speed control valve 17 is provided in the middle of the bypass passage 16. The bypass passage 16 and the idle speed control valve 17 may be omitted, and the idle rotation speed may be controlled by adjusting the intake air amount according to the opening of the throttle valve 14 even during idling.

  An intake pipe pressure sensor 18 for detecting the intake pipe pressure PM is provided on the downstream side of the throttle valve 14, and a fuel injection valve 19 is attached in the vicinity of the intake port 12 of each cylinder.

  On the other hand, an exhaust gas purifying catalyst 22 is installed in the middle of the exhaust pipe 21 connected to the exhaust port 20 of the engine 11. The cylinder block of the engine 11 is provided with a coolant temperature sensor 23 that detects the coolant temperature THW. A crank angle sensor 26 is installed facing the outer periphery of the signal rotor 25 attached to the crankshaft 24 of the engine 11, and the crank angle sensor 26 synchronizes with the rotation of the signal rotor 25 from the crank angle sensor 26 at every predetermined crank angle (for example, 30 ° C.). A crank pulse signal CRS is output every A). A cam angle sensor 29 is installed opposite to the outer periphery of the signal rotor 28 attached to the cam shaft 27 of the engine 11, and the cam pulse is generated at a predetermined cam angle in synchronization with the rotation of the signal rotor 28 from the cam angle sensor 29. Signal CAS is output.

  Further, rotation of a crank pulley 34 connected to the crankshaft 24 is transmitted to the alternator 33 (generator) via a belt 35. Thereby, the alternator 33 is rotationally driven by the power of the engine 11 to generate power. The load on the alternator 33 can be controlled by duty-controlling the power generation control current (field current) of the alternator 33.

  Outputs of the various sensors described above are input to an engine control circuit (hereinafter referred to as “ECU”) 30. The ECU 30 is mainly composed of a microcomputer, and controls the fuel injection amount and injection timing of the fuel injection valve 19 and the ignition timing of the spark plug 31 in accordance with the engine operating state detected by various sensors, and during idle operation. When a predetermined automatic stop condition is satisfied and an engine stop request is generated, an idle stop is executed to stop the engine rotation by stopping the ignition and / or fuel injection. When an operation for starting the vehicle (for example, an accelerator operation or the like) is performed, a predetermined automatic start condition is established, the starter (not shown) is energized, and the engine 11 is cranked and restarted.

  Further, the ECU 30 functions as a target trajectory calculating means for calculating a rotational behavior (hereinafter referred to as “target trajectory”) until the engine rotation stops at the target stop crank angle, and at the time of stopping the engine rotation, It functions as stop control means for controlling the load of the alternator 33 so as to match the target trajectory.

  Here, the target trajectory is obtained by calculating the relationship between the crank angle to the target stop crank angle and the target engine speed at a predetermined crank angle interval (for example, 30 CA interval) and assigning it to a table (see FIG. 3). is there. This target trajectory is calculated in the direction of turning the crank angle with the target stop crank angle as an initial value using a relational expression of an energy conservation law that considers loss torque (see FIG. 2). The relational expression of the energy conservation law is expressed by the following expression.

Ne (i + 1) ² = Ne (i) ² −2 / J × {Tloss (θ (i)) − Tref (Ne (i))}
Here, Ne (i + 1) is the engine rotation speed at a time point (i + 1) before a predetermined crank angle (30 CA in this embodiment) before the current time point (i), and Ne (i) is the current rotation speed at (i). Engine rotational speed, J is the moment of inertia of engine 11, and Tloss (θ (i)) is the total torque of the pumping loss and friction loss at the current crank angle θ (i). The loss torque Tloss (θ (i)) corresponding to the crank angle θ (i) at the present time (i) is calculated using the 12 maps. Tref (Ne (i)) is the reference load torque of the alternator 33 at the current engine speed Ne (i).

  In the relational expression of the above energy conservation law, “Tloss (θ (i)) − Tref (Ne (i))” is the sum of the pumping loss, the friction loss, and the reference load torque Tref (Ne (i)) of the alternator 33. Corresponds to loss torque.

  In this embodiment, the reference load torque Tref (Ne (i)) of the alternator 33 is set to half (1/2) of the maximum load that can be controlled by the alternator 33 as shown in FIG. In this way, unlike the motor generator, the alternator 33 can virtually control the load torque of the alternator 33 in both the positive and negative directions even when there is a situation where the assist torque cannot be output (below the reference load Tref). The load torque of the alternator 33 can be controlled by virtually setting the load torque of the generator 33 to be a negative load torque and the load torque of the reference load Tref or more as a positive load torque). Can be improved.

Note that the reference load torque Tref (Ne (i)) of the alternator 33 is not limited to half (1/2) of the maximum load, for example, 1/3, 1/4, 2/3, 3 / of the maximum load. 4 or the like may be used. In short, an appropriate load smaller than the maximum controllable load of the alternator 33 and larger than 0 may be set as the reference load torque Tref (Ne (i)).
0 <Tref (Ne (i)) <maximum load

  FIG. 6A shows a comparative example in which the engine rotation stop control is performed by setting the reference load torque Tref (Ne (i)) = 0. In this comparative example, since the load torque of the alternator 33 can be controlled only in the positive direction, when the actual engine rotation behavior overshoots, the actual engine rotation behavior cannot be matched with the target trajectory.

  On the other hand, if the reference load torque Tref (Ne (i)) of the alternator 33 is set to an appropriate load smaller than the maximum load as in this embodiment, the alternator is virtually set as shown in FIG. Since the load torque 33 can be controlled in both the positive and negative directions, as shown in FIG. 6B, even when the actual rotational behavior overshoots, the actual rotational behavior can be matched with the target trajectory.

  Further, in this embodiment, as shown in FIG. 7, when calculating the target trajectory, the target trajectory corresponding to the reference load torque Tref (Ne (i)) of the alternator 33 is calculated, and during engine rotation stop control, The reference load torque Tref (Ne (i)) corresponding to the engine speed Ne (i) is calculated, and the deviation between the target engine speed and the actual engine speed at the crank angle θ (i) at the current time (i) is calculated. The base load torque is calculated so as to reduce the required load torque Talt by adding the reference load torque Tref (Ne (i)) to the base load torque (actually, the pulley ratio is added to the required load torque Talt) The ratio is multiplied to convert to the required shaft torque Talt.final). Then, using the required load torque characteristics shown in FIG. 8, a power generation command (duty duty) corresponding to the current required load torque Talt (required shaft torque Talt.final) and the engine speed Ne (i) is calculated. The power generation control current (field current) of the alternator 33 is controlled by this power generation command (duty duty) to control the load torque of the alternator 33.

  Such control of the load torque of the alternator 33 is periodically executed at a predetermined crank interval (for example, 30 CA interval) until the engine rotational speed decreases below the power generation limit rotational speed Nelow of the alternator 33 (see FIG. 4). The load torque of the alternator 33 is feedback-controlled so that the engine rotation behavior is matched with the target trajectory.

The required load torque characteristic shown in FIG. 8 is a torque characteristic at the engine shaft, and is a characteristic when the output voltage of the alternator 33 is constant at 13.5 V. A similar characteristic is set for each output voltage. Yes.
The engine rotation stop control described above is executed by the ECU 30 according to the routines shown in FIGS. The processing contents of these routines will be described below.

[Target trajectory calculation routine]
The target trajectory calculation routine of FIG. 9 is executed at a predetermined period during engine operation, and serves as target trajectory calculation means in the claims. When this routine is started, first, at step 101, it is determined whether or not the target trajectory calculation completion flag is set to “0” which means that the target trajectory has not been calculated. If it is set to “1” meaning the completion of calculation, this routine is terminated without performing the subsequent processing.

  On the other hand, if it is determined in step 101 that the target trajectory calculation completion flag = 0 (before the target trajectory is calculated), the process proceeds to step 102 where the loss torque Tloss (θ (i)) and the reference load torque Tref (Ne) of the alternator 33 are obtained. (i)) is used to calculate the square of the target engine speed Ne (i + 1) at the next time point (i + 1) using the relational expression of the energy conservation law expressed by the following formula.

Ne (i + 1) ² = Ne (i) ² −2 / J × {Tloss (θ (i)) − Tref (Ne (i))}
Here, J is the moment of inertia of the engine 11, and Tloss (θ (i)) is the loss torque obtained by adding the pumping loss and the friction loss. The loss torque Tloss (θ (i)) corresponding to the angle θ (i) is calculated.

  In the relational expression of the above energy conservation law, “Tloss (θ (i)) − Tref (Ne (i))” is the sum of the pumping loss, the friction loss, and the reference load torque Tref (Ne (i)) of the alternator 33. Corresponds to loss torque.

  The initial values are i = 0, θ (0) = 60 CA (target stop crank angle), and Ne (0) = 0 rpm (engine speed at stop). The target trajectory is calculated for each predetermined crank angle (every 30 CA in this embodiment) in the direction of turning the crank angle with the target stop crank angle (θ (0) = 60 CA) as an initial value. The crank angle is expressed by intake ATDC. Therefore, θ (1) = 30 CA, θ (2) = 0 CA, θ (3) = 150 CA, θ (4) = 120 CA, θ (5) = 90 CA, θ (6) = 60 CA, θ (7) = 30 CA , Θ (8) = 0CA, θ (9) = 150CA,..., The square of the target engine speed Ne (i + 1) is calculated.

  After this, the routine proceeds to step 103, where it is determined whether or not the square of the target engine speed Ne (i + 1) exceeds the square of the maximum engine speed Nemax at which the engine rotation stop control can be executed. If it does not exceed the square of Nemax, the process proceeds to step 104, and the target trajectory calculation completion flag is maintained at “0” (reset).

Thereafter, the process proceeds to step 105, and the next crank angle θ (i + 1) is obtained by subtracting 30CA which is the calculation interval from the current crank angle θ (i).
θ (i + 1) = θ (i) −30

  Thereafter, the routine proceeds to step 106, where it is determined whether or not the next crank angle θ (i + 1) is “−30”, and if the next crank angle θ (i + 1) is “−30”. Then, it is determined that the next crank angle θ (i + 1) exceeds TDC, and the routine proceeds to step 107, where the next crank angle θ (i + 1) is rewritten to “150” in the intake ATDC expression and the target stop The counter n that counts the number of times TDC has been crossed up to the crank angle θ (0) is incremented (n = n + 1), and the routine proceeds to step 109.

  On the other hand, if it is determined in step 106 that the next crank angle θ (i + 1) is not “−30”, it is determined that the next crank angle θ (i + 1) still does not exceed TDC, The processing of step 107 is not performed, and the next crank angle θ (i + 1) calculated in step 105 is used without being changed. Thereafter, the routine proceeds to step 109, where the square root of the square of the target engine speed Ne (i + 1) is calculated to obtain the target engine speed Ne (i + 1), which is assigned to the target trajectory table of FIG. To end this routine. In order to reduce the calculation load on the ECU 30, the square of the engine speed may be assigned to the table as it is. The target trajectory table in FIG. 3 is stored in the memory of the ECU 30.

  The above processing is repeated, and the square of the target engine speed Ne (i + 1) is calculated every 30 CA in the direction of turning the crank angle with the target stop crank angle (θ (0) = 60 CA) as an initial value. The process of assigning the target engine speed Ne (i + 1) to the target trajectory table of FIG. 3 is repeated. When it is determined in step 103 that the square of the target engine speed Ne (i + 1) exceeds the square of the maximum engine speed Nemax at which the engine rotation stop control can be performed, the process proceeds to step 108, and the target The trajectory calculation completion flag is set to “1” which means the completion of the target trajectory calculation, and the process proceeds to step 109 to calculate the square root of the last target engine speed Ne (i + 1) and calculate the target engine speed Ne. (i + 1) is obtained, assigned to the target trajectory table of FIG. 3, and this routine is terminated.

[Engine rotation stop control routine]
The engine rotation stop control routine of FIG. 10 is executed at a predetermined cycle during engine operation, and serves as stop control means in the claims. When this routine is started, it is first determined in step 201 whether or not an engine stop request (idle stop signal) has been generated. If no engine stop request has been generated, the present process is performed without performing the subsequent processing. The routine ends and engine operation (fuel injection control and ignition control) continues.

  Thereafter, when it is determined in step 201 that an engine stop request has been generated, the routine proceeds to step 202, where the current crank angle θ and engine rotational speed Ne are calculated. Thereafter, the process proceeds to step 203, where it is determined whether or not the current crank angle θ is the load torque control timing of the alternator 33 (any one of 0, 30, 60, 90, 120, and 150 CA in the intake ATDC). If the control timing of the load torque of the alternator 33 is not reached, this routine is terminated without performing the subsequent processing.

  If it is determined in step 203 that the current crank angle θ is the control timing of the load torque of the alternator 33, the routine proceeds to step 204, where the current crank angle θ is the maximum engine speed at which engine rotation stop control can be executed. It is determined whether or not it is lower than Nemax. If the current crank angle θ is equal to or greater than the maximum engine speed Nemax, this routine is terminated without performing the subsequent processing.

  On the other hand, if it is determined in step 204 that the current crank angle θ is lower than the maximum engine speed Nemax, the routine proceeds to step 205, where the initial value setting completion flag is set to the initial value i of the target trajectory. It is determined whether or not “0” meaning previous is set. If this initial value setting completion flag is set to “0”, the process proceeds to step 206 to set the initial value i of the target trajectory. At this time, referring to the target trajectory table of FIG. 3, i (the number of calculations up to the target stop crank angle) corresponding to the current crank angle θ and the target engine rotational speed Netg closest to the engine rotational speed Ne is determined as the target trajectory. Is set as the initial value i.

  Thereafter, the process proceeds to step 207, where the initial value setting completion flag is set to “1”, which means that the initial value i has been set. The target engine speed Netg corresponding to i is set to the initial value of the target engine speed in the current engine rotation stop control, and the process proceeds to step 209 in FIG. Here, when the vehicle is an MT vehicle (manual transmission vehicle), it is possible to determine whether the clutch is in an open state, and to select a target track according to the clutch open / engaged state.

  If it is determined in step 205 that the initial value setting completion flag is set to “1”, which means that initial value setting is complete, the processing in steps 206 to 208 is skipped and the processing returns to step 209 in FIG. move on.

  In this step 209, the required load torque Talt is calculated by the following equation using the current engine speed Ne, the target engine speed Netg, and the reference load torque Tref (Ne) of the alternator 33.

Here, J is the moment of inertia of the engine 11, K is the feedback gain, and Δθ is the crank angle change amount (30CA).
Thereafter, the process proceeds to step 210, where the required load torque Talt is multiplied by the pulley ratio Ratio to convert it to the required shaft torque Talt.final of the alternator 33. Then, the process proceeds to step 211, and the battery voltage is detected.

  Thereafter, the process proceeds to step 212, where a required load torque characteristic map corresponding to the current battery voltage is selected from a plurality of required load torque characteristic maps (see FIG. 8) created for each battery voltage, and the current A power generation command (duty duty) corresponding to the required shaft torque Talt.final and the engine rotational speed Ne is calculated. Thereafter, the process proceeds to step 213, the value of the i counter is decremented (i = i−1), the next calculation timing after the change of Δθ (30CA) is set, and this routine is finished.

  An example of the engine rotation stop control of the present embodiment described above is shown in FIG. In this embodiment, a target trajectory corresponding to the reference load torque Tref set to half of the maximum load that can be controlled by the alternator 33 is calculated, and during the engine rotation stop control, the reference load torque Tref corresponding to the engine rotation speed Ne is calculated. And the required load torque Talt is calculated so as to reduce the deviation between the target engine speed and the actual engine speed based on the reference load torque Tref. When the calculated required load torque Talt is smaller than the reference load torque Tref, the load torque is virtually negative, and when the required load torque Talt is larger than the reference load torque Tref, the load torque is positive. In this way, unlike the motor generator, the alternator 33 can virtually control the load torque of the alternator 33 in both the positive and negative directions even when there is a situation where the assist torque cannot be output. The followability of the engine rotation behavior can be improved, and the engine rotation stop crank angle can be accurately controlled within the target crank angle range.

  In this embodiment, the load on the alternator 33 (generator) is controlled during the engine rotation stop control. However, the load on the auxiliary machine other than the alternator 33, for example, the compressor of the air conditioner is controlled. Also good.

  The target trajectory was obtained as the rotational behavior up to the target stop crank angle. As shown in FIG. 14, the engine rotation speed and the crank angle (for example, TDC) as the target stop crank angle are set as initial values. Alternatively, the target trajectory may be obtained from the energy conservation law formula. Here, FIG. 15 shows the relationship between the stop crank angle and the engine rotation speed at the TDC immediately before the stop, and the engine rotation speed that becomes the target stop crank angle can be obtained. This characteristic is obtained from the engine stop behavior based on the engine rotation speed and the stop crank angle at the TDC immediately before the stop. Further, learning also includes setting this characteristic in advance. Thereby, the initial value of the target trajectory can be set, and thereafter, the target trajectory can be obtained in the same manner as in the above embodiment.

It is a schematic block diagram of the whole engine control system in one Example of this invention. It is a figure explaining the calculation method of a target track. It is a figure explaining the table of a target track. It is a figure explaining an alternator load characteristic. It is a figure explaining the alternator load characteristic in appearance at the time of engine rotation stop control. (A) is a time chart for explaining a comparative example in which the engine rotation stop control is performed with the quasi-load torque Tref (Ne (i)) = 0, and (b) is a reference load torque Tref (Ne (i)). It is a time chart explaining the Example which set to half of the maximum load and performed engine rotation stop control. It is a block diagram explaining the engine rotation stop control function of ECU. It is a figure which shows roughly an example of the map of a request | requirement load torque characteristic. It is a flowchart which shows the flow of a process of target trajectory calculation routine. It is a flowchart which shows the flow of a process of an engine rotation stop control routine (the 1). It is a flowchart which shows the flow of a process of an engine rotation stop control routine (the 2). It is a figure which shows roughly an example of the map which calculates loss torque Tloss ((theta) (i)). It is a time chart which shows the behavior of the demand load torque Talt and engine speed Ne at the time of engine rotation stop control execution of the Example of this invention. It is a figure explaining the calculation method of a target orbit from engine speed in the middle. It is a figure explaining the relationship between the engine speed in TDC, and a stop crank angle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine, 13 ... Intake pipe, 14 ... Throttle valve, 19 ... Fuel injection valve, 21 ... Exhaust pipe, 26 ... Crank angle sensor, 29 ... Cam angle sensor, 30 ... ECU (target track calculation means, stop control means) 33 ... Alternator (generator)

Claims (8)

In an engine rotation stop control device for stopping ignition by stopping ignition and / or fuel injection when an engine stop request is generated,
Target trajectory calculating means for calculating rotational behavior (hereinafter referred to as “target trajectory”) until engine rotation stops at the target stop crank angle;
An engine rotation stop control device comprising: stop control means for controlling an auxiliary load of the engine so that the engine rotation behavior is matched with the target trajectory when the engine rotation is stopped. As the target trajectory, the relationship between the crank angle up to the target stop crank angle and the target engine speed is set at predetermined crank angle intervals,
2. The engine according to claim 1, wherein the target trajectory calculating unit calculates the target trajectory in a direction in which the crank angle is increased with the target stop crank angle as an initial value based on an energy conservation law in consideration of loss torque. Rotation stop control device.   The engine rotation stop control device according to claim 2, wherein the loss torque is switched between a low-rotation-side loss torque and a high-rotation-side loss torque at an arbitrary rotation speed. The initial value calculation means obtains an initial value of the crank angle and the engine speed at a certain point in the stop behavior at which the engine stops at the target stop crank angle, and the target trajectory includes a crank angle up to the initial value. And the target engine speed are set at predetermined crank angle intervals,
The target trajectory calculation means calculates the target trajectory in the direction of increasing the crank angle using the crank angle obtained by the initial value calculation means and the engine rotation speed as initial values based on an energy conservation law considering loss torque. The engine rotation stop control device according to claim 1.   The initial value calculating means learns the relationship between the engine rotation speed and the stop crank angle at a predetermined crank angle from the stop behavior of the engine, calculates the engine rotation speed that becomes the target stop crank angle at the predetermined crank angle, and calculates the calculated engine The engine rotation stop control device according to claim 4, wherein a rotation speed and a predetermined crank angle at that time are set as initial values of the target trajectory.   5. The engine rotation stop control device according to claim 2, wherein the target trajectory calculation unit obtains the loss torque by adding at least a pumping loss, a friction loss, and an auxiliary machine load.   The stop control means controls the load of the generator as the auxiliary load, and loads the generator based on a predetermined load (hereinafter referred to as “reference load”) smaller than the maximum load that can be controlled by the generator. The engine rotation stop control device according to any one of claims 1 to 6, wherein the engine rotation stop control is performed.   8. The engine rotation stop control device according to claim 7, wherein the target trajectory calculation means obtains the loss torque by summing at least a pumping loss, a friction loss, and the reference load.

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