JP2016037919A - Control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an engine, capable of effectively preventing torque chock when an electromagnetic clutch existing between the engine and a compressor is off (cut off).SOLUTION: An air-conditioning compressor 20 is driven via an electromagnetic clutch 30 by an engine E. A rotating speed of the compressor 20 is detected by a rotating speed sensor 33. A response delay time from when an off-command signal is output to make the electromagnetic clutch 30 off (cut off) to when the electromagnetic clutch 30 is actually cut off is estimated to be longer as the rotating speed of the compressor 20 detected by the rotating speed sensor 33 is higher. When the output of the off-command signal is followed by the passage of the estimated response delay time, an ignition timing is retarded to prevent torque shock associated with the electromagnetic clutch 30 being off. The response delay time can also be estimated in consideration of a refrigerant pressure (it is estimated to be longer as the refrigerant pressure is higher).SELECTED DRAWING: Figure 8

Description

  The present invention relates to an engine control apparatus.

  The vehicle air conditioner has an evaporator as a heat exchanger to cool the conditioned air. A compressor is used to compress the refrigerant flowing through the evaporator, and the compressor is generally driven by an engine. In order to stop the compressor appropriately according to the temperature adjustment of the evaporator and the air conditioning requirement, an electromagnetic clutch (sometimes called a magnet clutch) is also interposed in the drive transmission path between the engine and the compressor. ing.

  The compressor is a heavy load on the engine. For this reason, Patent Document 1 discloses that when a large engine load is required, the compressor is stopped to substantially increase the engine torque for traveling.

Japanese Patent Laid-Open No. 11-245656

  As described above, since the compressor is a heavy load on the engine, when the electromagnetic clutch is turned off (disconnected) to stop the compressor, a torque shock that temporarily increases the engine torque as the compressor load is released. Will occur. In particular, in order to control the temperature of the evaporator to be within a predetermined temperature range, the electromagnetic clutch is frequently turned off (disconnected) and turned on (connected) in many cases. It will be a thing.

  The present invention has been made in view of the above circumstances, and its purpose is to effectively prevent a torque shock when the electromagnetic clutch interposed between the engine and the compressor is turned off. It is to provide an engine control device.

In order to achieve the above object, the following solution is adopted in the present invention. That is, as described in claim 1,
An air conditioning compressor is an engine control device driven by an engine via an electromagnetic clutch,
A rotational speed detection means for detecting the rotational speed of the compressor;
Response delay time for estimating the response delay time from the output of the off command signal for disconnecting the electromagnetic clutch to the actual disconnection of the electromagnetic clutch as a longer time as the rotational speed of the compressor detected by the rotational speed detection means becomes higher An estimation means;
Torque adjusting means for suppressing torque fluctuation by retarding the ignition timing at the time when the response delay time estimated by the response delay time estimating means has elapsed from the time when the off command signal is output;
It is supposed to be equipped with. According to the above solution, a torque shock can be prevented by suppressing a temporary increase in engine torque when the electromagnetic clutch is turned off by retarding the ignition timing. In particular, the response delay time from the output of the OFF command signal to the electromagnetic clutch until the electromagnetic clutch is actually turned off changes according to the compressor rotation speed, and at an appropriate timing when this response delay time has elapsed. Since the ignition timing is retarded, torque shock can be effectively prevented.

A preferred mode based on the above solution is as described in claim 2 and the following claims. That is,
Pressure detecting means for detecting the pressure of the refrigerant compressed by the compressor;
The estimation of the response delay time by the response delay time estimation means is estimated to be longer as the refrigerant pressure detected by the refrigerant pressure detection means is higher.
(Corresponding to claim 2). In this case, the response delay time changes in accordance with the refrigerant pressure, which is preferable in preventing torque shock more sufficiently.

  Prior to the output of the off command signal, a pre-preparation control is performed in which the ignition timing is gradually advanced while gradually reducing the filling amount in advance, and the off command signal is output after the control of the preliminary completion. (Corresponding to claim 3). In this case, the ignition timing is advanced in advance in anticipation of the retard of the subsequent ignition timing, and pre-preparation control is performed to suppress the increase in engine torque accompanying this advance by reducing the charging amount. In addition, the ignition timing can be retarded for preventing torque shock without retarding the ignition timing from the reference value, which is preferable in preventing deterioration of fuel consumption.

A panic brake detecting means for detecting that the panic brake is in progress;
When it is detected by the panic brake detection means that the panic brake is being performed, the preparation control is prohibited and the off command signal is output immediately (corresponding to claim 4). In this case, the problem of engine stall is likely to occur during a panic brake. In this case, an off command signal for the electromagnetic clutch is output immediately without performing preparatory control, which is preferable for preventing engine stall.

  According to the present invention, it is possible to prevent a torque shock associated with turning off the electromagnetic clutch.

The system diagram which shows the engine coolant passage and the refrigerant passage in relation to the air conditioner. The figure which shows the example of a control system of this invention in a block diagram. The characteristic view which shows the relationship between compressor rotation speed and response delay time. The characteristic view which shows the relationship between a refrigerant | coolant pressure and response delay time. The time chart which shows the 1st example of control of this invention. The flowchart for performing control of FIG. The time chart which shows the 2nd example of control of this invention. The flowchart for performing control of FIG.

  FIG. 1 is a system diagram showing the cooling water passage and the refrigerant passage of the engine E in relation to the air conditioner K. First, the air conditioner K will be briefly described. Reference numeral 1 denotes an air conditioning passage. In the air conditioning passage 1, a blower 2, an air filter 3, an evaporator 4, and a heater core 5 are arranged in this order from the upstream side to the downstream side. A switching damper 6 is disposed on the upstream side of the blower 1, and an inside air circulation passage 9 extending from the vehicle interior is opened. The switching damper 6 switches between outside air introduction and inside air introduction into the air conditioning passage 1.

  An air mix damper 7 is disposed in the air conditioning passage 1 on the downstream side of the evaporator 3 and on the upstream side of the heater core 4. The air mix damper 7 changes the ratio of passing through the heater core 4 and the ratio of bypassing the heater core 4 in the conditioned air after passing through the evaporator 3, thereby adjusting the temperature of the conditioned air blown into the vehicle interior. Is called. The air conditioning passage 1 is connected to an air outlet 8 connected to the passenger compartment on the downstream side of the heater core 4 and the air mix damper 7. In FIG. 1, only one outlet 8 is shown for the sake of simplicity, but actually, a plurality of outlets 8 are provided for the feet, the face, the defroster, and the like. Since the above air conditioner K itself is known, further explanation is omitted.

  Next, a refrigerant circulation path for the evaporator 4 will be described. First, a belt 23 is wound between a pulley 21 attached to the rotation shaft of the compressor 20 and a pulley 22 attached to the engine E (crankshaft thereof), and the compressor 20 is mechanically driven to rotate by the engine E. The The refrigerant compressed by the compressor 20 is supplied to the evaporator 4 through the pipe 24. A condenser 25, a dryer (dryer) 26, a refrigerant pressure sensor 27, and an expansion valve 28 are connected to the pipe 24 sequentially from the compressor 20 side to the evaporator 4 side. The refrigerant that has passed through the evaporator 4 is returned to the compressor 20 via the pipe 29. The evaporator 4 is provided with a temperature sensor 32 for detecting the temperature.

  The high-temperature and high-pressure liquefied refrigerant compressed by the compressor 20 is cooled by the condenser 25 and then dried by the dryer 26. Thereafter, the refrigerant is vaporized and atomized by the expansion valve 28, and the evaporator 4 is in a low-temperature and low-pressure state. To be introduced. The refrigerant whose temperature has been raised by cooling the conditioned air by the evaporator 4 returns to the compressor 20 via the pipe 29, and the above-described operation is repeated.

  In the compressor 20, a pulley 21 attached to a rotary shaft thereof includes an electromagnetic clutch (magnet clutch) 30. The electromagnetic clutch 30 is turned off (disconnected) during demagnetization, and cuts power transmission between the engine E and the compressor 20. The electromagnetic clutch 30 is turned on (connected) by exciting it, and the compressor 20 is driven by the engine E. In order to switch between demagnetization and excitation of the electromagnetic clutch 30, a relay switch 31 is connected to the power supply path, and this relay switch 31 is controlled by a controller PCM described later.

  Next, the circulation path of the cooling water for the heater core 5 will be described. First, the engine E is provided with an inlet 41 and an outlet 42 for cooling water that are spaced apart in the crankshaft direction. An annular circulation passage 43 that connects the inlet 41 and the outlet 42 is provided for cooling the engine. In the circulation passage 43, a water pump 44 that is mechanically driven by the engine E is provided in the vicinity of the inlet 41. By driving the water pump 44, the cooling water sequentially flows to the inlet 41 again through the inlet 41, the inside of the engine (cooling water passage), the outlet 42, and the circulation passage 43. .

  A radiator 45 is connected to the circulation passage 43. That is, the inflow side passage 46 and the outflow side passage 47 for the radiator 45 are connected to the circulation passage 43 near the outflow port 42. A thermostat valve 48 is connected to the outflow side passage 47 in the vicinity of the circulation passage 43. The thermostat valve 48 is normally closed and is opened when the temperature of the cooling water near the outlet 42 becomes a high temperature equal to or higher than a predetermined temperature. When the thermostat valve 48 is opened, (a part of) the cooling water flows through the radiator 45 and is cooled. The radiator 45 is cooled together with the condenser 25 by a cooling fan cooling fan 49 (heat exchange with outside air). In FIG. 1, reference numeral 50 denotes a water temperature sensor that detects the cooling water temperature.

  A part of the high-temperature cooling water flowing through the circulation passage 43 is introduced into the heater core 5 through the supply passage 51. Then, the cooling water that has passed through the heater core 5 is returned to the circulation passage 43 via the return passage 52. An electric pump 53 that is driven on the premise of idling stop is connected to the supply passage 51. The electric pump 53 allows the flow of cooling water even when stopped. During heating, the electric pump 53 is driven when the engine E is automatically stopped by an idle stop. In other words, the cooling water flows through the heater core 5 even during idle stop, and the low temperature of the heater core 5 is prevented from being promoted, so that a long heating time can be ensured during idle stop.

  Here, driving the compressor 20 is a heavy load on the engine E. Therefore, when the electromagnetic clutch 30 is turned off (disconnected) to stop the driving of the compressor 20 from the state where the compressor 20 is being driven, a torque shock that temporarily increases the engine torque is likely to occur. . Hereinafter, a control example of the present invention for preventing this torque shock will be described with reference to FIG.

  FIG. 2 is a block diagram showing an example of the control system of the present invention. In FIG. 2, an air conditioner off request signal from the air conditioning controller UK is input to the PCM (also see FIG. 1) serving as an engine side controller that controls the relay switch 31 shown in FIG. 1. Yes. That is, the air conditioning controller UK outputs an air conditioner off signal to the PCM when the temperature of the evaporator 4 becomes a predetermined temperature (for example, 2 to 3 ° C.) or less, or when cooling or dehumidification is not required. Accordingly, the PCM turns off the electromagnetic clutch 30 (turns off the relay switch 31).

  In order to prevent torque shock when the electromagnetic clutch 30 is turned off, a signal from the rotation speed sensor 33 (see also FIG. 1) is input to the PCM in addition to the signal from the refrigerant pressure sensor 27. The rotation speed sensor 33 detects the rotation speed of the compressor 20. Since the rotational speed of the engine E and the rotational speed of the compressor 20 are in a fixed proportional relationship, in the embodiment, an engine rotational speed sensor is used as the rotational speed sensor 33. Alternatively, a dedicated rotational speed sensor may be provided.

  In order to prevent torque shock, which will be described later, the PCM controls the relay switch 31 (electromagnetic clutch 30), controls the ignition plug 60 (ignition timing thereof), and throttle valve 61 (filling amount, that is, intake air amount). ) Control.

  Here, the compressor 20 has a response delay time from the output of the off signal to the electromagnetic clutch 30 (relay switch 31) until it is actually turned off (until the driving load is reduced). This response delay time mainly depends on the compressor rotation speed, and secondarily also on the refrigerant pressure. That is, the response delay time corresponding to the rotation speed of the compressor 20 (electromagnetic clutch 30) is caused by the inertial force of the rotating system. In addition, the electromagnetic clutch 30 transmits a driving force by a torsional force, but when the refrigerant pressure increases, the torsional force increases and a response delay occurs until it is actually cut.

  FIG. 3 shows the relationship between the rotational speed of the compressor and the response delay time. The higher the rotational speed of the compressor 30, the longer (longer) the response delay time. FIG. 4 shows the relationship between the refrigerant pressure and the response delay time. The higher the refrigerant pressure, the longer (longer) the response delay time. Note that the characteristics shown in FIGS. 3 and 4 are obtained in advance by experiments.

  When the response delay time is finally determined based on the characteristics shown in FIGS. 3 and 4, the sum of both response delay times may be used, or a predetermined weight (based on the compressor speed) You may make it use the addition value after performing the weighting which the reflection degree of a response delay time becomes large. In addition, the characteristics shown in FIG. 3 can be set for each refrigerant pressure, and the response delay time can be determined according to the compressor speed selected according to the refrigerant pressure.

  In this embodiment, the response delay time is determined based on the characteristic diagrams shown in FIGS. 3 and 4, and the ignition is performed when the determined response delay time elapses from the OFF signal output time to the electromagnetic clutch 30. The timing is delayed. That is, since the ignition timing can be changed very quickly, a temporary increase in engine torque accompanying the turning off of the electromagnetic clutch 30 is prevented (or reduced) by retarding the ignition timing. It is.

  FIG. 5 is a time chart showing a first control example of the present invention. In FIG. 5, at time t1, there is a request for turning off the air conditioner from the air conditioning controller UK to the PCM. At this time t1, the PCM outputs an off signal for the electromagnetic clutch 30 (output of a signal for turning off the relay switch 31). After the time t1, the compressor 30 is actually turned off at the time t2 when the response delay time determined based on the characteristics shown in FIGS. 3 and 4 has elapsed, and the ignition timing is set to the reference value ( It is retarded from the base value (indicated by a1 in FIG. 5) (decrease in engine generated torque). Due to the retarded ignition timing, a temporary increase in engine torque due to the stop of the compressor 20 is prevented, and torque shock is prevented. Of course, the retard amount of the ignition timing corresponds to the load reduction due to the stop of the compressor 20 drive.

  After the time t2, the ignition timing is gradually advanced, and the charging amount is gradually reduced to suppress the increase in engine torque accompanying the advance of the ignition timing. At the time t3, the ignition timing becomes a reference value (the engine generated torque is different from the time t1, so it is different from the reference value a1 at the time t1), and the filling amount also corresponds to this. Note that the fuel injection amount is also changed in accordance with the change in the filling amount.

  FIG. 6 is a flowchart for performing control as shown in FIG. Hereinafter, FIG. 6 will be described. In the following description, Q represents a step. First, at Q1, it is determined whether or not there is an air conditioner off request from the air conditioning controller UK. When the determination of Q1 is NO, the determination of Q1 is repeated. If YES in Q1, the signal for turning off the electromagnetic clutch 30 is output in Q2 (corresponding to time t1 in FIG. 5). Thereafter, in Q3, the response delay time is determined based on the compressor speed and the refrigerant pressure as described above.

  After Q3, at Q4, it is determined whether or not the response delay time determined at Q3 has elapsed since the output time point of the OFF command signal at Q2. If the Q4 determination is NO, the determination of Q4 is repeated. If YES in Q4, the ignition timing is retarded by a predetermined amount in Q5 (corresponding to time t2 in FIG. 5). Note that the retard amount of the ignition timing is determined such that, for example, the driving torque of the compressor 20 is determined in advance based on the compressor speed and the refrigerant pressure, and the generated torque of the engine E decreases by the determined driving torque. Is set.

  After Q5, at Q6, the throttle valve 61 is gradually closed to reduce the filling amount, and the ignition timing is gradually advanced. Thereafter, in Q7, it is determined whether or not the ignition timing has been advanced to the reference value. When the determination of Q7 is NO, the determination of Q7 is repeated. When the determination in Q7 is YES, it is the state at time t3 in FIG. 5, and thus the torque shock prevention control is terminated.

  FIG. 7 is a time chart showing a second control example of the present invention for preventing torque shock, and corresponds to FIG. In this control example, at the time point t11, the air conditioner off request is made. After the time t11, the filling amount is gradually decreased to match the later ignition timing retardation, while the ignition timing is gradually advanced from the reference value a1. At time t12, an off signal of the electromagnetic clutch 30 is output, further advancement of the ignition timing is stopped, and further reduction of the filling amount is stopped (ignition timing at time t12 is maintained). And the filling amount is maintained). The difference between the ignition timing at the time point t12 and the ignition timing at the time point t11 is equivalent to the torque necessary for driving the compressor 20.

  Thereafter, the ignition timing is retarded at time t13, which is the time when the response delay time has elapsed from time t12 (decreased torque generated by engine E), thereby preventing a torque shock accompanying the stop of driving of compressor 20. In the control example of FIG. 7 as described above, since it is not necessary to retard the ignition timing from the reference value a1, it is preferable for improving fuel efficiency as compared with the control example of FIG.

  FIG. 8 is a flowchart for performing the control of FIG. 7, and FIG. 8 will be described below. First, in Q11, it is determined whether or not there is an air conditioner off request from the air conditioning controller UK. When the determination of Q11 is NO, the determination of Q11 is repeated. If YES in Q11, it is determined in Q12 whether or not it is a panic brake. That is, for example, when the ABS control device is activated, when the engine speed decreases rapidly (when the rate of change of the engine speed in the decreasing direction is greater than or equal to a predetermined value), when the vehicle speed decreases rapidly (of the vehicle speed) When the rate of change in the decreasing direction is greater than or equal to a predetermined value), and in an automatic transmission with a lockup clutch, when the brake pressure is greater than the predetermined value when the lockup clutch is on (connected), When any one of the conditions is satisfied, it is determined that the panic brake is being performed.

  When the determination in Q12 is NO, the control as shown in FIG. 7 is executed by the processing of Q13 to Q18. That is, at Q13, the throttle valve 61 is gradually driven in the valve closing direction, and the ignition timing is gradually advanced (corresponding to control from time t11 to time t12 in FIG. 7). Thereafter, at Q14, it is determined whether or not the ignition timing has been advanced to the target ignition timing. If the determination in Q14 is NO, the process returns to Q13.

  If YES in Q14, a signal for turning off the electromagnetic clutch 30 is output in Q15. Thereafter, in Q16, the response delay time is determined. Thereafter, in Q17, it is determined whether or not the response delay time set in Q15 has elapsed from the time when the electromagnetic clutch 30 is turned off in Q15. When the determination at Q17 is NO, the determination at Q17 is repeated. If YES in Q17, the ignition timing is retarded by a predetermined amount in Q18 (torque shock prevention).

  If the determination in Q12 is YES, the engine speed is rapidly decreased due to the panic brake, and the engine stall is likely to occur when the compressor 20 that is a heavy load is being driven. At this time, in Q19, a command signal for immediately turning off the electromagnetic clutch 30 is output. Thereafter, the response delay time is determined in Q20. After Q20, at Q21, it is determined whether or not a response delay time has elapsed since the output of the OFF command signal at Q19. When the determination of Q21 is NO, the determination of Q21 is repeated. If YES in Q21, the ignition timing is retarded by a predetermined amount in Q22. The processes Q19 to Q22 correspond to the processes Q2 to Q5 in FIG.

  Although the embodiments have been described above, the present invention is not limited to the embodiments, and appropriate modifications can be made within the scope of the claims. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable for preventing a torque shock in a case where an air conditioning compressor is driven by an engine via an electromagnetic clutch.

PCM: Controller (for torque shock prevention)
UK: Controller (for air conditioner)
E: Engine K: Air conditioning system 4: Evaporator 27: Pressure sensor (refrigerant pressure)
20: Compressor 30: Electromagnetic clutch 31: Relay switch 33: Speed sensor (compressor)
60: Spark plug (ignition timing adjustment)
61: Throttle valve (filling amount adjustment)

Claims (4)

An air conditioning compressor is an engine control device driven by an engine via an electromagnetic clutch,
A rotational speed detection means for detecting the rotational speed of the compressor;
Response delay time for estimating the response delay time from the output of the off command signal for disconnecting the electromagnetic clutch to the actual disconnection of the electromagnetic clutch as a longer time as the rotational speed of the compressor detected by the rotational speed detection means becomes higher An estimation means;
Torque adjusting means for suppressing torque fluctuation by retarding the ignition timing at the time when the response delay time estimated by the response delay time estimating means has elapsed from the time when the off command signal is output;
An engine control device comprising: In claim 1,
Pressure detecting means for detecting the pressure of the refrigerant compressed by the compressor;
The estimation of the response delay time by the response delay time estimation means is estimated to be longer as the refrigerant pressure detected by the refrigerant pressure detection means is higher.
An engine control device. In claim 1 or claim 2,
Prior to the output of the off command signal, a pre-preparation control is performed in which the ignition timing is gradually advanced while gradually reducing the filling amount in advance, and the off command signal is output after the control of the preliminary completion. An engine control device. In claim 3,
A panic brake detecting means for detecting that the panic brake is in progress;
The engine control device according to claim 1, wherein when the panic brake detecting means detects that the panic brake is being performed, the preparation control is prohibited and the off command signal is immediately output.

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