JP5783710B2 - Control device for idle stop car - Google Patents

Description

  The present invention relates to a control device for an idle stop vehicle that performs idle stop control when idle stop control is permitted based on the estimated gradient of the travel path. It relates to idle stop control in consideration.

  Conventionally, when the engine is started by an IG (ignition) on operation, the idle stop vehicle executes an idle stop control until the engine is stopped by an IG off operation, and the engine is stopped when a predetermined stop condition is satisfied. It stops automatically and repeats restarting the engine automatically when a predetermined restart condition is satisfied.

  By the way, if the traveling path is an ascending (or descending) gradient greater than a certain gradient, idle stop control is prohibited in order to avoid the occurrence of vehicle slippage when restarting the automatically stopped engine. Even if the stop condition is satisfied, the engine is not automatically stopped (see, for example, Patent Document 1 (paragraphs [0009], [0028], [0033], FIG. 1 to FIG. 5)).

  Note that the gradient of the traveling road includes an acceleration / deceleration component based on the gradient and an acceleration / deceleration component based on a change in the vehicle speed because the acceleration / deceleration detected by an acceleration sensor (hereinafter referred to as G sensor) includes the acceleration / deceleration component based on the change in vehicle speed. Based on the detected acceleration / deceleration and the calculated acceleration / deceleration calculated according to the following equation (1) based on the vehicle speed detected by the wheel speed sensor, it is estimated. Note that 1000 in the equation (1) is a coefficient for matching the vehicle speed unit and the cycle unit.

  Also, in order to further improve fuel efficiency, in recent idle stop vehicles, the engine is automatically activated if the vehicle is decelerated to a predetermined vehicle speed (for example, 7 km / h) or less by idle stop control even if the running is not completely stopped. It is being stopped.

JP-A-2005-207327

  In the case of an idle stop vehicle that automatically stops the engine during deceleration as described above, in particular, unless the idle stop control is appropriately enabled / disabled with respect to the gradient of the traveling path, It stops automatically and gives anxiety to the driver (user).

  And on roads where the running gradient changes frequently, such as rough roads with many undulations, the estimation of the gradient tends to be unstable, the accuracy of the estimation of the gradient decreases, and the idle stop control based on the estimated gradient There is a possibility that a permission / non-permission error may occur. In some cases, the engine may be automatically stopped by idling stop control while the vehicle is decelerating on a slope of a certain slope or higher.

To avoid such a problem, an electric hydraulic pump to the brake mechanism, when automatically stopping the engine during deceleration by idle stop control, the electric hydraulic pump thus generates a sufficient brake pressure estimate gradients not Although it is conceivable to prevent the vehicle from sliding down on a road with a large gradient change that becomes stable, in this case, an expensive electric hydraulic pump is required, which increases the cost of the idle stop vehicle. .

  It is an object of the present invention to prohibit idle stop control on a traveling road with a large gradient change in which the estimation of the gradient becomes unstable with a low-cost configuration that does not use an electric hydraulic pump or the like.

In order to achieve the above-described object, the control device for an idle stop vehicle according to the present invention includes an estimation unit that estimates a gradient of a traveling path based on a detected acceleration / deceleration of a gradient detection unit and a calculated acceleration / deceleration calculated from the vehicle speed. A control means for controlling automatic stop of the engine when a predetermined stop condition is satisfied when idle stop control is permitted based on the estimated gradient estimated by the estimation means for each predetermined period. In the control device, an absolute value of the difference between the estimated gradients for each predetermined period is accumulated for a preset time, and a calculating unit that calculates and calculates a change amount of the estimated gradient, and the recording unit accounts compared variation with a preset threshold, when the change amount is greater than the threshold value, the traveling path is estimated unstable der gradient a severe rough road undulations , And a and determination means estimates the gradient is stable when small, the threshold value, the estimated gradient is set to be smaller as larger than the set gradient, the control means, by said determining means When the estimation of the gradient is unstable and it is determined that the vehicle is traveling on a rough road, the idle stop control is prohibited even when the idle stop control is permitted from the magnitude of the estimated gradient. (Claim 1).

According to the first aspect of the present invention, the change amount of the gradient estimated by the estimation means is calculated and counted by the counting means, and depending on whether the change amount of the gradient calculated by the counting means is larger or smaller than the threshold value. , the estimated gradient is determined whether unstable or stable by determining means, the amount of change in the gradient that was reported is greater than the threshold value, it is determined that the determination means is unstable estimates of gradient, the control means Idle stop control is prohibited. For this reason, idle stop control is prohibited on gradient roads (such as bad roads) where the gradient estimation becomes unstable. It is possible to prevent the automatic stop. In addition, an electric hydraulic pump or the like is unnecessary, and the cost can be reduced. In addition, since the threshold value for comparing the amount of change in the estimated gradient obtained by integrating the absolute value of the gradient difference by the estimation unit for the set time is set to be smaller as the gradient by the estimation unit becomes larger than the set gradient, Even if the integrated value of the absolute values of the gradient differences is not so large, the idle stop control is prohibited, and the occurrence of a situation in which the engine is automatically stopped by the idle stop control during deceleration can be further reliably prevented.

It is a block diagram of one embodiment of a vehicle control device of the present invention applied to an idle stop vehicle. FIG. 2 is a waveform diagram for explaining the operation of FIG. 1, where (a) shows an example of a change in the gradient of a traveling road with a large change in gradient, a vehicle speed, a recorded value of the amount of change in gradient, and an example of prohibition of idle stop control; An example of a change in the gradient of a traveling road with little change, a vehicle speed, a recorded value of the amount of change in gradient, and an example of prohibiting idle stop control are shown. It is explanatory drawing of the example of a change according to the gradient of the threshold value used for the prohibition determination of idle stop control.

  Next, in order to describe the present invention in more detail, an embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG.

  FIG. 1 shows a block configuration of a vehicle control device provided in an idle stop vehicle 1. The idle stop vehicle 1 is a single lead battery having a relatively small capacity of 12V as a power source in order to reduce weight, size, and the like. 2 is provided. The lead battery 2 is an in-vehicle battery according to the present invention, and the negative terminal is connected to the casing of the idle stop vehicle 1.

  In FIG. 1, 3 is an engine of the idle stop vehicle 1, 4 is a CVT on the transmission side of the engine 3, and a torque converter (including a lock-up clutch mechanism) 5 is interposed between the engine 3 and the engine 3.

  Reference numeral 6 denotes a starter for starting the engine 3, and power is supplied from the lead battery 2 through the relay 7. A battery sensor 8 is provided close to the lead battery 2 between the positive terminal of the lead battery 2 and the relay 7, and detects the temperature and current of the lead battery 2. Reference numeral 9 denotes an alternator to which the rotational force of the engine 3 is transmitted via the belt 10 and charges the lead battery 2 with a power generation output during traveling.

  11 is an idle stop control unit formed by an idle stop control ECU, 12 is an engine control unit formed by an engine control ECU, 13 is an ABS control unit formed by an ABS (antilocked breaking system) control ECU, and 14 is CVT control. The control units 11 to 14 are each formed by a microcomputer or the like, and exchange information via a communication bus 15 such as a CAN.

  Reference numeral 16 denotes a display unit formed by a dashboard combination meter, which receives various display data from the communication bus 15.

  Reference numeral 17 denotes a G sensor of the idle stop vehicle 1 connected to the idle stop control unit 11 and forms the gradient detection means of the present invention. Reference numeral 18 denotes a wheel speed sensor that gives vehicle speed detection information to the ABS control unit 13, and 19 denotes a hydraulic pressure sensor that gives the ABS control unit 13 detection information of the master cylinder pressure of the brake mechanism.

  The general control and operation of the idle stop vehicle 1 will be described. When the driver turns on an IG key (not shown) to instruct the engine start, an IG on signal is sent from the communication bus 15 to the idle stop, for example. Based on this input, the idle stop control unit 11 is turned on by instantaneously energizing the relay 7, the power of the lead battery 2 is supplied to the starter 6, and the starter 6 is started and stopped. The engine 3 is started (first start). Once the engine 3 is started and the lead battery 2 is once fully charged with the power generated by the alternator 9, the idle stop control unit 11 is then idle stopped until the engine 3 is stopped by turning off the IG key. Execute control.

  The idle stop control unit 11 includes information on the engine control unit 12 (engine information such as engine speed and cooling water temperature), information on the current and temperature of the lead battery 2, and the ABS control unit via the communication bus 15. 13 information such as detected vehicle speed and master cylinder pressure, lock-up clutch information of the CVT control unit 14, detection information of the G sensor 17, information on switches in various parts of the vehicle such as a stop lamp switch and a courtesy switch not shown. The

  Based on this information, the idle stop control unit 11 during the idle stop control confirms that the driver depresses the brake pedal according to the red signal of the traffic signal and the like, and that the master cylinder pressure is equal to or higher than the predetermined depressing pressure. When detected, by confirming the establishment of a predetermined stop condition for idle stop control (for example, a condition that the stop lamp is lit and the vehicle speed is equal to or lower than the predetermined vehicle speed), the vehicle travels below the predetermined vehicle speed even if the travel is not completely stopped. If it decreases, the engine control unit 12 is instructed to stop the engine, and the engine control unit 12 automatically stops the engine 3 by reducing the fuel throttle.

  Next, when the driver removes his foot from the brake pedal, for example, the traffic signal changes to a green light, and detects that the master cylinder pressure has decreased to a predetermined release pressure, the idle stop vehicle 1 performs a predetermined restart of the idle stop control. By confirming that the condition (for example, the condition that the stop lamp is turned off and the door is closed) is satisfied, the idle stop control unit 11 is turned on by instantaneously energizing the relay 7, and the power source of the lead battery 2 is started. Power is supplied to 6 to start the starter 6 and the stopped engine 3 is automatically restarted.

  Thereafter, automatic stop of the engine 3 based on establishment of a predetermined stop condition during deceleration and automatic restart of the engine 3 based on establishment of a predetermined restart condition are alternately performed.

  By the way, when the engine is automatically stopped during deceleration by the idle stop control, as described above, unless the idle stop control is appropriately permitted / not permitted with respect to the gradient of the traveling path, the idle stop control is originally performed. The engine automatically stops while decelerating at a certain slope or higher, which not only gives the driver (user) anxiety, but also may cause the vehicle to actually slide down.

Therefore, the idle stop control unit 11 determines whether or not the idle stop control is permitted based on the gradient (absolute value) of the travel path, and performs automatic stop and restart of the engine 3 by the idle stop control while the idle stop control is permitted. Meanwhile the Hare name traveling road is greater than the set value the gradient of, running the idle stop control, when the slip-down of the vehicle along with the disappearance of the creep force when the restart of the engine 3 is likely to occur, the idle stop The control is prohibited so that the engine 3 is not automatically stopped.

  The gradient of the traveling road includes an acceleration / deceleration component based on the gradient and an acceleration / deceleration component based on a change in the vehicle speed because the detected acceleration / deceleration (hereinafter referred to as G sensor value) of the G sensor 17 includes the G sensor value, It can be estimated by obtaining the difference from the acceleration / deceleration value based on the time change (vehicle speed change) of the vehicle speed detected by the wheel speed sensor 18.

  Also, if you are traveling on a sloping road where the running gradient changes frequently, such as a rough road with severe undulations, if the estimation of the gradient becomes unstable, the idle stop control based on the estimated gradient is permitted / not permitted. There is a possibility that a permission error occurs, and there is a possibility that the engine is automatically stopped by the idle stop control by mistake during the deceleration.

  Therefore, the idle stop control unit 11 includes the estimation means, counting means, determination means, and control means of the present invention. These means are formed by the microcomputer executing each preset program.

  Based on the calculation of the equation (1), the estimation means determines whether the vehicle speed detected by the wheel speed sensor 18 from the ABS control unit 13 via the communication bus 15 from the difference for every minute set cycle of about several ms, for example. The momentary acceleration / deceleration of the stop vehicle 1 is calculated as a calculated acceleration / deceleration. Further, based on the G sensor value of the G sensor 17 and the calculated acceleration / deceleration, the slope of the travel path of the idle stop vehicle 1 is calculated and estimated from the following equation (2).

  The counting means is means for repeatedly measuring and counting the amount of change in the slope estimated by the estimating means at the set time. Any method may be used to record the estimated change amount of the gradient, but in the case of the present embodiment, the absolute value of the gradient difference estimated by the estimation unit every minute period (for example, several tens of milliseconds) is set. It is to repeatedly accumulate the time (for example, about 1 s or 2 s) and to calculate the integrated value of each set time as the amount of change in the slope estimated by the estimation means. In this case, the integrated value of each set time increases or decreases as the estimated gradient changes, and the integrated value of each set time increases and decreases with the period of the set time, and the integrated value (accounted value) of each set time increases as the change amount increases. .

  The determination means compares the integrated value of the set time of the counting means with a threshold value α of the set determination, and determines that the slope estimation is unstable while the integrated value is greater than the threshold value α. The idle stop control prohibition flag is set, and while the integrated value is equal to or less than the threshold value α, it is determined that the estimation of the gradient is stable and the idle stop control permission flag is set. The instability of the slope estimation is determined based on the integrated value of the change amount of the slope recorded by the counting means.

  The control means basically determines whether or not the idle stop control is permitted depending on whether or not the gradient (absolute value) of the travel path estimated by the estimation means is less than or equal to a threshold value for permission / denial. If the estimation means determines that the estimation is unstable, even if the gradient of the travel path estimated by the estimation means is less than or equal to the threshold value for permission / non-permission of idle stop control, The idle stop control is prohibited by giving priority to the determination of the means.

  FIG. 2 (a) shows an example of a slope change (solid line a1) on a slope (running path) with a large change in slope, a vehicle speed (broken line b1), an integrated value of absolute values of the slope change (solid line a1) (broken line c1), and idle stop control. An example of prohibition determination (solid line d1) is shown.

  FIG. 2B shows an absolute value of a slope change (solid line a2), which is an example of a recorded value of a slope change example (solid line a2), a vehicle speed (broken line b2), and a slope change amount with a small slope change (travel line). An integrated value (broken line c2) and an idle stop control prohibition determination example (solid line d2) are shown.

Then, the gradient of the travel path changes depending on the undulation state of the travel path. For example, if the travel path is a rough road with severe undulations, the estimated gradient as shown by the solid line a1 in FIG. The integrated value becomes larger than the threshold value α between time t1 and time t2 when the change is particularly large, and the vehicle is decelerating even when idle stop control is permitted due to the magnitude of the gradient. Is stopped (solid line d1). On the other hand, the less undulating uphill traveling, for example, Figure 2 changes in the gradient is estimated as shown by the solid line a2 in (b) is small, decelerating the integrated value is maintained below the threshold α Is not prohibited (solid line d2).

  Therefore, in the case of the present embodiment, during traveling on a rough road or the like where the estimation accuracy of the gradient is lowered, even if the idle stop control is permitted from the magnitude of the gradient, the idle stop control is prohibited. The engine 3 is not automatically stopped by idling stop control during deceleration by mistake on a predetermined or higher slope. In this case, an electric hydraulic pump or the like is unnecessary, and the cost of the idle stop vehicle 1 is not increased, which contributes to cost reduction.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. α may be a constant value or may be changed according to the estimated gradient magnitude.

  FIG. 3 shows an example in which the threshold value α changes in accordance with the estimated gradient (gradient). In this example, the threshold value is determined if the estimated gradient is a gentle range equal to or less than the set gradient θr. The value α is a large predetermined value α1, and the idle stop control is not prohibited unless the integrated value becomes considerably large. However, when the estimated gradient becomes larger than the set gradient θr and the gradient becomes steep, the threshold α is Even when the integrated value is not so large, the idling stop control is prohibited even when the integrated value is not so large, and the occurrence of a situation in which the engine 3 is automatically stopped by the idling stop control during deceleration is more reliably generated. Is prevented.

  Next, as another method for recording the estimated change in the slope, for example, an increase counter and a decrease counter are prepared, and the number of times the slope changes is counted by the increase counter at each set time. A method of counting and counting the number of times of decrease and change with a decrease counter may be used. In this case, if the difference between the count values of the two counters is equal to or smaller than a predetermined value, it is determined that the gradient estimation is unstable because the vehicle is traveling on a rough road, and the idle stop control may be prohibited.

  Next, in the embodiment, the magnitude of the threshold value α may be appropriately set based on experiments or the like.

  The present invention can be applied to vehicle control devices for various idle stop vehicles having at least an engine such as the engine 3 as a drive source.

1 Idle stop car 3 Engine 11 Idle stop control unit

Claims (1)

Estimating means for estimating the gradient of the travel path based on the detected acceleration / deceleration of the gradient detecting means and the calculated acceleration / deceleration calculated from the vehicle speed, and idle stop control based on the estimated gradient estimated by the estimating means for each predetermined period. A control device for an idle stop vehicle, comprising control means for controlling automatic stop of the engine by establishment of a predetermined stop condition when permitted,
An accounting means for calculating and accounting the amount of change in the estimated gradient by integrating the absolute value of the difference in the estimated gradient for each predetermined period with a preset set time;
Comparing the recorded unit is set in advance and the amount of change recorded threshold, when the change amount is greater than the threshold value, the traveling path is estimated gradient A severe rough road undulations unstable der is, a determination means determines that the estimated gradient is stable when small,
The threshold is set to be smaller as the estimated gradient becomes larger than a set gradient,
The control means, when the judgment means judges that the estimation of the slope is unstable and the vehicle is traveling on a rough road, even if idle stop control is permitted based on the magnitude of the estimated slope, A control device for an idle stop vehicle, wherein control is prohibited.

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