JP2006307866A - Road surface gradient measuring device, and device for automatically stopping and starting engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for automatically stopping and starting an engine capable of adequately controlling the automatic stop of the engine by measuring the road surface gradient with high accuracy when a vehicle is stopped. <P>SOLUTION: A gear in a gear transmission unit 6 is controlled by a hydraulic fluid in a hydraulic control unit 10. The hydraulic pressure of the hydraulic fluid in this hydraulic control unit 10 is controlled by an oil pump 16 operated by the driving force of the engine 2 while the engine 2 is operated. On the other hand, while controlling the automatic stop of the engine 2, the hydraulic fluid is sucked by an electric oil pump 18 from a suction hose 22 connected to a communication hole 20 opened in an oil pan 12 of the hydraulic control unit 10, and the hydraulic fluid is returned to the hydraulic control unit 10 in a regulated pressure via a discharge hose 24 and a hole 26 for detecting the line pressure. After the predetermined time from the stop of the vehicle, the road surface gradient is measured by using an acceleration sensor 35, and prohibition or permission of the automatic stop control of the engine 2 is determined based on the degree of the inclination of the gradient. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a road surface gradient measuring device that measures a road surface gradient based on an inertial force or gravity acting on a vehicle, and an engine automatic stop / start device that controls automatic engine stop based on the measurement result.

  An engine automatic stop / start device is known that automatically stops the engine when the vehicle stops, such as when waiting for a signal, and restarts the engine when the vehicle starts, for the purpose of improving fuel economy when driving in urban areas with a high stopping rate. .

  In a vehicle equipped with such an engine automatic stop / start device, it is necessary to carefully determine conditions for permitting the engine to be automatically stopped. For example, in a vehicle with a normal automatic transmission in which the engine is connected to the automatic transmission via a torque converter, a creep force is applied to the vehicle even when the vehicle is stopped. The vehicle can be braked accurately on the road. However, in a vehicle equipped with the engine automatic stop / start device, if the engine is automatically stopped on such an uphill road, a sufficient creep force cannot be obtained. The driver may feel uncomfortable.

Therefore, conventionally, as seen in Patent Document 1, for example, a road surface inclination sensor such as a pendulum type detects the degree of inclination (gradient) of the road surface, and the vehicle does not move even if the engine is automatically stopped. There has also been proposed a device that determines whether a sufficient brake pedal operation is performed based on the detection result of the road surface gradient and permits automatic engine stop on the condition that the brake pedal operation amount is sufficient.
Japanese Unexamined Patent Publication No. 2000-8905

    By the way, when the vehicle is stopped, usually, the posture change (nose down) of the vehicle accompanying the braking, the swinging, and the like often occur. For this reason, even if it is an apparatus given in the above-mentioned gazette, there is a possibility that the road surface gradient cannot be detected and measured with high accuracy because the detector of the road surface inclination sensor shakes.

  Note that the present invention is not limited to a device that measures the road surface gradient in a vehicle equipped with the engine automatic stop / start device, but a device that detects and measures the road surface gradient when the vehicle is stopped based on inertial force or gravity acting on the vehicle. This situation is generally common where there is a concern that the detection and measurement accuracy may decrease with braking.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a road surface gradient measuring device capable of detecting and measuring a road surface gradient when the vehicle is stopped with higher accuracy. Another object of the present invention is to provide an engine automatic stop / start device capable of performing more appropriate engine automatic stop control based on the road surface gradient at the time of vehicle stop detected and measured with high accuracy. is there.

In the following, means for achieving the above object and its effects are described.
According to a first aspect of the present invention, there is provided a road surface gradient measuring apparatus having a detecting means for detecting acceleration based on a force acting on a vehicle and measuring a gradient of a road surface on which the vehicle is placed. And a means for correcting the detection value of the detection means based on the calculated acceleration, and based on the corrected detection value after a predetermined time has elapsed since the vehicle stopped. The gist is to measure the slope of the road surface.

  In the above configuration, the acceleration of the vehicle is calculated based on the engine torque, and the detection value of the detection means is corrected based on the acceleration. Then, the road surface gradient is measured based on the detection value corrected after a predetermined time has elapsed since the vehicle stopped. For this reason, it is possible to eliminate the influence of the vehicle posture change (nose down), the swing, etc., which is applied to the braking, from the detection value of the detection means, and to measure the road surface gradient when the vehicle is stopped with higher accuracy. It becomes like this. Further, even when a change with time occurs in the detection means, it is possible to accurately measure the road surface gradient based on the detection value of the detection means.

  According to a second aspect of the present invention, there is provided an apparatus for controlling automatic stop and restart of an engine mounted on a vehicle, the detection means detecting acceleration based on a force acting on the vehicle, and the torque of the engine. The vehicle acceleration is calculated, the detection value of the detection means is corrected based on the calculated acceleration, and the road surface gradient is measured based on the corrected detection value after a predetermined time has elapsed since the vehicle stopped. The gist of the present invention is to include a measuring unit for performing the automatic stop control of the engine in accordance with the measured gradient.

When executing or prohibiting the automatic engine stop control, it is desirable to consider various conditions, and road surface gradient may be used as one of such conditions.
In this regard, in the above configuration, the road surface gradient is measured based on the detection value of the detection means after a predetermined time has elapsed since the vehicle stopped. Etc. can be excluded. Therefore, according to the above configuration, more appropriate automatic engine stop control can be performed based on the measured road gradient when the vehicle is stopped. Further, the acceleration of the vehicle is calculated based on the engine torque, and the detection value of the detecting means is corrected based on the acceleration. For this reason, even when a change over time or the like occurs in the detection means, it becomes possible to accurately measure the road surface gradient based on the detection value of the detection means.

  According to a third aspect of the present invention, there is provided a hydraulic transmission that holds a starting shift position using hydraulic oil pressurized by a pump driven by engine output, and the hydraulic pressure for operation when the engine is automatically stopped. An apparatus for controlling automatic stop and restart of the engine mounted on a vehicle including a hydraulic pressure holding means for holding the engine, a detection means for detecting acceleration based on a force acting on the vehicle, and a torque of the engine Based on the calculated acceleration, a means for correcting the detection value of the detection means based on the calculated acceleration, and a slope of the road surface based on the corrected detection value after a predetermined time has elapsed since the vehicle stopped. The gist of the present invention is to include measurement means for measuring the engine and prohibiting means for prohibiting the automatic engine stop control in accordance with the measured gradient.

  In the above configuration, when the hydraulic pressure for holding the start shift position cannot be secured only by holding the hydraulic pressure by the hydraulic pressure holding means, the engine automatic stop control is prohibited, and the pump is driven by the engine output. It is desirable to ensure hydraulic pressure. This oil pressure may depend on the road surface gradient.

  In this regard, according to the above configuration, the engine automatic stop control is prohibited in accordance with the gradient measured by the measuring means, so that more appropriate engine automatic stop control can be performed. Further, the acceleration of the vehicle is calculated based on the engine torque, and the detection value of the detecting means is corrected based on the acceleration. For this reason, even when a change over time or the like occurs in the detection means, it becomes possible to accurately measure the road surface gradient based on the detection value of the detection means.

  According to a third aspect of the present invention, as in the fourth aspect of the present invention, the transmission includes a gear transmission portion that forms a gear engagement state with the start shift position, and the gear transmission portion. A hydraulic control unit that maintains the engaged state of the gear by supplying hydraulic oil to the hydraulic oil, and the hydraulic pressure holding unit is an electric oil pump and is an oil provided in the hydraulic control unit. A configuration may be adopted in which hydraulic oil in the oil pan is sucked through a suction hose connected to a communication hole formed in the pan and is discharged to the hydraulic pressure control unit.

(First embodiment)
Hereinafter, a first embodiment of a road surface gradient measuring device and an engine automatic stop / start control device equipped with the road surface gradient measuring device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an outline of the configuration of the present embodiment. In the present embodiment, the output of the engine 2 shown in FIG. 1 is output from the output shaft 8 after being subjected to predetermined changes by the torque converter 4 and the gear transmission unit 6. The gear transmission unit 6 is provided with a plurality of planetary gear mechanisms to shift the input driving force in five forward speeds and one reverse speed, and maintaining the gear engagement state of these planetary gear mechanisms. The engagement is switched by a hydraulic control unit 10 provided below the gear transmission unit 6.

  The engine 2, the torque converter 4, and the gear transmission unit 6 are connected to the vehicle so that the axial direction of the power transmission shaft connected to the output shaft 8 is substantially coincident with the longitudinal direction of the vehicle and the engine 2 side is the forward direction of the vehicle. Installed.

  As shown by a broken line in FIG. 1, the hydraulic control unit 10 includes an oil pan 12 and a valve body 14 that controls the gear transmission unit 6 using hydraulic oil stored in the oil pan 12. I have. When the engine 2 is in operation, the oil in the oil pan 12 is pumped up and pressurized by an oil pump 16 provided between the torque converter 4 and the gear transmission 6 and driven by the power of the engine 2. And supplied to the valve body 14.

  Furthermore, an electric oil pump 18 that is operated during the automatic stop control of the engine 2 is provided in the vicinity of the torque converter 4 as another means for pressurizing the hydraulic oil of the hydraulic control unit 10. Then, the hydraulic oil in the oil pan 12 is sucked by the electric oil pump 18 through the suction hose 22 connected to the communication hole 20 provided in the vehicle front direction lower side of the side surface of the oil pan 12. Furthermore, the hydraulic oil is discharged into the valve body 14 by the electric oil pump 18 through the discharge hose 24 and discharged into the line pressure detection hole 26 provided in the gear transmission 6. Supplied.

The hydraulic transmission unit 6 is controlled by the hydraulic control unit 10 by using hydraulic oil pressurized by the oil pump 16 or the electric oil pump 18.
Specifically, the control of the gear transmission unit 6 by the hydraulic control unit 10 is performed by the clutches C0 to C2, the brakes B0 to B4, the one-way clutches F0 to F0 of the gear transmission unit 6 shown in the skeleton diagram of FIG. Of F2, the engagement mode of the hydraulically driven clutches C0 to C2 and the brakes B0 to B4 is controlled by hydraulic oil. In this way, by controlling the engagement mode of the clutches C0 to C2 and the brakes B0 to B4 with the hydraulic oil, the gear engagement control according to each gear stage shown in FIG. 3 is performed.

  The hydraulic control unit 10 for adjusting the engagement mode of the clutch and brake in the gear transmission unit 6, the electric oil pump 18, the engine 2, and the like are the electronic control unit (hereinafter referred to as ECU) shown in FIG. 30). In this electronic control unit 30, in addition to various known controls relating to vehicle travel, an ignition switch 31, a vehicle speed sensor 32 that detects the speed of the vehicle, an accelerator sensor 33 that detects the amount of depression of the accelerator pedal, and a brake are depressed. Based on the detection result of the brake sensor 34 or the like that detects whether or not there is an automatic stop / start control of the engine.

Here, the automatic stop / start control of the engine in the present embodiment will be described.
The control for automatically stopping the engine 2 is normally performed when the following condition is satisfied in a state where the ignition switch 31 is turned on in order to automatically stop the engine 2 when waiting for a signal or the like. That is, (a) the output signal of the vehicle speed sensor 32 indicates the vehicle speed “0”, (a) the output signal of the accelerator sensor 33 indicates that the accelerator pedal is not depressed, and (c) the brake sensor 34 The output signal indicates that the brake is being depressed.

  The automatic stop control of the engine 2 is performed by satisfying the above conditions (a) to (c). However, when the engine 2 is automatically stopped, the hydraulic oil cannot be pressurized by the oil pump 16. Then, when the hydraulic pressure of the hydraulic oil in the hydraulic control unit 10 decreases, the hydraulic pressure of the hydraulic oil is used among the engagements of the first speed clutch and brake shown in FIG. The engaged state of the clutches C0 and C1 that maintain the engagement cannot be maintained. If the engagement state of the clutch or the like corresponding to the starting shift position cannot be maintained due to the automatic stop control of the engine 2 in this way, the operating hydraulic pressure rises at the next automatic start of the engine 2 and this engagement is caused. The combined state will be recovered. However, at this time, since the rotational speed of the engine 2 is considerably increased, a shock may be transmitted to the vehicle due to this engagement.

  Therefore, in order to maintain the hydraulic pressure of the hydraulic oil in the hydraulic control unit 10 even when the engine 2 is automatically stopped, the hydraulic pressure is held by the electric oil pump 18 when the engine 2 is stopped as described above. I am doing so. By holding the hydraulic pressure in this manner, the clutch and brake in the gear transmission 6 are maintained in the engaged state corresponding to the starting shift position (first speed) even when the engine is stopped. Thereby, the start can be satisfactorily performed at the next start.

  By the way, when the engine automatic stop control is performed when the vehicle is on the uphill road, there may be a problem that the hydraulic oil pressure cannot be suitably maintained by the electric oil pump 18. That is, as can be seen from the arrangement of the communication holes 20 of the oil pan 12 shown in FIG. 1 above, the bottom of the oil pan 12 is lifted forward with respect to a plane perpendicular to the direction of gravity. In some cases, the hydraulic oil contained in the gas does not completely block the communication hole 20.

  In such a case, although the electric oil pump 18 is used, the hydraulic oil in the hydraulic control unit 10 cannot be kept at a sufficient hydraulic pressure during the automatic stop control of the engine 2, and the above-mentioned start There may be a problem in the engagement of the clutch or the like corresponding to the shift position. That is, among the clutches and brakes related to the engagement, the clutches C0 and C1 that are held by the hydraulic pressure are not sufficiently engaged. When the vehicle is started, there is a possibility that poor engagement may occur in the clutch C1 controlled by the same hydraulic pressure even if no problem occurs because the clutch C0 is connected to the one-way clutch F0.

  Furthermore, such a problem may occur not only when the engine automatic stop control is performed when the vehicle is on an uphill road, but also when the control is performed on a road surface that rises to the left. In this case, as can be seen from the arrangement of the communication holes 20 of the oil pan 12 shown in FIG. 1, the oil left side of the vehicle is lifted with respect to a plane perpendicular to the direction of gravity. The hydraulic oil stored in the pan 12 may not completely block the communication hole 20.

  Therefore, it is desirable to prohibit the automatic stop control of the engine 2 in accordance with the degree of inclination of the road surface gradient, in other words, in accordance with the degree of inclination of the oil level in the hydraulic control unit 10 with respect to the plane orthogonal to the direction of gravity. Therefore, in this embodiment, the vector from the rear to the front of the vehicle (within the oil surface) is inclined by “+ α” or more with respect to the plane perpendicular to the direction of gravity (with the direction from the same plane going vertically upward) When the vector from the right side to the left side of the vehicle (within the oil surface) has an inclination of “+ β” or more with respect to a plane perpendicular to the direction of gravity (with the direction from the same plane going vertically upward) Then, it is determined that the road is an uphill road where engine automatic stop control is prohibited.

  In order to measure the gradient of the road surface, in this embodiment, a sensor that detects a force caused by acceleration (inertial force) or gravity applied to itself is used. Specifically, the road surface gradient is detected using a piezoelectric acceleration sensor 35 illustrated in FIG. As shown in FIG. 7, the acceleration sensor 35 includes a piezoelectric element 35v having a piezoelectric effect, a weight 35m, and a base 35b that supports them. In the acceleration sensor 35, when a force is applied to the weight 35m, the force is transmitted to the piezoelectric element 35v, and an electrical signal proportional to the force is output from the piezoelectric element 35v. Therefore, the combined acceleration of the gravitational acceleration applied to the acceleration sensor 35 and the acceleration accompanying the propulsion of the vehicle can be detected by this electrical signal.

  However, as described above, when the vehicle is stopped, it is difficult to accurately measure the gradient of the road surface due to a change in the attitude of the vehicle (nose down), a turnback, or the like. That is, the detection value of the acceleration sensor 35 does not accurately reflect the slope of the road surface even when the vehicle is stopped, due to the force applied to the weight 35m due to the change in the posture of the vehicle and the turning back.

  Therefore, in this embodiment, the road surface gradient is measured based on the detection value of the acceleration sensor 35 after a predetermined time has elapsed since the vehicle stopped. As described above, by measuring the road surface gradient after a predetermined time has elapsed since the vehicle stopped, it is possible to eliminate the above-described influences such as the change in the posture of the vehicle and the turning back, and to accurately measure the road surface gradient. it can.

  Specifically, in the present embodiment, prior to the above measurement, the road surface gradient is estimated and calculated based on the traveling state of the vehicle, and the engine surface is capable of automatic engine stop control based on the road surface gradient calculated when the vehicle is stopped. Is determined (temporary climbing judgment). In this way, by estimating and calculating the slope of the road surface when the vehicle is running, the engine is automatically activated when the automatic stop control of the engine 2 is permitted, such as when the road surface when the vehicle is stopped is a flat road surface. Stop control can be performed. When it is estimated that the road surface gradient is greater than or equal to a predetermined value during traveling, the road surface gradient is measured using the acceleration sensor 35 after a predetermined time has elapsed since the vehicle stopped.

  More specifically, the road surface gradient estimation calculation in this traveling state is more specifically based on the reference acceleration calculated from the estimated value of the output torque of the engine 2 and the output shaft of the gear transmission unit 6 (the output shaft of the automatic transmission: output shaft). This is performed based on the difference from the actual acceleration based on the rotational speed of 8). The estimated value of the output torque of the engine 2 is basically calculated based on the intake air amount of the engine and the engine speed.

  In this embodiment, in order to perform estimation and calculation of the road surface gradient in this traveling state, an air flow meter 36 that detects the intake air amount of the engine 2, an engine rotation speed sensor 37 that detects the rotation speed of the engine 2, and the output shaft 8. And an output shaft rotational speed sensor 38 for detecting the rotational speed of the motor.

  Here, a process for estimating and calculating the road surface gradient performed in the traveling state of the vehicle and determining the temporary climbing slope performed based on the estimated value will be described with reference to FIG. FIG. 4 is a flowchart showing the procedure of the process. This process is repeatedly executed at a predetermined cycle.

  In this series of processing, first, the actual acceleration of the vehicle is calculated based on the rotational speed of the output shaft 8 (step 100). That is, here, the rotational speed is detected for a drive transmission system that is variably controlled by the automatic transmission and has a direct correlation with the output rotational speed transmitted to the drive wheels (not shown) of the vehicle. Thereby, the actual acceleration of the vehicle can be calculated.

  On the other hand, in step 110, an estimated value of engine torque is calculated based on the intake air amount and the engine speed. Here, it is desirable that the engine torque estimated and calculated based on the intake air amount and the engine rotation speed is corrected by the ignition timing, the outside air temperature, or the like.

  In step 120, a reference acceleration based on the estimated value of the engine torque is calculated. This reference acceleration is an acceleration assumed to be applied to the vehicle when traveling on a predetermined road surface (here, a flat road surface is assumed as an example).

  When the reference acceleration and the actual acceleration are calculated in this way, the gradient inclination is calculated based on the value obtained by subtracting the actual acceleration from the reference acceleration (step 130). That is, the actual acceleration is an acceleration that is actually applied to the vehicle by the engine torque while traveling on the road surface. On the other hand, the reference acceleration is an acceleration that is assumed to be applied to the vehicle by the engine torque while traveling on a flat road surface. Accordingly, the value obtained by subtracting the actual acceleration from the reference acceleration multiplied by the vehicle body weight corresponds to the gravity acting in the traveling direction of the vehicle. The degree of slope of the road surface gradient can be estimated and calculated based on the gravity equivalent value acting in the traveling direction of the vehicle.

  When the slope of the gradient thus calculated exceeds a predetermined value, a temporary climbing judgment flag is set (steps 140 and 150). The uphill determination flag is used to notify that the above-described processing for determining whether or not to execute the engine automatic stop control using the acceleration sensor 35 when the vehicle is stopped should be executed.

  On the other hand, the predetermined value defines an inclination of the gradient that can perform the automatic stop control of the engine 2 without measuring the gradient by the acceleration sensor 35. For this reason, considering that the slope of the gradient changes from the vehicle running state to the vehicle stop state, a margin is set for a criterion for prohibiting and permitting automatic stop control by the acceleration sensor 35. Yes. In other words, the predetermined value in step 140 is a predetermined value smaller than the predetermined value “+ α” with respect to the degree of inclination of the vector from the rear to the front of the vehicle on the road gradient (relative to the plane perpendicular to the direction of gravity). It is set to “+ α ′”. The predetermined value is a predetermined value “+ β ′” smaller than the predetermined value “+ β” with respect to the degree of inclination (with respect to a plane orthogonal to the direction of gravity) of the vector from the right side to the left side of the road surface gradient. Is set to

When the degree of inclination is equal to or less than the predetermined value in step 140 or when the temporary climbing slope determination flag is set in step 150, this process is temporarily ended.
The series of processes is performed on the condition that the vehicle speed is equal to or higher than a predetermined value in order to ensure the calculation accuracy of the actual acceleration. That is, since the calculation of the actual acceleration uses the rotational speed of the output shaft 8, it takes into account that the accuracy decreases when the rotational speed is extremely small.

  Next, a process for determining whether or not to perform slope measurement of the uphill road and automatic engine stop control by the acceleration sensor 35 in the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the procedure of the process. This process is repeatedly executed at a predetermined cycle.

  In this series of processing, it is first determined in step 200 whether or not the vehicle has stopped. That is, here, it is determined whether or not to perform a series of processes related to determination as to whether or not to perform engine automatic stop control.

  Then, if it is determined that the vehicle is stopped, it is determined in step 210 whether or not the temporary uphill determination flag is set by the processing shown in FIG. That is, here, it is determined whether or not a strict gradient measurement by the acceleration sensor 35 is necessary for determining whether to prohibit or permit the engine automatic stop control.

  If it is determined that strict gradient measurement by the acceleration sensor 35 is necessary, the engine automatic stop control is prohibited for a predetermined time after the vehicle stops (steps 220 and 230). The standby for the predetermined time is for removing the influence of the detection accuracy of the acceleration sensor 35 due to a change in the posture of the vehicle (nose down), a turnback, and the like. 35 is set to a time when the gradient can be detected with high accuracy.

  When a predetermined time has elapsed, in step 230, the acceleration sensor 35 is used to measure the degree of inclination of the road surface gradient, and it is determined whether the degree of inclination should prohibit the engine automatic stop control ( Climbing judgment). Here, it is determined whether or not the inclination degree exceeds the predetermined value “+ α” or the predetermined value “+ β”. When the uphill determination is made, the engine automatic stop control is prohibited (step 240). When it is determined that the road is not the uphill road, the engine automatic stop control is permitted (step 250).

When it is determined in step 200 that the vehicle is not stopped, or when the process of step 240 or 250 is performed, this series of processes is temporarily ended.
According to the embodiment described above, the following effects can be obtained.

  (1) The determination of prohibition or permission of the engine automatic stop control is performed in accordance with the measurement of the inclination degree of the gradient using the acceleration sensor 35, and the measurement of the inclination degree is performed after a predetermined time has elapsed from the stop of the vehicle. As a result, it is possible to eliminate the influence of posture change (nose down) and swinging upon stopping of the vehicle from the detection value of the acceleration sensor 35 when the vehicle is stopped, and thus, more accurate automatic stop control of the engine is performed. be able to.

  (2) The gradient of the road surface was calculated based on the running state when the vehicle was running, and a provisional climbing judgment was made as to whether or not engine automatic stop control should be prohibited. Thus, when the engine automatic stop control can be permitted without measuring the road surface gradient by the acceleration sensor 35 such as a flat road surface, the control can be permitted immediately.

(Second Embodiment)
Hereinafter, a road surface gradient measuring device according to the present invention and a second embodiment of an engine automatic stop / starting device equipped with the road surface gradient measuring device will be described with reference to the drawings with a focus on differences from the first embodiment. explain.

  In the first embodiment, the road surface gradient is measured using the acceleration sensor 35 when the vehicle is stopped. This makes it possible to measure the gradient of the road surface with high accuracy when the gradient calculation cannot be performed accurately by calculation of the road surface gradient based on the traveling state of the vehicle as shown in FIG. Proper judgment of prohibition or permission of automatic stop control became possible.

  However, the detection of the road surface gradient by the acceleration sensor 35 may be affected by the installation error of the acceleration sensor 35 or the change of the sensor itself over time, and this makes it possible to accurately determine whether to prohibit or permit the engine automatic stop control. There is a concern that cannot be done.

  Therefore, in the present embodiment, the detection value of the acceleration sensor 35 is corrected using the reference acceleration calculated based on the estimated engine torque shown in FIG. That is, as described above, the reference acceleration calculated based on the estimated engine torque takes into account the inertia and gravity of the vehicle. Therefore, the reference acceleration is equivalent to the acceleration detected by the acceleration sensor 35, and the detection value of the acceleration sensor 35 can be corrected (learning correction) using this reference acceleration.

  Specifically, correction is performed so that the detected value of the acceleration sensor 35 approaches the reference acceleration calculated based on the estimated engine torque when the vehicle travels. Specifically, the zero point of the acceleration sensor 35 is feedback-corrected based on the difference between the reference acceleration calculated based on the estimated engine torque and the detected value of the acceleration sensor 35.

  Further, in the present embodiment, in order to ensure the accuracy of the feedback correction, the correction is performed when the traveling state of the vehicle is stabilized. That is, when the running state of the vehicle is not stable, not only the detection accuracy of the acceleration sensor 35 is lowered, but also due to the transition period of the input torque, the occurrence of a shift shock, the influence of friction loss before warming up, etc. Therefore, it is considered that the reference acceleration based on the estimated engine torque cannot be accurately calculated.

  Specifically, the state in which the vehicle is in a stable state is: (a) a change amount of the throttle opening is small, (b) is not being shifted, (c) at least one after completion of warming up of the engine and the automatic transmission, etc. In addition, it is desirable that all the conditions are satisfied.

FIG. 6 shows the processing procedure of the feedback correction. This process is repeatedly executed at a predetermined cycle.
In the processing relating to the feedback correction, it is first determined whether or not the absolute value of the difference between the reference acceleration based on the estimated engine torque and the acceleration detected by the acceleration sensor 35 exceeds a predetermined value (step 300). This predetermined value is set to a value for which feedback correction based on the reference acceleration is desirable because the detected value of the acceleration sensor 35 deviates from the reference acceleration based on the estimated engine torque. Actually, the acceleration detected by the acceleration sensor 35 is a value obtained by adding the previous zero point feedback correction value (learning value) to the detection value of the acceleration sensor 35.

  If it is determined that the value exceeds the predetermined value, feedback correction (learning control) of the zero point of the acceleration sensor 35 is performed in step 310. Here, the previously calculated zero point learned value GVSCLN (i) is set to the learned value GVSCLN (i + 1) based on the difference between the reference acceleration and the detected value of the acceleration sensor 35 (and the sum of GVSCLN (i)). Updated. This update is performed using the feedback gain α.

  Note that when the absolute value is equal to or smaller than the predetermined value in step 300, or when the zero-point learning value is updated in step 310, this process is temporarily terminated. Further, it is desirable that the learning value of the zero point is stored and retained in a backup ram or the like even when the engine is stopped and used in the next trip.

According to the present embodiment described above, the following effects can be obtained in addition to the effects (1) and (2) of the first embodiment.
(3) Since the detection value of the acceleration sensor 35 is corrected based on the reference acceleration calculated from the estimated engine torque, it is possible to more accurately determine whether to prohibit or permit the engine automatic stop control by the acceleration sensor 35.

Each of the above-described embodiments described above may be modified as follows.
-Even if the temporary climbing judgment illustrated in FIG. 4 is not necessarily performed, the determination regarding prohibition or permission of the automatic engine stop control is accurately performed by measuring the gradient using the acceleration sensor when the vehicle is stopped. Can do.

  -About the correction | amendment aspect of the detected value of the acceleration sensor 35, what is necessary is just to perform appropriate correction | amendment based on the reference acceleration calculated from not only what was illustrated by the said 2nd Embodiment but estimated engine torque.

  The acceleration sensor 35 is not limited to that illustrated in FIG. In short, any detection means for detecting the gradient and acceleration of the road surface by detecting the inertial force (acceleration) and gravity applied to itself may be used.

  The arrangement of the electric oil pump 18 and the like is not limited to the above. Furthermore, the means for holding the hydraulic pressure during the automatic stop control of the engine 2 is not limited to the electric oil pump 18. In short, when a structure in which hydraulic pressure control of hydraulic oil by hydraulic pressure holding means such as the electric oil pump 18 is not sufficiently performed due to the gradient of the road surface, the gradient is measured using an acceleration sensor and based on this Thus, the application of the present invention is effective when making a determination regarding prohibition or permission of the automatic engine stop control.

-The configuration of the automatic transmission and the setting of each shift are arbitrary.
In addition, the present invention is not limited to a vehicle using an automatic transmission, and the present invention is effective as long as it has a configuration in which hydraulic oil is used to maintain the engagement state of a clutch or a brake with respect to a starting shift position. .

  Further, the present invention is not limited to the case where the working hydraulic pressure is taken into account, and the present invention is an arbitrary engine automatic stop / start device that determines prohibition and permission of engine automatic stop control according to the road gradient measured when the vehicle stops. The application of is effective.

-The conditions for performing the engine automatic stop control are not limited to those described above.
In addition, the present invention is not limited to automatic engine stop or restart control, but is applicable to any road surface gradient measuring device that measures the road surface gradient when the vehicle is stopped.

  The engine is not limited to an internal combustion engine and may be an arbitrary prime mover.

The figure which shows the whole structure about 1st Embodiment of the engine automatic stop start apparatus which mounts the road surface gradient measuring apparatus of this invention, and the road surface gradient measuring apparatus. The skeleton figure which shows the arrangement | positioning aspects, such as a clutch in the gear transmission part in the embodiment. The figure which shows the engagement aspects, such as a clutch at the time of each shift in the same embodiment. The flowchart which shows the procedure of the temporary climbing slope determination process in the embodiment. The flowchart which shows the process sequence about determination of climbing in the same embodiment, and prohibition and permission of engine automatic stop control. The flowchart which shows the correction processing procedure of the detected value of the acceleration sensor in the 2nd Embodiment of this invention. The figure which shows the acceleration sensor in each said embodiment typically.

Explanation of symbols

  B0-B4 ... Brake, C0-C2 ... Clutch, F0-F2 ... One-way clutch, 2 ... Engine, 4 ... Torque converter, 6 ... Gear transmission, 8 ... Output shaft, 10 ... Hydraulic controller, 12 ... Oil pan DESCRIPTION OF SYMBOLS 14 ... Valve body, 16 ... Oil pump, 18 ... Electric oil pump, 20 ... Communication hole, 22 ... Inhalation hose, 24 ... Discharge hose, 26 ... Line pressure detection hole, 30 ... Electronic control unit, 31 ... Ignition switch 32 ... Vehicle speed sensor, 33 ... Accelerator sensor, 34 ... Brake sensor, 35 ... Acceleration sensor, 35b ... Base, 35v ... Piezoelectric element, 35m ... Weight, 36 ... Air flow meter, 37 ... Engine rotation speed sensor, 38 ... Output shaft Rotational speed sensor.

Claims (4)

In a road surface gradient measuring device having a detecting means for detecting acceleration based on a force acting on a vehicle and measuring a road surface gradient on which the vehicle is placed,
A means for calculating an acceleration of the vehicle based on a torque of an engine mounted on the vehicle, and correcting a detection value of the detection means based on the calculated acceleration; and performing the correction after a predetermined time has elapsed since the vehicle stopped. A road surface gradient measuring apparatus that measures the gradient of the road surface based on the detected value. A device for controlling automatic stop and restart of an engine mounted on a vehicle,
Detecting means for detecting acceleration based on a force acting on the vehicle;
Means for calculating the acceleration of the vehicle based on the torque of the engine, and correcting the detection value of the detection means based on the calculated acceleration;
Measuring means for measuring the slope of the road surface based on the corrected detection value after a predetermined time has elapsed since the vehicle stopped;
Prohibiting means for prohibiting the automatic stop control of the engine according to the measured gradient;
An engine automatic stop and start device comprising: A hydraulic transmission that holds the starting shift position using hydraulic oil pressurized by a pump driven by the engine output; and a hydraulic pressure holding means that holds the hydraulic pressure for the operation when the engine is automatically stopped. An apparatus mounted on a vehicle for controlling automatic stop and restart of the engine,
Detecting means for detecting acceleration based on a force acting on the vehicle;
Means for calculating the acceleration of the vehicle based on the torque of the engine, and correcting the detection value of the detection means based on the calculated acceleration;
Measuring means for measuring the slope of the road surface based on the corrected detection value after a predetermined time has elapsed since the vehicle stopped;
Prohibiting means for prohibiting the automatic stop control of the engine according to the measured gradient;
An engine automatic stop and start device comprising: The transmission includes a gear transmission unit that forms a gear engagement state with respect to the start shift position, and a hydraulic control unit that maintains the gear engagement state by supplying hydraulic oil to the gear transmission unit. The hydraulic pressure holding means is an electric oil pump and is connected to a communication hole formed in the oil pan provided in the hydraulic pressure control unit via a suction hose. The engine automatic stop and start device according to claim 3, wherein the hydraulic oil is sucked and discharged to the hydraulic pressure control unit.

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