JP6819214B2 - Automatic engine stop device - Google Patents

Description

The present invention relates to an automatic engine stop device.

A vehicle equipped with an engine is equipped with an automatic engine stop device capable of improving fuel efficiency by automatically stopping the engine when a predetermined automatic stop condition is satisfied while the vehicle is running.

As a vehicle equipped with such an automatic engine stop device, an idle stop vehicle that automatically stops the engine according to the slope of the road surface on which the vehicle travels is known (see, for example, Patent Document 1).

In this idle stop vehicle, the automatic stop condition is satisfied when the road surface gradient is smaller than the first predetermined value and equal to or less than the second predetermined value based on the road surface gradient information of the inclination angle sensor that detects the road surface gradient when the vehicle is stopped. Occasionally, the engine is automatically stopped to determine the failure of the idle stop device, and automatic stop on a road surface gradient greater than the second predetermined value is prohibited until the failure determination is completed.

Japanese Unexamined Patent Publication No. 2012-255383

However, in such a conventional idle stop vehicle, when the inclination angle sensor fails, the vehicle is stopped on a road surface having a gradient larger than the first predetermined value. There is a risk of erroneous detection such as detection of a road surface gradient smaller than the first predetermined value due to a failure of the inclination angle sensor.
At this time, the idle stop vehicle may determine that the idle stop condition is satisfied and automatically stop the engine. As a result, the vehicle may move against the intention of the driver.

An object of the present invention is to provide an automatic engine stop device capable of preventing a vehicle from moving on a sloped road surface when the slope of the road surface is erroneously determined based on the detection information of the road surface slope detecting unit. Is.

The present invention includes a road surface gradient detection unit that detects the slope of the road surface on which the vehicle travels, and a predetermined automatic stop condition that includes an automatic stop condition of the road surface gradient that is set based on the road surface gradient information detected by the road surface gradient detection unit. An abnormality in the road surface gradient detection unit based on the road surface gradient information input from the road surface gradient detection unit, which is an automatic engine stop unit that automatically stops the engine when the stop condition is satisfied and an automatic engine stop device provided. The engine automatic stop unit is provided with a failure determination unit that determines that the road surface gradient detection unit is a failure when the first predetermined time is continued, and the engine automatic stop unit automatically stops the road surface gradient under the predetermined automatic stop conditions. When the condition is satisfied for a second predetermined time longer than the first predetermined time, the engine is configured to allow automatic stop, and the start time of the first predetermined time and the second predetermined time is set. It is characterized by being the same .

According to the present invention, when the slope of the road surface is erroneously determined based on the detection information of the road surface slope detection unit, it is possible to prevent the vehicle from moving on the sloped road surface.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle provided with an automatic engine stop device according to an embodiment of the present invention. FIG. 2 is a functional configuration diagram of an automatic engine stop device according to an embodiment of the present invention. FIG. 3 is a diagram comparing the time for determining the establishment of the automatic stop condition for the road surface gradient and the time for determining the failure state of the road surface gradient sensor in the automatic engine stop device according to the embodiment of the present invention. FIG. 4 is a flowchart of a failure detection process of the road surface gradient sensor included in the automatic stop process executed by the automatic engine stop device according to the embodiment of the present invention. FIG. 5 is a flowchart of the process of determining the establishment of the automatic stop condition of the road surface gradient included in the automatic stop process executed by the automatic stop device of the engine according to the embodiment of the present invention. FIG. 6 is a flowchart of an engine automatic stop determination process included in the automatic stop process executed by the engine automatic stop device according to an embodiment of the present invention.

The automatic engine stop device according to the embodiment of the present invention has a road surface gradient detecting unit that detects the slope of the road surface on which the vehicle travels, and a road surface that is set based on the road surface gradient information detected by the road surface gradient detecting unit. An engine automatic stop device including an engine automatic stop unit that automatically stops the engine when a predetermined automatic stop condition including an automatic slope stop condition is satisfied, and the road surface gradient input from the road surface gradient detection unit. Based on the information, if the abnormality of the road surface gradient detection unit is continued for the first predetermined time, the road surface gradient detection unit is provided with a failure determination unit that determines that the failure is caused, and the engine automatic stop unit is included in the predetermined automatic stop conditions. When the automatic stop condition of the road surface slope is satisfied for the second predetermined time longer than the first predetermined time, the automatic stop of the engine is permitted.
As a result, when the slope of the road surface is erroneously determined based on the detection information of the road surface slope detection unit, it is possible to prevent the vehicle from moving on the sloped road surface.

Hereinafter, a hybrid vehicle equipped with an automatic engine stop device according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the hybrid vehicle 1 includes an HCU (Hybrid Control Unit) 10 that comprehensively controls an engine 2 as an internal combustion engine, a transmission 3, a motor generator 4, a drive wheel 5, and a hybrid vehicle 1. The ECM (Engine Control Module) 11 that controls the engine 2, the TCM (Transmission Control Module) 12 that controls the transmission 3, the ISGCM (Integrated Starter Generator Control Module) 13, the INVCM (Invertor Control Module) 14, and so on. It includes a low-voltage BMS (Battery Management System) 15 and a high-voltage BMS 16. The hybrid vehicle 1 of the present embodiment constitutes the vehicle of the present invention.

A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder.

An ISG (Integrated Starter Generator) 20 and a starter 21 are connected to the engine 2. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a belt 22 or the like. The ISG 20 has a function of an electric motor that starts the engine 2 by rotating when electric power is supplied, and a function of a generator that converts the rotational force input from the crankshaft 18 into electric power.

In this embodiment, the ISG 20 functions as an electric motor under the control of the ISGCM 13 to restart the engine 2 from a stopped state by the idling stop function. The ISG 20 can also assist the running of the hybrid vehicle 1 by functioning as an electric motor.

The starter 21 includes a motor (not shown) and a pinion gear. The starter 21 rotates the crankshaft 18 by rotating the motor to give the engine 2 a rotational force at the time of starting. In this way, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stopped state by the idling stop function.

The transmission 3 shifts the rotation output from the engine 2 and drives the drive wheels 5 via the drive shaft 23. The transmission 3 includes a constantly meshing type transmission mechanism 25 composed of a parallel shaft gear mechanism, a clutch 26 composed of a normally closed type dry clutch, and a differential mechanism 27.

The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and the shift is controlled by an actuator (not shown) controlled by the TCM 12.

Specifically, the actuator switches the shift stage in the transmission mechanism 25 and connects and disengages the clutch 26. The differential mechanism 27 transmits the power output by the transmission mechanism 25 to the drive shaft 23.
The motor generator 4 is connected to the differential mechanism 27 via a power transmission mechanism 28 such as a chain. The motor generator 4 functions as an electric motor.

As described above, the hybrid vehicle 1 constitutes a parallel hybrid system in which the powers of both the engine 2 and the motor generator 4 can be used to drive the vehicle, and at least one of the engine 2 and the motor generator 4 outputs the power. It is designed to run on power.

The motor generator 4 also functions as a generator, and generates electricity by traveling the hybrid vehicle 1. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheels 5 so as to be able to transmit power, and does not necessarily have to be connected to the differential mechanism 27.

The hybrid vehicle 1 includes a first power storage device 30, a low voltage power pack 32 including a second power storage device 31, a high voltage power pack 34 including a third power storage device 33, a high voltage cable 35, and a low voltage cable 36. And have.

The first power storage device 30, the second power storage device 31, and the third power storage device 33 are composed of a rechargeable secondary battery. The first power storage device 30 is made of a lead battery. The second power storage device 31 is a power storage device having a higher output and a higher energy density than the first power storage device 30.

The second power storage device 31 can be charged in a shorter time than the first power storage device 30. In this embodiment, the second power storage device 31 is made of a lithium ion battery. The second power storage device 31 may be a nickel-metal hydride storage battery.

The first power storage device 30 and the second power storage device 31 are low-voltage batteries in which the number of cells and the like are set so as to generate an output voltage of about 12 V. The third power storage device 33 is made of, for example, a lithium ion battery.

The third power storage device 33 is a high-voltage battery in which the number of cells and the like are set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31, and for example, an output voltage of 100 V is generated. The state such as the remaining capacity of the third power storage device 33 is managed by the high voltage BMS 16.

The hybrid vehicle 1 is provided with a general load 37 as an electric load and a protected load 38. The general load 37 and the protected load 38 are electrical loads other than the starter 21 and the ISG 20.

The protected load 38 is an electric load that is always required to have a stable power supply. The protected load 38 includes a stability control device 38A that prevents the hybrid vehicle 1 from skidding, an electric power steering control device 38B that electrically assists the operating force of the steering wheels, and a headlight 38C. The protected load 38 also includes lamps and meters of an instrument panel (not shown) and a car navigation system.

The general load 37 is an electric load that is temporarily used without requiring a stable power supply as compared with the protected load 38. The general load 37 includes, for example, a wiper (not shown) and an electric cooling fan that blows cooling air to the engine 2.

The low-voltage power pack 32 has switches 40 and 41 and a low-voltage BMS 15 in addition to the second power storage device 31. The first power storage device 30 and the second power storage device 31 are connected via a low voltage cable 36 so as to be able to supply electric power to the starter 21, the ISG 20, the general load 37 as an electric load, and the protected load 38. There is. The first power storage device 30 and the second power storage device 31 are electrically connected in parallel to the protected load 38.

The switch 40 is provided on the low voltage cable 36 between the second power storage device 31 and the protected load 38. The switch 41 is provided in the low voltage cable 36 between the first power storage device 30 and the protected load 38.

The low-voltage BMS 15 controls the opening and closing of the switches 40 and 41 to control the charging / discharging of the second power storage device 31 and the power supply to the protected load 38. When the engine 2 is stopped due to idling stop, the low voltage BMS 15 closes the switch 40 and opens the switch 41 to supply electric power from the second power storage device 31 having high output and high energy density to the protected load 38. It is designed to supply.

The low-voltage BMS 15 is the first by closing the switch 40 and opening the switch 41 when the engine 2 is started by the starter 21 and when the engine 2 stopped by the idling stop control is restarted by the ISG 20. Power is supplied from the power storage device 30 to the starter 21 or the ISG 20. When the switch 40 is closed and the switch 41 is opened, power is also supplied from the first power storage device 30 to the general load 37.

As described above, the first power storage device 30 is adapted to supply at least electric power to the starter 21 and the ISG 20 as the starting devices for starting the engine 2. The second power storage device 31 is adapted to supply at least power to the general load 37 and the protected load 38.

The second power storage device 31 is connected so as to be able to supply power to both the general load 37 and the protected load 38, but preferentially supplies power to the protected load 38, which is always required to have a stable power supply. The switches 40 and 41 are controlled by the low voltage BMS 15.

The low-voltage BMS 15 stabilizes the protected load 38 while considering the charging state (remaining charge) of the first power storage device 30 and the second power storage device 31 and the operation requirements for the general load 37 and the protected load 38. The switches 40 and 41 may be controlled differently from the above-described example in order to give priority to the operation.

The high-voltage power pack 34 has an inverter 45, an INVCM 14, and a high-voltage BMS 16 in addition to the third power storage device 33. The high-voltage power pack 34 is connected via the high-voltage cable 35 so as to be able to supply electric power to the motor generator 4.

The inverter 45 is controlled by the INVCM 14 to convert the AC power applied to the high voltage cable 35 and the DC power applied to the third power storage device 33 to each other. For example, when the motor generator 4 is forced to run, the INVCM 14 converts the DC power discharged by the third power storage device 33 into AC power by the inverter 45 and supplies it to the motor generator 4.

When the motor generator 4 is regenerated, the INVCM 14 converts the AC power generated by the motor generator 4 into DC power by the inverter 45 and charges the third power storage device 33.

The HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16 each have a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and backup data. It is composed of a computer unit having a flash memory for storing, an input port, and an output port.

The ROM of these computer units stores various constants, various maps, and the like, as well as programs for making the computer unit function as HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16, respectively. ..

That is, when the CPU executes the program stored in the ROM using the RAM as the work area, these computer units are used as the HCU10, ECM11, TCM12, ISGCM13, INVCM14, low voltage BMS15, and high voltage BMS16 in this embodiment, respectively. Function.

In this embodiment, the ECM 11 is adapted to execute idling stop control. In this idling stop control, the ECM 11 stops the engine 2 when a predetermined automatic stop condition is satisfied, and drives the ISG 20 via the ISGCM 13 to restart the engine 2 when the predetermined restart condition is satisfied. There is. Therefore, unnecessary idling of the engine 2 is not performed, and the fuel efficiency of the hybrid vehicle 1 can be improved.

The hybrid vehicle 1 is provided with CAN communication lines 48 and 49 for forming an in-vehicle LAN (Local Area Network) conforming to a standard such as CAN (Controller Area Network).

The HCU 10 is connected to the INVCM 14 and the high voltage BMS 16 by a CAN communication line 48. The HCU 10, INVCM14, and high-voltage BMS16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

The HCU 10 is connected to the ECM 11, TCM 12, ISGCM 13 and low voltage BMS 15 by a CAN communication line 49. The HCU10, ECM11, TCM12, ISGCM13, and low-voltage BMS15 mutually transmit and receive signals such as control signals via the CAN communication line 49.

In FIG. 2, a hydraulic pressure sensor 51, a vehicle speed sensor 52, an accelerator opening sensor 53, and a road surface gradient sensor 54 are connected to the ECM 11. The hydraulic pressure sensor 51 detects the brake fluid pressure P and outputs the detection information to the ECM 11.

The vehicle speed sensor 52 detects the traveling speed (vehicle speed) V of the hybrid vehicle 1 and outputs the detection information to the ECM 11. The accelerator opening sensor 53 outputs a signal proportional to the accelerator opening AP corresponding to the amount of operation of the accelerator pedal 53A to the ECM 11.

The road surface gradient sensor 54 is composed of, for example, an acceleration sensor, and outputs a signal θ corresponding to the magnitude of the gradient of the road surface on which the hybrid vehicle 1 travels to the ECM 11. The automatic stop device 70 is configured by including the ECM 11 and the road surface gradient sensor 54 of this embodiment. The automatic stop device 70 constitutes the automatic stop device for the engine of the present invention.

The ECM 11 functions as an engine automatic stop unit 61. The engine automatic stop unit 61 sets the engine 2 based on the brake fluid pressure information detected by the hydraulic pressure sensor 51, the vehicle speed information detected by the vehicle speed sensor 52, and the road surface gradient information detected by the road surface gradient sensor 54. Automatically stop.

In the engine automatic stop unit 61, for example, the brake fluid pressure P is equal to or higher than a specific pressure, the vehicle speed is equal to or lower than a predetermined speed value (for example, Vthkm / h), and the magnitude θ of the road surface gradient is within a predetermined range (for example, the road surface). The automatic stop of the engine 2 is permitted under the condition that the gradient θ is −N ₁ % ≦ θ ≦ + N ₂ %) as a predetermined automatic stop condition.

The ECM 11 sets the engine 2 on a predetermined restart condition, for example, on the condition that the opening degree of the accelerator pedal 53A detected by the accelerator opening degree sensor 53 becomes larger than 0 or the brake is turned off. Restart. The road surface gradient sensor 54 of this embodiment constitutes the road surface gradient detection unit of the present invention.

The ECM 11 functions as a failure determination unit 62. Based on the road surface gradient information input from the road surface gradient sensor 54, the failure determination unit 62 determines that the road surface gradient sensor 54 is a failure when the abnormality of the road surface gradient sensor 54 is continued for the first predetermined time.

The failure of the road surface gradient sensor 54 is that the road surface gradient sensor 54 cannot accurately detect the magnitude of the road surface gradient. For example, if the output value of the road surface gradient sensor 54 is fixed or the state where there is no output is continued, the failure determination unit 62 determines that the road surface gradient sensor 54 is abnormal, and this state is the first. When the predetermined time is continued, the failure of the road surface gradient sensor 54 is confirmed. In this way, the condition that the first predetermined time elapses to determine the failure of the road surface gradient sensor 54 excludes, for example, the case where the output value temporarily becomes a value indicating an abnormality due to noise or the like. To do.

The engine automatic stop unit 61 permits the automatic stop of the engine 2 when the automatic stop condition of the road surface gradient is satisfied for a second predetermined time longer than the first predetermined time among the predetermined automatic stop conditions. In FIG. 3, the second predetermined time T2 is set longer than the first predetermined time T1.

The first predetermined time T1 is a failure state determination time required from the detection of the abnormality of the road surface gradient sensor 54 to the determination of the failure. The second predetermined time T2 is the time required from the detection of the road surface gradient information by the road surface gradient sensor 54 to the determination of the establishment of the automatic stop condition of the road surface gradient. The first predetermined time T1 of the present embodiment corresponds to the first predetermined time of the present invention, and the second predetermined time T2 corresponds to the second predetermined time of the present invention.
Hereinafter, the first predetermined time may be referred to as a failure state determination time, and the second predetermined time may be referred to as an automatic stop condition establishment determination time for the road surface gradient.

For example, in FIG. 3, when the start time of T1 and T2 is t1, the failure determination unit 62 determines the failure state of the road surface gradient sensor 54 before the second predetermined time T2 elapses because T2> T1. Can be done.
If the abnormality of the road surface gradient sensor 54 continues for the first predetermined time T1, the engine automatic stop unit 61 determines that the road surface gradient sensor 54 is out of order and prohibits the automatic stop of the engine 2. When the engine automatic stop unit 61 determines that the road surface gradient sensor 54 is normal, it determines that the automatic stop condition for the road surface gradient is satisfied at t2 when the second predetermined time T2 has elapsed.

Next, the automatic stop processing of the engine 2 will be described with reference to FIGS. 4 to 6.
4 to 6 are flowcharts of the automatic stop processing program of the engine 2, and the automatic stop processing program is stored in the ROM of the ECM 11 and repeatedly executed by the ECM 11 at predetermined time intervals.

In FIG. 4, the failure determination unit 62 of the ECM 11 determines whether or not an abnormality in the road surface gradient sensor 54 has been detected based on the detection information of the road surface gradient sensor 54 (step S1). The failure determination unit 62 detects an abnormality in the road surface gradient sensor 54, for example, when the output value of the road surface gradient sensor 54 is fixed for a certain period of time.
Here, when the road surface gradient sensor 54 is fixed to an output value indicating a flat road, for example, the road surface is erroneously detected as a flat road even though the road surface has a slope.

In step S1, the failure determination unit 62 returns this routine when it is determined that the failure of the road surface gradient sensor 54 has not been detected.

When the failure determination unit 62 determines in step S1 that an abnormality in the road surface gradient sensor 54 has been detected, the failure determination unit 62 starts counting the failure state determination time T1 of the road surface gradient sensor 54 (step S2), and determines the failure state. It is determined whether or not the time T1 has elapsed (step S3).

In step S3, if it is determined that the failure state determination time T1 has not elapsed, the failure determination unit 62 returns this routine. In step S3, when the failure determination unit 62 determines that the failure state determination time T1 has elapsed while the failure state is continued, the road surface gradient sensor 54 has failed after the failure state determination time T1 has elapsed. It is confirmed (step S4).

In FIG. 5, the engine automatic stop unit 61 of the ECM 11 determines whether or not the road surface gradient is equal to or less than the automatic stop determination value of the engine 2 based on the detection information from the road surface gradient sensor 54 (step S11). The automatic stop determination value of the engine 2 of this embodiment is the absolute upper limit value or lower limit value of the range θ (−N ₁ % ≦ θ ≦ + N ₂ %) between the predetermined uphill slope and the predetermined downhill slope. Let it be a value.

When the road surface slope is larger than the predetermined uphill slope or the road surface slope is larger than the predetermined downhill slope, the hybrid vehicle 1 may start moving along the road surface when the engine 2 is stopped. Therefore, the engine 2 is automatically operated. Not preferable to stop. Therefore, the automatic stop determination value is set to a value in the range of the road surface gradient at which the hybrid vehicle 1 does not start to move even if the engine 2 is automatically stopped.

In step S11, when the engine automatic stop unit 61 determines that the road surface gradient is larger than the automatic stop determination value of the engine 2, the hybrid vehicle 1 may start moving when the engine 2 is automatically stopped. This routine is returned without satisfying the automatic stop condition by judging that there is.

In step S11, when the engine automatic stop unit 61 determines that the road surface gradient is equal to or less than the automatic stop determination value of the engine 2, the engine automatic stop unit 61 starts counting the road surface gradient automatic stop condition establishment determination time T2 (step S12). , It is determined whether or not the automatic stop condition establishment confirmation time T2 of the road surface gradient has elapsed (step S13).

In step S13, when the engine automatic stop unit 61 determines that the automatic stop condition establishment confirmation time T2 of the road surface gradient has not elapsed, the engine automatic stop unit 61 returns this routine, and the automatic stop condition establishment confirmation time T2 of the road surface gradient is set. If it is determined that the lapse has passed, the automatic stop condition of the road surface gradient is satisfied (step S14).

In FIG. 6, the engine automatic stop unit 61 determines whether or not the failure of the road surface gradient sensor 54 is confirmed (step S21), and if it is determined that the failure of the road surface gradient sensor 54 is confirmed, the failure state. After the lapse of the fixed time T1, the automatic stop of the engine 2 is prohibited (step S22), and this routine is returned.

In step S21, when the engine automatic stop unit 61 determines that the failure of the road surface gradient sensor 54 has not been confirmed, it determines whether or not the automatic stop condition of the road surface gradient is satisfied (step S23). If it is determined that the automatic stop condition for the road surface gradient is not satisfied, this routine is returned.

In step S23, when the engine automatic stop unit 61 determines that the automatic stop condition of the road surface gradient is satisfied, it determines that the signal input from the road surface gradient sensor 54 corresponds to the gradient. Allowing the automatic stop of the engine 2 (step S24). At this time, if the automatic stop condition other than the automatic stop condition of the road surface gradient is satisfied, the engine 2 is automatically stopped.

As described above, the automatic stop device 70 of the present embodiment has the road surface gradient sensor 54 that detects the slope of the road surface on which the hybrid vehicle 1 travels, and the road surface gradient that is set based on the road surface gradient information detected by the road surface gradient sensor 54. An engine automatic stop unit 61 for automatically stopping the engine 2 when a predetermined automatic stop condition including the automatic stop condition of the above is satisfied.

Further, the automatic stop device 70 determines that the road surface gradient sensor 54 has failed if the abnormality of the road surface gradient sensor 54 continues for the first predetermined time T1 based on the road surface gradient information input from the road surface gradient sensor 54. The failure determination unit 62 for determining is provided, and the engine automatic stop unit 61 automatically stops the engine 2 when the automatic stop condition of the road surface gradient is satisfied during the second predetermined time T2, which is longer than the first predetermined time T1. to approve.

As a result, it is possible to secure a time for detecting the abnormality of the road surface gradient sensor 54 during the second predetermined time T2, so that the failure of the road surface gradient sensor 54 is determined before the automatic stop condition of the road surface gradient is satisfied. In that case, it is possible to perform control for prohibiting the automatic stop of the engine 2.

As a result, when the hybrid vehicle 1 erroneously determines the slope of the road surface based on the detection information of the road surface gradient sensor 54, it is possible to prevent the hybrid vehicle 1 from moving against the driver's intention on the sloped road surface.

Further, if the failure of the road surface gradient sensor 54 is not determined before the automatic stop condition of the road surface gradient is satisfied, it is possible to control the automatic stop of the engine 2, so that the fuel efficiency of the engine 2 can be improved. ..

In the automatic stop device 70 of the present embodiment, the engine automatic stop unit 61 prohibits the automatic stop of the engine 2 when the failure determination unit 62 determines that the road surface gradient sensor 54 has a failure.

As a result, when the hybrid vehicle 1 is stopped on a sloped road surface and the engine automatic stop unit 61 erroneously determines the road surface gradient based on the detection information of the road surface gradient sensor 54, the hybrid is contrary to the driver's intention. It is possible to more reliably prevent the vehicle 1 from moving.

The automatic stop device 70 of this embodiment automatically stops the engine 2 based on the detection information of the road surface gradient sensor 54, but is not limited to this, and the engine is based on the detection information of the negative pressure detection device. The automatic stop of 2 may be carried out.

When the negative pressure detecting means is out of order, if the negative pressure detecting means mistakenly determines that the negative pressure of the engine 2 is large and automatically stops the engine 2, the negative pressure is not generated, so depress the brake pedal. The assist power at the time decreases.

Therefore, the negative pressure detection device fails by making the time from the detection of the negative pressure by the negative pressure detection device to the determination of the magnitude of the negative pressure longer than the time for detecting the failure of the negative pressure detection device. The automatic stop of the engine 2 may be prohibited while the engine 2 is running.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 ... hybrid vehicle (vehicle), 2 ... engine, 54 ... road surface gradient sensor (road surface gradient detection unit), 61 ... engine automatic stop unit, 62 ... failure determination unit, 70 .. .Automatic stop device

Claims (2)

A road surface slope detection unit that detects the slope of the road surface on which the vehicle travels,
It is provided with an engine automatic stop unit that automatically stops the engine when a predetermined automatic stop condition including the automatic stop condition of the road surface gradient set based on the road surface gradient information detected by the road surface gradient detection unit is satisfied. It is an automatic engine stop device
Based on the road surface gradient information input from the road surface gradient detection unit, if the abnormality of the road surface gradient detection unit is continued for the first predetermined time, the road surface gradient detection unit is provided with a failure determination unit for determining that the failure is present.
The engine automatic stop unit permits the automatic stop of the engine when the automatic stop condition of the road surface gradient is satisfied for a second predetermined time longer than the first predetermined time among the predetermined automatic stop conditions. Configured to
An automatic engine stop device characterized in that the start time of the first predetermined time and the start time of the second predetermined time are the same . The automatic engine stop device according to claim 1, wherein the automatic engine stop unit prohibits the automatic stop of the engine when the failure determination unit determines that the road surface gradient detection unit is out of order. ..

Images