FR3057912A1 - AUTOMATIC MOTOR STOP CONTROL SYSTEM - Google Patents

Abstract

The present invention relates to an automatic engine stop control system (70), including a road gradient sensor (54) that is used to detect a road category (θ) of a road surface on which a vehicle (1) rolls, and an automatic stop-start system (61) configured to automatically stop a motor (2) of the vehicle (1) in one of predetermined auto-off conditions, including an auto-off condition relating to a category of road which is established on the basis of the category of road (θ) detected. In the automatic engine stop control system (70), there is provided a failure determination section (62) configured to determine a failure in the automatic stop-start system (61) upon expiration of a first predetermined period of time (T1) if a fault in the automatic stop-start system (61) remains on the first predetermined period of time (T1).

Description

© Publication number: 3,057,912 (use only for reproduction orders)

©) National registration number: 17 60080 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © IntCI ⁸ : F 02 D 28/00 (2017.01), F 02 D 29/02

A1 PATENT APPLICATION

©) Date of filing: 25.10.17. © Applicant (s): SUZUKI MOTOR CORPORATION - © Priority: 26.10.16 JP 2016209743. JP. @ Inventor (s): OZERA AKIHIKO, SAITO MASAKAZU, UCHIDA NAOHIRO and OKAWACHI RYO- (43) Date of public availability of the HEI. request: 04.27.18 Bulletin 18/17. ©) List of documents cited in the report preliminary research: The latter was not established on the date of publication of the request. (© References to other national documents ® Holder (s): SUZUKI MOTOR CORPORATION. related: ©) Extension request (s): © Agent (s): CABINET PLASSERAUD.

AUTOMATIC ENGINE STOP CONTROL SYSTEM.

FR 3,057,912 - A1 (P / d The present invention relates to an automatic engine stop control system (70), including a route gradient sensor (54) which is used to detect a road category (θ) a road surface on which a vehicle (1) is traveling, and an automatic start-stop system (61) configured to automatically stop an engine (2) of the vehicle (1) under one of the stopping conditions predetermined automatic conditions, including an automatic stop condition relating to a road category which is established on the basis of the detected road category (θ). In the automatic engine stop control system (70) there is provided a failure determination section (62) configured to determine a failure in the automatic start-stop system (61) upon expiration of a first predetermined time period (T1) if a fault in the system automatic start-stop (61) remains for the first period of time to predict mined (T1).

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! PRESSURE SENSOR IL_- j BRAKE FLUID | Λ-h Λ - 6Ϊ i SPEED SENSOR | V j OE VEHICLE | * I STOP SYSTEM- | j OEM AUTOMATIC ARRAGg | cf y- '54 p CRAMENT SENSOR | -θ§—> f DETERMINATION 1, FAILURE SECTION | -ENGINE

AUTOMATIC ENGINE STOP CONTROL SYSTEM

The present invention relates to an automatic engine stop control system.

Some motor vehicles are equipped with an automatic “Stop-Start” system, which automatically stops and restarts the vehicle engine to reduce the vehicle’s fuel consumption under certain conditions, such as when the engine is idling.

Document JP 2012-255383A discloses a known motor vehicle equipped with a stop-start system. In operation, this motor vehicle stop-start system interrupts the engine in response to a gradient (or category) of the road in progress.

In the so-called known idling stop vehicle, the fault diagnosis of the start-stop system is carried out on the basis of a signal from an on-board inclinometer after the engine has stopped automatically when the automatic stop condition of the engine is established with a road category less than or equal to a second predetermined threshold which is smaller than a first predetermined threshold. Until the fault diagnosis is completed, the automatic stopping of the engine with road category exceeding the second predetermined threshold is inhibited.

Patent literature 1: JP 2012-255383A

The motor vehicle equipped with the known automatic starting system presents the potential problem that the motor vehicle can move against the intention of the driver if the motor vehicle ends up being immobilized when it enters a steep slope from a flat road before completion of the failure diagnosis initiated by automatic engine shutdown.

An object of the present invention is to provide an automatic engine stop control system capable of preventing a motor vehicle from moving along a slope having a significant road category even in the event of a failure in an automatic start-stop system.

According to the present implementation, an automatic engine stop control system is proposed, including a route gradient sensor which is used to detect a category of road of a road surface on which a vehicle is driving, and an automatic start-stop system configured to automatically stop an engine of the vehicle under one of predetermined automatic stop conditions, including an automatic stop condition relating to a road category which is established based on the category detected route, in which there is provided a failure determination section configured to determine a failure in the automatic start-stop system upon expiration of a first predetermined period of time if a fault in the automatic start-stop remains above the first predetermined period of time; and in the case where a current road category is greater than or equal to a predetermined value, the automatic start-stop system allows an automatic stop of the engine when the second predetermined period of time which is longer expires that the first predetermined period of time if the automatic stopping condition relating to the road category which is established remains on the second predetermined period of time.

According to the invention, there is provided an automatic engine stop control system capable of preventing a motor vehicle from moving along a slope having a significant road category even in the event of a failure in a automatic start-stop system.

Figure 1 is a diagram of a vehicle system of a motor vehicle in which a system for controlling automatic engine shutdown can be used.

Figure 2 is a block diagram of system components for controlling automatic engine shutdown.

Figure 3 illustrates a first predetermined period of time (T1) required to determine a failure in an automatic start-stop system and a second predetermined period of time (T2) required to determine an automatic stop condition relating to the category of road when a current road category is greater than or equal to a predetermined value, and another second predetermined period of time (T3) required to determine an automatic stop condition relating to the road category when a category of current route is less than a predetermined value.

FIG. 4 is a flow diagram illustrating an example of an algorithm aimed at determining the failure in the automatic stop-start system.

FIG. 5 is a flow diagram illustrating an example of an algorithm for determining the automatic stop condition relating to the road category.

FIG. 6 is a flow diagram illustrating an example of an algorithm for controlling automatic engine shutdown.

A system for controlling automatic engine shutdown of the present invention includes a road gradient sensor which is used to detect a road category of a road surface on which a vehicle is traveling, and a stop system. automatic start configured to automatically stop an engine of the vehicle under one of predetermined automatic stop conditions, including an automatic stop condition relating to a road category which is established on the basis of a detected road category. In the automatic engine stop control system, there is provided a failure determination section configured to determine a failure in the auto start stop system upon expiration of a first predetermined period of time if a fault in the automatic start-stop system persists for the first predetermined period of time. In the event that the current road category is greater than or equal to a predetermined value, the automatic start stop system authorizes the automatic stopping of the engine when the second predetermined period of time which is longer than the expiration first predetermined period of time if the automatic stop condition relating to the route category of the predetermined automatic stop conditions established persists during the second predetermined period of time. This configuration prevents the motor vehicle from traveling on a steep slope even in the event of a failure in the automatic start-stop system.

Referring to the accompanying drawings, Figure 1 illustrates a vehicle system of a motor vehicle in the form of, but not limited to, a hybrid electric vehicle in which an automatic engine shutdown control system can to be employed.

Referring to Figure 1, a motor vehicle can include, but is not limited to, a hybrid electric vehicle 1. In the present implementation, the hybrid electric vehicle 1 includes: a motor 2 in the form of a motor internal combustion; a transmission 3; a converter group 4; a set of drive wheels, only one being illustrated and designated by 5; a hybrid control unit (HCU) 10 configured to exhaustively control the hybrid electric vehicle 1; an electronic control unit or an electronic control module (ECM for "Engine Control Module") 11 configured to control the motor 2; a transmission control module (TCM) 12 configured to control the transmission 3; an integrated starter-alternator control module (ISGCM for “Integrated Starter Generator Control Module”) 13; an inverter control module (INVCM for "INVerter Control Module") 14; a low-voltage battery management system (LVBMS for “Low-Voltage Battery Management System”) 15; and a high-voltage battery management system (HVBMS) 16.

The engine 2 is formed from a plurality of cylinders. In the present example, the engine 2 is a four-stroke engine, meaning that four piston times are necessary to complete a cycle. The cycle includes four separate processes: intake, compression, combustion and explosion times, and exhaust.

An integrated starter-generator (ISG) 20 and a starter 21 are operationally connected to the engine 2. The ISG 20 is connected to a crankshaft 18 of the engine 2 by means of a belt 22. The ISG 20 works, as an electric motor, to start motor 2 when an electricity supply, and it works, as an electricity generator, to generate electricity when a electricity supply torque from crankshaft 18.

In the present implementation, under the control of ISGCM 13, the ISG 20 operates, as an electric motor, to restart motor 2 after an automatic engine stop function has automatically stopped motor 2 rather than allowing engine 2 to idle. The ISG 20 works like the engine to provide assistance when the engine 2 powers the hybrid electric vehicle 1.

The starter 21 includes a motor and sprockets, none of which is illustrated. The starter 21 supplies starting torque to the engine 2 by rotating the crankshaft 18 with the engine. Engine 2 is started by starter 21 in this way so that it is restarted by ISG 20 after the auto engine stop function has automatically stopped engine 2.

The transmission 3 changes the speed of the output rotation coming from the motor 2 to propel the set of drive wheels 5 via a drive shaft 23. The transmission 3 comprises a gear change mechanism in constant engagement 25 of a mechanism d '' parallel shaft gear; a clutch 26 of the dry single-clutch and normally closed clutch type; and a differential 27.

As described, the transmission 3 is configured as an automatic transmission called an automated manual transmission (AMT) in which a gear change is made by an actuator, not shown, which is controlled by the TCM 12.

In detail, the actuator changes gears in the gear change mechanism 25, and another actuator engages or disengages the clutch 26. The differential 27 transmits energy from the gear change mechanism 25 to the shaft d 23.

The converter unit 4 is connected to the differential 27 by means of a power transmission mechanism 28, such as a chain, etc. The converter group 4 operates like an electric motor.

As described, the hybrid electric vehicle 1 is configured for a parallel hybrid system in which both the energy from the engine 2 and that from the converter unit 4 can be used for propulsion so that the hybrid electric vehicle 1 is powered by at least one of the energy coming from the motor 2 and that coming from the converter group 4.

The converter unit 4 can operate as an electricity generator, allowing the generation of electricity under certain circumstances when the hybrid electric vehicle 1 is driving. It is not essential to couple the converter group 4 to the differential 27. The converter group 4 can be coupled at any point on an axis between the motor 2 and the drive wheel 5.

The hybrid electric vehicle 1 includes a first electricity storage device 30; a low voltage power supply 32 including a second electricity device 31; a high voltage power supply 34 including a third electricity storage device 33; a high voltage cable 35; and a low voltage cable 36.

The first electricity storage device 30, the second electricity storage device 31 and the third electricity storage device 33 are secondary or rechargeable batteries. In the present implementation, the first electricity storage device 30 is in the form of a lead-acid battery. The second electricity storage device 31 has a higher power output and energy density than the first electricity storage device 30.

The second electricity storage device 31 can be recharged in a shorter time than the first electricity storage device 30. In the present implementation, the second electricity storage device 31 is in the form of '' a lithium-ion battery. The second electricity storage device 31 can be in the form of a metal nickel hydride battery.

Each of the first and second electricity storage devices 30 and 31 is a low voltage battery in which the number of cells is fixed so that it can generate an output voltage of about 12 volts. The third electricity storage device 33 is in the form, for example, of a lithium-ion battery.

The third electricity storage device 33 is a high-voltage battery in which the number of cells is fixed so that it can generate a higher output voltage, for example of 100 volts, than an output voltage generated by the first and second electricity storage devices 30 and 31. The state of the third electricity storage device 33, such as the residual capacity, is managed by the HVBMS 16.

The hybrid electric vehicle 1 is equipped with groups of electrical charges, that is to say a group of general charges 37 and a group of significant charges 38. The general charges 37 and the significant charges 38 are electrical charges at the exception of starter 21 and ISG 20.

The large charges 38 are electric charges such that they always require a stable supply. Large loads 38 include an electronic stability control system 38A which improves the stability of the hybrid electric vehicle 1; an electronic power steering control system 38B which assists a driver in steering by increasing the steering effort of the steering wheel; and 38C headlights. In addition, major loads 38 include lamps and meters within a dashboard and a car navigation system.

General loads 37 are electrical loads as they are used temporarily and therefore do not require a stable power supply compared to large loads 38. General loads 37 include, for example, a wiper and an electric cooling fan which sends cooling air to the engine 2.

The low voltage power supply 32 includes switches 40 and 41, and the LVBMS 15 in addition to the second electricity storage device 31. The first electricity storage device 30 and the second electricity storage device 31 are connected via the low voltage cable 36 to the starter 21, the ISG 20, and loads including general loads 37 and large loads 38 to supply them. As for large loads 38, the first and second electricity storage devices 30 and 31 are connected in parallel.

The switch 40 is formed in the low voltage cable 36 between the second electricity storage device 31 and the large loads 38. The switch 41 is formed in the low voltage cable 36 between the first electricity storage device 30 and the significant charges 38.

The LVBMS 15 controls the charge (that is to say the recharge) of the second electricity storage device 31 with the alimentatron coming from the ISG 20 and the feeding of the large loads 38 coming from the second storage device of electricity 31 by selectively putting the switches 40 and 41 in on and / or off states. Vehicle 1 is a stop / start vehicle equipped with an automatic engine stop function. This function automatically stops the engine 2 during certain periods of operation, for example when the vehicle 1 is stopped rather than allowing the engine 2 to idle. When this function interrupts the motor 2, the LVBMS 15 opens the switch 41 with the switch 40 closed, disconnecting the second electricity storage device 31 from the ISG 20 and connecting the second electricity storage device 31 to heavy loads 38 to provide a stable supply from the high energy density and high output power storage device 31.

When starter 21 starts engine 2 or ISG 20 restarts engine 2, LVBMS 15 opens switch 41 with switch 40 closed, causing the first electricity storage device 30 to supply power to starter 21 or at the ISG 20. When the switch 41 is open with the switch 40 closed, the first electricity storage device 30 also supplies the general loads 37.

As described, the first electricity storage device 30 supplies at least the power to the starter 21 and to the ISG 20 which serve as starting gears for the motor 2. The second electricity storage device 31 supplies the less the supply to general expenses 37 and to significant expenses 38.

The second electricity storage device 31 is switched on so that it can supply power to both general loads 37 and heavy loads 38, but the LVBMS 15 controls switches 40 and 41 so that the second device for storing electricity 31 preferably supplies the large loads 38 which always require a stable supply.

With regard to the state of charge (SOC) for each of the first and second electricity storage devices 30 and 31, operating requests for general charges 37 and significant charges 38, and the large loads 38 which must operate stably, the LVBMS 15 sometimes controls the switches 40 and 41 in a manner different from what is described above.

The high voltage power supply 34 includes an inverter 45, the INVCM 14 and the HVBMS 16 in addition to the third electricity storage device 33. The high voltage power supply 34 is connected to the converter block 4 via the high voltage cable 35 so that it can supply the converter unit 4.

Under the control of the INVCM 14, the inverter 45 converts a DC input discharged from the third electricity storage device 33 into an AC output passing through the high voltage cable 35 under certain circumstances and converts an input of alternating current passing through the high voltage cable 35 to a direct current output delivered to the third electricity storage device 33 in other circumstances. For example, the INVCM 14 converts a direct current discharged by the third electricity storage device 33 into alternating current delivered by the converter group 4 in response to a power request to operate the converter group 4 in power mode. .

The INVCM 14 converts the alternating current generated by the converter group 4 into direct current delivered to the third electricity storage device 33 to recharge the latter in response to a regeneration request in order to operate the converter group 4 in mode of regeneration.

In the present example, each of the HCU 10, the ECM 11, the TCM 12, the ISGCM 13, the INVCM 14, the LVBMS 15 and the HVBMS 16 consists of a unit d computer which includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a flash memory for data backup , input ports and output ports.

The ROMs of these computer units store programs in addition to various constants and tables to cause each of the computer units to function as the corresponding one among the HCU 10, ECM 11, TCM 12, l 'ISGCM 13, INVCM 14, LVBMS 15 and HVBMS 16.

In other words, each of these computer units is required to function as one of the HCU 10, the ECM 11, the TCM 12, the ISGCM 13, the INVCM 14, the LVBMS 15 and the HVBMS 16 by allowing the CPU to execute programs stored in the ROM using the RAM as work area.

In the present implementation, the ECM linked an automatic engine stop function. This function automatically stops the engine during certain periods of operation to conserve fuel. For example, the automatic stop function can be engaged when the vehicle 1 is stopped rather than allowing the engine 2 to idle. Engine 2 can be restarted by ISG 20 under the control of ISGCM 13 when the driver releases the brake or operates the accelerator or gas pedal.

The hybrid electric vehicle 1 comprises CAN communication lines 48 and 49 forming a local network (LAN for "Local Area Network") which meets the standards of CAN networks (Controller Area Network).

The HCU 10 is connected to the INVCM 14 and the HVBMS 16 via the CAN 48 communication line. Via this CAN 48 communication line, the HCU 10, the INVCM 14 and the HVBMS 16 transmit and receive signals, such as control signals, to each other.

The HCU 10 is connected to the ECM 11, the TCM 12, the ISGCM 13, and the LVBMS 15 via the CAN 49 communication line. Via this CAN 49 communication line, the HCU 10, ECM 11, TCM 12, ISGCM 13, and LVBMS 15 transmit and receive signals, such as control signals, to each other.

Referring now to Figure 2, an automatic engine shutdown control system 70 includes the ECM 11. The ECM 11 communicates with sensors. The sensors include, but are not limited to, a brake fluid pressure sensor 51, a vehicle speed sensor 52, an accelerator position sensor 53, and a gradient sensor 54.

The brake fluid pressure sensor 51 provides a pressure signal (P) which is indicative of a brake fluid pressure in a brake system of the electric hybrid vehicle 1 at the ECM 11. The vehicle speed sensor 52 provides a vehicle speed signal (V) which is indicative of a travel speed of vehicle 1 to the ECM 11. The accelerator position sensor 53 of an accelerator pedal 53A provides a position signal the accelerator pedal (AP for “Accelerator Pedal”) which corresponds to a request from the propulsion driver at the ECM 11.

The gradient sensor 54 provides a signal GS which is indicative of a gradient or a slope from vehicle 1 to the ECM 11. Vehicle 1 includes a road category estimator or algorithm (not shown) which determines the gradient or the road category Θ according to the signal GS. The ECM 11, the brake fluid pressure sensor, the vehicle speed sensor 52, the accelerator pedal position sensor 53 and the gradient sensor 54 constitute in part an automatic stop control system for motor 70.

The ECM 11 functions as the heart of the automatic start-stop system 61 which automatically interrupts and restarts the engine 2 to reduce fuel consumption under certain conditions. The automatic start-stop system 61 receives a current brake fluid pressure by communication with the brake fluid pressure sensor 51, a current vehicle speed by communication with the vehicle speed sensor 52, and a category of road in progress Θ by communication with the gradient sensor 54. In response to the current brake fluid pressure, the vehicle speed and the road category Θ, the automatic start-stop system 61 controls the automatic engine shutdown 2.

The automatic start-stop system 61 can automatically stop the engine 2 when predetermined automatic stop conditions are true or satisfied. Such automatic shutdown conditions include, but are not limited to, a brake fluid pressure P greater than or equal to a specified pressure, a vehicle speed less than or equal to a predetermined threshold speed Vth km / h, and a category of road Θ which is within a predetermined range, namely -Ni% ^ 9â-N2%.

In the present implementation, on the basis of the outputs (that is to say information detected) concerning, without being limited to, the brake fluid pressure sensor 51, the vehicle speed sensor 52, the accelerator pedal position sensor 53, and the gradient sensor 54, the automatic engine stop control system 70 issues an automatic stop instruction which authorizes the automatic stop of the engine 2 if the conditions of predetermined automatic shutdowns are true or satisfied. The system 70 can issue such an automatic stop instruction based on the outputs of other sensors on the motor vehicle 1.

If the engine 2 is maintained in a self-stopped condition, the engine 2 is self-started or restarted in response to an actuation by the driver of an accelerator pedal 53A, that is to say in response at a position of the accelerator pedal 53A greater than 0 and in response to an anticipation of a vehicle launch event according to brake release conditions.

The ECM 11 includes a failure determination section 62. The failure determination section 62 determines a failure in the system 70 if a fault found in the automatic start-stop system 61 remains continuously over a first period of time predetermined Tl. In the present implementation, the fault in the stop-start system 61 indicates or refers to the state that the stop-start system 61 fails to identify input signals from the brake fluid pressure sensor 51, the vehicle speed sensor 52, the accelerator pedal position sensor 53, and the gradient sensor 54.

If such a fault occurs in the start-stop system 61, it is likely that an automatic stop instruction is issued where the automatic stop of engine 2 is not recommended or that engine 2 is restarted with difficulty in the condition stopped automatically. Thus, the failure determining section 62 determines a failure in the start-stop system 61 when the first predetermined time period Tl expires or ends if the fault remains continuously on the first time period predetermined Tl. Specifically, there is a timer used to track the fault. The timer begins to count down when the fault is detected, but stops and resets the time elapsed when Ton fails to detect the same fault. Monitoring the fault to know if it persists during the first predetermined period of time T1 consists in neglecting temporal changes in the output of the gradient sensor 54 which could appear in the presence of noise.

There are predetermined automatic shutdown conditions. The predetermined automatic stop conditions include an automatic stop condition relating to a road category. If a current road category is greater than or equal to a predetermined value, the automatic start-stop system 61 determines the automatic stop condition relating to the road category upon expiration of the cessation of a second predetermined time period T2 if a current road category Θ persists without interruption in the predetermined range of -N |% î5E) ii = + N2% during the second predetermined time period T2. Specifically, we have a timer used to track the road category Θ. The timer starts to count down when it detects that the road category Θ is in the predetermined range, but stops and resets the elapsed time when Ton fails to detect the road category Θ as being in the same predetermined range . The second predetermined period of time T2 is longer than the first predetermined period of time T1 as illustrated in FIG. 3. In the present implementation, the automatic start-stop system 61 transmits an automatic stop request in response to the predetermined automatic stop conditions and to the automatic stop inhibit condition.

The predetermined value of the road category Θ is a standard for determining whether the automatic engine shutdown 2 will cause the motor vehicle 1 to move. The predetermined value of the road category Θ is determined so that the motor vehicle 1 is likely to move if the engine 2 is stopped automatically under the condition of an increased road category Θ greater than or equal to the predetermined value, c ' that is to say that the motor vehicle 1 is stopped on a slope or a steep terrain. If a current road category Θ is less than the predetermined value, the motor vehicle 1 is less likely to move, that is to say that the motor vehicle 1 is stopped on a less steep slope or on a flat road.

The first predetermined time period T1 is a time period required to determine the failure in the automatic start-stop system 61. The first predetermined time period T1 may be called a failure determination time period. The second predetermined time period T2 is a time period required to determine the automatic stop condition relating to the road category. The second predetermined time period T2 can be called a time period for determining the automatic stop condition relating to the road category. The time t2 when the automatic stop condition relating to the road category is determined is set at a time later than the time tl when the failure in the automatic start stop system 61 is determined.

In addition to the aforementioned second predetermined time period T2, another second predetermined time period T3 is established. This other second predetermined time period T3 is a time period required to determine the automatic stopping condition relating to the road category if a current road category Θ is small and less than the predetermined value. This second predetermined time period T3 can be called another time period for determining the automatic stop condition relating to the road category.

The second predetermined time period T3 is set shorter than the second predetermined time period T2. The time t2 when the automatic stop condition relating to the road category is determined is established at a time later than the time t3 when the automatic stop condition relating to the road category is determined.

The automatic start-stop system 61 establishes the second predetermined time period T2 when a current road category Θ is greater than or equal to the predetermined value, but establishes the second predetermined time period T3 when the current road Θ is less than the predetermined value.

In addition, the second predetermined time period T3 is shorter than the first predetermined time period Tl. This relationship allows the automatic start-stop system 61 to promptly issue an automatic stop instruction when a road category in progress Θ is less than the predetermined value of the motor 2, that is to say when, with the automatic stopping of the motor 2, the motor vehicle 1 is less likely to move. This allows an increased frequency of and an increased duration of the idling reduction to reduce the fuel consumption of engine 2.

As described, the automatic start-stop system 61 performs a change in the second predetermined period of time between T2 and T3 according to the size of a current road category Θ.

The failure determining section 62 determines a failure in the automatic start-stop system 61 upon expiration of the first predetermined time period T1 if a fault in the automatic start-stop system 61 remains on the first predetermined time period Tl. When a current road category Θ is greater than or equal to the predetermined value, the ECM 11 determines the automatic stop condition relating to the road category which is one of the conditions of predetermined automatic stop at the expiration of the second predetermined time period T2, which is longer than the first predetermined time period Tl, if the automatic stop condition relating to the road category remains on the second time period predetermined T2. The ECM 11 issues an automatic stop inhibit instruction when a determination is made of the failure in the automatic start stop system 61 when the first predetermined period of time T1 has expired if the fault in the system automatic stop-start 61 remains on the first predetermined period of time T1. In response to this automatic stop inhibition instruction, the automatic stop of the motor 1 is inhibited.

Referring to FIG. 3, the automatic stop condition relating to the road category is illustrated by way of example of the predetermined automatic stop conditions. In addition to the automatic stop condition for the road category, an automatic stop condition for the brake fluid pressure and / or an automatic stop condition for the vehicle speed may be included in the predetermined automatic shutdown conditions.

Referring to FIGS. 4 to 6, a method of controlling engine start-stop is illustrated. In the present implementation, the algorithm described in FIGS. 4 to 6 is used.

Referring to FIG. 4, it is determined whether or not a fault in the automatic start-stop system 61 is detected (in step SI). In step S1, for example, it is decided whether a fault exists in the automatic start-stop system 61 on the basis of the incident according to which the state in which the automatic start-stop system 61 fails not to identify an input signal to the ECM 11 remains for a certain period of time. After determining the fault, the command goes to step S2.

If the determination in step SI is negative, that is to say that the fault in the automatic start-stop system 61 is not detected, the command proceeds to the end of the algorithm marked "RETURN "

In step S2, the elapsed time is counted and it is stored in a variable Tlei. The command goes to step S3. In step S3, it is determined whether the first predetermined time period Tl has expired or not by comparing the variable Tl _e i with the first predetermined time period Tl to determine whether Tl _e i = Tl or not. If the determination in step S3 is negative, that is to say that the first predetermined period of time T1 has not expired, the command proceeds to the end of the algorithm marked "RETURN".

If the fault in the automatic start-stop system 61 is detected without interruption in step S1, the elapsed time is counted without interruption in step S2 until the determination is made that the first predetermined period of time T1 is expired in step S3. If the determination in step S3 is positive, that is to say that the first predetermined period of time T1 has expired, then the control passes to step S4. In step S4, the failure in the automatic start-stop system 61 is determined.

Referring to FIG. 5, in step S11, it is determined whether a current road category catégorie according to the output of the category sensor 54 is or is not within the predetermined range -N |% â) ^ + N2 %, ie if the absolute value of the current road category | θ | is less than or equal to an automatic shutdown authorization limit value. In the present implementation, the automatic stop authorization limit value is the absolute value of the upper limit + N2% of the predetermined range, that is to say a predetermined uphill road category, or that of the lower limit -Ni of the predetermined range, that is to say a predetermined descending road category.

If a current road category Θ is greater than the predetermined ascending road category + N2% or less than the predetermined descending road category -Ni%, the motor vehicle 1 is liable to move when the engine 2 is stopped automatically after that the motor vehicle 1 ended up being immobilized on a slope, then it is preferable not to authorize the automatic stopping of the engine 2. Thus, the limit value of authorization of automatic stopping can adopt a category of road chosen in a group consisting of road categories on which the automatic stopping of engine 2 should be inhibited.

If the determination in step SI 1 is negative, that is to say that the automatic start-stop system 61 determines that the current road category Θ is not within the predetermined range, it is ie -Ni% ^ 9â-N2% or that the absolute value of the current road category | θ | is greater than the automatic stop authorization limit value, then the command goes to the end of the algorithm marked "RETURN" without determining an automatic stop condition.

If the determination in step SI 1 is positive, that is to say that the automatic start-stop system 61 determines that the current road category Θ is in the predetermined range (-Ni% â) ^ -N2%) or that the absolute value of the current road category | θ | is less than or equal to the automatic stop authorization limit value, then control proceeds to step S12. In step S12, it is determined whether a current road category Θ is greater than or equal to a predetermined value θ _χ or not.

The predetermined value θ _χ is a standard for determining whether the automatic stopping of the engine 2 will cause the motor vehicle 1 to move.

If the determination in step S12 is positive, that is to say if the current road category Θ is greater than or equal to the predetermined value θ _χ , the control proceeds to step S13. If the determination in step S12 is negative, that is to say if the current road category Θ is less than the predetermined value θ _χ , the control proceeds to step S17.

In step S13, the automatic start-stop system 61 determines that a predetermined time period T2 which is longer than the first predetermined time period T1 is established as the second predetermined time period T *. In step S17, a predetermined period of time T3 which is shorter than the first predetermined period of time T1 is established as the second predetermined period of time T *. After step S13 or step S17, control proceeds to step S14. In step S14, the automatic start-stop system 61 determines that the elapsed time is counted and it is stored in a variable T * _e i. Control proceeds to step S15. In step S15, it is determined whether the second predetermined period of time T * (that is to say T2 or T3) has expired or not by comparing the variable T * _e i with the second predetermined period of time T * to determine whether T * _e i = T * or not.

If the determination in step S15 is negative, that is to say that the second predetermined period of time T * has not expired, the command proceeds to the end of the algorithm marked "RETURN". If the determination in step S15 is positive, that is to say that the second predetermined period of time T * has expired, then the control passes to step S16. In step S16, an automatic stop condition relating to the road category is determined.

Referring to Figure 6, in step S21, in the failure determination section 62 it is determined whether the failure in the automatic start-stop system 61 is determined or not. If the determination in step S21 is positive, that is, the failure in the road category sensor 54 is determined, then control proceeds to step S22. In step S22, a request for inhibition of automatic stopping is sent to inhibit the automatic stopping of engine 2. After step S22, the command passes at the end of the algorithm marked "RETURN".

If the determination in step S21 is negative, that is to say that the failure in the automatic start-stop system 61 is not determined, then control passes to step S23. In step S23, it is determined whether the automatic stop condition relating to the road category is determined or not. If the determination in step S23 is negative, that is to say that the automatic stop condition relating to the road category is not determined, the command proceeds to the end of the algorithm marked “RETURN "

If the determination in step S23 is positive, that is to say that the automatic start-stop system 61 determines that the automatic stop condition relating to the road category is determined, the control passes to l 'step S24. In step S24, an automatic stop request is issued to authorize the automatic stop of engine 2. If other automatic stop conditions are true or satisfied, engine 2 is stopped automatically.

In the present implementation, the automatic engine stop control system 70 includes the gradient sensor 54, and the automatic start-stop system 61. The automatic start-stop system 61 issues an automatic stop request to authorize the automatic stop of engine 2 if the predetermined automatic stop conditions are true or satisfied. The predetermined automatic stop conditions include the automatic stop condition relating to the road category which is based on the output of the gradient sensor 54.

The system 70 also includes the failure determination section 62. The failure determination section 62 determines the failure in the automatic start-stop system 61 upon expiration of the first predetermined period of time T1 if the fault in the automatic start-stop system 61 persists during the first predetermined period of time T1. When a current road category is greater than or equal to the predetermined value, the system 70 further determines the automatic stop condition relating to the road category at the end of the second predetermined time period T2 if a current road category Θ in the predetermined range persists during the second predetermined time period T2, where: the second predetermined time period T2 is longer longer than the first predetermined period of time Tl. The system authorizes the automatic stop of the motor 2 in response to the relative automatic stop condition ive to the determined road category and to the determined failure.

The failure in the automatic start-stop system 61 is determined at the expiration of the first predetermined period of time T1. This allows the system 70 to inhibit the automatic stop of the engine 2 when a category of road in course is greater than or equal to the predetermined value if the failure in the automatic start-stop system 61 is determined before determining the automatic stop condition. This configuration inhibits the automatic stopping of the engine 2 in the event of a failure in the automatic starting stop system 61, preventing the motor vehicle 1 from moving on a steep slope.

If the failure in the automatic start-stop system 61 is not determined before determining the automatic stop condition relating to the road gradient, the automatic stop of the engine 2 is authorized when the motor vehicle is stopped on a steep slop. This improves fuel consumption.

In the present implementation, the automatic engine stop control system 70 inhibits the automatic shutdown of engine 2 in response to the determination of the failure in the automatic start-stop system 61. This configuration reliably prevents the motor vehicle 1 to move on a steep slope against the intention of the driver.

In the automatic engine stop control system 70, the automatic start-stop system 61 selects the predetermined time period T3 which is shorter than the predetermined period T2 as the second predetermined time period when a category of current route is less than the predetermined value. This shortens the second predetermined period of time from T2 to T3 when the motor vehicle 1 comes to a stop on a road having a road category where the motor vehicle 1 is less likely to move against the intention of the driver during the automatic stop of the engine 2. The automatic start-stop system 61 promptly authorizes the automatic stop of the engine 2, that is to say upon the expiration of the second predetermined period of time T3, reducing the consumption of fuel.

Although the disclosure relates to, but is not limited to, the present implementation, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the present invention. All of these modifications and their equivalents are intended to be covered by the following claims described in the scope of the claims.

1 ... Motor vehicle (hybrid electric vehicle), 2 ... Motor,

51 .... Pressure fluid sensor, 52 ... Vehicle speed sensor,

54 ... Route gradient sensor, 61 ... Automatic start-stop system,

62 ... Failure determination section.

Claims (3)

1. An automatic engine stop control system (70), including a road gradient sensor (54) which is used to detect a road category of a road surface on which a vehicle (1) is driving, and an automatic start-stop system (61) configured to automatically stop an engine of the vehicle under one of the predetermined automatic stop conditions, including an automatic stop condition relating to a road category which is established on the basis of the detected road category, characterized in that there is provided a failure determination section configured to determine a failure in the automatic start-stop system upon expiration of a first predetermined period of time (Tl) if a fault in the automatic start-stop system (61) remains above the first predetermined period of time (T1); and in the case where a current road category (Θ) is greater than or equal to a predetermined value, the automatic start-stop system (61) allows an automatic stop of the engine (2) upon expiration of the second predetermined period of time (T2) which is longer than the first predetermined period of time (T1) if the automatic stopping condition relating to the road category which is established remains on the second predetermined period of time (T2). 2. System (70) according to claim 1, in which, in the case where the current road category is less than the predetermined value, the automatic start-stop system (61) establishes the second predetermined period of time ( T2) shorter than the first predetermined time period (Tl). The system (70) according to claim 1 or 2, wherein the automatic start stop system (62) inhibits automatic engine stop (2) if the failure determination section (62) determines the failure in the sensor. road gradient (54). 1/5