DE102013107937B4 - Engine stop and start control device - Google Patents

Abstract

An engine stop and start device for performing an automatic engine stop and an automatic engine restart of an engine (10) mounted on a vehicle, the engine stop and start device comprising: a first calculation section (20) configured to calculate a vehicle acceleration value of a vehicle based on detection signals transmitted from an acceleration sensor (24) capable of detecting acceleration applied to the acceleration sensor (24); a vehicle speed calculating section (20) configured to calculate a vehicle speed of the vehicle based on detection signals transmitted from a wheel speed sensor (25) capable of detecting a rotational speed of a wheel of the vehicle; a second calculation section (20) configured to calculate a wheel acceleration value based on a change in the vehicle a pitch angle calculation section (20) configured to calculate a pitch angle of a current road on which the vehicle is traveling based on the vehicle acceleration value calculated by the first calculation section (20) and calculate the wheel acceleration value calculated by the second calculating section (20); a pitch angle holding section (20) configured to, during a period in which the vehicle speed of the vehicle is within a low speed range, a previously calculated Holding the pitch angle as the pitch angle holding value of the current road, the previously calculated pitch angle while the vehicle is running at a time immediately before the vehicle speed enters the low speed range not greater than a low speed indiability judgment value (Vd) calculated by the pitch angle calculating section (20); anda stop control section (20) configured to judge, while the vehicle is traveling before the vehicle speed of the vehicle enters the low speed range, based on a pitch angle calculated by the pitch angle calculating section (20) whether an automatic engine stop is being performed or not, and during a period in which the vehicle speed of the vehicle is within the low speed range, judging whether or not the automatic engine stop can be performed based on the pitch angle holding value held by the pitch angle holding section (20).

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to an engine stop and start control device for carrying out idle reduction control of an internal combustion engine mounted on, for example, a motor vehicle.

2. Description of the related art

There is a conventional technique in which there is provided an idle reduction control device that performs automatic engine stop and automatic engine restart of an internal combustion engine mounted on a vehicle when a driver's operation of an accelerator and / or a brake pedal is detected. That is, when it is detected that the driver of the vehicle operates the accelerator pedal or the brake pedal of the vehicle, the idling reduction device automatically stops or restarts the combustion of the internal combustion engine to reduce fuel consumption of the internal combustion engine.

Recently, various techniques have been proposed for further reducing fuel consumption of an internal combustion engine of a vehicle. A conventional technique automatically stops the combustion of an internal combustion engine before a vehicle speed reaches zero when some conditions are met, which conditions are used to perform an automatic engine stop while the vehicle is traveling on a road.

There is a known system which can perform an automatic engine stop while a vehicle is traveling on a road when an angle of inclination (gradient) of the road is not greater than a predetermined angle of inclination. For example, there has been proposed a conventional method of calculating a slope angle of a road on which a vehicle is traveling, based on a vehicle acceleration and a wheel acceleration. The vehicle acceleration value is calculated based on detection signals transmitted from an acceleration sensor that can detect acceleration of the vehicle based on a force (including an attractive force) applied to the acceleration sensor. On the other hand, the wheel acceleration value is calculated based on detection signals transmitted from a wheel speed sensor that can detect a rotating speed of the wheel. For example, Japanese Patent Laid-Open JP H02 - 161 308 A discloses such a technique for calculating such a vehicle acceleration value.

However, the wheel speed sensor for detecting a rotating speed of the wheel (i.e., a wheel rotating speed) of the vehicle has a detection limit. It is difficult for the wheel speed sensor to detect a wheel rotation speed of not more than a value within a range of 3 to 5 km / h, for example. In addition to the disadvantage, a calculation error of a pitch angle is generated when a calculation accuracy of the wheel speed decreases, the pitch angle being calculated based on a vehicle acceleration value and a wheel acceleration value. Therefore, there is a possibility that a control accuracy of a system that executes the idle reduction control based on a calculated gradient angle on the road on which the vehicle is traveling may decrease.

For example, in a system that allows the automatic engine stop to be carried out only when a gradient angle of a road on which a vehicle is traveling is smaller than a predetermined gradient angle, and a calculated gradient angle of the road obtained based on detection signals obtained from transmitted to the acceleration sensor and the wheel speed sensor is smaller than an actual gradient angle of the current road, the possibility that the automatic engine stop will be performed even if the actual gradient angle on the current road is not smaller than the predetermined gradient angle. In this case, after the automatic engine stop is performed, the vehicle is likely to roll backward on the current road when a braking force generated by the driver's braking operation is small compared to an attractive force applied to the vehicle is.

On the other hand, the calculated slope angle of the current road is larger than the actual slope angle of the road, and the execution of the automatic machine stop is likely to be suppressed, although the situation allows the automatic machine stop to be executed. This increases fuel consumption of the engine of the vehicle, since this erroneous control lowers the regular execution of the automatic engine stop.

the DE 10 2012 213 448 A1 discloses a system comprising a first module configured to record a position of a vehicle To determine the height level of the vehicle and / or a road gradient at the position of the vehicle. A second module is designed to prevent an engine from auto-stopping, which includes that a start-stop signal is generated based on the position of the vehicle, the height level of the vehicle and / or the road gradient at the position of the vehicle. An actuator control module is designed to prevent the auto-stop by adjusting a spark parameter, a fuel parameter and / or an air flow parameter of the engine based on the start / stop signal.

the DE 10 2005 055 592 A1 discloses a vehicle control system that reduces rollback of a vehicle after a brake is released. The control system includes a braking system, a vehicle grade measuring device, and a controller that modulates the applied brake pressure of the braking system based on a grade of the grade measuring device. The controller actuates a brake holding device that communicates with the braking system based on the slope measure via pulse width modulation. The control system communicates with a motor generator and an internal combustion engine to provide starting power to the internal combustion engine after the brake is released based on the slope measure. Fuel injection valves of the internal combustion engine are released on the basis of the gradient after the brake is released. The control system also communicates with a transmission forward clutch to provide a selective rotational connection between the transmission and the internal combustion engine based on the degree of pitch.

From the DE 10 2009 045 567 A1 An invention is known, relating to a method for operating a drive device of a motor vehicle which comprises at least one internal combustion engine and at least one electrical machine, a driving resistance, in particular an incline, being determined and the internal combustion engine being operated as a function thereof. It is provided that the internal combustion engine is operated as a function of an expected driving resistance, which is determined as a function of a current driving resistance. The invention also relates to a drive device for a motor vehicle.

the DE 10 2012 206 694 A1 discloses an auto-stop / start system for a vehicle which includes an object identification module, a distance determination module, and an auto-stop / start control module. The object identification module determines a location of an object that is in a path of the vehicle. The distance determination module determines a distance between the vehicle and the whereabouts of the object. The auto stop / start control module selectively deactivates the delivery of fuel to an engine of the vehicle based on the distance while an ignition system of the vehicle is on.

SHORT VERSION

It is therefore desirable to provide an engine stop and start control device that provides improved controllability of automatic engine stop and automatic engine restart based on a gradient angle of a road on which the vehicle is traveling, and reduced fuel consumption of an engine of the vehicle .

An exemplary embodiment provides an engine stop and start control device. The engine stop and start control device executes automatic engine stop control and automatic engine restart control of an engine mounted on a vehicle. The engine stop and start control device has a first calculation section, a vehicle speed calculation section, a second calculation section, a pitch angle calculation section, a pitch angle holding section, and a stop control section. The first calculating section calculates a vehicle acceleration value of a vehicle based on detection signals transmitted from an acceleration sensor. The acceleration sensor detects an acceleration that acts on the acceleration sensor. The vehicle speed calculating section calculates a vehicle speed of the vehicle based on detection signals transmitted from a wheel speed sensor. The wheel speed sensor detects a rotating speed of a wheel of the vehicle. The second calculating section calculates a wheel speed value based on a change in vehicle speed calculated by the vehicle speed calculating section. The pitch angle calculation section calculates a pitch angle of a current road on which the vehicle is traveling based on the vehicle acceleration value calculated by the first calculation section and the wheel acceleration value calculated by the second calculation section. The pitch angle holding section holds a previously calculated pitch angle as the pitch angle holding value of the current road during a period in which the vehicle speed of the vehicle is within a low speed range. The previously calculated pitch angle is while the vehicle is running at a time immediately before the vehicle speed enters the low speed range not greater than a low speed evaluation value Vd, has been calculated by the pitch angle calculating section. The stop control section, while the vehicle is running, before the vehicle speed of the vehicle enters the low speed range, judges whether or not automatic engine stop can be performed based on a pitch angle calculated by the pitch angle calculating section. The stop control section judges, during a period in which the vehicle speed of the vehicle is within the low speed range, based on the pitch angle hold value held by the pitch angle hold section, whether or not the automatic engine stop can be performed.

When the vehicle is traveling on the current road, the first calculation section calculates a vehicle acceleration value, and the second calculation section calculates the wheel acceleration value. Specifically, the pitch angle calculation section calculates at a time immediately before the vehicle speed of the vehicle enters the low speed range, which is not greater than the predetermined low speed judgment value Vd, based on the vehicle acceleration value calculated by the first calculation section and the wheel acceleration value calculated by the second Calculating section is calculated, a pitch angle, ie a previously calculated pitch angle of the current road. Thereafter, the pitch angle holding section holds this pitch angle as the pitch angle holding value, i.e. the previously calculated pitch angle of the current road. The stop control section uses the pitch angle holding value (as previously calculated pitch angle) held by the pitch angle holding section as the pitch angle of the current road during the period in which the vehicle speed of the vehicle is within the low speed range. Further, during the period in which the vehicle speed of the vehicle is within the low speed range, the stop control section determines whether the automatic engine stop is permitted / not to be performed based on the pitch angle hold value (as previously calculated pitch angle) held by the pitch angle hold section. This structure and operation of the engine stop and start control device can perform the automatic engine start and the automatic engine stop in accordance with an actual slope angle of the current road on which the vehicle is running, and increase the controllability of the idle reduction control, since this structure and operation of the engine stop and -start control device determines with high accuracy whether or not the automatic engine stop can be performed using a slope angle calculated immediately before the vehicle speed of the vehicle enters the low speed range. During the low speed range, the accuracy for calculating the pitch angle is generally reduced.

Figure list

• 1 eine schematische Ansicht ist, die einen Gesamtaufbau eines Fahrzeugmaschinensteuersystems zeigt, das mit einer Maschinenstopp und -start-Steuervorrichtung gemäß einer ersten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgestattet ist;
• 2A bis 2D schematische Ansichten sind, die eine Veränderung eines Fahrzeugsbeschleunigungswerts und eines Radbeschleunigungswerts zeigen, die basierend auf Erfassungssignalen berechnet werden, die von einem Beschleunigungssensor und einem Radgeschwindigkeitssensor übertragen werden;
• 3 eine schematische Ansicht ist, die ein Flussdiagramm einer Routine einer Leerlaufminderungssteuerung zeigt, welche durch die Maschinenstopp und -start-Steuervorrichtung gemäß der ersten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgeführt wird;
• 4A bis 4D Zeitablaufdiagramme in einem tatsächlichen Fall sind, bei dem die Leerlaufminderungssteuerung durch die Maschinenstopp und -start-Steuervorrichtung gemäß der ersten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgeführt wird;
• 5A bis 5D Zeitablaufdiagramme in einem tatsächlichen Fall sind, bei dem die Leerlaufminderungssteuerung durch die Maschinenstopp und -start-Steuervorrichtung gemäß einer zweiten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgeführt wird;
• 6 eine Ansicht ist, die ein Flussdiagramm einer Routine einer Leerlaufminderungssteuerung zeigt, welche durch die Maschinenstopp und -start-Steuervorrichtung gemäß einer dritten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgeführt wird;
• 7A bis 7D Zeitablaufdiagramme in einem tatsächlichen Fall sind, bei dem die Leerlaufminderungssteuerung durch die Maschinenstopp und -start-Steuervorrichtung gemäß der dritten beispielgebenden Ausführungsform der vorliegenden Erfindung ausgeführt wird;
• 8 eine Ansicht ist, die ein Verhältnis zwischen einer Entschleunigung eines Fahrzeugs und einem Niedriggeschwindigkeitsbeurteilungswert zeigt, das von der Maschinenstopp und -start-Steuervorrichtung gemäß den Ausführungsformen der vorliegenden Erfindung verwendet wird;
• 9 ein Zeitablaufdiagramm der Leerlaufminderungssteuerung gemäß einer Modifikation der beispielgebenden Ausführungsformen der vorliegenden Erfindung ist;
• 10 eine Ansicht ist, die ein Verhältnis zwischen einem Steigungswinkel einer Straße und einem Druck eines Hauptzylinders zeigt, wenn die Ausführung der Leerlaufminderungssteuerung zugelassen wird; und
• 11A bis 11C Zeitablaufdiagramme der Leerlaufminderungssteuerung gemäß einer anderen Modifikation der beispielgebenden Ausführungsformen der vorliegenden Erfindung sind.

A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

• 1 Fig. 3 is a schematic view showing an overall configuration of a vehicle engine control system equipped with an engine stop and start control device according to a first exemplary embodiment of the present invention;
• 2A until 2D are schematic views showing a change in a vehicle acceleration value and a wheel acceleration value calculated based on detection signals transmitted from an acceleration sensor and a wheel speed sensor;
• 3 Fig. 13 is a schematic view showing a flowchart of an idle reduction control routine executed by the engine stop and start control device according to the first exemplary embodiment of the present invention;
• 4A until 4D Fig. 12 are timing charts in an actual case where the idle reduction control is executed by the engine stop and start control device according to the first exemplary embodiment of the present invention;
• 5A until 5D Fig. 12 are timing charts in an actual case where idle reduction control is executed by the engine stop and start control device according to a second exemplary embodiment of the present invention;
• 6th Fig. 13 is a view showing a flowchart of an idle reduction control routine executed by the engine stop and start control device according to a third exemplary embodiment of the present invention;
• 7A until 7D Fig. 13 are timing charts in an actual case where the idle reduction control is executed by the engine stop and start control device according to the third exemplary embodiment of the present invention;
• 8th Fig. 13 is a view showing a relationship between deceleration of a vehicle and a low speed judgment value used by the engine stop and start control device according to embodiments of the present invention;
• 9 Figure 13 is a timing diagram of idle mitigation control according to a modification of the exemplary embodiments of the present invention;
• 10 Fig. 13 is a view showing a relationship between a slope angle of a road and a pressure of a master cylinder when the execution of the idle reduction control is permitted; and
• 11A until 11C 6 are timing charts of idle mitigation control according to another modification of the exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Various embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description of the various embodiments, the same or equivalent components are denoted throughout the several diagrams by the same reference symbols or numbers.

First exemplary embodiment

The following is a description of an engine stop and start control device according to a first embodiment with reference to FIG 1 until 4th .

In the first embodiment, the concept of the engine stop and start control device according to the first embodiment is applied to a vehicle engine control system mounted on a vehicle. In the vehicle engine control system, an electronic control unit (ECU) controls operation of the engine.

1 Fig. 13 is a schematic view showing an overall configuration of the vehicle engine control system equipped with the engine stop and start control device according to the first embodiment.

As in 1 As shown, the vehicle engine control system mounted on a vehicle is composed of an internal combustion engine 10 (hereinafter the machine 10 ), an electronic control unit (ECU) 20th (hereinafter the ECU 20th ), different types of sensors 21 until 25th , and other components 26th until 37 together.

In the construction of the vehicle control system shown in 1 shown is the machine 10 a four-cylinder machine as a multi-cylinder machine. The machine 10 is with an injector 11 , an ignition 12th and a throttle valve (not shown). The injector 11 serves as a fuel injector section for supplying fuel into the cylinders. The ignition 12th controls a spark plug attached to each of the cylinders to generate an electrical spark to ignite a compressed air / fuel mixture. The throttle valve adjusts an amount of the intake air to be supplied to the interior of each cylinder.

The ECU 20th is equipped with a central processing unit (CPU), a microcomputer which is well known, and a holding section with various types of memories such as a read-only memory (ROM) and a random access memory (RAM). The ECU 20th receives detection signals from the rotational speed sensor 21 , the accelerator pedal sensor 22nd , the brake pedal sensor 23 , the accelerometer 24 and the wheel speed sensor 25th be transmitted. Based on the received detection signals from the sensors 21 until 25th are received, the ECU performs 20th perform various engine control processings to adjust an amount of fuel to be supplied into the cylinders, an ignition timing, and execution times for executing an idle reduction control such as an automatic engine stop.

In particular, the rotational speed sensor generates 21 a rectangular shaft detection signal at every predetermined crank angle (° CA) of the engine 10 (for example at a distance of 10 ° CA) and outputs this.

The accelerator pedal sensor 22nd detects a depression amount of the accelerator pedal 31 (an accelerator operation amount). The brake pedal sensor 23 detects whether the driver of the vehicle presses the brake pedal or not (as a brake pedal operation). The speed sensor 24 detects a vehicle speed. The wheel speed sensor 25th detects a rotational speed of the wheel.

The accelerometer 24 detects an acceleration of the vehicle based on a force applied to the acceleration sensor 24 acts itself. For example, uses the accelerometer 24 a pendulum or a strain gauge. The wheel speed sensor 25th generates a pulse signal at regular intervals. The vehicle engine control system included in 1 uses the wheel speed sensor 25th of an electromagnetic pick-up type. The wheel speed sensor 25th generates a pulse signal in response to passing teeth at a predetermined distance (for example, at a distance of 8 ° CA) 27 attached to a pulse generator 26th are formed that rotates with the wheels of the vehicle. The ECU 20th receives the detection signal from the wheel speed sensor 25th is transmitted, and calculates a vehicle speed based on a pulse interval of the received detection signals. The ECU 20th then calculates a wheel acceleration value based on the change in the calculated vehicle speed.

(Second calculation section)

In the idle reduction control, the ECU leads 20th the automatic machine stop control to stop the machine from burning 10 to stop when one or more predetermined conditions for automatic machine stop are met. The ECU 20th performs an automatic engine restart control to stop the engine from burning 10 restart when one or more predetermined conditions for restarting the machine are met.

• (a1) wenn der Fahrer des Fahrzeugs das Gaspedal auslässt, d.h. das Gaspedal in einem Leerlaufzustand positioniert ist;
• (a2) wenn der Fahrer des Fahrzeugs das Bremspedal 31 durchdrückt, d.h. der Fahrer betätigt die Bremsbetätigung;
• (a3) wenn die Fahrzeuggeschwindigkeit des Fahrzeugs kleiner als eine zulässige Fahrzeuggeschwindigkeit Vi zum vorbestimmten Leerlaufstopp (IS) wird (zum Beispiel ein vorbestimmter Wert innerhalb eines Bereichs von 7 km/h bis 10 km/h); und
• (a4) wenn ein Steigungswinkel der derzeitigen Straße, auf der das Fahrzeug fährt, kleiner als ein vorbestimmter Steigungswinkel ist (zulässiger Steigungswinkel für einen Leerlaufstopp (IS)).

For example, there are the following predetermined conditions for automatic machine stop:

• (a1) when the driver of the vehicle releases the accelerator pedal, that is, the accelerator pedal is positioned in an idling state;
• (A2) when the driver of the vehicle depresses the brake pedal 31 pushes through, ie the driver actuates the brake;
• (a3) when the vehicle speed of the vehicle becomes less than an allowable vehicle speed Vi at the predetermined idling stop (IS) (for example, a predetermined value within a range of 7 km / h to 10 km / h); and
• (a4) when a slope angle of the current road on which the vehicle is traveling is smaller than a predetermined slope angle (allowable slope angle for idling stop (IS)).

• (b1) wenn der Fahrer des Fahrzeugs die Gaspedalbetätigung betätigt, d.h. der Fahrer des Fahrzeugs drückt das Gaspedal durch;
• (b2) wenn der Fahrer des Fahrzeugs die Bremspedalbetätigung auslässt, d.h. der Fahrer des Fahrzeugs lässt das Bremspedal 31 aus; und
• (b3) wenn ein Steigungswinkel der derzeitigen Straße, auf der das Fahrzeug fährt, größer als ein Steigungswinkel für einen IS ist.

There are also the following predetermined conditions for automatic machine restart, such as:

• (b1) when the driver of the vehicle depresses the accelerator pedal, ie the driver of the vehicle depresses the accelerator pedal;
• (b2) when the driver of the vehicle releases the brake pedal, ie the driver of the vehicle leaves the brake pedal 31 the end; and
• (b3) when a pitch angle of the current road on which the vehicle is traveling is larger than a pitch angle for an IS.

In the idle reduction control, the ECU leads 20th the automatic machine stop to the machine 10 to stop when the predetermined condition for the automatic engine stop is met even when the vehicle speed reaches zero. This makes it possible to reduce the fuel consumption of the machine 10 to reduce. In the vehicle engine control system equipped with the engine stop and start control device according to the first embodiment, the ECU performs 20th executes the automatic engine stop in the various states using different values of the allowable pitch angle for an IS when the vehicle is running (during a running state) and when the vehicle is stopped (during a stop state). In particular, when the vehicle is traveling on the current road, the ECU uses 20th When executing the automatic machine stop, a driving state threshold value α (which corresponds, for example, to a value within a range of 2 to 3%) as the permissible gradient angle for an IS. On the other hand, when the vehicle is stopped, the ECU uses 20th When executing the automatic machine stop, a stop state threshold value y (which corresponds, for example, to a value within a range of 14 to 15%) that is greater than the driving state threshold value α is used as the permissible gradient angle for an IS.

The ECU 20th calculates the slope angle of the current road on which the vehicle is traveling based on at least a vehicle acceleration value and a wheel acceleration value. The vehicle acceleration value is calculated based on detection signals received from the acceleration sensor 24 be transmitted. The wheel acceleration value is calculated based on detection signals received from the wheel speed sensor 25th be transmitted. In particular, when the vehicle is traveling on the current road, the ECU calculates 20th the slope angle of the current road based on both the vehicle acceleration value and the wheel acceleration value. On the other hand, while the vehicle is stopped, the ECU calculates 20th the The slope angle of the current road based only on the vehicle acceleration value.

The ECU 20th may use a weighted average of a previously calculated current road grade to calculate a current road grade.

The vehicle is equipped with a hydraulic braking (or an oil braking) mechanism that provides braking force to each of the driven wheels and non-driven wheels (omitted from the drawings). Strictly speaking, in the hydraulic braking mechanism is the brake pedal 31 with a brake booster 32 connected to a braking force using a negative pressure of an air inlet which the engine 10 is fed to reinforce. The brake booster 32 is with the main cylinder 33 tied together. The main cylinder 33 generates an oil pressure that corresponds to the driver's braking operation, that is, the amount of depression of the brake pedal 31 . The main cylinder 33 is connected to each of the wheel cylinders by a connecting pipe. This allows the braking force to be exerted by the brake pedal 31 is generated to be transmitted to the wheel cylinder to brake the wheels of the vehicle.

Main cylinder 33 is with a hydraulic pressure sensor 34 fitted. The hydraulic pressure sensor 34 detects a pressure of the hydraulic oil in the master cylinder 33 . The hydraulic pressure sensor 34 generates a detection signal and sends it to the ECU 20th the end. The ECU 20th sequentially receives the detection signals from the hydraulic pressure sensor 34 be transmitted.

• (a2) wenn der Fahrer des Fahrzeugs das Bremspedal 31 durchdrückt, d.h. der Fahrer betätigt die Bremsbetätigung;
• (a3) wenn die Fahrzeuggeschwindigkeit des Fahrzeugs kleiner als eine zulässige Fahrzeuggeschwindigkeit Vi für einen IS wird (zum Beispiel ein vorbestimmter Wert innerhalb eines Bereichs von 7 km/h bis 10 km/h, wie zuvor beschrieben);
• (a4) wenn ein Steigungswinkel der derzeitigen Straße, auf der das Fahrzeug fährt, kleiner als der zulässige Steigungswinkel für einen IS ist; und
• (a5) wenn ein Druck des Hauptzylinders 31 nicht kleiner als ein zulässiger Druck des Hauptzylinders 31 für einen Leerlaufstopp (IS) wird.

In the first exemplary embodiment, the ECU performs 20th the automatic engine stop when the pressure of the hydraulic oil in the master cylinder 33 is not less than a predetermined idle stop (IS) master cylinder allowable pressure (for example, 0.4 MPa). While the vehicle is moving, the ECU performs 20th the automatic machine stop to stop the machine from burning 10 stop when the following conditions are met:

• (A2) when the driver of the vehicle depresses the brake pedal 31 pushes through, ie the driver actuates the brake;
• (a3) when the vehicle speed of the vehicle becomes lower than an allowable vehicle speed Vi for an IS (for example, a predetermined value within a range of 7 km / h to 10 km / h as described above);
• (a4) when a pitch angle of the current road on which the vehicle is traveling is smaller than the allowable pitch angle for an IS; and
• (a5) when a pressure of the master cylinder 31 not less than an allowable pressure of the master cylinder 31 for an idle stop (IS).

In general, an electromagnetic pickup type wheel speed sensor has a recommended detection limit for detecting a vehicle speed (as a wheel rotation speed) with high accuracy. Accordingly, such an electromagnetic pickup type wheel speed sensor has a large detection error when a vehicle speed is detected within a low speed range not greater than a predetermined low speed judgment value Vd. The predetermined low speed judgment value Vd is smaller than the allowable vehicle speed Vi for an IS. For example, the predetermined low speed judgment value Vd is within a range of 3 to 5 km / h. When a calculation error of a vehicle speed increases, a calculation error of a slope angle of the current road on which the vehicle is traveling also increases. That is, when a vehicle speed is in a low speed range smaller than the predetermined low speed judgment value Vd, an interval between pulses detected by passing the teeth increases or it becomes difficult to detect the teeth. As a result, it will be for the ECU 20th difficult to detect a gradient angle of the current road with high accuracy, and this increases the possibility of causing a wrong judgment about the execution of the automatic machine stop, and consequently the judgment accuracy is lowered.

The following is a description of the deterioration in judgment accuracy with reference to FIG 2A until 2D described in detail.

2A until 2D 13 are schematic views showing a change in a vehicle acceleration value and a wheel acceleration value calculated based on detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th be transmitted.

In 2A until 2D calculates the ECU 20th the vehicle acceleration value based on the detection signal of the acceleration sensor 24 . The ECU 20th calculates the wheel acceleration value based on the detection signal received from the wheel speed sensor 25th is transmitted. 2A until 2D show a case where that Vehicle travels on a flat road. The solid line that appears in 2A indicates a change in the wheel acceleration value based on the detection signals received from the wheel speed sensor 25th transmitted, is calculated. The alternating long and short dashed line in 2A indicates a change in the vehicle acceleration value calculated based on detection signals received from the acceleration sensor 24 be transmitted.

In 2A until 2D When the vehicle is traveling on the flat road, the vehicle acceleration value becomes equal to the wheel acceleration value. After a time t1 at which the vehicle is being decelerated, the vehicle acceleration value and the wheel acceleration value each have a negative value, as in FIG 2A is shown. Thereafter, when the vehicle speed decreases to a value close to the predetermined low speed judgment value Vd, the wheel acceleration value (calculated value) gradually approaches zero compared to the vehicle acceleration value as an updated time of the vehicle speed becomes long (the pulse interval of the detection signal des Wheel speed sensor 25th becomes long). At this time the ECU calculates 20th , as in 2 B is shown, a pitch angle θ of the current road on which the vehicle is traveling based on the vehicle acceleration value and the wheel acceleration value. The ECU 20th recognizes a difference between the vehicle acceleration value and the wheel acceleration value as a slope angle of the current road. This causes an erroneous calculation of the slope angle θ of the current road.

That is, when the vehicle is traveling on an uphill road, the gradient angle of the current road becomes based on the detection signals of the acceleration sensor 24 and the wheel speed sensor 25th is calculated to be smaller than an actual slope angle of the current road. On the other hand, when the vehicle is traveling on a sloping road, the slope angle of the current road calculated based on the detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th are transmitted larger than the actual gradient of the current road.

When the vehicle is traveling on an uphill road, there is a likelihood that the ECU 20th performs the automatic engine stop even though the actual slope angle of the current road is larger than the allowable slope angle for an IS when the vehicle speed of the vehicle is within a low speed range. In this case, there is a possibility that the vehicle will roll backward on an uphill road on which the vehicle is traveling when a braking force applied by the driver's braking operation on the brake pedal 31 is less than a rolling force of the vehicle generated based on the actual gradient angle of the uphill road.

On the other hand, when the vehicle is traveling on a sloping road, the ECU is likely to 20th does not perform the automatic engine stop even though the actual slope angle of the current road is smaller than the allowable slope angle to the IS when the vehicle speed of the vehicle is within the low speed range. In this case, there is a possibility that a decrease in the fuel consumption of the machine 10 prevented because the ECU 20th lowers the frequency with which the automatic machine stop is carried out.

In order to avoid the disadvantages described above, the ECU calculates 20th a slope angle (as a previously calculated value) of the current road on which the vehicle is traveling based on detection signals received from the acceleration sensor 24 and detection signals from the wheel speed sensor 25th are transmitted immediately before the vehicle speed of the vehicle enters the low speed range. This low speed range is not larger than the predetermined low speed judgment value Vd. The ECU also stops 20th during the low-speed region not larger than the predetermined low-speed judgment value Vd, derives the calculated slope angle as the slope angle (ie, slope angle holding value) of the current road in the stopping section. When the vehicle speed of the vehicle is within the low speed range not greater than the predetermined low speed judgment value Vd, the ECU determines 20th whether or not the automatic machine stop can be performed based on the pitch angle hold value.

A description will now be given of the idle reduction control (ie, the engine automatic stop control and the engine automatic restart control) performed by the ECU 20th is executed in the engine stop and start control device according to the first exemplary embodiment, with reference to FIG 3 . The ECU 20th leads the in 3 routine shown at every predetermined interval.

3 Fig. 13 is a view showing a flowchart of the routine of idle reduction control executed by the ECU 20th as machine stop and start Control device according to the first embodiment is carried out.

The ECU 20th calculates a vehicle speed based on detection results obtained from the wheel speed sensor 25th be transmitted.

At step S101 the in 3 The routine shown is detected by the ECU 20th whether or not the calculated vehicle speed is greater than the permissible vehicle speed Vi for an IS, and whether the driver of the vehicle is applying the brake, that is, depressing the brake pedal 31 , executes or not. If the acquisition result at step S101 is positive ("YES" for step S101 ), the operation starts at step S102 away.

At step S102 records the ECU 20th whether or not the calculated vehicle speed is greater than the predetermined low speed judgment value Vd (which is less than the allowable vehicle speed Vi for an IS). If the acquisition result at step S102 is positive ("YES" for step S102 ), the operation starts at step S103 away.

At step S103 calculates the ECU 20th a pitch angle θ of the current road on which the vehicle is traveling. In particular, the ECU calculates 20th a vehicle acceleration value based on detection signals received from the acceleration sensor 24 be transmitted. The ECU 20th calculates a wheel acceleration value based on detection signals received from the wheel speed sensor 25th be transmitted. The ECU 20th calculates a calculated slope angle θa based on the calculated vehicle acceleration value and the calculated wheel acceleration value. In the first embodiment, the ECU subtracts 20th the calculated wheel acceleration value (as a wheel gravitational (G) acceleration) from the calculated vehicle acceleration value (as a vehicle gravitational (G) acceleration) to obtain the calculated pitch angle θa. The ECU 20th uses the calculated pitch angle θa as the current pitch angle θ of the current road. In an actual case, since a position of the vehicle changes due to acceleration / deceleration and a corner, the ECU can 20th in consideration of an inclination portion (an acceleration compensation value) of the position of the vehicle when the vehicle is decelerated and an influence portion (turning compensation value) of a centrifugal force generated when the vehicle is turning, calculate a compensation value of the calculated inclination angle θa. The ECU 20th can use the compensation value of the calculated slope angle θa. The operational process sets at step S104 away.

At step S104 represents the ECU 20th the driving state threshold value α to the permissible gradient angle for an IS. The operational flow continues at step S 105.

At step S105 records the ECU 20th whether or not the current pitch angle θ of the current road is smaller than the allowable pitch angle for an IS. If the acquisition result at step S105 is positive ("YES" for step S105 ), that is, if the current slope angle θ of the current road is smaller than the allowable slope angle for an IS (if the current road is either an uphill road with a slight gradient, a sloping road with a slight gradient or a flat road), the Operation flow at step S106 away.

At step S106 stops the ECU 20th the combustion of the machine 10 when the other conditions for executing the automatic machine stop are met.

On the other hand, if the detection result at step S105 is negative ("NO" at step S105 ), that is, when the current slope angle θ of the current road is not smaller than the allowable slope angle for an IS (when the current road is either an uphill road with a steep slope or a downhill road with a steep slope), the operation continues at step S107 away.

At step S107 omits the ECU 20th the execution of the automatic machine stop.

After the acquisition result at step S101 is positive ("YES" for step S101 ), the operation starts at step S102 away. If the acquisition result at step S102 is negative ("NO" at step S102 ), ie it when it is indicated that the calculated vehicle speed is not greater than the predetermined low speed judgment value Vd, the flow goes to step S108 away.

At step S108 records the ECU 20th whether or not the calculated vehicle speed is greater than a vehicle stop judgment value Vs. The vehicle stop judgment value is a threshold value for detecting whether or not the vehicle is stopped. The vehicle stop judgment value Vs is smaller than the predetermined low speed judgment value Vd. For example, the vehicle stop judgment value Vs is zero or close to zero. If the acquisition result at step S108 is positive ("YES" for step S108 ), that is, it is indicated that the calculated vehicle speed is greater than the vehicle stop judgment value Vs, the operation proceeds to step S109 away.

At step S109 calculates the ECU 20th the current pitch angle θ of the current road. In particular, the ECU 20th a calculated pitch angle θa at a time immediately before the vehicle speed of the vehicle reaches the predetermined low speed judgment value Vd as a pitch angle holding value θh. The ECU 20th sets the pitch angle hold value θh to the current pitch angle θ. In other words, the ECU uses 20th the pitch angle hold value θh as the current pitch angle θ. That is, in a very low vehicle speed range not larger than the predetermined low speed judgment value Vd, the ECU uses 20th consecutively the pitch angle θ obtained based on the detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th are transmitted at a time immediately before the vehicle speed of the vehicle enters the very low vehicle speed range which is not greater than the predetermined low speed judgment value Vd. The operational process sets at step S104 away. At step S104 up step S107 compares the ECU 20th the pitch angle hold value θh (as the current pitch angle θ) with the allowable pitch angle for an IS (the driving state threshold value α). If the comparison result at step S105 is positive ("YES" for step S105 ), that is, θh <α, the operational flow resets at step S106 away. At step S106 runs the ECU 20th the automatic machine stop to stop the machine from burning 10 to stop. On the other hand, if the comparison result at step S105 is negative ("NO" at step S105 ), that is, θh> α, the operational flow resets at step S107 away. At step S107 omits the ECU 20th the execution of the automatic machine stop.

Incidentally, if the detection result at step S108 is negative ("NO" at step S108 ), that is, it is indicated that the vehicle speed is not greater than the vehicle stop judgment value Vs (vehicle speed vehicle stop judgment value Vs), the operation proceeds to step S110 away.

At step S110 records the ECU 20th whether or not a predetermined time T1 extending from a time when the vehicle is stopped has elapsed. The predetermined time T1 is a time required to stop the vibration of the vehicle after the vehicle is stopped. The first exemplary embodiment uses a fixed value (for example several seconds) as the predetermined time period T1. If the acquisition result at step S110 is negative ("NO" at step S110 ), the operation starts at step S111 away.

At step S111 uses the ECU 20th consecutively the pitch angle hold value θh as the current pitch angle θ. The operational process sets at step S113 away.

On the other hand, if the detection result at step S110 is positive ("YES" for step S110 ), the operation starts at step S112 away.

At step S112 calculates the ECU 20th the current pitch angle θa of the current road on which the vehicle has stopped based on the detection signals (as acceleration of gravity (G)) received from the acceleration sensor 24 be transmitted. The ECU 20th sets the calculated pitch angle θa to the current pitch angle θ of the road. The operational process sets at step S113 away.

At step S113 represents the ECU 20th the stop state threshold value y to the permissible slope angle for an IS. The operational process sets at step S105 away.

At step S105 records the ECU 20th whether or not the current slope angle θ of the current road is smaller than the allowable slope angle for an IS (as a stop state threshold value y). If the acquisition result at step S105 is positive ("YES" for step S105 ), that is, if θ <γ, the flow advances to step S106 away. At step S106 stops the ECU 20th the combustion of the machine 10 when the other conditions for executing the automatic machine stop are met.

On the other hand, if the detection result at step S105 is negative ("NO" at step S05 ), that is, θ> γ, the operational flow resets at step S107 away. At step S107 omits the ECU 20th the execution of the automatic machine stop.

A description will now be given of the idle reduction control executed by the engine stop and start device according to the first exemplary embodiment with reference to FIG 4A until 4D given.

4A until 4D 12 are timing charts of an actual case where the idle reduction control is executed by the engine stop and start control device according to the first exemplary embodiment. In 4A until 4D is the road the vehicle is traveling on an uphill road with a predetermined gradient angle. The predetermined gradient angle is greater than the driving state threshold value α and smaller than the stopping state threshold value y.

As in 4A until 4D as shown, there is a situation where the vehicle speed of the vehicle is decelerated to less than the allowable vehicle speed Vi for IS after the driver of the vehicle depresses the brake pedal 31 while the vehicle is moving. In this situation the ECU leads 20th the combustion in the machine 10 continues and does not omit the execution of the automatic engine stop because the calculated slope angle θa at time t10 when the vehicle speed of the vehicle is less than the allowable vehicle speed Vi for an IS (vehicle speed <Vi) is larger than the allowable slope angle α for an IS (ie, the driving condition threshold value α) becomes where the calculated pitch angle θa is obtained based on the detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th be transmitted.

Thereafter, when the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd, the ECU uses 20th the pitch angle hold value θh. The ECU 20th has calculated this pitch angle holding value θh at a time immediately before the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd. The ECU 20th uses the pitch angle hold value θh as the current pitch angle θ of the road on which the vehicle is traveling. The ECU 20th uses the pitch angle hold value θh for a period of time T11 runs up to a time t14. Incidentally, time t14 elapses after a predetermined length of time T1 running from time t13 at which the vehicle stops.

After the time t14, the ECU calculates 20th gradually based on detection signals only from the acceleration sensor 24 is transmitted to use a pitch angle θa instead of using the pitch angle hold value θh, and it uses this calculated pitch angle θa as the current pitch angle θ of the road.

When the ECU 20th , during the low speed range not larger than the predetermined low speed judgment value Vd, calculates the pitch angle θ based on detection signals received from both the acceleration sensor 24 as well as the wheel speed sensor 25th are transmitted, the calculated gradient angle θa differs from an actual gradient angle of the current road on which the vehicle is running, and the difference increases as shown by the dotted line in FIG 4A is shown.

When the ECU 20th , during the low speed range not larger than the predetermined low speed judgment value Vd based on the calculated pitch angle θa obtained by detection signals received from the acceleration sensor 24 and the wheel acceleration value are thus transmitted, judging whether or not the automatic engine stop can be performed, accordingly, there is a possibility that the ECU 20th the combustion of the machine 10 stops even if the actual slope angle of the current road is larger than the allowable slope angle α for an IS (driving state threshold value α) as indicated by the time12 in FIG 4A and 4C is shown.

To prevent this disadvantage, the ECU stops 20th in the engine stop and start control device according to the first exemplary embodiment, the pitch angle hold value θh calculated at time t11 immediately before the vehicle speed enters the low speed range as described above, thereby increasing the detection accuracy of the wheel speed sensor 25th is reduced. The ECU 20th judges whether the ECU judges based on the pitch angle hold value θh 20th executes the automatic machine stop or not. This makes it possible to avoid erroneous judgment as to the automatic engine stop control during the low speed range not larger than the predetermined low speed judgment value Vd.

The engine stop and start control device according to the first exemplary embodiment has the following superior effects.

(E1) While the vehicle is running on a road, the ECU calculates 20th at a time immediately before the vehicles of the vehicle enters the low-speed range not larger than the predetermined low-speed judgment value Vd, a pitch angle based on detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th be transmitted. The ECU 20th holds this calculated gradient angle and uses it as the gradient angle of the road during the low-speed region not larger than the predetermined low-speed judgment value Vd. The ECU 20th judged using the pitch angle hold value θh as the current pitch angle θ of the current one Road whether or not the automatic engine stop can be performed when the vehicle speed of the vehicle is within the low speed range not greater than the predetermined low speed judgment value Vd. This enables the automatic engine stop and automatic engine restart control during the low-speed range to be carried out in accordance with the actual slope angle of the current road with high accuracy, since the slope angle hold value θh which is used at the time immediately before the vehicle speed of the vehicle enters the low-speed range is used in which the detection accuracy is lowered is calculated. As a result, it is possible to increase the controllability of the engine stop and start control of the engine.

As described above, the structure and control of the engine stop and start control device according to the first exemplary embodiment can perform the automatic engine stop and start control with high accuracy in consideration of the actual slope angle of the current road, since the slope angle hold value during the low speed region θh calculated immediately before the vehicle speed of the vehicle enters the low speed range is used. This makes it possible to increase the controllability of the idle reduction control which the automatic engine stop and start control device executes.

(E2) The ECU 20th holds the slope angle hold value θh and uses it as the slope angle θ of the current road for a period that passes from a time when the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd until a time after it has elapsed the predetermined length of time T1 from when the vehicle is stopped. During the predetermined length of time T1 immediately after the vehicle is stopped, since the vehicle often vibrates due to the deceleration of the vehicle, the calculation accuracy of the slope angle of the road is generally lowered, and the slope angle of the current road is calculated based on the detection signals received from the Accelerometer 24 and the wheel speed sensor 25th be transmitted. On the other hand, the ECU judges 20th in the engine stop and start control device according to the first exemplary embodiment, using the pitch angle hold value θh as the pitch angle θ of the road, whether the automatic engine stop and the automatic engine restart can be performed. This makes it possible to avoid erroneous judgment caused by vibrations of the vehicle.

(E3) After the lapse of the predetermined length of time T1 which extends from the time when the vehicle is stopped, the ECU judges 20th using a calculated slope angle θa obtained during the period of the vehicle stop as the slope angle θ of the current road on which the vehicle is running or stopping whether or not the automatic engine stop can be performed, it is the ECU 20th after the vehicle is stopped, it is possible to allow or refrain from executing the automatic machine stop based on the actual slope angle of the current road.

The following is a description of the engine stop and start control device according to a second exemplary embodiment with reference to FIG 5A until 5D .

5A until 5D 12 are timing charts of an actual case of the idle reduction control executed by the engine stop and start control device according to the second exemplary embodiment.

A difference between the second exemplary embodiment and the first exemplary embodiment will be described. As described above, the ECU uses 20th In the engine stop and start control device according to the first exemplary embodiment, the pitch angle hold value θh as the pitch angle θ of the current road up to the time after the predetermined length of time T1 has elapsed from the time when the vehicle is stopped.

On the other hand, the ECU holds 20th in the engine stop and start control device according to the second exemplary embodiment, the gradient angle hold value θh and uses it as the gradient angle θ of the current road up to a predetermined time after a predetermined length of time from when the vehicle is restarted.

The following is a description of the idle reduction control executed by the engine stop and start control device according to the second exemplary embodiment with reference to FIG 5A until 5D . As in the case of the 4A until 4D is the current street the vehicle is on 5A until 5D drives an uphill road with a predetermined gradient angle. The predetermined gradient angle is greater than the permissible gradient angle α for an IS (as the driving state threshold value α) and smaller than the stop state threshold value γ.

As in 5A until 5D as shown, there is a situation where the vehicle speed of the vehicle is decelerated to less than the allowable vehicle speed Vi for IS after the driver of the vehicle depresses the brake pedal 31 while the vehicle is moving. In this situation the ECU leads 20th the combustion in the machine 10 continues and does not omit the execution of the automatic engine stop because the calculated slope angle θa at time t20 when the vehicle speed of the vehicle becomes less than the allowable vehicle speed Vi for an IS (vehicle speed <Vi) is larger than the allowable slope angle α for an IS (ie the driving state threshold value α).

Thereafter, when the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd, the ECU uses 20th the pitch angle hold value θh. The ECU 20th has calculated the above-mentioned pitch angle holding value θh at a time t21 immediately before the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd. The ECU 20th continuously uses the pitch angle hold value θh for the period from time t21 to time t24, as in FIG 5A and 5B is shown. During the period from time t21 to time t24, the vehicle speed of the vehicle becomes lower than the predetermined low speed judgment value Vd at time t21 and thereafter the vehicle stops, and after the vehicle is restarted, the vehicle speed of the vehicle becomes higher than at time t24 the predetermined low speed judgment value Vd. After the time t24, the ECU uses 20th the calculated pitch angle θa as the actual pitch angle θ of the current road.

According to the second exemplary embodiment, the ECU stops 20th during the period running from a first time to a second time in which the first time is a time when the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd and the second time is Time is when the vehicle speed of the vehicle after the vehicle restarts becomes greater than the predetermined low speed judgment value Vd, the calculated pitch angle θ as the pitch angle holding value θh. When the ECU 20th executes the automatic engine stop while the vehicle is running, this structure and control enables the state of the engine stop to continue during the period from when the vehicle is stopped to when the vehicle starts again to travel. In addition, it is possible to prevent the driver of the vehicle from feeling uncomfortable by using the machine 10 restarted immediately after the vehicle stops.

Third exemplary embodiment

The following is a description of the engine stop and start control device according to a third example in embodiment with reference to FIG 6th and 7th .

A difference between the third exemplary embodiment and the first exemplary embodiment will be described.

As described above, the ECU uses 20th In the engine stop and start control device according to the first exemplary embodiment, the ECU uses both the driving state threshold value α and the stop state threshold value γ as the allowable slope angle for an IS, and in addition to the first exemplary embodiment 20th Further, in the engine stop and start control device according to the third exemplary embodiment, a threshold value during the holding period for holding the pitch angle holding value θh.

Since the vehicle speed of the vehicle is not greater than the predetermined low speed judgment value Vd, the gradient angle of the current road on which the vehicle is traveling is likely to change. For example, it is considered that the vehicle is traveling on a road with a first gradient angle and the vehicle speed of the vehicle is in the low speed range smaller than the predetermined low speed judgment value Vd, and that the vehicle enters a road with the second gradient angle thereafter that is greater than the first pitch angle. In this situation, there occurs a difference between the pitch angle hold value θh and the actual pitch angle of the current road on which the vehicle is now traveling, and hence the ECU is likely to make an erroneous judgment in executing the automatic engine stop.

To solve this problem, the engine stop and start control device according to the third exemplary embodiment judges using the allowable slope angle for an IS during a period (as a predetermined holding period) in which the ECU 20th continuously holds the pitch angle θ as the pitch angle holding value θh, whether the automatic engine stop may or may not be carried out, for a period from a time when the vehicle skill of the vehicle is in the low-speed range not larger than the predetermined low-speed judgment value Vb to a time when the vehicle is stopped, the permissible pitch angle for an IS is determined taking into account a pitch angle (as the starting pitch angle Δθ). The starting slope angle Δθ is defined so that the vehicle is for a period from a time when the vehicle skill of the vehicle is in the low-speed range, which is not greater than the predetermined low-speed judgment value Vb, to a time when the vehicle is stopped, can drive on a road with the starting slope angle Δθ.

More specifically, the ECU uses 20th According to the third exemplary embodiment, the permissible slope angle for an IS is one of a first threshold value α, a second threshold value β and a third threshold value γ. The first threshold value α is a threshold value slope angle such as the allowable slope angle for an IS, which is used before the vehicle speed of the vehicle is no longer greater than the predetermined low speed judgment value Vd. The second threshold β is a threshold slope angle during a holding period in which the ECU 20th holds the pitch angle hold value θh when the vehicle speed of the vehicle is within the low speed range not greater than the predetermined low speed judgment value Vd. The third threshold value γ is a threshold value slope angle that is used after the holding period in a period while the vehicle is stopped. In particular, the first threshold value α is smaller than the third threshold value γ. For example, the first threshold value α used in the third exemplary embodiment corresponds to a value within a range of 3% to 5%, and the third threshold value γ used in the third exemplary embodiment corresponds to a value within a range of 14% to 15%. Furthermore, the second threshold value β used in the third exemplary embodiment is larger than the first threshold value α and smaller than the third threshold value γ. In the third exemplary embodiment, the second threshold value β is obtained by subtracting the starting slope angle Δθ from the third threshold value γ, the ECU 20th calculates the starting slope angle based on the vehicle speed of the vehicle that is within the low speed range not greater than the predetermined low speed judgment value Vd.

In the third exemplary embodiment, the first threshold value α corresponds to the driving state threshold value used in the first exemplary embodiment, and the third threshold value γ corresponds to a stop state threshold value used in the first exemplary expression.

The following is a description of the idle reduction control performed by the ECU 20th as the engine stop and start control device according to the third exemplary embodiment, with reference to FIG 6th .

6th Fig. 13 is a view showing a flowchart of the routine of idle reduction control executed by the ECU 20th is implemented as the engine stop and start control device according to the third exemplary embodiment. The ECU 20th leads the in 6th routine shown in each predetermined period.

The processings at step S301 up step S307 , in the 6th are shown corresponding to the processings at step S101 up step S107 , in the 3 are shown. In the processings at step S301 up step S307 assesses the ECU 20th based on the grade of the current road on which the vehicle is traveling before the vehicle speed of the vehicle becomes lower than the predetermined low speed judgment value Vd, whether or not the automatic engine stop can be performed.

When the vehicle speed of the vehicle is not greater than the predetermined low speed judgment value Vd while the vehicle is running, the detection result at step falls S302 negative ("NO" at step S302 ), and the operation continues at pace S308 away.

At step S308 records the ECU 20th whether or not the vehicle speed of the vehicle is lower than the vehicle stop judgment value Vs. That is, the ECU 20th judged at step S308 whether the vehicle is in a state immediately before the vehicle stops. The acquisition result at step S308 is positive ("YES" at step S308 ), and the operation continues at pace S309 away.

At step S309 represents the ECU 20th sets the pitch angle hold value θh to the current pitch angle θ of the current road. The operational process sets at step S310 away.

At step S310 represents the ECU 20th the second threshold value β to the permissible slope angle for an IS. The third is exemplary In the embodiment, the predetermined low speed judgment value Vd is a constant value, and the second threshold value β is a constant value corresponding to, for example, a value within a range of 9 to 11%.

In the third exemplary embodiment, a value obtained by subtracting the starting grade angle from the third threshold value γ is calculated based on a weighted average value of a previous grade angle of the current road previously calculated and a friction loss that occurs between the vehicle and a road surface is generated. The ECU 20th it is possible to use the adjusted value as the second threshold value β.

The weighted average value from the previous slope angles is a component in consideration of a delay caused by the weighted average processing when the slope angle is calculated based on the detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th be transmitted. Such a weighted average value is calculated, for example, based on a vehicle speed of the vehicle. In particular, the more the vehicle speed of the vehicle increases, the greater the value of the weighted average value becomes. Furthermore, the friction loss is based on the pressure of the master cylinder 33 calculated. The more the pressure of the master cylinder 33 increases, the more the friction loss increases.

After the ECU 20th has set the second threshold value β to the permissible slope angle for an IS, the operating sequence resets at step S305 away.

As with the processing at step S105 and step S106 , in the 3 the ECU compares 20th in processing at step S305 , in the 6th is shown, the pitch angle θ with the permissible pitch angle for an IS. The ECU 20th performs the automatic machine stop at step S306 the end. The ECU 20th completes the routine contained in 6th is shown.

After the vehicle is stopped, the ECU performs 20th on the other hand, the processing at step S311 up step S314 from that in 6th are shown.

Processing at step S311 up step S314 , in the 6th correspond to the processings at step S111 up step S114 , in the 3 are shown. At step S311 up step S314 assesses the ECU 20th after the car is stopped, based on the slope angle of the current road, whether or not the automatic machine stop can be carried out.

The following is a description of the idle reduction control executed by the engine stop and start control device according to the third exemplary embodiment with reference to FIG 7A until 7D .

7A until 7D Fig. 13 are timing charts of an actual case of the idle reduction control performed by the ECU 20th is actually carried out as the engine stop and start control device according to the third exemplary embodiment.

In a situation that is in 7A until 7D shown, the vehicle is decelerated on a current road having a gradient angle greater than the first threshold value α and smaller than the second threshold value β, and the vehicle enters the low-speed range immediately before the vehicle speed of the vehicle enters the low-speed range that is not greater than the predetermined low speed judgment value Vd, enters a road having a gradient angle larger than the third threshold value γ.

In a situation that is in 7A until 7D is shown in which the driver of the vehicle performs the brake operation, ie the brake pedal 31 is pushed through, the vehicle speed of the vehicle is decelerated so that it is less than the permissible vehicle speed Vi for an IS. At time t40 (vehicle speed <Vi), the ECU is executing 20th does not carry out the automatic machine stop because the calculated pitch angle θa is greater than the permissible pitch angle α for an IS. Thereafter, at time t41, when the vehicle speed of the vehicle takes a value that is within the low-speed range that is not greater than the predetermined low-speed judgment value Vd, the ECU uses 20th as the current pitch angle θ of the current road on which the vehicle is currently traveling, the pitch angle hold value θh immediately before the vehicle speed of the vehicle enters the low speed range not greater than the predetermined low speed judgment value Vd is calculated. The ECU 20th further holds the pitch angle hold value θh as the current pitch angle until a time after a predetermined length of time T2 has elapsed from when the vehicle stops. The pitch angle hold value θh is a value between the second threshold value β and the third threshold value γ as in FIG 7A is shown.

During the slope angle holding period, which runs from time t41 to time t43, in the the ECU 20th holds the pitch angle hold value θh as the current pitch angle of the current road, the ECU uses 20th the second threshold value β as the permissible slope angle for an IS. The second threshold value β is a value between the first threshold value α and the third threshold value γ. In addition, the second threshold value β is determined in consideration of the starting slope angle Δθ at which the vehicle can travel by the kinetic energy of the vehicle at the predetermined speed judgment value Vd. In particular, the ECU aims 20th decreases the starting slope angle Δθ from the third threshold value γ, and uses the subtraction result as the second threshold value β. It is the ECU 20th During the pitch angle holding period running from time t41 to time t43, it is possible to judge a variable pitch angle and judge whether or not the automatic engine stop can be carried out. When, based on a comparison result between the calculated incline angle θa and the third threshold value γ, after the lapse of the holding period from time t41 to time t43, the ECU is likely to be 20th executes the automatic machine stop, it is the ECU 20th possible to omit the execution of the automatic machine stop during the pitch angle holding period running from time t41 to time t43, as shown in FIG 7A until 7D is shown.

(Other modifications)

The concept of the present invention is not limited to the first to third exemplary embodiments described above. For example, the engine stop and start control device is possible to have the following modifications.

In the engine stop and start control device according to the first to third exemplary embodiments described above, the ECU is used 20th the predetermined low speed judgment value Vb which is a fixed value. However, it is the ECU 20th possible to use a variable value of the low speed judgment value Vb. That is, the engine stop and start control device according to a modification further includes a setting section for changing the low speed judgment value Vd based on deceleration of the vehicle, that is, negative acceleration. The low speed range affects or lowers the calculation accuracy of the vehicle speed of the vehicle calculated based on the detection signals received from the wheel speed sensor 25th be transmitted. The calculation accuracy changes due to deceleration when the vehicle is decelerated. That is to say, in the low-speed range, the more the deceleration of the vehicle increases, the more the calculation accuracy of the vehicle speed of the vehicle decreases. By having the setting section, it is possible to suppress the decrease in the judgment accuracy caused by the decrease in the calculation accuracy of the current road as to whether or not the automatic engine stop can be performed.

8th Fig. 13 is a view showing a relationship between a vehicle acceleration and a low speed judgment value used by the engine stop and start control device according to the modification of the embodiments. As in 8th is shown, the more the deceleration of the vehicle increases, the more the setting section increases the low speed judgment value Vd.

In the engine stop and start control device according to the third exemplary embodiment described above, the ECU determines 20th the allowable pitch angle for an IS used during the pitch angle holding period running from time t41 to time t43 in consideration of a starting slope angle Δθ of the current road on which the vehicle is traveling for the period from a time when the vehicle speed of the vehicle is in the low speed judgment value Vd until a time when the vehicle stops can travel. That is, the ECU 20th In the engine stop and start control apparatus according to the third exemplary embodiment, uses the second threshold value β, which is between the first threshold value α and the third threshold value γ, as an allowable pitch angle for an IS used during the holding period for holding the pitch angle θ .

On the other hand, the engine stop and start control device according to the modification further includes a pitch angle adjusting section. The ECU 20th calculates a slope angle θ of the current road at a time immediately before the vehicle speed of the vehicle enters the low speed range.

The calculated pitch angle is held as a first pitch angle holding value θ in the holding section. The the pitch angle adjusting section then adjusts the first pitch angle holding value θ based on a starting pitch angle Δθ at which the vehicle can travel for the period running from a time when the vehicle speed of the vehicle enters the low speed range (which does not is greater than the low speed judgment value Vd) until a time when the vehicle stops.

During the holding period of the first pitch angle holding value θ, the ECU judges 20th based on a comparison result between the adjusted first pitch angle holding value (which has been adjusted by the pitch angle adjusting section) and the third threshold value γ, whether or not the automatic engine stop can be performed.

9 Fig. 13 is a timing chart of idle reduction control according to the modification of the exemplary embodiments.

As in 9 in particular, the ECU adds 20th add the starting pitch angle Δθ to a first pitch angle holding value θh1 to obtain a second pitch angle holding value θh2 at which, as described above, the vehicle can travel on the starting pitch angle Δθ when the vehicle is running at the low speed judgment value Vd. After this addition, the ECU compares 20th the second slope angle holding value 0h2 with the third threshold value γ. When the comparison result indicates that the second held pitch angle 0h2 is smaller than the third threshold value γ, the ECU leaves 20th execution of the automatic machine stop. On the other hand, when the comparison result indicates that the second pitch angle holding value 0h2 is not smaller than the third threshold value γ, the ECU omits 20th the execution of the automatic machine stop.

In the above-described embodiments, the ECU compares 20th the pitch angle (as the calculated pitch angle θa or the pitch angle holding value θh) with the allowable pitch angle for an IS, and judges based on the comparison result whether or not the automatic engine stop can be performed. Thus, the ECU judges 20th permitting / refraining from executing the automatic engine stop based on the pitch angle (as the calculated pitch angle θa or the pitch angle hold value θh).

On the other hand, the engine stop and start control device according to another modification has an adjusting section for adjusting a pressure of the master cylinder (as an allowable pressure of the master cylinder pressure for an idling stop (IS)) in accordance with a gradient angle of the current road on which the vehicle is traveling. on. The ECU 20th In the engine stop and start control device according to the modification, compares a pressure of the master cylinder obtained by the hydraulic pressure sensor 34 is detected with the allowable pressure of the master cylinder for an IS obtained by the setting section. The ECU 20th judges whether or not the automatic engine stop can be carried out based on the comparison result.

• (a2) wenn der Fahrer des Fahrzeugs das Bremspedal 31 drückt, d.h. der Fahrer betätigt die Bremsbetätigung;
• (a3) wenn die Fahrzeuggeschwindigkeit des Fahrzeugs kleiner als die vorbestimmte zulässige Fahrzeuggeschwindigkeit Vi für einen IS wird; und
• (a5) wenn ein Druck des Hauptzylinders 31 kleiner als der zulässige Druck des Hauptzylinders 31 für einen IS wird.

For example, when the vehicle is running on a road, the ECU stops 20th the combustion of the machine 10 to execute the automatic machine stop when the following conditions are met:

• (A2) when the driver of the vehicle depresses the brake pedal 31 presses, ie the driver applies the brake actuation;
• (a3) when the vehicle speed of the vehicle becomes less than the predetermined allowable vehicle speed Vi for an IS; and
• (a5) when a pressure of the master cylinder 31 less than the allowable pressure of the main cylinder 31 for an IS will.

10 Fig. 13 is a view showing a relationship between a gradient angle of a road and a pressure of a master cylinder when the execution of the idle reduction control is permitted.

As in 10 as shown, the more the pitch angle (as a calculated pitch angle θa or a pitch angle holding value θh) of the current road increases, the more the allowable pressure of the master cylinder pressure for an IS is increased.

In the first exemplary embodiment, the ECU stops 20th the pitch angle θ up to the time (as the pitch angle holding end time t14 shown in 4A until 4D shown) after the predetermined length of time T1 from a time when the vehicle stops (t13, which is in 4A until 4D shown). On the other hand, the ECU detects 20th In the engine stop and start control device according to another modification, vibration of the vehicle at a vehicle speed not greater than the vehicle stop judgment value V. The ECU 20th sets, based on the amplitude of the detected vibration, the pitch angle holding end time during which the pitch angle is held in the holding section

The ECU 20th In the engine stop and start control device according to the modification, calculates a pitch angle θ (as a calculated pitch angle θa) based on the detection signals received from the acceleration sensor 24 and the wheel speed sensor 25th be transmitted. The ECU 20th calculates the amplitude of the vibration of the vehicle based on the amplitude of the calculated pitch angle θa, that is, a difference between a maximum value and a minimum value of the calculated pitch angle θa. The ECU 20th holds the calculated pitch angle θa in the holding section until a time when the amplitude of the calculated pitch angle θa does not become larger than a judgment value TH. When the amplitude of the calculated pitch angle θa does not become larger than the judgment value TH after this time, the ECU starts 20th calculate a pitch angle θ of the current road on which the vehicle is traveling.

The following follows with reference to FIG 11 A until 11 C a description of an example of detecting the time when the amplitude of the calculated pitch angle θa does not become larger than the judgment value TH.

11A until 11C Fig. 13 are timing charts of idle reduction control according to the modification of the exemplary embodiments. As in 11 A until 11 C is shown, the ECU starts 20th hold the pitch angle θ at a time t50 when the vehicle speed of the vehicle becomes lower than the predetermined low speed judgment value Vd. After a time t51 when the vehicle speed of the vehicle does not become greater than the vehicle stop judgment value Vs, the ECU calculates 20th the amplitude of the calculated pitch angle θa, that is, a difference between a maximum value and a minimum value of the calculated pitch angle θa. The ECU 20th compares the calculated amplitude of the calculated slope angle θa with the judgment value TH.

After a time t52 when the amplitude of the calculated pitch angle θa does not become larger than the judgment value TH, the ECU starts 20th calculate a pitch angle θ of the current road on which the vehicle is traveling. The ECU 20th judges whether or not the automatic engine stop and start control can be carried out using the calculated slope angle θa.

In the first exemplary embodiment, the ECU stops 20th the pitch angle θ up to the time t14 (as in 4A until 4D is shown) after the predetermined length of time T1 has elapsed after the vehicle stops. However, it is for the ECU 20th acceptable, the pitch angle θ up to the time t13 (as in 4A until 4D shown).

In the second exemplary embodiment, the ECU stops 20th the pitch angle θ up to the time t24 (as in 5A until 5D at which the vehicle speed of the vehicle becomes greater than the predetermined low speed judgment value Vd after the vehicle is started. However, it is the ECU 20th possible to change the pitch angle θ up to the time t23 (as in 5A until 5D is shown) at which the vehicle starts moving, or until a time after the lapse of a predetermined length of time from time t23.

In the first exemplary embodiment, the ECU stops 20th the pitch angle θ during a time length T3 from time t15 when the vehicle starts moving to a time when the vehicle speed of the vehicle becomes greater than the predetermined low speed judgment value Vd. In this case the ECU 20th sets the calculated pitch angle to the pitch angle hold value θh, the calculated pitch angle being obtained based on detection results obtained from the acceleration sensor 24 at a time immediately before the vehicle starts. The ECU 20th holds the pitch angle hold value θh continuously during the length of time T3.

In the various exemplary embodiments described above, the vehicle engine control system shown in FIG 1 shown is the wheel speed sensor 25th of the electromagnetic pick-up type. However, the concept of the present invention is not limited to this. It is possible to use other pulse detection sensors which can detect a rotation of a wheel of a vehicle, for example sensors with a magnetoresistive effect.

While certain embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications and alternatives could be made in light of the entire teachings of the disclosure. Accordingly, the specific arrangements disclosed are for illustration only and do not limit the scope of the present invention, the full breadth of which is determined from the following claims and their equivalents.

Claims (8)

An engine stop and start device for performing an automatic engine stop and an automatic engine restart of an engine (10) mounted on a vehicle, the engine stop and start device comprising: a first calculation section (20) configured to calculate a vehicle acceleration value of a vehicle based on detection signals transmitted from an acceleration sensor (24) having a Can detect acceleration acting on the acceleration sensor (24); a vehicle speed calculating section (20) configured to calculate a vehicle speed of the vehicle based on detection signals transmitted from a wheel speed sensor (25) capable of detecting a rotating speed of a wheel of the vehicle; a second calculating section (20) configured to calculate a wheel acceleration value based on a change in vehicle speed calculated by the vehicle speed calculating section (20); a pitch angle calculation section (20) configured to calculate a pitch angle of a current road on which the vehicle is traveling based on the vehicle acceleration value calculated by the first calculation section (20) and the wheel acceleration value calculated by the second calculation section (20) ) is calculated, to calculate; a slope angle holding section (20) configured to hold a previously calculated slope angle as the slope angle holding value of the current road during a period in which the vehicle speed of the vehicle is within a low speed range, the previously calculated slope angle becoming a Time immediately before the vehicle speed enters the low speed range, which is not greater than a low speed judgment value (Vd), has been calculated by the pitch angle calculating section (20); and a stop control section (20) configured to judge, while the vehicle is traveling before the vehicle speed of the vehicle enters the low speed range, based on a pitch angle calculated by the pitch angle calculation section (20), whether or not an automatic engine stop may be performed or not, and during a period in which the vehicle speed of the vehicle is within the low speed range, judging whether or not the automatic engine stop can be performed based on the pitch angle holding value held by the pitch angle holding section (20). Engine stop and start control device after Claim 1 and further comprising a setting section (20) configured to change the low speed judgment value (Vd) in accordance with deceleration of the vehicle. Engine stop and start control device after Claim 1 or 2 wherein the pitch angle holding section (20), while a predetermined holding period extending from a time when the vehicle stops after the vehicle speed of the vehicle takes the low speed range, holds the previously calculated pitch angle as the pitch angle holding value of the current road, and the Stop control section (20) during the predetermined holding period based on the pitch angle holding value held by the pitch angle holding section (20) judges whether or not the automatic engine stop can be carried out, and the stop control section (20) after the lapse of the predetermined holding period based on a The pitch angle calculated from the vehicle acceleration during a period in which the vehicle is stopping, judges whether or not the automatic engine stop can be carried out. Engine stop and start control device after Claim 3 , further comprising a vibration detection portion (20, 24, 25) configured to detect a degree of vibration of the vehicle after the vehicle stops, the pitch angle holding portion (20) based on the degree of vibration of the vehicle generated by the vibration detection portion (20) is detected, adjusts an end time of the predetermined holding period. Engine stop and start control device after Claim 3 or 4th wherein the stop control section (20) allows execution of the automatic engine stop when the gradient angle of the current road is smaller than a predetermined gradient angle threshold value, and refrains the execution of the automatic engine stop when the gradient angle of the current road is larger than a predetermined gradient angle threshold value, and when the vehicle is running, the stop control section uses a first threshold value during a time before the predetermined holding period, a second threshold value during the predetermined holding period, and a third threshold value during a time after the predetermined holding period as the predetermined slope angle threshold value, the second threshold value being larger than the first threshold and less than the third threshold. Engine stop and start control device after Claim 5 , wherein the stop control section (20) subtracts from the third threshold value a starting slope angle calculated based on the low speed judgment value (Vd) as a slope angle at which the vehicle can travel for a period starting from a time when the vehicle speed of the vehicle is in enters the low speed range until a time when the vehicle stops, can continue to travel, and uses the subtracted pitch angle as the second threshold value. Engine stop and start control device after Claim 3 or 4th wherein the stop control section (20) allows the automatic engine stop to be carried out when the slope angle of the current road is smaller than a predetermined slope angle threshold value, and the stop control section (20) forbids the execution of the automatic engine stop when the slope angle of the current road is greater than a predetermined one Slope angle threshold value, and the stop control section (20) uses a driving state threshold value and a stop state threshold value as the predetermined slope angle threshold value, the driving state threshold value being used during a period when the vehicle is running and the stop state threshold value being used during a period when the vehicle stops, the The engine stop and start control device further comprises a pitch angle setting portion (20) configured to base the pitch angle holding value held by the pitch angle holding portion adjust d to the holding angle calculated based on the low speed judgment value (Vd) as a slope angle at which the vehicle extends for a period extending from a time when the vehicle speed of the vehicle enters the low speed range to a time when the vehicle stops, the stop control section (20) judges whether or not the automatic engine stop can be performed based on a comparison result between the pitch angle hold value set by the pitch angle setting section (20) and the stop state threshold value during the predetermined holding period not. Engine stop and start control device after Claim 1 or 2 wherein the pitch angle holding portion (20) extends the previously calculated pitch angle during the predetermined holding period ranging from a time when the vehicle speed of the vehicle enters the low speed range to a time when the vehicle starts again after the vehicle stops as the pitch angle of the current road, and the stop control section (20) judges whether or not the automatic engine stop can be performed based on the pitch angle hold value held by the pitch angle holding section (20) during the predetermined holding period.

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