RU2684155C2 - Method and system to control transport vehicle with starter motor - Google Patents

Abstract

FIELD: vehicles.

SUBSTANCE: invention relates to a vehicle with an engine, in particular to controlling the engagement of a starter motor used to start a vehicle engine. Disclosed is a method of controlling the engagement of starter motor 1001 for starting vehicle engine 1000, in which when a signal is detected on the need to restart engine 1000 during the engine off, the engagement of starter motor 1001 will be prohibited, if engine rpm is in preset limits, and engine rpm 1000 is reduced.

EFFECT: technical result is reduction of engine restart time.

10 cl, 9 dwg

Description

FIELD OF THE INVENTION

The invention relates to a vehicle with an engine, in particular, to control the engagement of a starter motor used to start a vehicle engine.

State of the art

It is known a vehicle with a start-stop control system for automatically starting and stopping an internal combustion engine that provides vehicle movement.

The start-stop system automatically stops the engine if it is determined, at least in part, based on the actions of the driver, which will reduce fuel consumption and the amount of emissions from the engine.

Depending on the type of gearbox (manual or automatic) of the vehicle, various driver actions can be used to determine whether to start and stop the engine. When using a manual gearbox, two main control modes are distinguished, which are called “stop in the engaged gear” and “stop in the neutral gear”.

Often there are situations when the driver changes his intention for a certain period of time between the decision to stop the engine and the actual stop of the engine. A change in intention may occur as a result of an unexpected change in driving conditions or because the driver accidentally switches one or more manual control devices so that the system decides to restart the engine.

In the event of a change in intention, it is preferable to reduce the delay (t) between the moment of the change of intention and restarting the engine to a minimum.

It is known that the starter motor can be engaged without damaging the starter motor itself or the ring gear for which it engages when the engine rotates forward (in the normal direction) at a sufficiently low speed, for example, at 200 rpm. However, the engagement of the starter motor during rotation of the engine in the opposite (negative) direction is usually avoided due to the high probability of damage to the gears of the starter motor and / or ring gear, for which it engages. In this regard, there is a need to ensure that the engine stops before it is engaged.

The inventors have found that using the improved method of controlling the starter motor described in the present invention, compared with known methods, will achieve a significant reduction in engine restart time.

Disclosure of invention

The aim of the invention is to provide a method for reducing engine restart time in the event of a change of intention during engine shutdown.

A method for controlling the engagement of a starter motor of a vehicle’s engine during engine shutdown is proposed, in which, when the engine speed is reduced, engagement of the starter motor is excluded, the current engine speed being in the range from a negative speed limit value to a positive speed limit value.

If the current engine speed is in the range from the negative speed limit to the positive speed limit, engagement of the starter motor may be allowed when the engine speed is constant or increases.

Engagement of the starter motor may be prohibited in any case if the current engine speed is below the negative speed limit.

The engine shutdown may be a shutdown performed by a start-stop system, and the engagement of the starter motor may be an engagement requiring a restart of the engine when the driver changes intention during engine shutdown.

Also proposed is a vehicle control system with a starter motor used to start a vehicle engine, which includes an electronic controller and several inputs, allowing to obtain data of at least the current engine speed and the need to shut down or restart the engine, moreover the electronic controller is configured to prohibit the engagement of the starter motor to restart the engine during engine shutdown, if the speed engine rotation is reduced, and the current engine speed is in the range from a negative speed limit value to a positive speed limit value.

The system may include an engine speed sensor for displaying data on the current engine speed, and if the engine speed sensor detects that the current engine speed is in the range from a negative speed limit to a positive speed limit, electronic the controller will be able to prevent the starter motor from engaging until the engine speed stops decreasing.

The system may include an engine speed sensor for displaying data on the current engine speed, and if the engine speed sensor detects that the current engine speed is in the range from a negative speed limit value to a positive speed limit value, then engagement of the starter motor will not be prohibited if the engine speed is constant or increases.

Engagement of the starter motor may be prohibited by the electronic controller in any case if the current engine speed is below the negative speed limit.

The system may further include a start / stop controller, wherein the engine shutdown may be a shutdown performed by the start-stop system, and the engagement of the starter motor may be an engagement requiring a restart of the engine when the driver changes intention during engine shutdown.

Also proposed is a vehicle having an engine with a control system in accordance with the above system.

Brief Description of the Drawings

The invention will now be described by way of example with reference to the accompanying drawings, in which:

In FIG. 1a and 1b show high-level flowcharts of a method for controlling engagement of an engine starter motor during engine shutdown in accordance with the invention;

in FIG. 2a is a graph showing the relationship between engine speed and time for a first variation of intention when turning off and restarting an engine in accordance with the prior art;

in FIG. 2b is a graph showing the relationship between engine speed and time for the first variation of intention when turning off and restarting the engine using the method in accordance with the invention;

in FIG. 3a is a graph showing the relationship between engine speed and time for a second variation of intention when turning off and restarting the engine in accordance with the prior art;

in FIG. 3b is a graph showing the relationship between engine speed and time for a second variation of intention when turning off and restarting the engine using the method in accordance with the invention;

in FIG. 4a is a graph showing the relationship between engine speed and time for a third variation in intention when turning off and restarting the engine in accordance with the prior art;

in FIG. 4b is a graph showing the relationship between engine speed and time for a third variation in intent when the engine is turned off and restarted according to the method of the invention;

in FIG. 5 is a schematic view of a vehicle with a control system in accordance with the invention.

The implementation of the invention

In FIG. 1a and 1b are high-level flowcharts for a method 100 for controlling starting and stopping an engine, for example, engine 1000 of FIG. 5 having a starter motor 1001.

The method starts at step 110, in which the driver of the vehicle MV in which the engine 1000 is mounted turns on the ignition and starts the engine manually.

Then, the method proceeds to step 120, in which the engine is in operating mode. At step 130, it is checked whether the start / stop conditions are satisfied. By way of non-limiting example, this condition can be an excess of a predetermined value of the engine coolant temperature or the presence of a sufficient battery charge level to perform a restart.

If these conditions are not met, the engine will not be able to stop even if it is possible to stop it, and the method will cyclically perform steps 130 and 120 until the conditions are met or the ignition is turned off, after which the method ends.

If at step 130 these conditions are met, the method proceeds to step 140, where, based on the actions of the driver, the presence of a signal to stop the engine is checked. To signal the need to stop the engine, various combinations of conditions can be used, for example, to indicate the need to stop the engine of a vehicle having an automatic transmission, the MV vehicle should be stationary, the gas pedal not depressed, and the brake pedal depressed.

If there is no signal to stop the engine, the method returns to step 120, otherwise the method proceeds to step 150.

At step 150, the engine is turned off. Various means of turning off the engine are known from the prior art, but in the general case, when using a diesel engine, the fuel supply is stopped, and in the case of a gasoline engine, the glow plugs are turned off and the fuel supply is stopped.

After step 150, at step 160, the intention is changed during engine shutdown. In other words, when the engine is turned off, the driver can take his foot off the brake pedal, which will be a change in state that requires a signal to restart the engine.

If a change of intention (CoM) occurs in step 160, the method proceeds from step 160 to step 170.

The method then cycles through steps 170 and 160 until the engine stops, or until a restart signal is detected at step 160.

After the engine is stopped, the method proceeds from step 170 to step 180, after which it cyclically performs steps 170 and 180 until a signal is found that a restart is necessary, for example, when the driver takes his foot off the brake pedal.

When a signal is detected about the need to restart at step 180, the method proceeds to step 190, where the engine can be instantly started using the starter motor, since before that it was stationary.

After that, the method returns from step 190 to step 120, in which the engine is in operating mode.

There is a delay (δt) between the moment you start the procedure or give the command to perform the gearing and the moment the starter motor gear comes into contact with the ring gear attached to the engine flywheel, which is called the gear moving time. Thus, even when the engine can be started immediately, there is a slight delay (δt) until the actual start.

The duration of this small delay (δt) depends on several factors, including the electrical and mechanical systems of the starter motor, the wiring and power supply of the starter motor, as well as environmental and wear conditions, such as temperature, battery level, and starter contamination. Typically, the gear travel time (δt) can be of the order of several tens of milliseconds, for example, 50 ms.

If the intention is changed in step 160, the method proceeds from step 160 to step 165.

At step 165, it is checked how safe it will be to engage the starter motor to start the engine. If the engine rotation speed exceeds the threshold value of the n_thresh-auto speed for automatic starting, at which the inertia of the engine can be used to restart the engine without using the starter motor, the method proceeds to step 167. At step 167, the engine automatically starts and the method returns to step 120, in which the engine is in operating mode.

However, if during the check from step 165, the engine speed is lower than the threshold for automatic start, the method will proceed from step 165 to step 210.

At step 210, it is checked that the engine speed is below the positive speed limit (n_thresh +). If the current engine speed is greater than or equal to the positive speed limit value (n_thresh +), the method proceeds to step 230, where the starter motor can be engaged. Between steps 210 and 230, additional checks can be performed to verify that the engine speed in the positive direction is not too high, since the starter motor cannot be engaged at a very high speed without risk of damage.

Therefore, if the engine speed is too high, then you can wait until the engine speed drops to a certain lower level, for example, to 200 rpm.

After step 230, the method proceeds to step 190, where the engine is started. As mentioned earlier, there is a slight delay (δt) between the start of the gearing procedure and the actual gearing of the starter motor.

From step 190, the method returns to step 120, in which the engine is in operating mode.

If at step 210 it is determined that the current engine speed is below the positive speed limit (n_thresh +), the method proceeds to step 220, in which engagement of the starter motor will be disabled, and then to step 240.

At step 240, compliance with the prohibition conditions of the engagement of the starter motor is checked. In doing so, check the following:

1) whether the engine speed is reduced. In other words, is the change in engine speed negative (change n <0);

or

2) whether the engine speed is lower than the negative speed limit value (n_thresh-). In other words, it is checked whether the engine rotates in a negative direction with a negative rotation speed exceeding the negative speed limit value (n_thresh-).

If at least one condition is not met, the method proceeds to step 260, where the starter motor is engaged, and then to step 190, where the engine is started. After step 190, the method returns to step 120, in which the engine is in operating mode.

However, when both conditions are checked, checked at step 240, the method returns to step 220, and the engagement of the starter motor remains prohibited. If the current engine speed is below the negative speed limit value (n_thresh-) or if the engine speed decreases, i.e. if it becomes more negative, then there will be a return to step 220. It should be noted that to go to step 240, the engine speed must be below the positive speed limit (n_thresh +), that is, at step 240, the following check will be performed:

if (n_thresh +)> engine speed> (n_thresh-), and the engine speed decreases, then the starter motor engagement will be prohibited.

In this case, the method will be completed at any stage when the ignition is turned off.

In FIG. 2a-4b show several situations in which there was a change of intention, which would allow a better understanding of the basic principles of the invention.

The value of the engine rotation speed in the negative direction can be determined experimentally, at which the starter motor can be engaged without serious damage to the ring gear, including the formation of notches. The inventors also noticed that in order to avoid serious damage for a given combination of the starter motor and the ring gear, two values of negative speeds can be selected. The first negative speed is the negative speed at which the negative engine speed increases, that is, becomes more negative, and the second negative speed at which the negative engine speed decreases, that is, becomes less negative. Both of these speeds are shown in FIG. 3b and 4b as -n1 and -n2, respectively. If the engine speed is less negative compared to the speed -n1 when the engine speed decreases, or compared to the speed -n2 when the engine speed increases, then it will not be seriously damaged when the starter motor is engaged.

Therefore, based on the data of speeds -n1, -n2, threshold values for the engine speed can be obtained, which can be used to determine the need to prohibit the engagement of the starter motor.

The first of these thresholds is a positive speed limit value (n_thresh +), suitable for situations in which the engine rotates in the forward direction. If the engine rotation speed is higher or equal to this threshold value (n_thresh +) when starting the gearing procedure for the starter motor, the starter motor is engaged before the engine speed drops below the first negative speed -n1.

The second of these thresholds is a negative speed limit value (n_thresh-), suitable for situations in which the motor rotates in the opposite (negative) direction. This threshold value (n_thresh-) is set so that the starter motor catches after the engine speed has passed the second negative speed value -n2 if the engine speed is equal to or exceeds this threshold value (is less negative), and engagement is performed at positive change in engine speed. In other words, the negative engine speed must be lower than -n2 at the moment the gear actually engages.

In FIG. 2a shows a method for turning off and starting an engine known in the art, in which the engine speed never becomes negative.

A change in intention (CoM) occurs at the moment the engine is turned off, and the engine is restarted at the moment “t” after CoM. In this case, the engine stops, and then after a delay of 5t, corresponding to the time of movement of the gear, it restarts.

In FIG. 2b shows the same variant of CoM intent change as in FIG. 2a, but using the method in accordance with the present invention. In this case, there is no need to prohibit starting the engine, since the engine rotation speed exceeds the positive speed limit (n_thresh +), and the engine will restart after the delay δt corresponding to the gear travel time. In this case, the engine start is started immediately after the change of intention, therefore, the delay "t" after the COM before restarting is equal to δt, since it is not necessary to wait for the engine speed to drop to zero, as is the case using the method known from the prior art, according to FIG. 2a.

In FIG. 3a shows a method of turning the engine off and starting, known in the art, in which the engine speed has a small negative value during shutdown.

A change in intention (CoM) occurs at the moment depicted as the moment the engine is turned off, when the engine rotates in the opposite direction, that is, when in this case the maximum negative rotation speed is reached. The engine is restarted after a delay of “t” seconds after CoM. In this case, the engine is stopped, after which it is restarted after the delay δt necessary to engage the gears of the starter motor over the ring gear of the engine.

In FIG. 3b shows the same variant of CoM intent change as in FIG. 3a, but using the method in accordance with the invention. In this case, due to the fact that the engine speed is below the positive speed limit (n_thresh +), the engine speed drops to a level located in the area Z1, where the engagement of the starter motor is prohibited. The engine speed never reaches the negative speed limit (n_thresh-), so the engine can be restarted when the change in engine speed becomes positive. In this case, due to the fact that CoM occurs at the maximum negative speed, the change in the engine rotation speed instantly becomes positive, therefore, the gearing procedure of the starter motor can be started immediately, and after the time δt necessary for gear engagement has elapsed, the engine is restarted. Thus, in this case, the start of the engine starting procedure is performed immediately after CoM; that is, since it is not necessary to wait for an increase in the engine speed to zero, as with the method known from the prior art, as shown in FIG. 3a, the delay “t” from the moment of CoM to restart will be equal to δt.

In FIG. 4a shows a method of turning the engine off and starting, known in the art, in which the rotation speed of the engine has a large negative value during shutdown.

A change in intention (CoM) occurs at the moment depicted as the moment the engine is turned off when the engine rotates in the opposite direction. The engine is restarted after a delay of “t” seconds after CoM. In this case, the engine is stopped, after which it is restarted after the delay necessary to engage the gears of the starter motor over the ring gear of the engine. Accordingly, the start of the starting procedure is delayed before the engine stops completely.

In FIG. 4b shows the same variation of CoM intent as in FIG. 4a, but using the method in accordance with the invention. In this case, due to the fact that the engine speed is below the positive speed limit (n_thresh +), the engine speed drops to a level located in the region Z2, where the engagement of the starter motor is prohibited. The peak negative value of the engine speed, which is reached at time t _m , is below the negative speed limit value (n_thresh-), i.e. the engine rotates with a higher negative rotation speed compared to the negative speed limit value (n_thresh-) and, accordingly, cannot be restarted.

However, as soon as the change in engine speed becomes positive, and the negative speed becomes less than the negative speed limit value (n_thresh-), the engine can be restarted again. In this case, the prohibition of engagement of the starter motor is removed at the moment when the engine speed changes in the positive direction and becomes higher than the negative speed limit value (n_thresh-). In other words, when the engine speed increases and the level of the negative speed limit (n_thres-) passes, the starter motor engages, and after the delay δt necessary to engage the starter motor gear onto the engine ring gear, the engine starts. Therefore, in this case, it is not necessary to wait until the engine rotation speed increases to zero, as in the case of using the method known from the prior art depicted in FIG. 4a. When using the method in accordance with the present invention, which is shown in FIG. 4b is t "seconds, not t seconds, as in the case of using the method known from the prior art depicted in Fig. 4a.

Therefore, in all cases, the engine starts with a lower delay than when using the method known from the prior art, in which the engine must stop before it becomes possible to restart.

In FIG. 5 shows an MV vehicle with an internal combustion engine 1000 and a control system comprising a system control unit 1050.

The engine 1000 is started using a starter motor 1001 with a gear (not shown) engaged in a gear ring (not shown) attached to a flywheel (not shown) of the engine 1000. Upon receipt of a signal from the control unit 1050, which engages the ring gear and the engine is cranked 1000 using the starter motor 1001, the starter motor 1001 is supplied with power from the starter motor power source 1002.

The engine 1000 has an intake manifold 1003 in which an inlet throttle valve 1005 is mounted to allow air flow to the engine 1000 to be regulated. The engine 1000 also includes several glow plugs (not shown) and a fuel injection system (not shown) for supplying fuel to the engine 1000 in accordance with prior art. The inlet throttle valve 1005 is controlled by an actuator 1006, which is activated when a control signal is received from the control unit 1050 to rotate the throttle valve 1005 in the intake manifold 1003. The throttle valve 1003 regulates the flow of air into the engine 1000 in the direction indicated by arrow “A ". To control the operation of engine 1000, absolute pressure downstream of throttle valve 1005 can be measured using a manifold absolute pressure sensor 1010 connected to control unit 1050.

In this case, the control unit 1050 includes a start / stop controller 1100, however, the start / stop controller 1100 may also be a separate device operably connected to the control unit 1050.

The control unit 1050 has several inputs 1015, 1020, 1025, 1030, 1035 and 1040 used to control the operation of the engine.

The first input corresponds to the input with which you can determine the engine speed using the engine speed sensor 1015.

The second input 1020 corresponds to several inputs, with which you can determine the operating conditions of the vehicle MV, for example, atmospheric pressure, ambient temperature, exhaust gas composition, engine coolant temperature, vehicle speed and main battery charge level.

The third input 1025 corresponds to the input with which you can determine the state of the gearbox (not shown) of the vehicle MV. It usually indicates whether the gearbox is in the neutral position or in the gear position.

The fourth input 1030 corresponds to the input with which you can determine the state of the gas pedal (not shown) used by the driver of the vehicle MV to indicate the required torque transmitted from the engine 1000.

The fifth input 1035 corresponds to the input with which you can determine the status of the brake pedal (not shown) of the vehicle MU. Input 1035 indicates whether the brake pedal is pressed or not.

The sixth input 1040 corresponds to the input with which you can determine the condition of the clutch pedal (not shown) of the vehicle MV. Input 1040 indicates whether the clutch pedal is depressed or not. This input is used only if the MV vehicle is equipped with a manual gearbox with manual control for engaging and disengaging the clutch between the engine 1000 and the gearbox. This configuration allows you to calibrate the movement of the clutch pedal so that the clutch pedal is considered “fully depressed” when the release is safe and considered “partially depressed” or “released” when it is not fully depressed. A partially depressed state is a state in which the driver does not move the clutch pedal sufficiently to ensure that the clutch is fully disengaged.

It is known from the prior art that the second to fifth inputs 1025-1040 can be used by the start / stop controller 1100 in various combinations and in various ways to determine when it is necessary to automatically stop the engine 1000 to reduce fuel consumption, and when it needs to be restarted after stopping.

To more clearly describe the operating principle of the control system in accordance with the invention, the states of controlled variable conditions for starting and stopping the engine 1000 are indicated below. However, other combinations of the states of controlled variable conditions can be used and the invention is not limited to the specific combinations described.

Engine shutdown is performed under the following conditions:

a) the gearbox is in the neutral position;

b) the clutch pedal is released;

c) the brake pedal is depressed;

d) the vehicle is stationary.

The engine is started under the following conditions:

e) the gearbox is in the neutral position;

and one of the following conditions

f) the condition of the clutch pedal changes from released to any other; or

g) the state of the brake pedal changes from depressed to released.

The principle of operation of this control system is described below.

The control unit 1050 continuously monitors the inputs 1020 and the input connected to the manifold pressure sensor 1010, which makes it possible to regulate the normal operation of the engine 1000 and control the throttle valve 1005 using the actuator 1006 to provide the necessary torque transmitted from the engine 1000 and satisfy the requirements for emissions for engine 1000.

A start / stop controller 1100 monitors inputs connected to an engine speed sensor 1015, a gearbox state sensor 1025, a gas pedal position sensor 1030, a brake pedal position sensor 1035, and a clutch pedal position sensor 1040. All signals received by the control unit 1050 can be transmitted to the start / stop controller 1100 and vice versa.

If the start / stop controller 1100 determines that the state of all of the monitored variable conditions a-d above are consistent with the stop conditions, a signal will be given to stop the engine 1000 to reduce fuel consumption and emissions.

After that, the start / stop controller 1100 performs the necessary actions to turn off the engine, which in this case means stopping the fuel supply to the engine 1000, turning off the glow plugs, and closing the intake throttle valve 1005. After performing these steps, the engine 1000 starts to stop or inertia to complete stopping after a certain time.

After the engine is turned off, it can be started if the state of all controlled variable conditions meets the requirements specified in paragraphs e-f. In other words, if the gearbox is in the neutral position, if the state of the clutch pedal changes from released to any other (partially or fully depressed), or if the state of the brake pedal changes from partially depressed to released, then engine 1000 is instantly started by starter motor 1001, to which, upon receipt of a signal from the control unit 1050, power is supplied from the starter motor power source 1002. Moreover, between the start of the engine starting procedure and the actual engine cranking, there is a certain delay, the so-called gear movement time δt.

If a change in intention occurs during shutdown, for example, when the condition of the clutch pedal changes from released to partially depressed during shutdown, or when the condition of the brake pedal changes from partially depressed to released during shutdown, then if this is possible, engine 1000 will need to be restarted .

If the engine speed remains relatively high, then the use of a starter motor may not be necessary, since the engine can be restarted in the "automatic start" mode either by supplying the required amount of fuel when working with a diesel engine, or by supplying fuel and a spark during operation with spark ignition engine.

If the engine speed is below this threshold for automatic starting, then to start the engine, you will need to use a starter motor. However, as mentioned above, the starter motor 1001 can only be engaged if specific requirements for engine speed are observed in order to prevent damage to the starter motor 1001 and, in particular, the gears of the starter motor and the ring gear on the flywheel.

Thus, before the starter motor 1001 engages, the conditions for safe restart are first checked. In accordance with the present invention, this check provides a check for detecting a decrease in engine speed (change n <0) and whether the current engine speed is in the range from a negative speed limit value (n_thresh-) to a positive speed limit value (n_thresh +).

The specified check is performed by the control unit by using the value of the engine speed, which the control unit receives from the engine speed sensor 1015 to obtain the current engine speed and compare it with the previous engine speed obtained with a small interval to date, which allows you to know the change engine speed. If the engine slows down, then the change in rotation speed will be negative, if the rotation speed of the engine increases, then the change in rotation speed will be positive, and if the rotation speed of the engine has not changed, then the change in rotation speed will be zero.

If it is determined that the engagement of the starter motor 1001 is not prohibited, then depending on the particular construction used, upon receipt of a signal from the control unit 1050 or from the start / stop controller 1100, current will be supplied to the starter motor from the starter motor power source 1002.

If the current engine speed exceeds the positive speed limit (n_thresh +), then the starter motor may be engaged. In some cases, this test may contain an additional limit value that will prevent the starter motor 1001 from engaging if a certain increased rotation speed is exceeded, lower than the threshold for automatic start, but higher than the positive speed limit (n_thresh +). In this case, the pre-set increased speed is a speed that is above a certain level and at which it is impossible to engage the starter motor without damage or malfunction.

However, if the engine rotation speed does not exceed the positive speed limit value (n_thresh +), then the engagement of the starter motor 1001 will be prohibited while the engine is decelerating and the engine speed exceeds the negative speed limit value (n_thresh-). Moreover, from the point of view of the rotation of the engine in the negative direction, the term "deceleration" means an increase in the magnitude of rotation in the negative direction or that the rotation speed of the engine becomes more negative.

If the engine rotation speed is below the negative speed limit value (n_thresh-), then the engagement of the starter motor 1001 will always be enabled regardless of whether the engine slows down or accelerates.

When engagement is prohibited, the control unit 1050 does not provide a start signal to the starter motor 1001.

If the engine rotation speed is below the positive speed limit value (n_thresh +), then the engagement of the starter motor 1001 is not prohibited if the engine is accelerated and the engine speed exceeds the negative speed limit value (n_thresh-).

When the engine speed and the change in engine speed indicate that engagement of the starter motor with the engine 1000 is not prohibited, engagement of the starter motor 1001 is allowed, after which the control unit 1050 starts the engine 1000.

If the positive speed limit value (n_thresh +) is set to plus 50 rpm., And the negative speed limit value (n_thresh-) is set to minus 70 rpm., Then:

1) engine rotation speed of 100 rpm. exceeds the positive and negative speed limits (n_thresh +) and (n_thresh-);

2) engine speed minus 50 rpm. below the positive speed limit (n_thresh +) and above the negative speed limit (n_thresh-);

3) engine rotation speed minus 100 rpm. below the positive and negative speed limits (n_thresh +) and (n_thresh-).

The engine speed decreases if its value decreases with a positive direction of rotation and increases with a negative direction of rotation.

For example, if the engine speed changes from plus 100 to plus 50 or minus 50 rpm, then the speed decreases. Similarly, if the engine speed changes from minus 50 rpm. minus 100 rpm., then the speed will decrease, despite the fact that the magnitude of the negative rotation speed increases.

One of the advantages of the present invention is that the delay in response to a change in intention can be easily reduced without the need for complex means regarding instantaneous speed values.

The second advantage of the invention is that all the hardware for implementing the invention is already installed in most vehicles with a start / stop control system, which eliminates the additional production costs.

Although the invention has been described by way of example with reference to one or more embodiments, it is not limited to the disclosed embodiments and other variations can be made without departing from the essence of the invention.

Claims (10)

1. A method for controlling the engagement of a starter motor of a vehicle engine during engine shutdown, the method comprising: inhibiting engagement of the starter motor if the current engine speed is between a positive threshold speed value and a negative threshold speed value and the engine speed is reduced. 2. The method according to claim 1, wherein if the current engine speed is between a positive threshold speed value and a negative threshold speed value, engagement of the starter motor is not prohibited if the engine rotation speed is constant or increases. 3. The method according to claim 1 or 2, in which the engagement of the starter motor is always prohibited if the current engine speed is below the negative limit value of the rotation speed. 4. The method according to claim 1, in which the engine shutdown is a shutdown caused by the start-stop system, and the engagement of the starter motor is the engagement required to restart the engine when the driver changes his intention during engine shutdown. 5. A control system for a vehicle having a starter motor for starting a vehicle engine, the system including an electronic controller and several inputs for indicating at least the current engine speed and the need to shut down or restart the engine, the electronic controller being made with the ability to prohibit the engagement of the starter motor to restart the engine during engine shutdown, if the current engine speed is tsya between the positive threshold and the negative threshold speed value speed and the engine speed decreases. 6. The system of claim 5, wherein the system comprises an engine speed sensor for indicating a current engine speed, and if the current engine speed indicated by the engine speed sensor is between a positive threshold speed value and a negative threshold speed value, the electronic controller is configured with the ability to prohibit the engagement of the starter motor, while the engine speed is reduced. 7. The system of claim 5, wherein the system comprises an engine speed sensor for indicating the current engine speed and, if the current engine speed indicated by the engine speed sensor is between a positive threshold speed value and a negative threshold speed value, the starter motor engages it is not prohibited if the engine speed is constant or increases. 8. The system according to claim 5, in which using the electronic controller always prohibit the engagement of the starter motor if the current engine speed is below the negative limit value of the rotation speed. 9. The system of claim 5, further comprising a start / stop controller, wherein the engine shutdown is a shutdown caused by the start-stop system, and the starter motor engagement is the starter motor engagement required to restart the engine when the driver changes intention during engine shutdown. 10. A vehicle with an engine having a control system according to any one of paragraphs. 5-9.

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