DE102017127531A1 - Method for stopping the engine of a vehicle - Google Patents

Abstract

The present invention relates to a method of stopping an engine of a vehicle, comprising the steps of monitoring a human machine interface (HMI) of the vehicle to receive a command to stop the engine, verifying a state of motion of the vehicle to determine if the vehicle is in motion Vehicle is at a standstill or not, and stopping the engine when the vehicle is at a standstill. In order to avoid an unintentional stopping of the engine, an information or a warning message is transmitted to the driver, which indicates that the driver should take over control again, if the vehicle is not at a standstill.

Description

The present invention relates to a method of stopping an engine of a vehicle, comprising the steps of monitoring a human-machine interface (HMI) of the vehicle to receive a command to stop the engine, verifying a state of motion of the vehicle to determine whether the vehicle is at a standstill or not, and stopping the engine when the vehicle is at a standstill.

The present invention also relates to a control unit for a vehicle for carrying out the above method.

Older vehicles use as HMI a "classic" mechanical key or an ignition lock to switch on the ignition, to start the engine, to stop the engine or to switch off the ignition. This is done by the driver by turning the key in at least two predetermined positions "ignition on" and "starter on". In some cases, a steering wheel lock is also unlocked or triggered, or some consumers, such as the windshield wipers, are powered. Turning back the key will stop the engine and turn off the ignition. Then the key can be removed from the lock. These terms have been developed for most common vehicles with an internal combustion engine. However, these terms are also used when referring to electrically powered vehicles or vehicles with different types of engines, including combinations of different types of engines. The latter are commonly referred to as hybrid vehicles.

More advanced vehicles of the prior art have a "start-stop" button as an HMI, which the driver must press to start or stop the engine. Since only stopping the engine is of interest to the present invention, there are two possibilities: if the car is already at a standstill or running at a very low speed, the engine is stopped by simply briefly pressing the button by the driver. If the vehicle is traveling at a higher speed, a short press is not enough. The driver or passenger next to him has to press the button longer, usually for a few seconds, to stop the engine. For example, some manuals of conventional vehicles with respect to the start-stop push-button indicate that the drive system can be turned off by pressing and holding the start / stop button for three seconds while the vehicle is in motion.

This is a safety feature in case the driver loses consciousness and the person next to him stops the ride. When switching off the ignition while driving, safety-related functions are only limited or not available at all. This could affect the power steering and the brake booster. Both features require more power, are supported for a limited time only, and have limited capabilities.

Conventional vehicles respond directly to a corresponding interaction with the HMI and stop the engine directly when the driver presses the start-stop push button even when the vehicle is in motion.

The described direct stopping of the motor after receiving the stop command has the advantage that in the case of manual driving, as long as the driver keeps himself "up to date" and continuously checks the state of the powertrain, it is simple, easy to understand and adequately secured. The driver can simply hear whether the engine is running or has stopped running. It may also have its status indicated by pictograms and / or the engine speedometer, e.g. in the dashboard of the vehicle, see.

When driving is partially automated, which is also referred to as Autonomous Driving (AD) Level 2, the vehicle may e.g. Carry out tasks to automatically park or automatically hold the lane or the distance, wherein acceleration and deceleration processes are performed by driving support systems, but monitored by the driver. The function of an emergency stop can also be automated. For example, some high-end vehicles offer functionalities such as so-called "emergency assistance". That is, if the driver does not respond to two or three prompting tone signals by doing anything, the vehicle will start a "minimum-risk maneuver" to gently stop the vehicle. The minimum-risk maneuver is based on the assumption that the driver has lost consciousness. The system will only control the longitudinal driving behavior of the vehicle with the aim of decelerating the vehicle more or less slowly depending on the surrounding situation. The vehicle will select the right hand lane or the side lane and stop it gently. Such behavior has long ago been introduced as a "dead man's switch" or "dead man's grip" in the railroad field. If the driver does not press a special button every minute, the train stops automatically.

When driving is further automated, ie autonomous driving from level 3 onwards without monitoring vehicle behavior by the driver, stopping the engine may be even more dangerous because stopping the engine also means reducing the energy supplied to other autonomous vehicle systems, such as brakes or steering. Of course, once it has been detected that the engine is off, the automated function should return the control to the driver and even start a minimum-risk maneuver to secure the vehicle if the driver does not quickly regain control.

On the other hand, it should always be possible for the driver or the passenger next to him to stop the engine in a panic situation, such as an inadvertent acceleration or loss of braking function. Therefore, all cars on the market have the overriding command that the engine actually stops when the driver or someone else keeps the start / stop button pressed long enough. It would be quite unusual and difficult to accept that the engine keeps running when the button is held down longer.

In this context, the term "standstill" means that the vehicle is really stationary (zero speed) or moving only at a very low speed (speed of a pedestrian, maximum 5 km / h). "On the move" means the normal driving / movement of the vehicle at a speed higher than the speed of a pedestrian.

The invention has for its object to provide a solution to prevent unintentional stopping of the engine while the vehicle is moving.

The solution to this problem is provided by the independent claims. Advantageous embodiments are specified in the subclaims.

In particular, the invention provides a method of stopping an engine of a vehicle, comprising the steps of monitoring a human machine interface (HMI) of the vehicle to receive a command to stop the engine, verifying a state of motion of the vehicle to determine if the vehicle is at a standstill or not, and stopping the engine if the vehicle is at a standstill and transmitting to the driver information or warning message indicating that he should regain control if the vehicle is not at a standstill ,

According to the invention, there is also provided a control unit for a vehicle for executing the above method, wherein a logic circuit for detecting the state of the movement or the standstill and detecting the command of the driver is provided, and wherein an output function for transmitting information to the driver is provided ,

The basic idea of the invention is the decoupling of the command from the action of the system in the control unit. It is avoided to stop the engine even if an inadvertent "stop" request of the driver is detected. The engine is not switched off immediately. The driver is informed to do something, i. continue to act or react. He has to react or regain control of the vehicle. The engine keeps running and supplies power to the accessories until a second command confirms the driver's desire to stop. This is even more important when the system is performing automated driving. For the driver, it is always possible to stop the engine in an emergency or in a panic situation.

In any case, turning off the engine while driving can be dangerous. In autonomous driving, autonomous systems may not know how to handle this situation. Further, engine shutdown typically involves deactivating multiple auxiliary systems that may be required to move the vehicle. Moreover, the shutdown may be dangerous to the engine itself, e.g. when the wheels continue to turn the engine. This concerns both an internal combustion engine and an electric motor.

It should be noted that there are two general options for interacting with the driver of the vehicle: one option is a general warning to the driver to do something, i. "To act", which can play a role in the "normal" driving condition. The other option is to send a warning message to the driver indicating that he should take control again when the vehicle is in autonomous driving condition.

The term human-machine interface (HMI) can refer here to various interfaces. The HMI may include a mechanical or electrical key, a start / stop button, or other electronic device, such as a smartphone, through which commands may be entered by gestures or speech. To "stop" the engine is synonymous with the terms "turn off", "turn off", "turn off", "pause" and "turn key switch off". It should also be noted that the term "key switch "older" motor vehicles is used to indicate that the engine (s) and accessories are typically stopped with a mechanical key. "Engine" is used synonymously for "drive", "ignition" or "powertrain". "Standstill" means actually standing (zero speed) or driving at a very low speed (speed of a pedestrian, maximum 5 km / h). "On the move" means normal driving / movement of the vehicle at a speed higher than the speed of a pedestrian.

Future cars may be equipped with modern HMIs such as electronic devices, smartphones that are either held in the hand or e.g. are mounted in the steering wheel, or command systems that receive commands of the driver by clicking, swiping, gestures or voice input, or the like.

According to a modified embodiment of the invention, after the step of stopping the engine or transmitting an information or warning message to the driver indicating that it should retake control, the method returns to the step of monitoring the vehicle's HMI, the Method has an additional step of evaluating receipt of an emergency signal to stop the vehicle, and wherein the method has an additional step for switching the engine in the event of receiving the emergency signal.

In accordance with a modified embodiment of the invention, the method includes an additional step of performing a minimum risk maneuver to stop the vehicle. The system will only control the longitudinal driving behavior of the vehicle with the aim of driving the vehicle e.g. slow down more or less slowly as a function of an environmental situation. The vehicle selects the right lane or the side strip and stops gently. Such behavior has long been introduced as a "dead man's switch" or "dead man's grip" in the railroad field and is based on the assumption that the driver has lost consciousness or for any other reason is unable to control the vehicle.

According to a modified embodiment of the invention, the step of transmitting to the driver an information or warning message indicating that he should retake the control, in the event that the vehicle is not in a stoppage state, comprises transmitting a warning message indicating that the engine will stop if the driver continues to insist on the stop command or repeats the stop command via the HMI, for example by repeatedly pressing a button or holding down a button, turning a key, depressing the brake pedal, commanding transmits or enters by voice input. The transmission of a command can also be done by pressing, clicking, swiping a field on a screen, for example when providing an interactive screen or a smartphone. The transfer may also be done by moving hands or arms when the vehicle has a gesture-responsive command system. Speech input is the way to enter commands when the vehicle has a command system with voice input. If the driver does not respond, the system recognizes that the stop command was unintentional and continues driving.

According to a modified embodiment of the invention, the step of evaluating receipt of an emergency signal to stop the vehicle includes monitoring a repeated receipt of a command to stop the engine, receiving a longer command to stop the engine, receiving a signal indicating a key turn , receiving a brake pedal operation, receiving a command, or receiving a spoken command.

According to a modified embodiment of the invention, the method comprises verifying an autonomous driving state of the vehicle, and in the event that the vehicle is not in an autonomous driving state, performing a regular "shutdown" procedure for stopping the engine of the vehicle.

In accordance with a modified embodiment of the invention, the method includes an additional step of performing a process of passing control of the vehicle to a driver prior to performing a regular "shutdown" procedure to stop the engine of the vehicle.

According to a modified embodiment of the invention, the step of transmitting information or warning message to the driver comprises transmitting information indicating that the driver is to take control of the vehicle.

If the driver wishes to continue the AD mode after receiving a warning that the system is initiating a handover process, he must respond accordingly. If it does not respond, the system initiates a minimum-risk maneuver to gently stop the vehicle.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described below. Individual features illustrated in the embodiments may, alone or in combination, form an aspect of the present invention. Features of the various embodiments may be transferred from one embodiment to another embodiment.

As mentioned above, all HMIs may be used in conjunction with the invention, but for the following detailed description of preferred embodiments, the "start-stop" pushbutton will be selected. The reason for this is that a classic mechanical key as HMI does not seem suitable for a vehicle with an autonomous driving function. In fact, in a vehicle having such a mechanical key interface, it will be rather unusual and difficult for the driver to accept that the engine may remain on when the key is switched to the OFF position. In other words, in the case of a vehicle operating in the AD mode, the situation could arise that the driver for some reason switched the classic key to the OFF position (and perhaps even removed the key from the lock) Engine, however, continues to run. The driver would find this situation rather strange or "unnatural".

• 1 ein Ablaufdiagramm eines erfindungsgemäßen Arbeitsablaufs für ein „normales“ Fahrzeug;
• 2 ein Ablaufdiagramm eines erfindungsgemäßen Arbeitsablaufs für ein autonomes Fahrzeug; und
• 3 einen anderen Arbeitsablauf für ein autonomes Fahrzeug.

Show it:

• 1 a flow chart of a workflow according to the invention for a "normal"vehicle;
• 2 a flow chart of a workflow according to the invention for an autonomous vehicle; and
• 3 another workflow for an autonomous vehicle.

1 shows a process according to the invention, which runs in a control unit of a "normal" vehicle. This means that the state of autonomy corresponds to the AD (autonomous driving) level 0, according to which only the driver steers and accelerates the vehicle, the AD level 1, according to which some assistance systems support the driver, such as the adaptive cruise control (ACC). , or AD Level 2, according to which partial automatic parking, automatic lane keeping, or standby or other functions are performed. In all cases, driving is always under the control or supervision of the driver.

The first step is to check if the powertrain is ON. The second step is to check the state of the "Start Stop" button. If the "Start Stop" button is not pressed, the system does not need to respond. When the "Start Stop" button is pressed, the system checks whether the vehicle is moving or at a standstill. If it is moving, the system will test to confirm the driver's intention to stop the engine, for example, whether the "start-stop" button is held down for more than three seconds or repeatedly pressed. If the intention of the driver is confirmed, the engine is stopped. If the intention of the driver is not confirmed, the system transmits information to the driver to confirm his intention to stop the engine. When the vehicle is at a standstill, the system detects the driver's desire to shut off the engine and stops the engine.

2 shows a flowchart of an inventive workflow for an autonomous vehicle in AD Level 3 (highly automated). This embodiment can also be used in vehicles in AD Level 4 (fully automated) or AD Level 5 (no driver required).

The first step is to check if the powertrain is in the ON state. The second step is to check the "autonomous driving" state. An AD "Level 3" function is considered active when it has been selected and activated by the driver, so that the control of the longitudinal and lateral driving behavior is adopted by the system. If the driver temporarily overrides either longitudinal or lateral control, the AD "Level 3" function will still be considered active. If the system has already initiated a transfer process (so that the driver can regain control), but neither the driver has completely retaken control nor the system has completed its automatic minimum-risk maneuver (that in the decommissioning of the vehicle to a safe Way), the AD "Level 3" function is still considered active.

If the AD "Level 3" is not enabled, the system will default to a "shutdown" workflow. This means that the in 1 described standard workflow is applied. The engine will not stop immediately when the vehicle is moving at high speed. The driver is asked to confirm his request (by pressing and holding the "Start-Stop" button, repeated presses or other safety confirmation). When the AD "Level 3" is activated, the system continuously checks the state of the "Start Stop" button. If the "Start Stop" button is not pressed, the system will not have to respond and the journey will continue. If If the "Start-Stop" button is pressed, the system checks whether the vehicle is moving or at a standstill. When it moves, the system transmits information to the driver and asks him to take control again, because he has detected a contradiction, and waits for a new / second command by the "autonomous driving" - (AD) Condition is checked again. When the vehicle is at a standstill, the condition of the brake pedal is checked. When the brake pedal is depressed, there is no danger of the engine being stopped and the AD "Level 3" function being disabled as the vehicle has been stopped by the driver and kept locked. The system shuts off the engine. If the brake pedal is not depressed, the control unit transmits information to the driver indicating that it should retake control and waits for a new command from the driver by rechecking the "autonomous driving" (AD) state. The information for the driver indicating that he should retake control is a message or warning message that prompts the driver to perform a defined process to regain control (this process is for the "Level 3"). Function specific and should be known to the driver). This can for example be realized by a double action, such as hands on the steering wheel on the one hand and a certain pressure or pedal operation on the other hand.

It is assumed that the "start-stop" button can be accidentally or not pressed at any time when the vehicle is at a standstill or not. In addition, it should be clarified that the loop is provided from the block "Informing the driver to regain control" to the block "Checking the" Autonomous Driving "state", because if "start stop" Button is intentionally (and not accidentally) pressed and the driver really wants to stop the engine, the engine is stopped. Therefore, in the step "informing the driver to regain control", the operation of the button is ignored unless the driver has regained control (i.e., by disabling the AD function). Or the vehicle comes to a halt when the driver depresses the brake pedal.

3 shows a flowchart of another workflow according to the invention for an autonomous vehicle in level 3 (highly automated). This embodiment may also be used in Level 4 (fully automated) or Level 5 (no driver required) vehicles.

The first step is to check if the powertrain is in the ON state. The second step is to check the "autonomous driving" state. If the AD "Level 3" is not enabled, the system will apply the default "shutdown" workflow 1 on. When AD Level 3 is enabled, the system checks the status of the Start Stop button. If the "Start Stop" button is not pressed, the system does not need to respond. When the "Start Stop" button is pressed, the system will check if the "Start Stop" button is pressed repeatedly. When the "start-stop" button is repeatedly depressed, the system recognizes the driver's request or command and warns him that the system initiates a handover process and / or initiates a minimum-risk maneuver to stop the vehicle when the driver does not react accordingly. To perform the minimum risk maneuver, the engine should continue running until the vehicle is automatically placed in a safe condition. After stopping the engine can be switched off.

If the "Start Stop" button is not pressed repeatedly, the system will check to see if the vehicle is moving or at a standstill. When it moves, the system transmits information to the driver and asks him to regain control because he has detected a contradiction, and waits for a new / second command by rechecking the "autonomous driving" state becomes. When the vehicle is at a standstill, the condition of the brake pedal is checked. When the brake pedal is depressed, the system detects the driver's desire to shut off the engine and stops the engine. If the brake pedal is not actuated, the control unit transmits the information to the driver indicating that it should retake control and again waits for a new command from the driver by rechecking the "autonomous driving" state.

This embodiment has advantages for some situations, namely when a fault occurs in the transmission or powertrain or when an unexpected acceleration occurs. Then it can happen that the driver panics. Instead of stopping the AD function by the usual deactivation procedure, it may happen that it tries to stop the engine by pressing the "Start Stop" button. If this action is repeated in this manner, the system recognizes that it can not be an unintended or random sequence, such as, but not limited to, the key 2 or 3 Press and release in less than 5 seconds. A permanent longer press, eg for more than 5 seconds, can lead to the same result, namely that the system recognizes a "real" stop request.

Claims (7)

Method for stopping an engine of a vehicle, comprising the steps of: Monitoring a human machine interface (HMI) of the vehicle to receive a command to stop the engine; Verifying a state of motion of the vehicle to determine whether the vehicle is at a standstill or not; and Stopping the engine if the vehicle is at a standstill and transmitting to the driver information or warning message indicating that the driver should retake control if the vehicle is not at a standstill. Method according to Claim 1 characterized in that the method comprises an additional step of evaluating receipt of an emergency signal to stop the vehicle; and the method includes an additional step of turning off the engine in the event of receiving the emergency signal. Method according to Claim 2 characterized in that the method comprises an additional step of performing a minimum-risk maneuver to stop the vehicle. Method according to Claim 2 or 3 characterized in that the step of transmitting to the driver an information or a warning message indicating that the driver is to resume control, in the event that the vehicle is not at a standstill, comprises transmitting a warning message indicating in that the engine will stop when the driver insists on the stop command or repeats the stop command via the HMI, eg by repeatedly pressing a button or holding a button down, turning a key, depressing the brake pedal, transmitting a command or voice input enters. Procedure after previous Claim 4 characterized in that the step of evaluating receipt of an emergency signal to stop the vehicle comprises monitoring the repeated receipt of a command to stop the engine, receiving a longer command to stop the engine, receiving a signal indicative of a key turn, Receive an operation of the brake pedal, the receipt of a command or the receipt of a voice input input command. Method according to one of the preceding claims, characterized in that the method comprises verifying an autonomous driving state of the vehicle, and, if the vehicle is not in the autonomous driving state, carrying out a normal "shutdown" procedure for stopping the engine of the vehicle. Control unit for a vehicle for carrying out a method according to any one of the preceding claims, characterized in that a logic circuit for detecting a movement state or a standstill state and detecting the command of the driver is provided and an output function for transmitting information to the driver is provided.

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