FR2816891A1 - Automatic starting and stopping control for motor vehicle internal combustion engine has sensors for vehicle operating parameters connected to control for engine starting and stopping circuits - Google Patents

Abstract

The automatic starting and stopping control for a motor vehicle internal combustion engine sensors (11-15) to determine the operating conditions of the vehicle. The sensors are connected to a control circuit (30) for the starting (52,54) and stopping (50) circuits of the engine. The sensors include a vehicle speed sensor and condition sensors for the clutch position, engine condition and temperature.

Description

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 The present invention relates generally to starting and stopping systems of a thermal engine and more particularly to an improved system for automatically controlling the starting and stopping of said engine.

- un capteur de position du frein à main. WO-98/14702 describes such a system. This system includes an electronic card which controls the stopping or restarting of the heat engine from information supplied by two sensors: - a clutch pedal position sensor,

- a hand brake position sensor.

 If the clutch pedal is not depressed and the parking brake is applied, then the engine is stopped automatically.

 If the clutch pedal is depressed and the parking brake is released, then the engine will restart automatically.

 This system also uses an engine speed sensor which deactivates the electronic card if the engine speed is below a certain threshold and an engine temperature sensor which inhibits automatic engine controls if the engine has not reaches its operating temperature.

 However, the consumption, pollution and noise pollution generated by the heat engine are not satisfactorily minimized with known systems.

 Indeed, for this, the vehicle engine must be stopped automatically as soon as the speed is almost zero, because it has been calculated that on average, a vehicle is stationary, engine running, for about 10% of the time of rolling.

 For example, in the document cited above, during a stop in front of a red light, the engine is not switched off, because the driver of the vehicle does not generally pull the hand brake in such a situation.

 Furthermore, the known solutions of the aforementioned type are purely material. Consequently, their complexity and in particular that of the electronic card increases rapidly when the number of pieces of information taken into account for controlling the motor increases. These solutions also do not make it possible to simply solve the problems which call for a more complex engine control strategy, for example during a parking maneuver.

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 The present invention aims to remedy the drawbacks of known systems by creating a system which makes it possible to implement more efficient management, starting and automatic engine shutdown strategies.

 It therefore relates to a system for automatically starting and stopping a thermal engine of a vehicle comprising means for stopping and starting the engine, sensors for information on the state of the vehicle, and means for controlling said engine stop and start means from information from the sensors, characterized in that said control means comprise a computer containing an algorithm for controlling said engine acting as a function of the data delivered by said information sensors.

 According to other features of the invention: - said information sensors include a speed sensor; - the information used by the control algorithm consists of the data of an engaged gear ratio sensor, a clutch position sensor, an engine speed sensor, a temperature sensor engine and data from said speed sensor; the information used by the control algorithm includes the data from a tilt sensor; - the information used by the control algorithm includes the data of a door contactor; - Said engine starting means is a reversible alternator and the control algorithm comprises means for detecting and managing a blockage of said reversible alternator; - The control algorithm includes timing means to avoid unnecessary stops of the engine during a parking maneuver; the system comprises first and second means for starting the engine, a switch having at least first and second positions and the computer controls only the first starting means when the switch is in the first position and controls only the second means when the switch is in the second position.

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 The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawings in which: - FIG. 1 represents a hardware architecture of the entire system of the invention; - Fig. 1 a represents the software architecture of the system of the invention of the invention; - Figs. 2a, 2b, and 2c represent alternative embodiments of the hardware architecture of the system shown in FIG. 1; and - Fig. 3 shows a flowchart for controlling the automatic starts and stops of a vehicle heat engine.

 FIG. 1 represents a vehicle 1 equipped with a heat engine 3, an ignition key 5 intended for manually controlling the starting or stopping of the engine 3 and a means 7 for selecting an operating mode.

 The means 7 for selecting an operating mode is for example a three-position switch, added to the passenger compartment of the vehicle.

 In an alternative embodiment, the means 7 consists of three additional positions added to an already existing switch.

 The system 1 comprises five sensors for information on the operating state of the vehicle 1: - an engine speed sensor 11 delivering information on the engine rotation speed; - a vehicle speed sensor 12; - A clutch position sensor 13 intended to indicate the position of the clutch pedal; - a speed ratio sensor 14 engaged in the gearbox; an engine cooling water temperature sensor 15 intended to give information on the engine temperature.

 The ignition key 5, the means 7 for selecting an operating mode and the five sensors for information 11 to 15 on the state of the vehicle are connected by electrical conductors 20 to a means 30 for controlling the engine 3.

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 The electrical conductors 20 are connected to an input interface 32 of the control means 30. This input interface 32 is produced using circuits for conditioning the electrical signals such as analog-digital converters (not shown).

 The control means 30 also includes a computer 34 and an output interface 40. The computer 34 used is for example a microcontroller 36 associated with electronic memories 38.

 It is important to note that the computer 34 within the meaning of the present invention is defined more generally as being any system in which a control algorithm can be implemented using programming means and containing at least one memory.

 A programmable logic network of the ASIC type could be used.

 The output interface 40 is composed of three relays 41, 42 and 43. The relays 41, 42 and 43 are connected by electrical conductors 48 respectively to a means 50 for stopping the motor 3, a first starting means 52 and a second starting means 54.

 The stop means 50 is an ignition and injection computer on which it is possible to act to control the stopping of the engine 3. The first starting means 52 is a conventional starter of a heat engine with a notched crown . The second starting means 54 is a reversible inverter and alternator as described in French patent No. 2,718,285.

 The advantage of using two starting means will appear later on reading the following description.

 FIG. 1a represents an example of software architecture making it possible to carry out a control algorithm contained in the electronic memories 38.

 The software architecture is divided into two modules. A first module 55 called low-level software groups the commands specific to the hardware architecture used, such as reading a signal on one of the inputs of the microcontroller 36 or transmitting an output signal. This software is specific to the microcontroller used. The second module 56, called high-level software, is specific to the application produced.

 In the present invention, the second module is used to implement the strategy for managing automatic starts and stops of the engine 3. It

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 is done in a programming language such as C language.

 Figures 2a, 2b and 2c show alternative embodiments of Figure 1. Consequently, only the elements added compared to those of Figure 1 are shown, the others remaining identical.

 FIG. 2a represents a variant in which an inclination sensor 61 is connected by an electrical conductor 62 to the control means 30 of FIG. 1.

 FIG. 2b represents a variant in which a door contactor 63 is connected by an electrical conductor 64 to the control means 30 of FIG. 1.

 FIG. 2c represents a variant in which a sensor 65 of the battery current is connected by an electrical conductor 66 to the control means 30 of FIG. 1.

 The operation of the system, the structure of which has been presented previously in FIGS. 1 and 1 a, will now be described with the aid of FIGS. 1, 1a and 3.

 The driver of vehicle 1 gets into his vehicle and turns the ignition key 5.

 The information sensors 11, 12, 13, 14 and 15 on the operating state of the vehicle, the control means 30 and all of the electrical devices are energized.

 Consequently, the information sensors 11 to 15 permanently measure the operating state of the vehicle 1 and send electrical signals corresponding to this state, via the electrical conductors 20 to the input interface 32 of the means of command 30.

 Electrical signals indicating the position of the ignition key 5 and of the switch 7 are also transmitted to the input interface 32 via the electrical conductors 20.

 The input interface 32 composed of conditioning circuits converts these electrical signals into a format compatible with the operation of the microcontroller 36.

 The electrical signals indicating the position of the ignition key 5 are directly managed by the low-level software module 55. Thus a request to stop the engine using the ignition key 5 leads

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 systematically when the computer 34 is deactivated and when the heat engine 3 is stopped whatever the control algorithm implemented in the software module 56.

 The electrical signals containing the information on the state of the vehicle 1 and on the position of the switch 7 are managed by the microcontroller 36 in accordance with the control algorithm implemented in the high-level software module 56. The microcontroller 36 as a function of the signals previous electrical and control algorithm generates control signals transmitted to the output interface 40.

 The output interface 40 actuates the output relays 41, 42 and 43 which compose it as a function of the signals received from the microcontroller 36.

 The closure of the relay 41 controls the stop means 50, which in turn controls the stopping of the engine 3. The closure of the relay 42 actuates the conventional starter 52 which starts the engine 3. The closure of the relay 43 actuates the alternator reversible 54 which drives the motor shaft 3 in rotation to start the motor.

 This last starting means has the advantage of being less noisy than a conventional starter.

 The operation of the system is governed by the control algorithm implanted in the memories 38 and described with the aid of the flow chart represented in FIG. 3.

 The control algorithm includes a first time delay step 72: During the 20 seconds following a first start, no task is performed in order to wait for the engine 3 to be warm.

 In the present embodiment, the engine 3 is considered to be hot when the cooling water temperature sensor 15 indicates a temperature above 70 ° C. Otherwise, the engine 3 is said to be cold.

 This step is important because a cold engine is much more polluting when starting than a hot engine. It is therefore necessary to avoid starting a cold engine as much as possible so as not to pollute and also not to disturb the operation of the catalytic converters.

 After this step, the position of the three-position switch 7 is read in step 74 and this information is recorded in one of the

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 electronic memories 38. The position of the three-position switch 7 makes it possible to select an operating mode.

 Three operating modes are provided: - in the first, the automatic management of engine starts and stops is completely inhibited and only the ignition key 5 can be used; in the second, the actuated starting means is a conventional starter 52: - in the third, the actuated starting means is a reversible alternator 54.

 The choice of operating mode is made at all times by the driver, who manually actuates the switch 7.

 If the first operating mode has been selected, the computer continuously scans the position of the switch 7 and step 74 does not end until the second or third operating mode is selected.

 If an operating mode different from the first has been selected, the process continues with step 76.

 During step 76, the computer checks whether the conditions for automatically controlling the stopping of the engine 3 are met.

 The conditions for automatically stopping the engine 3 are met when the input signals from the microcontroller 36 are simultaneously in the following states: the signal from the cooling water temperature sensor 15 indicates that the engine is hot; - the signal from the engine speed sensor 11 indicates that the engine is running.

 The engine is considered to be running if the measured engine speed is greater than 600 rpm in the case where the information recorded during step 74 indicates that the selected operating mode is the second corresponding to the use of the starter. classic.

 If the information recorded in step 74 indicates that this is the third operating mode, corresponding to the use of a reversible alternator, the measured engine speed must be greater than 900 rpm ;

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 the signal from the speed sensor 12 indicates that the speed is almost zero, that is to say in the present embodiment, that the speed is less than 2 km / h; - the signal from the clutch position sensor 13 indicates that the clutch pedal is raised; - the signal from the gear ratio sensor 14 engaged indicates that the gear lever is in neutral.

 If the five preceding conditions are met for a period of 1.5 consecutive seconds, the engine stop control step 78 is executed. Otherwise, that is to say if the engine stop conditions are not met or if the stop conditions have not been met for 1.5 consecutive seconds, step 80 of checking the engine start conditions is directly executed. The duration of 1.5 consecutive seconds allows the driver in a parking maneuver to switch alternately from first to reverse while avoiding unnecessary and annoying engine stops.

 During step 78, a command to stop the motor 3 is sent to the output interface 40 which causes the relay 41 to close. The closing of the relay 41 controls the stop means 50 which stops the motor 3.

 Step 78 ends when an engine stop command has been generated and step 80 is executed.

 During step 80, the computer checks whether the conditions for controlling the starting of the engine 3 are met.

These conditions are met when the input signals of the microcontroller 36 are simultaneously in the following state: - the signal from the engine speed sensor 11 indicates that the engine is stopped, that is to say that the engine speed is zero; - the signal from the clutch position sensor 13 indicates that the clutch pedal is depressed; the signal from the gear ratio sensor 14 engaged indicates that a gear ratio is engaged, including reverse gear;
If the three preceding conditions are met, step 82 is executed, otherwise the control algorithm returns to step 74. During step

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 82, a command to start the engine is sent to the output interface 40.

 The output interface 40 closes the relay 42 corresponding to the conventional starter 52 if the operating mode memorized in step 74 is the second.

On the other hand, if the operating mode memorized in step 74 is the third, the interface 40 closes the relay 43 corresponding to the reversible alternator. Then, the computer checks whether the engine has restarted, by scanning the signal received from the engine speed sensor 11. As long as the engine is not considered to be running in the sense defined above, a start-end command is not sent to the output interface 40.

 Finally, when this last command is sent, the previously activated relay 42 or 43 is deactivated and the activated starting means is put to rest. Step 82 ends and the control algorithm returns to step 74.

 As long as the computer is supplied with power, the process defined above is repeated.

 According to other embodiments, the control system is modified so as to increase the safety of the driver.

 For example, it is useful to prevent the engine from stopping when the road is on a slope to avoid driving assistance being unavailable in such a situation.

 For the implementation of this improvement, the hardware architecture used is that shown in FIG. 2a.

 The inclination sensor 61 sends to the electric conductor 62 a signal proportional to the inclination of the road. This signal is transmitted to the input interface 32 where it is packaged in a format compatible with the operation of the microcontroller 36.

The signal thus converted therefore forms part of the input signals of the microcontroller 36 which can be taken into account for the control algorithm of the computer 30. The sequence of the control algorithm of this variant is similar to that described in help of figure 3 except for step
76.

 Step 76 is modified so as to take into account an additional condition. Stopping the engine by the control means is only allowed

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 if the signal from the tilt sensor 61 indicates a slope less than a predetermined threshold.

 The hardware architecture of another variant linked to security is shown in FIG. 2b.

 In this variant, starting of the vehicle engine by the control means 30 is prohibited when a door switch 63 indicates that a door is open. The processing of the signal from the contactor 63 is similar to the processing of the signal from the sensor 61 described above.

The flow of the computer control algorithm is similar to that described with the aid of FIG. 3 except for step 80. Step 80 is modified so as to take into account an additional condition: starting the engine. is only authorized if the signal from contactor 63 corresponds to closing the doors
Another variant consists in taking into account for the control of the computer 34, the information from a sensor 65 of the battery current to know the state of charge of the latter. Based on this information, the engine 3 start and stop commands are inhibited to avoid excessively discharging the battery.

 The operation of the hardware architecture of this variant shown in FIG. 2c is similar to that described with the aid of FIG. 2a since the tilt sensor 61 is simply replaced by a battery current sensor 65.

 The sequence of the computer control algorithm is similar to that described with the aid of FIG. 3 except for step 76. Step 76 is modified so as to take into account an additional condition: automatic shutdown of motor 3 is only authorized if an algorithm for estimating the remaining capacity of the battery estimates as a function of the data from sensor 65 (estimation of the currents entering and leaving the battery) that the energy remaining in the battery is sufficient to restart the vehicle engine with certainty during step 80.

 In another possible variant, the engine speed sensor 11 is used to indicate whether the engine is blocked. The engine is considered to be blocked if, simultaneously, the engine speed is zero and an engine start command is present for two consecutive seconds.

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 The material structure of this variant is identical in all respects to that described with the aid of FIG. 1.

 The sequence of the computer control algorithm is similar to that described with the aid of FIG. 3 except for step 82. Step 82 is modified so that during the period of scanning the engine speed, to find out if the latter has restarted, we also check that the motor is not blocked in the sense defined above.

 In the event of an engine blocking and if the operating mode recorded during step 74 is the third, that is to say that corresponding to the use of the reversible alternator 54, then the computer 34 sends to the interface output 40 an end of start command followed by a start command of the engine 3 using the conventional starter 52.

 This automatically switches from the second starting means to the first, the first starting means serving in this case as a backup element. This can be useful, for example, if the battery energy is not sufficient to start the engine using the reversible alternator but is sufficient to start the engine using the conventional starter.

 It is important to note that by combining the hardware architecture of the different variants described above and by making the modifications to the corresponding computer control algorithm, it is possible to combine several of these variants in a single mode of production.

 For example, if all the variant embodiments described with reference to FIGS. 2a to 2c are combined in the same embodiment, the control algorithm must be modified as follows: - the additional condition stated during the description of the operation of the variant described using FIG. 2a becomes a sixth condition for stopping the engine; the additional conditions described with the aid of FIGS. 2b and 2c respectively become the fourth and fifth conditions for starting the engine 3.

 It appears that an automatic starting and stopping system of an engine according to the invention makes it possible to implement more effective automatic starting and stopping strategies without increasing the complexity and the cost of the equipment used.

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 It will also be noted that the invention is not limited to the embodiments described.

 Thus, sensors for additional information on the state of the vehicle can be used and other strategies for monitoring and controlling engine starts and stops can be implemented.

 It will also be noted that the invention can be implemented even if only one means of starting the engine is used.

Claims (8)

 CLAIMS 1. System for automatically starting and stopping a heat engine (3) of a vehicle (1) comprising means for starting (52,54) and stopping (50) the engine (3), sensors (11, 12, 13, 14, 15) of information on the operating state of the vehicle, and control means (30) of said means for stopping and starting the engine from information from the sensors (11 to 15), characterized in that said control means (30) comprise a computer (34) containing an algorithm for controlling said motor acting as a function of the data delivered by said information sensors (11 to 15).  2. Control system according to claim 1, characterized in that said information sensors (11 to 15) comprise a speed sensor (12).  3. Starting system according to claim 2, characterized in that the information used by the control algorithm consists of data from a gear ratio sensor (14) engaged, a position sensor (13) clutch, an engine speed sensor (11), an engine temperature sensor (15) and data from said speed sensor (12).  4. Starting system according to any one of the preceding claims, characterized in that the information used by the control algorithm comprises the data of a tilt sensor (61).  5. Starting system according to any one of the preceding claims, characterized in that the information used by the control algorithm comprises the data of a door contactor (63).  6. Starting system according to any one of the preceding claims, characterized in that said starting means (54) of the engine (3) is a reversible alternator and that the control algorithm comprises means for detecting and managing a blockage. of said reversible alternator.  7. Starting system according to any one of the preceding claims, characterized in that the control algorithm comprises timing means to avoid unnecessary stops of the engine (3) during a parking maneuver.  8. Starting system according to any one of the preceding claims, characterized in that it comprises first and second means <Desc / Clms Page number 14>  starting (52,54) of the engine, a switch (7) having at least first and second positions and in that the computer (34) controls only the first starting means (52) when the switch is on the first position and controls only the second starting means (54) when the switch is in the second position.