EP0618998B1 - Motor control system comprising a motorized butterfly body - Google Patents

Abstract

System comprising a motorized butterfly body (2), with a butterfly (5), a spindle (6), a body (4), an actuator (7), a position sensor (8) and a butterfly control unit (3) being incorporated into a single assembly (1). The engine control unit (15), which is connected to sensors (17) for detecting engine operation parameters and to the accelerator pedal (27), generates injection and ignition commands and the reference value of the butterfly's position, which is transmitted by a connecting line (40) to unit (3) which sets the position of the butterfly (5) to the reference value and transmits the butterfly position signal via line (40) to unit (15). Application to spark ignition engines fitted with a fuel injection system.

Description

The invention relates to an engine control system with motorized throttle body, for an internal combustion engine of a motor vehicle, equipped with a fuel supply installation by injection.

In the most conventional injection fuel supply installations, currently equipping internal combustion engines with positive ignition of a motor vehicle, at least one shutter member, called a butterfly valve, pivotally mounted on an axis in a conduit of a throttle body, is connected to the accelerator pedal by a mechanical cable transmission, allowing the angular position of the throttle valve to be controlled in the duct, so as to vary the intake air flow to the engine, depending on the driver request. Simultaneously, modern spark-ignition engines are equipped with an electronic command and control unit, known as an engine control unit, which includes a computer, and which has the function of controlling and controlling the operation of the ignition circuit and of the engine fuel injection system. This engine control unit is connected to several sensors for engine operating parameters, from which it receives signals representing in particular the engine speed, the position of the engine shaft, the air pressure in the intake manifold. , as well as possibly the air temperature, and the temperature of the water in the cooling circuit, without this list being limiting. From the signals received from the sensors to which this engine control unit is connected, as well as possibly from data recorded in the memories of this unit, the latter develops control orders for the ignition and injection circuits. , which it transmits to actuators of these circuits, such as the injector windings, a fuel pump, and ignition coils, to activate them. So that the operation of the ignition and injection circuits is properly controlled, in certain engine operating configurations, in particular during cold starts and idling, as well as in a manner consistent with the control of the air supply, as it results from the driver's request, the angular position of the throttle valve is detected by a sensor transmitting a signal corresponding to the engine control unit, which takes this signal into account not only to develop the signals of control which it transmits to the actuators of the ignition and injection circuits, but also to develop a control signal which it transmits to an actuator, such as an electric stepper motor for operating a valve, mounted in a bypass air intake circuit on the throttle valve, for the engine start-up and idling phases.

Furthermore, it is also known to equip motor vehicles with safety or driving comfort facilities, for example an anti-skid system, an anti-lock braking system, or even a system regulating the vehicle speed to a speed chosen by the driver. Each of these systems also includes an electronic command and control unit, which receives information from appropriate sensors, testifying to the operating state of the vehicle and certain of its components, and which prepares, from this information, control orders transmitted to appropriate actuators. For each of the particular systems mentioned above, one of the appropriate actuators is an actuator, for example an electric motor, which controls the angular position of the butterfly, in parallel with the mechanical control by cable connecting this butterfly to the pedal. accelerator, the anti-skid system actuator, or the anti-lock system having, for obvious reasons of safety, priority over the control exerted by the driver by the action on the accelerator pedal.

However, outside the periods of intervention of the safety systems (anti-skid, anti-blocking), the control of the admitted air remains under the direct control of the driver, by his action on the accelerator pedal. This leads, in particular, to a more or less controlled engine torque at the drive wheels, as well as to variable behavior of the vehicle during transients. To remedy this drawback, it has been proposed to replace the mechanical transfer law between the position of the accelerator pedal and the position of the throttle, a programmable transfer law, integrating a dynamic throttle correction function as well as a progressivity control function in its angular displacement, and finally a regulation of the idling speed. It has therefore been proposed to install, between the accelerator pedal and the throttle valve, an additional command and control unit, comprising a computer, as well as an additional actuator, such as an electric motor, the additional control unit receiving a signal from a sensor of the angular position of the accelerator pedal and developing, taking this signal into account, a control signal from the actuator, which operates the throttle valve.

To simplify such an installation, which comprises, for the operation of the throttle valve, at least two different actuators, one of which, directly controlled by the engine control unit, is involved in cold starts and for regulating the idle speed , and the other of which is an actuator controlled from the control unit sensitive to the position of the accelerator pedal, and involving the dynamic correction and progressiveness functions, to which a third can optionally be added, or even a fourth actuator, belonging respectively to the speed regulation system and to the traction control system, it was recently proposed to control the throttle position using a single actuator, itself controlled by its own electronic command and control unit, called the throttle control unit, developing the law of transfer between the position of the pedal accelerator and that of the throttle valve, not only from a feedback signal of the angular position of the accelerator pedal, received from a corresponding sensor, but also from a signal received from the engine control unit , to which the throttle control unit is connected by a communication line, as well as from signals received from suitable contactors, for example from the vehicle speed control system, in order to place the throttle in a position enabling it to maintain the selected speed, and possibly the traction control system, in order to close the butterfly if necessary.

In addition, in such an installation, the single actuator of the throttle valve and the sensor of the angular position of the throttle valve were each already integrated into the throttle body.

In this case, the throttle control unit is directly connected, on the one hand, to the throttle actuator, which it controls via an electronic power circuit, and, on the other hand, to the throttle position sensor, from which a throttle position signal is received by a throttle position control circuit, provided in the throttle control unit for comparing said throttle position signal to at least one position reference signal, and to develop, from an error signal resulting from this comparison, a throttle position control order, which is transmitted to the power circuit.

The disadvantage of such an installation is that throttle control is only ensured by the throttle control unit, so that any failure of this unit, or also of the communication line through which it receives information from the control unit. control engine, is a factor of insecurity. This insecurity at the level of the throttle closure, in order to reduce the engine power, is also found at the level of the driver's demand control, which is only ensured by the directly connected accelerator pedal position sensor. to the throttle control unit. Similarly, control of the throttle position is only ensured by the corresponding sensor, directly connected to the throttle control unit.

EP-A-0 222 081 discloses an engine control system with a motorized throttle body, for an internal combustion engine with positive ignition equipped with an injection fuel supply installation, according to the first part of claim 1.

However, this known system does not control the ignition of the engine, and all the sensors are connected to a single electronic calculation and control unit, ensuring control of the throttle valve.

Furthermore, US-A-4,894,781 discloses a system for controlling communications between electronic devices and the application of such a system to the control of an injection engine as well as numerous other pieces of equipment of a motor vehicle. . The control principle is that several electronic control units are linked by a common line of information exchange. At least one sensor is connected in parallel to at least two control units, each of which includes diagnostic circuits monitoring exclusive input circuits and a communication line connecting the exclusive input to the sensor. In the event of failure of the exclusive input or of the line connecting to the sensor, the diagnostic circuits control an auxiliary input receiving the signal from the sensor by another control unit, via the common communication line, to control an actuator. .

In its application to a motor vehicle, the system includes six electronic control units, one of which for engine control, controlling injection and ignition from numerous signals of engine operating parameters, such as engine temperature. intake air and flow rate, engine speed and position, engine temperature, as well as the throttle position, an operating actuator of which is controlled by another control unit, for controlling an automatic gearbox. This other control unit receives signals from various sensors, including the accelerator pedal position sensor. The control units can exchange sensor signals with which each of them is alone in communication, and the system does not include a motorized throttle body, on which the throttle angular position sensor and the throttle actuator are integrated into the throttle body, nor of the electronic throttle control unit, which is located directly on the throttle body so as to constitute a single assembly with it.

By the present invention, it is proposed to overcome the drawbacks of engine control systems with motorized throttle bodies of the types presented above, and the invention aims to provide such a control system with improved safety, at twice from the point of view of the architecture adopted and of the components used to make it, and better suited to the various requirements of the practice than the systems known from the prior art.

More specifically, on this subject, a particular object of the invention is to propose such a system in which redundancies are provided not only for controlling the position of the throttle valve, the driver's request, the proper functioning of one and / or the other of two control units used, but also to reduce the power of the engine if necessary, even when a communication line between the two control units is cut.

Another object of the invention is to propose an engine control system with a motorized throttle body making it possible to group together in an engine control unit, distinct from a throttle control unit, all the functions for managing the air circuits , fuel and engine ignition.

Yet another object of the invention is to propose such an engine control system with a motorized throttle body, of a structure such that its cost can be sufficiently limited to allow application on motor vehicles from the medium range, and not only high-end.

Another object of the invention is finally to propose such a motor control system, in which it is advantageous to use all the pins available on connectors with which the motor control units are fitted. currently used, with respect to which the engine control units according to the invention are only relatively little modified, remain compatible with the dimensions and the connection with the environment of the system, and geometrically interchangeable, so that the layout engine control units of a system according to the invention on currently equipped engines does not pose a problem.

• une seconde unité électronique de calcul et de contrôle, pour le contrôle du moteur, reliée auxdits capteurs de paramètres de fonctionnement du moteur, dont elle reçoit également des informations relatives à la vitesse de rotation du moteur et la position de l'arbre du moteur et élaborant lesdits ordres de commande d'injection ainsi que des ordres de commande d'allumage, qu'elle transmet auxdits actionneurs du circuit d'injection de combustible ainsi qu'à des actionneurs du circuit d'allumage du moteur, dont elle contrôle le fonctionnement, ledit signal de consigne de position du papillon étant élaboré dans l'unité de contrôle du moteur, à partir d'au moins ledit signal de position de la pédale d'accélérateur délivré par ledit capteur correspondant auquel l'unité de contrôle moteur est directement reliée, ledit signal de consigne ainsi que d'autres informations étant transmis à l'unité de contrôle du papillon, à laquelle l'unité de contrôle du moteur est reliée par une ligne de communication, tandis que le signal de la position angulaire du papillon est transmis de l'unité de contrôle du papillon à l'unité de contrôle moteur par ladite ligne de communication.

To this end, the subject of the invention is an engine control system with a motorized throttle body, of the type known by EP-A-0 222 081 and as presented above, and which is characterized in that said system further includes:

• a second electronic calculation and control unit, for controlling the engine, connected to said engine operating parameter sensors, from which it also receives information relating to the speed of rotation of the engine and the position of the engine shaft, and drawing up said injection control orders as well as ignition control orders, which it transmits to said actuators of the fuel injection circuit as well as to actuators of the engine ignition circuit, the operation of which it controls , said throttle position reference signal being produced in the engine control unit, from at least said accelerator pedal position signal delivered by said corresponding sensor to which the engine control unit is directly linked, said setpoint signal and other information being transmitted to the throttle control, to which the engine control unit is connected by a communication line, while the signal for the angular position of the throttle is transmitted from the throttle control unit to the engine control unit by said line of communication.

Thus, the engine control unit ensures, in normal operating configuration, the simultaneous control of the three air, fuel and ignition circuits of the engine.

In an advantageous embodiment, the actuator of the motorized throttle body is mounted directly on the throttle axis, so that this axis is common to the throttle and to the actuator, which limits the number of parts used, and this actuator is an electric actuator with bipolar control, without holding torque when it is not supplied, which makes it possible to control it in the closing as well as the opening direction by an electrical command produced in the throttle control. In addition, the motorized throttle body includes at least one return spring, moving the throttle in the direction of closing, when the actuator is no longer supplied, said return spring preferably closing the throttle valve in a position of small opening, corresponding to an accelerated idling operation of the engine, allowing the vehicle to move at slow speed. In the event of a failure of the communication line, or of the throttle control unit, leading to deactivation of the actuator, the return spring brings the throttle back to a position which still allows the vehicle to move, but at speed slow, to a garage or repair shop.

In order to improve this ability, and while the vehicle engine is running, a lack of activation of the actuator, corresponding to an order from the engine control unit or the throttle control unit, or all other causes, such as a break in the communication line, and resulting in a return of the throttle valve to the accelerated idle position, defined by the return spring, or to a neighboring position, causes in the engine control unit a correction of the ignition time and / or the injection duration, in order to limit the engine speed.

In order to improve safety, the throttle control unit is directly connected to at least one brake sensor, so that if the brake pedal is actuated, the throttle control unit cuts, possibly after delay, l power supply to the actuator, the signal from the brake sensor being transmitted from the throttle control unit to the engine control unit via the communication line.

With the same aim of improving safety, in particular in the event of failure of the accelerator pedal position sensor, the throttle control unit is directly connected to at least one sensor for actuating the pedal. accelerator, which is a contactor for actuating this pedal or a second position sensor this pedal, in order to decouple the signals from the accelerator pedal to the engine control unit and to the throttle control unit, the signal from the accelerator pedal actuation sensor being transmitted from the throttle control unit to the engine control unit via the communication line.

Always to improve safety, the engine control unit draws up, from the information it mainly receives from the pressure and / or air flow sensors in the intake and engine speed manifold, a signal of the reconstituted angular position of the throttle, that at least one consistency control procedure, implemented in the engine control unit, compares to the setpoint signal and / or to the signal of the angular position sensor of the throttle received from the throttle control unit via the communication line, the reconstituted position signal being transmitted to the throttle control unit through the communication line. Thus, in the event of failure of the throttle position sensor, the throttle control unit can use the reconstructed throttle position signal, sent by the engine control unit, and associated with servo parameters adapted to position substantially the throttle compared to the setpoint delivered by the engine control unit.

In addition, in order to take into account certain particular states of the vehicle and / or the value of certain physical quantities linked to the operation of the engine, to control the air circuit without only taking into account the request of the driver expressed on the pedal. accelerator, the engine control unit can substitute, at least partially, for the setpoint developed from the signal received from a position sensor of the accelerator pedal, a setpoint corresponding to a programmed law, developed taking into account at least one other signal, such as engine speed, for regulating the engine speed idling, and possibly coming from at least one additional sensor of an engine operating parameter, such as the temperature of the engine cooling water, and / or from at least one other unit for calculating and controlling the vehicle, such as an anti-skid, anti-lock wheel control unit, automatic gearbox control, vehicle speed regulator or limiter, vehicle attitude control, or else at least one signal produced by the engine control unit from operating parameters of the injection and ignition circuits, such as the quantity of fuel injected, the volume of air admitted into the engine, or the progressive movement of the accelerator pedal and / or the variation of engine torque in transient mode.

In particular, the motor vehicle can be equipped with a speed regulation system. In this case, it is advantageous for the speed control command signals, such as on / off signals of the regulation, of choice of the speed setpoint, of the brake, and / or of the clutch, coming from the driver. or from another source, and taken into account by the engine control unit, are transmitted to it by the communication line from the throttle control unit, which receives them by at least one clutch switch, from brake, on / off, and / or choice of speed setpoint. Thus, the throttle control unit is used as an interface, through which transit information intended for the engine control unit, without the need to reconfigure the connector of the latter to receive this information, since terminals to this effect can be made available on the throttle control unit, due to the small number of connection terminals otherwise necessary for the connection of this throttle control unit to the other components of the system.

Regarding the communication line, it can be a parallel link, serial link, plain or bidirectional single or doubled, or a bidirectional line with one or two wires in which the information flows in both directions according to a defined sequencing and protocol, such as a so-called "VAN" or "CAN" protocol. However, preferably, this line is a bidirectional serial line, comprising at least two electrical and / or optical conductors, each of which provides unidirectional communication between the engine control and throttle control units, the serial line possibly comprising at least an additional conductor, transmitting clock signals between the two control units. For the connection of this line to the engine control unit, it is then advantageous to use the terminals provided on the connector of a state-of-the-art engine control unit for controlling the actuator for regulating the flow of idle operating air.

In order to further improve the operational safety of the system, each of the two control units implements self-diagnostic and interactive diagnostic procedures performing, in each unit, the diagnosis of the inputs / outputs of the unit, of its calculations and the information it receives from the other unit via the communication line, the proper functioning of which is checked by tests carried out in each of the control units by management circuits of said line and a communication protocol. To this end, each of the two control units directly receives enough signals to ensure the diagnosis, even if the communication line and / or the other control unit is faulty. Such a configuration is advantageous because it allows, in certain cases of diagnosed fault, to limit the opening of the throttle valve by the engine control unit or by the throttle control unit, preferably made so that it comprises at at least one microcontroller, ensuring at least the throttle position control, and the actuator power control, this microcontroller being integrated in the throttle body.

Preferably, moreover, each of the two control units comprises a microcontroller. It is then advantageous to obtain that, in the event of the appearance of a fault, the throttle control unit directly controls the closing of the throttle by an electrical command or a deactivation of the actuator, and / or, if the connection line is still operational, ask the engine control unit to modulate and / or cut off the injection and / or ignition. Symmetrically, in the event of the appearance of a fault, the engine control unit can directly control the modulation and / or cut off of the injection and / or ignition, and / or ask, if the line is still operational, at the throttle control unit, to close the throttle by electric control or deactivation of the actuator.

To reconstruct the angular position of the throttle valve, as an alternative to the embodiment presented above, an air flow measurement device can also be used in place of or in addition to the pressure sensor, and advantageously incorporated into the motorized throttle body , and a corresponding signal can be transmitted by the communication line, from the throttle control unit to the engine control unit, which takes it into account with the engine speed signal it receives for processing of a reconstructed position signal of the butterfly.

When the injection installation is of the so-called "single-point" type, comprising an injector, or possibly two injectors side by side, upstream of the throttle valve to inject the fuel into the intake manifold, it is also possible to incorporate into the motorized throttle body a fuel supply circuit, comprising the injector (s) and a pressure regulator, the command of each injector then being transmitted, for example, in the form of digital signals, from the engine control unit to the throttle control unit through the communication line.

Other advantages of the invention will emerge from the description given below, of an exemplary embodiment with reference to the single figure of the drawings, which represents a block diagram of the system.

The engine control system with a motorized throttle body, schematically represented in the single figure, comprises a block 1 comprising an electro-mechanical assembly constituted by a motorized throttle body 2, and an electronic calculation and control unit called the control unit. throttle control 3.

The motorized throttle body 2 comprises a throttle body 4 proper, for example made of aluminum alloy, traversed by a conduit in which a throttle 5 is pivotally mounted on an axis 6, as well as an actuator 7 for controlling the rotation of the butterfly 5, and that a sensor 8 of the angular position of the butterfly 5, the actuator 7 and the sensor 8 being directly incorporated in the butterfly body 4.

The actuator 7 is a rotary electric actuator, mounted directly on the axis 6 of the butterfly 5, so that this single axis 6, supported by two ball bearings to ensure good precision and reduced friction, is provided for the actuator 7 and the butterfly 5 so as to limit the number of mechanical parts.

Although a stepping motor can be used, the actuator 7 is preferably a torque motor, with stator with O-ring winding and with permanent magnet rotor, brushless, with relatively large rotor / stator air gap (up to 0 , 8 mm) which facilitates mounting and limits the risks of mechanical blockage of the rotor in the stator, and without residual holding torque when it is not supplied. It is supplied with direct current with low power consumption stabilized, and can operate at low voltage (around 5.5 V) for positioning the throttle valve 5 during starts. This torque motor is bipolar control, so that it can be controlled by an electrical signal in the direction of opening and closing of the butterfly 5, and allows an angular excursion of 90 ° of the butterfly 5, on which the torque motor has a substantially constant torque, this angular excursion can be traversed in a short time, for example of the order of 100 ms in one or the other direction, which is consistent with the response times of the motor and of the vehicle’s drive train. The choice of such a torque motor rather than a stepper motor makes it possible to obtain a better angular resolution (greater than 0.1 °) for the position of the throttle 5, at the same time as the safety of an absence of residual torque when the motor is not energized, as well as greater ease of assembly and great simplicity and mechanical robustness, hence great reliability at a limited cost.

In the motorized throttle body 2, a return spring (not shown) biases the throttle 5 towards its closed position, and, when the actuator 7 is not supplied, it returns the throttle 5 to a rest position which is a position of low opening, allowing the engine to operate in accelerated idle, so that the vehicle can continue to move, but at slow speed. This rest position of the return spring, which is not a fully closed position of the butterfly, can be obtained by a structure and an arrangement of a single return spring which gives it a negative and then positive characteristic. As a variant, two springs can be used which define an equilibrium point corresponding to this rest position with low opening of the butterfly 5.

The sensor 8 for the angular position of the butterfly valve 5 can be a Hall effect sensor, but preferably a potentiometer for copying the angular position of the butterfly valve is chosen, this potentiometer being able to be integrated into actuator 7.

A motorized throttle body 2 is thus obtained without additional air valve, of reduced size and weight, interchangeable with conventional throttle bodies. Note that the motorized throttle body 2 has two energy sources capable of closing the throttle 5, under all operating conditions of the engine, namely the electric actuator 7 (the torque motor with bipolar control) and the spring. reminder.

The electronic butterfly control unit 3 is directly installed on the butterfly body 4. It comprises a power circuit 9 for controlling the actuator 7, to which this circuit 9 is directly connected, a microcontroller 10, with preferably integrated analog-digital converter, which is directly connected to the sensor 8 for copying the angular position of the throttle 5, this microcontroller 10 ensuring in particular the control in position of the throttle 5 by comparing a signal received from the sensor 8 to a throttle position reference signal (developed and transmitted to the throttle control unit 3 under specified conditions below) and by developing, from an error signal resulting from the comparison, an order for controlling the angular position of the throttle valve, which is transmitted to the power circuit 9 via possibly an intermediate stage 11, which is a interface stage between the power stage 9 and the microcontroller 10, and ensures the shaping of the control signals.

In the power stage 9, the power is delivered by an H-bridge controlled by a pulse signal with pulse width modulation, so that, when the output of the microcontroller 10 remains blocked, the H-bridge is deactivated . The movements of the throttle valve 5 are commanded and controlled by a closed servo loop of proportional, integral and derivative type, providing sufficient resolution, greater than 0.1 °, to ensure regulation of the idle speed. Unit 3 of control of the throttle valve also comprises an electrical power supply unit 12, connected by conductive wires 13 and 14 to a battery (not shown) and supplying, on the one hand, the power stage 9, and, on the other hand, under different voltages, the microcontroller 10, the shaping stage 11, and the potentiometer 8 for copying the angular position of the butterfly. The signal from this potentiometer 8 is read only by the microcontroller 10 installed on the motorized throttle body 2, which avoids interference. The throttle control unit 3 also performs other functions, which are mentioned below.

The system also includes an electronic calculation and control unit 15, called the engine control unit, also produced in the form of a microcontroller and with an integrated analog-to-digital converter. In terms of its internal architecture, this engine control unit 15 presents only limited modifications compared to that of standard engine control computers, and, in particular, it is equipped with a connector identical to that of a computer. motor control standard and has the same geometric shape and the same size. The engine control unit 15 is connected, at 16, to sensors for engine operating parameters, which sensors are schematically represented at 17, and detects, at 18, engine speed and shaft position signals from the engine, at 19 signals for air pressure in the intake manifold, and at 20 for engine cooling water temperature signals. On the basis of these signals, the unit 15 develops injection and ignition control commands, which it transmits at 21 to actuators, schematically represented at 22, of the fuel injection and ignition circuits of the engine, of which it commands and controls the operation. In particular, the unit 15 determines the instants and durations of injection, which, taking into account a fuel supply pressure, also makes it possible to determine the quantities of fuel injected, and it transmits the control orders corresponding to the winding of the injectors, at 23, and to the fuel pump, at 24. Simultaneously, the unit 15 defines the instants and the ignition energy and transmits corresponding control signals to the ignition coils at 25.

The engine control unit 15 also receives at 26 an angular position signal from the accelerator pedal 27, which it receives from at least one angular position sensor 28, which is for example a position feedback potentiometer. angle of the pedal 27. This sensor 28 can be integrated into the accelerator pedal 27, or separated from this pedal 27 and connected to the latter by a cable. In both cases, the sensor 28 has two return springs.

The accelerator pedal 27, which can optionally have a hard point for the so-called "kick down" function, is also associated with a sensor 29 for actuating this pedal which is, for example, a so-called "raised foot" multi-contactor "sensitive to the actuation of the pedal 27, but which can be a second angular position sensor of this pedal 27, for example a second potentiometer, and this sensor 29 is directly connected by the conductor 30 to the control unit of the throttle valve 3, so as to decouple the signals coming from the accelerator pedal 27 towards, on the one hand, the engine control unit 15, and, on the other hand, the throttle control unit 3. The latter is also directly connected to a brake sensor which, in this example, is a contactor 32 for actuating the brake pedal 31, and connected to the throttle control unit 3 by the conducting wire 33.

In parallel to the driver 33, the throttle control unit 3 is connected by at least one conductive wire, and for example by four conductive wires 34 to 37 to the control block 38 of the speed control function of the vehicle, the driver 34 being for example connected to a on / off switch of this system, the driver 35 to a clutch or automatic gearbox switch, and the drivers 36 and 37 respectively to switches for memorizing the selected speed and resuming this memorization, for the choice of vehicle speed setpoint. In addition, by the conducting wire 39, the throttle control unit 3 is connected to an indicator light indicating the operation of the speed regulation system.

The two control units 3 and 15 are connected to each other by a communication line 40 by which they exchange information, and which can be of different types. Advantageously, however, a bidirectional serial line is used comprising at least two conductive wires 41 and 42, the first of which transmits information from the engine control unit 15 to the throttle control unit 3, and the second of which transmits information in the opposite direction. These conductors 41 and 42, each of which provides one-way communication between the control units 3 and 15, are electrical conductor wires, but can be fiber optic conductors if each of the two control units 3 and 15 is equipped with a appropriate opto-electronic converter. This line 40 advantageously comprises at least one additional conductor 43, which transmits clock signals between the two control units 3 and 15. As a variant, for security reasons, the bidirectional serial line 40, limited to the two conductors 41 and 42, can be doubled, which makes it possible to use, for the connection of line 40 to the motor control unit 15, terminals available on the connector with which conventional motor control units are equipped, for their connection to the actuator of the additional air control valve of the throttle bodies of the prior art. This faculty reinforces the advantage of using as engine control unit 15 of the invention, a control unit as little modified as possible with respect to that of the state of the art, with which the terminals available on the connector with which they are fitted are thus used, without the need to mount additional connectors.

Each of the two control units 3 and 15 comprises a stage for managing the exchange of information with the outside of the unit in question, according to a procedure ensuring the consistency of the signals received and transmitted, and manages the communication line series 40, the proper functioning of which is checked by tests carried out in each of units 3 and 15 and the communication protocol. Each of the control units 3 and 15 thus advantageously integrates the management and processing functions, input / output, including the serial interface functions, and includes the appropriate memories.

Via the serial line 40, the two control units 3 and 15 exchange information: the throttle control unit 3 transmits to the engine control unit 15 in particular the angular position signals of the throttle 5, which it receives from the sensor 8, the contactor 29 for "lifted foot" associated with the accelerator pedal 27, and from the contactor 32 for actuation of the brake pedal 31, as well as the signals which come to it from the control unit 38 of the vehicle speed control function, i.e. on / off signals for this function, actuation of the clutch or automatic gearbox and memorization or resumption of memorization of the setpoint speed chosen for the vehicle. These speed regulation control signals, coming from the control block 38, and intended to be taken into account by the engine control unit 15, do not pass through the throttle control unit 3 and by the serial line 40 because it is more advantageous to install corresponding connection terminals on the connector of unit 3, while the direct connection of lines 34 to 39 on the control unit engine 15 would require reconfiguring its connector. In addition, the throttle control unit 3, like the engine control unit 15, implements self-diagnostic and interactive diagnostic procedures, performing, in each unit, the diagnosis of the inputs / outputs of the unit, its calculations and information it receives from the other unit by the serial line 40. Consequently, the unit 3 transmits to the unit 15, by the line 40, self-diagnostic information motorized throttle body 2 and unit 3, as well as a communication validation message.

In the opposite direction, the engine control unit 15 transmits to unit 3 a throttle position reference signal, which it produces, a reconstructed angular position signal from the throttle valve, which it also develops, for controlling the throttle valve. 5, perform the calculations and implement the necessary consistency procedures, carry out the diagnostics and, if necessary, apply the backup modes defined below, as well as a control signal from the indicator light indicating the operation of the speed control system 38, and that the unit 3 retransmits to this indicator by the conductive wire 39, and also information linked to the self-diagnosis of the engine control unit 15 as well as validation messages of the communication.

In the engine control unit 15, the reconstruction of the reconstructed angular position signal of the throttle valve is ensured mainly from the air pressure signals in the intake manifold and engine speed, which the unit 15 receives corresponding sensors. The unit 15 implements a consistency control procedure, which compares the angular position signal of the butterfly, received by the line 40 of the unit 3, the reconstituted angular position signal of the butterfly, and the signal setpoint that it develops and, optionally, the position signal of the accelerator pedal 27, received from the sensor 28. Similarly, the throttle control unit 3 implements a consistency control procedure comparing the angular position signal of the throttle, which it receives directly from the sensor 8, and the setpoint and reconstituted angular position signals. the throttle valve, which it receives via the serial line 40 of the engine control unit 15.

Alternatively, an intake air flow signal is substituted for the air pressure signal in the intake manifold, and primarily combined with the engine speed signal to obtain the reconstructed angular position signal of the throttle valve. In this case, a flow meter, for example of the hot film or hot wire type, can be incorporated in the motorized throttle body 2 and the intake air flow signal can be, in this case, read by the control unit 3 of the throttle valve and transmitted by the serial line 40 to the engine control unit 15.

As mentioned above, another function of the engine control unit 15 is to calculate the angular position which the throttle 5 must take, that is to say to draw up a throttle position setpoint, simultaneously with the injection and ignition management. This throttle position reference signal is given by a programmed accelerator pedal 27 / throttle 5 transfer law which takes into account, in "pedal follow-up" mode, that is to say as a function of the request sent. by the driver via the accelerator pedal 27, essentially the position signal of this pedal provided by the potentiometer 28, this setpoint law can also take into account other parameters, such as the speed of the vehicle, "speed control" mode, and possibly signals from other on-board computers, such as those from an anti-skid system, anti-lock, or from a gearbox or transmission with electronic control, the signals of which can be directly transmitted to the engine control unit 15 by the connecting wires 44 to 46 respectively, or even transmitted to the unit control valve 3, which transmits them to the engine control unit 15 via the serial line 40.

The setpoint law also takes into account certain engine operating conditions, such as the coolant water temperature and the engine speed, in particular in "idle speed regulation" mode. This setpoint law also takes into account strategies adopted in terms of comfort, and takes into account weighting factors to introduce a progressive angular displacement of the butterfly 5 relative to the stroke of the accelerator pedal 27, and to apply corrections. dynamic butterfly. Another strategy taken into account can be an antipollution strategy and a reduction in consumption, by synchronized management of the intake air and the quantity of fuel injected. In addition, the setting law for the position of the throttle valve is also produced from the state diagnosed by the unit 15.

In summary, this engine control unit 15 essentially performs the following functions: the preparation of the throttle position setpoint, as mentioned above, from at least one signal representative of an input physical quantity and / or a state of the system, or of an associated system, self-diagnosis and interactive diagnosis with the other unit 3 for controlling the throttle valve, the application of emergency modes if necessary, and the management of the serial line 40. In the event of a diagnosed fault, the unit 15 can command an indicator light by the conductive wire 47.

For its part, the throttle control unit 3, in addition to the functions already mentioned for managing the serial line 40, for acquiring the inputs necessary for the operation of the speed regulation system and transmission of the corresponding signals by the line 40 to the other unit 15, of self-diagnosis and interactive diagnosis with this unit 15, and application of the emergency modes, fulfills the other essential functions that are the application of the throttle position reference signal, which it receives from the unit 15 by the line 40, for the control in position of the throttle 5, in order to position the latter so precise on the setpoint delivered by the engine control unit 15, and the initialization of the throttle position 5 with a power-up control.

When one and / or the other of the units 3 and 15 diagnoses a failure or when the implementation of the consistency procedures reveals a discrepancy between the signals produced in the unit considered and / or received from sensors connected to this unit, with signals received from the other unit by the serial line 40, backup modes are applied by one and / or the other of the two units 3 and 15, depending on the degree of failure or discrepancy. Emergency mode strategies are applied gradually according to the fault diagnosed to preserve passenger safety, while allowing the vehicle to be able to continue to travel at a slow speed, except in the event of danger, which could force the operation of the vehicle to stop. engine.

In standby mode, the progressive action depending on the origin and severity of the failure can start with a limited intervention on a secondary function, for example the prohibition to operate in vehicle speed regulation mode. It can be continued by limiting the maximum opening of the throttle valve 5, controlled by the engine control unit 15 or by the throttle control unit 3 in certain cases of diagnosed fault. The emergency mode applied can also consist of an electrical control for closing the throttle valve 5, which can come from one and / or the other of the two units 15 and 3. An emergency mode also consists in deactivating the actuator 7 of the throttle valve 5, while preserving a mechanical function which still allows the vehicle to move at low speed. This lack of activation of the actuator 7 can correspond to an electrical order coming from the engine control unit 15 or the throttle control unit 3, and can be caused by a break in the serial line 40 or a failure of the unit 15 Its consequence is the return of the throttle valve 5 to the accelerated idle position, under the action of the return spring, or to a neighboring position, and it causes in the engine control unit 15 a correction of the instant of ignition and / or injection, in order to limit the engine speed.

In case of danger, separate tracks allow the engine power to be reduced, even if the 40 series line is cut. On the one hand, the engine control unit 15 can control the cut off of the injection and / or ignition, and, on the other hand, the throttle valve 5 can be closed, and this by two means, either electrically by a command from the engine control unit 15 or from the throttle control unit 3, either mechanically by the return spring, after deactivation of the actuator power control stage 9.

The engine control unit 15 can therefore control the modulation or cut off of the injection and / or ignition, in order to reduce the engine power, when a fault in the serial line 40 is detected, and when it detects the appearance of a fault which could cause the driver to lose control of engine power.

The power supply to the actuator 7 can also be cut off, possibly after a time delay, by the throttle control unit 3, when the brake pedal 31 is actuated.

It can thus be seen that the architecture of the system authorizes the overall management of the engine, by its three air, fuel and ignition supply circuits, by the only engine control unit 15 which is thus able to intervene very quickly and simultaneously on these three circuits, if necessary. The integrated block 1, associating with the motorized throttle body 2 the electronic unit 3 for controlling the throttle valve, is thus such that the motorized throttle body 2 behaves as an intelligent actuator with respect to the engine control unit 15, with which the throttle control unit 3 is put in master relationship -slave.

The system has a high degree of reliability and guarantees maximum security in the event of failure, due to the security linked to the components, as described above, to the security linked to the architecture of the system, as presented above, and system redundancies.

In particular, each control unit 3 and 15 receives sufficient information to ensure sufficient self-diagnosis, even in the event of disturbance or interruption of the serial line 40 and / or if the other control unit fails.

In addition, the system offers two separate means for controlling the position of the butterfly valve 5. The first means is the sensor 8, such as a potentiometer on the axis of the butterfly valve, the signal of which is read directly by the control unit 3 of the throttle valve and transmitted by line 40 to the engine control unit 15, and the second means is the reconstituted angular position signal of the throttle valve, calculated by the engine control unit 15 in particular from the engine speed and either the intake air pressure, i.e. the intake air flow. Note that in the event of failure of the throttle position sensor 8, the throttle control unit 3 can use the reconstructed throttle position signal, which it receives via line 40 of the control unit motor 15, and associate it with servo-control parameters suitable for replacing it with the detected position signal of the throttle valve in order to ensure the servo-control in position of the latter, that is to say in order to substantially position the throttle valve compared to the setpoint delivered by the engine control unit 15, with performance possibly degraded, but which remains sufficient for acceptable control of the throttle valve 5.

The system also offers two separate ways to control driver demand. The first means is the sensor 28 or potentiometer for copying the angular position of the accelerator pedal 27, the signal of which is read directly by the engine control unit 15, and the second means is the contactor 29 of "lifted foot" "or second potentiometer, also sensitive to the actuation of the accelerator pedal 27, and whose signal is read directly by the throttle control unit 3, but retransmitted by line 40 to the engine control unit 15 Consequently, in the event of a failure of the angular position sensor 28 of the accelerator pedal, the engine control unit 15 always has, via the throttle control unit 3 and the contactor 29, d '' information on the operation of the accelerator pedal 27.

It is further noted that these redundancies and this security are obtained without the need to double the sensors of the engine operating parameters used. Indeed, the signals necessary for the operation of each of the two control units 3 and 15, and coming from sensors to which this unit is not directly connected, reach it by passing through the other control unit and the serial line 40. It is also noted that each of the two control units 3 and 15 can be used as an interface to send information coming from outside the system or an associated system to the other unit, or, in the opposite direction, to send to outside or to an associated system of information coming from this other control unit.

In addition to the accelerator pedal / programmable throttle transfer law, a major advantage of the system according to the invention is that the distribution of the functions on two separate microcontrollers, with mutual monitoring tests, gives access to a large number of functions achievable, some of which are new, and which can be classified into two categories according to whether they intervene on the control of the engine or according to whether they intervene on the control of the vehicle.

In the first category, to achieve the objective of carrying out the dosage of engine power and optimizing its operation, in particular in terms of emission of pollutants and consumption, we can integrate into the accelerator pedal transfer law / programmable throttle valve, pre-positioning of the throttle valve for starting, especially in cold conditions, regulation of the idling speed, depending for example on the water temperature, as well as damping functions for the angular movements of the butterfly, wealth monitoring of the air / fuel mixture during transients, and the limitation of engine speed.

The functions belonging to the second category are those through which the control of the throttle position produces consequences at the vehicle level, to improve comfort, driving pleasure and safety. These functions are functions of regulation and / or limitation of the vehicle speed, throttle control for anti-skid and / or anti-lock, reduction of jolts, and interactions with a gearbox. electronic speed control, an anti-collision system, a guidance system, and / or a vehicle attitude control system, for example when cornering, such as an active suspension system.

For the realization of the motor control unit according to the invention, the architecture of a motor control unit of the state of the art can be essentially preserved, the terminals of the connector for controlling the actuator of the circuit additional air supply in a conventional engine control unit being used, in the system according to the invention, for the connection of the serial line 40 to the engine control unit 15, including the electronics control, compared to that controlling the additional air circuit in a conventional unit, is extended to the entire dynamic range of the throttle valve (for example from 0 to 400 kg of air per hour).

The system described above with reference to the single figure is particularly suitable for injection installations of the multipoint type, that is to say comprising an injector at least for each cylinder of the engine, and ensuring injection downstream of the throttle body, in the downstream end of the injection pipe, in the immediate vicinity of the cylinder head of the engine. If the device must be adapted to a single-point type injection, then the single injector, or the two side-by-side injectors is or are mounted directly integrated in the throttle body 4, so as to inject the fuel directly upstream of the throttle valve 5, and the supply pressure regulator of the injector (s) is also integrated into this body 4.

Claims (23)

1. Engine control system with motorized butterfly body, for a spark-ignition internal combustion engine equipped with a fuel injection system, comprising:

   - a motorized butterfly body (2), including at least one butterfly (5) mounted so that it can rotate on a spindle (6) in a duct of the body (4), at least one butterfly actuator (7) which causes the rotation of the spindle (6) of the butterfly (5) and which is incorporated within the butterfly body (4), and at least one sensor (8) for sensing the angular position of the butterfly, and which is also incorporated within the butterfly body (4),

   - a first electronic calculation and control unit (3), for controlling the butterfly (5), and which is directly built into the butterfly body (4) so as to constitute a single assembly (1) with it, and includes at least one circuit (9) for operating the actuator (7) of the butterfly (5), to which the control unit (3) of the butterfly is directly connected, said control unit (3) of the butterfly being also directly connected to said sensor (8) for sensing the butterfly angular position, said control unit (3) of the butterfly including also at least one circuit (10) for automatically controlling the butterfly in terms of position, comparing a signal received from said sensor (8) for sensing the angular position of the butterfly with at least one reference signal about the position of the butterfly (5), and formulating, on the basis of an error signal resulting from the comparison, an order for regulating the position of the butterfly (5), which is transmitted to said circuit (9) for operating the actuator (7), which is a power circuit,

   - sensors (17) for sensing operating parameters of the engine, delivering information relating at least to the pressure and/or flowrate of air in the intake manifold (19) for formulating at least injection control orders transmitted to actuators (22) of the fuel injection circuit, and

   - at least one sensor (28) for sensing the position of the accelerator pedal (27) and delivering at least one corresponding signal,

   characterized in that said system further includes :

   - a second electronic calculation and control unit (15) for controlling the engine, connected to said sensors (17) for sensing operating parameters of the engine, from which it receives also information relating to the rotational speed of the engine (18) and the position of the shaft of the engine, and formulating said injection control orders as well as ignition control orders, which it transmits to said actuators (22) of said fuel injection circuit as well as to actuators of the ignition circuit of the engine, the operation of which it controls, said reference signal about the position of the butterfly (5) being formulated within the control unit (5) of the engine, on the basis of at least said signal about the position of the accelerator pedal (27) delivered by said corresponding sensor (28) to which the engine control unit (15) is directly connected, said reference signal as well as other information being transmitted to the control unit (3) of the butterfly, to which the control unit (15) of the engine is connected by a communication line (40), whereas the signal about the angular position of the butterfly (5) is transmitted from the control unit (3) of the butterfly to the engine control unit (15) by said communication line (40).
2. System according to claim 1, characterized in that the actuator (7) of the motorized butterfly body (2) is an electrical actuator, with two-pole control, without a holding torque when it is not powered, preferably a torque motor.
3. System according to either one of claims 1 and 2, characterized in that the actuator (7) of the motorized butterfly body (2) is fitted directly on the spindle (6) of the butterfly (5) so that the spindle (6) is common to the butterfly (5) and to the actuator (7).
4. System according to any one of claims 1 to 3, characterized in that the motorized butterfly body (2) comprises at least one return spring, moving the butterfly (5) in the direction of closure, when the actuator (7) is no longer powered, the said return spring preferably closing the butterfly (5) back to a position in which it is slightly open, corresponding to the engine operating at an accelerated low idle, allowing the vehicle to move along at a low speed.
5. System according to claim 4, characterized in that an absence of activation of the actuator (7), while the engine is operating, corresponding to an order from the engine control unit (15) or from the control unit (3) of the butterfly, or any other cause, such as a breakdown in the communication line (40), and having as consequence a return of the butterfly (5) to the accelerated low idle position, defined by the return spring, or to a neighboring position, leads to a correction in the moment of ignition and/or in the injection period, within the engine control unit (15), in order to limit the speed of the engine.
6. System according to any one of claims 1 to 5, characterized in that the control unit (3) of the butterfly is directly connected to at least one braking sensor (32), so if the brake pedal (31) is actuated, the control unit (3) of the butterfly cuts off, possibly after a time delay, the supply to the actuator (7), the signal from the braking sensor (32) being transmitted from the control unit (3) of the butterfly to the control unit (15) of the engine by the communication line (40).
7. System according to any one of Claims 1 to 6, characterized in that the control unit (3) of the butterfly is directly connected to at least one sensor (29) for sensing the actuation of the accelerator pedal (27), which sensor is a contactor for sensing the actuation of this pedal or a second sensor for sensing the position of this pedal, in order to dissociate the signals coming from the accelerator pedal (27) toward the engine control unit (15) and toward the control unit (3) of the butterfly, the signal from the sensor (29) for sensing actuation of the accelerator pedal (27) being transmitted from the control unit (3) of the butterfly to the engine control unit (15) by the communication line (40).
8. System according to any one of claims 1 to 7, characterized in that the control unit (15) of the engine formulates, on the basis of the information which it receives mainly from the sensors for sensing the pressure and/or flowrate of air in the intake manifold (19) and the speed of the engine (18), a signal about the reconstructed angular position of the butterfly, that at least one coherency-control procedure, implemented in the control unit (15) of the engine, compares with the reference signal and/or with the signal from the sensor (8) for the sensing the angular position of the butterfly (5) received from the control unit (3) of the butterfly via the communication line (40), the reconstructed position signal being transmitted to the control unit (3) of the butterfly by the communication line (40).
9. System according to claim 8, characterized in that the control unit (3) of the butterfly implements at least one coherency control procedure comparing with each other at least two signals from among the reference signal for the butterfly, and the signal about the reconstructed position of the butterfly, which the control unit (3) of the butterfly receives via the communication line (40) from the control unit (15) of the engine, and the signal about the angular position of the butterfly (5) received directly from the corresponding sensor (8).
10. System according to any one of claims 1 to 9, characterized in that the control unit (15) of the engine can substitute, at least partially, for the reference formulated on the basis of the signal received from a sensor (28) sensing the position of the accelerator pedal (27), a reference corresponding to a programmed law, formulated taking account of at least one other signal, such as the engine speed (18), in order to set the low idle speed, or the speed of the vehicle, in order to set or limit the speed of the latter, and coming possibly from at least one additional sensor for sensing an operating parameter of the engine, such as the temperature (20) of the cooling water of the engine, and/or from at least one other calculation and control unit of the vehicle, such as a unit (44) for preventing wheelspin, a unit (45) for preventing the wheels from locking up, a unit (46) for controlling an automatic gear box, a unit for controlling the attitude of the vehicle, or even from at least one signal formulated by the engine control unit (15) on the basis of operating parameters of the injection and ignition circuits, such as the quantity of fuel injected, the volume of air taken into the engine, or even the progressive nature of the movement of the accelerator pedal (27) and/or the variation in engine torque under transient conditions.
11. System according to any one of claims 1 to 10, characterized in that signals for demanding the setting of speed, such as signals for starting/stopping the setting (36), for choosing the speed reference (35), braking signals (33), and/or clutch signals (37) coming from the driver or from some other source (38) and taken into account by the control unit (15) of the engine, are transmitted to it by the communication line (40) from the control unit (3) of the butterfly, which receives these signals by means of at least one clutch contactor, brake contactor, contactor for starting/stopping and/or choosing the speed reference.
12. System according to any one of claims 1 to 11, characterized in that the communication line (40) is a parallel or serial, one way or two way, one conductor or twin-conductor line, or a two way line with one or two conductors in which the information flows in both directions according to defined sequencing and protocol, such as a so-called "VAN" or "CAN" protocol.
13. System according to claim 12, characterized in that the communication line (40) is a two-way serial line comprising at least two electrical and/or optical conductors (41, 42), each of which provides for a one way communication between the control unit (15) of the engine and the control unit (3) of the butterfly, it being possible for the serial line (40) to comprise at least one additional conductor (43), transmitting clock signals between the two control units (3, 15).
14. System according to any one of claims 1 to 13, characterized in that each of the two control units (3, 15) implements self-diagnostic procedures and interactive diagnostic procedures which perform, within each unit, diagnostics on the inputs/outputs of the unit, of its calculations and of the information which it receives from the other unit via the communication line (40), the correct operation of which is checked by tests carried out in each of the control units by circuits for managing the said line and a communication protocol.
15. System according to claim 14, characterized in tha each of the two control units (3, 15) directly receives enough signals to provide for the diagnostics, even if the communication line (40) and/or the other control unit is defective.
16. System according to either one of claims 14 and 15, characterized in that, in the case of a defect arising, the control unit (3) of the butterfly directly demands the closure of the butterfly (5) by means of an electrical control or deactivation of the actuator (7) and/or in the case where the connection line is still operational, asks the engine control unit (15) to modify and/or cut off the injection and/or the ignition.
17. System according to any one of claims 14 to 16, characterized in that, in the case of a defect arising, the engine control unit (15) directly demands the modification and/or cutting-off of the injection and/or the ignition and/or, if the line is still operational, asks the control unit (3) of the butterfly to close the butterfly (5) again by electric control or by deactivating the actuator (7).
18. System according to any one of claims 1 to 17, characterized in that each of the two control units (3, 15) comprises at least one microcontroller.
19. System according to any one of claims 9 to 18, such as attached to claim 8, characterized in that, in the event of failure of the sensor (8) for sensing the position of the butterfly (5), the control unit (3) of the butterfly uses the signal about the reconstructed position of the butterfly (5), this signal being sent by the engine control unit (15), and associated with automatic-control parameters designed to position the butterfly (5) substantially with respect to the reference delivered by the engine control unit (15).
20. System according to any one of claims 1 to 19, characterized in that the extent to which the butterfly (5) is opened is limited by the engine control unit (15) or the control unit (3) of the butterfly, in certain cases where faults have been diagnosed.
21. System according to any one of claims 1 to 20, characterized in that the electronic control unit (3) of the butterfly, comprising at least one microcontroller providing at least for the automatic control of the butterfly in terms of position and the power operation of the actuator, is incorporated into the butterfly body (4).
22. System according to any one of claims 1 to 21, characterized in that a device for measuring the intake air flowrate is also incorporated into the motorized butterfly body (2), and the communication line (40) can then transmit, from the control unit (3) of the butterfly to the engine control unit (15), a signal corresponding to the air flowrate, particularly taken into account with the signal about the speed of the engine (18) for formulating a signal about the reconstructed position of the butterfly by the engine control unit (15).
23. System according to any one of claims 1 to 22, for an engine equipped with an injection system of the so-called "single-point" type, characterized in that a fuel supply circuit exhibiting at least one injector and a pressure regulator is also incorporated into the motorized butterfly body (2), it being possible for the control for each injector to be transmitted, in the form of digital signals, from the engine control unit (15) to the control unit (3) of the butterfly by the communication line (40).

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