FR3005624A1 - METHOD OF SECURING THE STARTING OF THE THERMAL MOTOR OF A HYBRID VEHICLE COMPRISING TWO STARTING MEANS - Google Patents

Abstract

Method for securing the starting of a heat engine (2), for a hybrid vehicle comprising a second independent motor (20), the heat engine having a first nominal starting means (12) and a second starting means independent (8), characterized in that the engine control system having detected a failure of the nominal starting means (12) during a rolling cycle, from the beginning of the next rolling cycle it systematically tests the starting of the thermal engine (2) with this nominal starting means (12).

Description

The present invention relates to a method of securing the starting of the heat engine for a hybrid vehicle, as well as to a hybrid vehicle implementing such a method. BACKGROUND OF THE INVENTION A known type of hybrid vehicle, presented in particular in document FR-A1-2955533, comprises a heat engine driving the front wheels, which may be of the gasoline or diesel type, and a second independent motor comprising an electric traction machine powered by batteries, which drives the rear wheels. The electric machine can operate as a motor delivering a traction torque on the rear wheels, by taking electrical energy from the batteries, or by a generator receiving a torque from these rear wheels, by recovering the kinetic energy of the vehicle to produce a current of recharging these batteries. It is thus possible to achieve different modes of operation, including a hybrid mode associating the two engines to reduce energy consumption, an electric mode or "ZEV" using only the electric motor, which is without emission of gaseous pollutants, a mode with four-wheel drive "E-AWD" using both engines to drive the two trains of the vehicle to improve the motor skills and handling of the vehicle, and a sport mode promoting the performance of the vehicle. The heat engine comprises a starter delivering a high torque, in particular to start the engine cold. The heat engine also comprises an alternator-starter that can work as a generator to charge the battery of the on-board network, and engine to deliver to the engine a torque that is lower than that of the starter. This alternator-starter is a nominal means of starting the engine when the engine is hot, either at the beginning of the driving cycle during the start of the powertrain, or during the driving cycle. These starts are then quickly and silently. In the case of hybrid operation of the vehicle, it has during a rolling cycle of successions of starts and stops of the engine to reduce energy consumption, the rear electric machine delivering a traction torque between two operations of this engine to ensure traction of the vehicle. However during a driving cycle, after a shutdown of the engine, the alternator-starter may fail to restart the engine normally due to a failure specific to this machine used as a starter, or following a failure related when using this machine as a starter. Automatic procedures then make it possible to overcome these failures, in order to restart the engine anyway. For the sake of clarity, the rest of the discussion summarizes all these failures under the term "failure of the nominal starting means".

However, depending on the nature of the failure, there is a risk during the following driving cycle that this failure of the nominal starting means persists. The present invention is intended to provide safety for the next rolling cycles, while avoiding if possible a complete stop of the vehicle to allow movement despite this failure. To this end, it proposes a method for securing the starting of a heat engine for a hybrid vehicle comprising a second independent motor, the heat engine having a first nominal starting means during a rolling cycle, and a second independent starting means, characterized in that the engine control system having detected a failure of the nominal starting means during a rolling cycle, from the beginning of the next rolling cycle it always tests the engine start thermal with this nominal starting means, and in the case of a failure if the second starting means is operational it allows the departure of the vehicle with a degraded operating mode providing security. An advantage of this method of securing is that the systematic start test at the beginning of the next rolling cycle makes it possible to check before the start of this run whether the first nominal starting means is fully functional. In the case where it is not, then it is possible if the second starting means is operational, still allow the start of the next rolling cycle to ensure the transport, but with the degraded operating mode which ensures from the beginning of this cycle the security taking into account this failure.

The security method according to the invention may further include one or more of the following features, which may be combined with each other. Advantageously, the degraded operation includes a request to start the engine as soon as the powertrain is put into service, and a prohibition of stopping the engine during the driving cycle if the independent starting means does not allow a satisfactory restart. of the engine after a temporary stop of this engine during the driving cycle. Advantageously, after detection of the fault, a fault management function and reconfigurations having emitted a fault signal of the control of the alternator-starter and a software reconfiguration flow following the pilot fault, this signal and this flow are maintained after stopping the driving cycle. Advantageously, the fault signal of the control of the alternator-starter and the software reconfiguration flow following the piloting fault, are eliminated in the event of a successful start of the engine during the test with the nominal starting means. The invention also relates to a hybrid vehicle comprising a heat engine and a second independent motor, the heat engine having a first nominal starting means during a rolling cycle, and a second independent starting means , this vehicle comprising means implementing a method for securing the starting of this engine, comprising any one of the preceding characteristics.

In particular, the nominal starting means of the heat engine, may comprise an alternator-starter connected to this heat engine by a belt. The independent starting means may comprise a conventional starter, or a reinforced starter allowing a large number of engine starts made during the running cycles. The heat engine can drive the front wheels, and the second independent motor drives the rear wheels. The invention will be better understood and other features and advantages will appear more clearly on reading the following description given by way of example and in a nonlimiting manner with reference to the appended drawings in which: FIG. 1 is a diagram of a hybrid vehicle implementing a boot securing method according to the invention; FIG. 2 is a diagram showing the main control functions related to this method; - Figure 3 is a detailed diagram of the function "start / stop of the engine"; and FIGS. 4 to 6 are graphs showing, as a function of time, starts of the heat engine respectively comprising a faulty starter-starter and a functional starter, these two faulty elements, and these two functional elements.

FIG. 1 shows a hybrid vehicle comprising a heat engine 2 constituting a first motorization driving the front wheels 6 by a transmission 4. The heat engine 2 comprises an electric starter 8, powered by a low voltage battery 10. An alternator-starter 12 constituting an auxiliary electrical machine, is permanently coupled to the heat engine 2, to assist in its operation. The transmission 4 can be made according to the various known types, including including manual gearboxes, robotized gearboxes, dual clutch gearboxes and automatic transmissions. A main electric machine 20 is a second motor that can be coupled to the rear wheels 22 of the vehicle. The two electrical machines 12, 20 are connected to an inverter 14, which is itself connected to a main electrical energy storage system 16, such as high voltage batteries, for delivering or receiving a large electrical power. A DC-DC converter 18 is interposed between the low-voltage battery 10 and the high-voltage batteries 16, in order to recharge this low-voltage battery if necessary from an energy taken from the high-voltage batteries, with an adaptation of the voltage achieved by the converter. The hybrid vehicle can thus operate with different driving modes, comprising a hybrid mode combining the two engines 2, 20, an electric mode or "ZEV" using only the main electrical machine 20, the engine 2 being stopped and the transmission 4 realizing a decoupling between the crankshaft of the engine and the drive wheels by a dead center or the opening of clutches, a mode with four-wheel drive and a sport mode using both engines to drive the two trains of the vehicle.

FIG. 2 shows a first power-up start-up request function, which can come from the driver acting on a starter key or a button present in the passenger compartment, from a remote control, or from a automatic control system like those used at the end of the vehicle assembly line. This first function 30 exchanges powertrain start-up request signals with a second function 32 including a supervision algorithm ensuring the safety of the activation and shutdown of the vehicle powertrain. This algorithm authorizes the starting and stopping of the heat engine, under satisfactory safety conditions. The second function 32 exchanges signals with a third function of starting and stopping the heat engine 34, which decides and executes the start-ups and shutdowns. shutdowns of the engine. This second function 32 also exchanges signals with a fourth function 36 for managing the alternative engines, which is in this example the independent electric drive driving the rear axle. A fifth defect management and reconfiguration function 38 exchanges signals with the second function comprising the supervision algorithm 32 and the third function of starting and stopping the heat engine 34, with a sixth function 40 delivering security information and The sixth function 40 includes information relating to the safety and the regulations concerning a prohibition of start-up of the power train, or a judgment of it if it is already in place. working. This sixth function 40 exchanges information with the fifth defect management and reconfiguration function 38, to prohibit, for example, certain starting of the engine or the complete start-up of the powertrain in the case where the depollution conditions of this engine are not insured, or prohibit a power supply of an electric machine or the complete start-up of the powertrain after an accident that may cause insulation faults in the electrical system, and the risk of electric shock to persons. The fifth defect management and reconfiguration function 38 performs, after each failure reported to it, a reconfiguration of the engine control system in an attempt to overcome the problem, and sends a signal to the man-machine interface 42 in order to inform the driver. FIG. 3 details the third function for starting and stopping the heat engine 34, comprising a supervisor for starting and stopping the heat engine 50 which decides to start, restart or stop this engine by a command transmitted to a manager of the starting components of the heat engine 52. The start and stop supervisor 50 implements in particular the method of securing the starting of the heat engine according to the invention, receiving systematically after failure of a start during the cycle preceding, at the beginning of a new vehicle running cycle, a reconfiguration request from the fifth defect management and reconfiguration function 38.

During a driving cycle, the failure of a restart of the engine can be found in particular by the supervisor on and off 50, which at the time of a request to start this engine, finds in the end a defined time that the engine is not running. In this case the fifth fault management function and reconfigurations 38 is informed of this anomaly, and in return applies a reconfiguration that forces the restart of the engine, as long as the anomaly persists. The manager of the start-up devices 52 receiving a start request from the start and stop supervisor 50, selects the starting member of the most appropriate thermal engine with respect to the current situation.

In particular for a cold start at the beginning of a running cycle, the manager of the starting members 52 selects the starter 8. For a warm start at the beginning or during the rolling cycle, he favors the alternator-starter 12 which is faster, and provides a better delivery.

In the case where the transmission of the heat engine is controlled automatically, the manager of the starting members 52 can also if the speed of the vehicle is sufficient, engage a report of the transmission and drive the clutch 58 by closing it, in order to use the kinetic energy of this vehicle to drive the engine.

The walk and stop supervisor 50 exchanges information with a control system of the engine 60 which includes the control functions of this engine such as the intake air loop and the fuel injections, in order to start it, or obtain the requested torque instruction. This control system 60 determines a rotating thermal engine state meaning that the heat engine is functional, rotating autonomously, and being controllable to meet the required setpoint with sufficient accuracy. FIGS. 4 to 6 show, as a function of time t, successively starting from the top of each graph, the speed of rotation of the heat engine 70, the state of the ignition key operated by the driver 72, the state of the powertrain 74, the state of the heat engine 76, the running set point of this heat engine 78, the fault signal of the control of the alternator-starter 80, and the software reconfiguration flow following this piloting fault 82.

At the bottom of the graph is the activation state of the starting members, comprising the starter 8, the alternator-starter 12 and the clutch 58. The graphics first show up to time t10 a complete cycle of rolling which is each time the same, including a failure of the alternator-starter.

At time t1 the driver puts the ignition. At time t2 the driver requests activation of the powertrain, the manager of the start organs 52 controls the start of the engine by the starter 8, the engine starts its rotation. At time t3 the engine has reached its idle speed, the starter is deactivated.

At time t4, the start and stop supervisor 50 requests the stopping of the heat engine, for example in a hybrid driving mode, because the charge level of the high-voltage battery is sufficient to allow rolling only with the machine. main electric. Stopping the engine ends at time t5.

At time t6, the start and stop supervisor 50 requests the restart of the heat engine, and controls the alternator-starter 12 which is activated, constituting the nominal starting means during the rolling cycle. At time t7 the supervisor on and off 50 notes the failure of starting this engine with the alternator-starter. This failure can be noted for example by an increase in speed of the engine insufficient in relation to the time elapsed. There is an anomaly preventing sufficient drive of the heat engine, such as for example a rotor of the starter-starter blocked, an open electrical circuit, a alternator-starter belt broken, or sliding following in particular a water projection. The start and stop supervisor 50 then activates the fault signal of the control of the alternator-starter 80, and transmits the information to the fault and reconfiguration manager 38 which warns the driver via the human-machine interface 42 The start and stop supervisor 50 activates the software reconfiguration flow following the piloting fault 82. This reconfiguration flow on the one hand forces the start of the engine with the same starting means at the next start-up. of the powertrain, and secondly in order to continue the driving cycle in the best possible conditions, can inhibit this means and select another starting means, or in the absence of alternative available force a new attempt to start the engine with this same starting means. The start and stop supervisor 50 also controls the boot securing method according to the invention, comprising during the following driving cycle, systematically a test of the alternator-starter at the beginning of this cycle. In this example the system starts the engine with another starting means, the clutch 58 of the transmission using the vehicle speed sufficiently high. At time t8 the engine has started. At time t9 the driver requests a stop of the powertrain by a maneuver of the ignition key, the stopping of the engine ends at time t10, the electrical machines are stopped by a power off of the electrical circuit.

FIG. 4 shows at time t11 the beginning of a new rolling cycle, the driver putting the ignition on. At time t12 the driver requests activation of the powertrain. It will be noted that the fault signal of the control of the alternator / starter 80 has remained activated, despite a break in contact by the ignition key actuated by the driver. This fault signal 80 implements the method of securing according to the invention at the beginning of the following cycle, the manager of the starting members 52 systematically controls the starting of the engine by the alternator-starter 12 which has failed. This manager 52 finds again at time t13, the failure of starting by the same starting means 12. The manager of the starting members 52 then controls the starting of the engine by another starting means, which is here the starter 8 In this example, the starter corresponds to a conventional unsized model for frequent starts of the engine, and does not allow a restart of the engine as it is still rotating. This last aspect may have a disadvantage for safety if the starter is used during the driving cycle, because the time of provision of the engine engine torque in case of restarting the engine during shutdown will be degraded.

At time t14 the engine has started, the driving cycle can then begin with a degraded operation according to the independent starting means, and the judgment of the resulting service. In our example the stops of the engine are prohibited because the provision of restart of the engine to the starter is considered unsatisfactory. Otherwise, temporary shutdowns of the engine could be allowed, particularly if the starter is strengthened, and allows the motor to be driven independently of the speed of the engine. Degraded operation thus ensures safety with this systematic control of the starting means of the engine at the beginning of the next cycle, which makes it possible to check their states, and to obtain at any moment a significant torque coming from this engine which would answer a request. driver, for example to allow overtaking. At time t11, FIG. 5 shows the beginning of a new driving cycle, with the driver putting the ignition on. At time t12 the driver requests activation of the powertrain. In the same way, the manager of the starting members 52 systematically controls the starting of the engine by the alternator-starter 12 which has failed. This manager 52 finds again at time t13, the failure of starting by the same starting means 12. The starter manager 52 also finds that it does not have an alternative starting means, for example because the starter is also suffering from a malfunction. The activation of the powertrain is a failure, and it is disabled in order to render inert the other parts of this powertrain, in particular the rear electric machine using electrical energy. There is no new driving cycle because it would be dangerous to allow a taxi even at low speed with electric power, knowing that the engine can not start, and that the driver will not be able to any time a significant couple providing security. The LED display of the man-machine interface continues, to indicate to the driver the need for intervention.

At time t12, FIG. 6 shows the request for activation of the powertrain. In the same way, the manager of the starting members 52 systematically controls the starting of the engine by the alternator-starter 12 which has failed. The manager of the start-up devices 52 notes at time t13, the success of starting by the alternator-starter. In this case the anomaly was transient, for example because of a loss of torque capacity of the alternator-starter due to excessive heating of its power electronics, or because of a slippage of the belt. drive due to particular humidity and temperature conditions.

The driving cycle then continues normally if all the other conditions are met, with the stopping of the engine normally provided for in the hybrid operating mode. The fault signal of the control of the alternator-starter 80 and the software reconfiguration flow following this piloting fault 82, are removed at this time.

Claims (8)

CLAIMS 1 - Method for securing the starting of a heat engine (2), for a hybrid vehicle comprising a second independent motor (20), the heat engine having a first nominal starting means (12) during a cycle of rolling, and a second independent starting means (8), characterized in that the engine control system having detected a failure of the nominal starting means (12) during a rolling cycle, from the beginning of the following rolling cycle he always tests the starting of the heat engine (2) with this nominal starting means (12), and in the case of a failure if the second starting means (8) is operational, it authorizes the departure of the vehicle with degraded operation ensuring safety. 2 - boot securing method according to claim 1, characterized in that the degraded operation comprises a start request of the engine (2) from the start of the powertrain, and a prohibition of stopping the engine at course of the driving cycle if the independent starting means (8) does not allow a satisfactory restart of the engine after a temporary stop of the engine during the driving cycle. 3 - Method of securing the starting according to claim 1 or 2, characterized in that after the detection of the fault, a fault management function and reconfigurations (38) having emitted a fault signal of the steering of the alternator a starter (80) and a software reconfiguration flow following the pilot fault (82), this signal and this flux are maintained after the stopping of the driving cycle. 4 - Boot securing method according to claim 3, characterized in that the fault signal of the control of the alternator-starter (80) and the software reconfiguration flow following the pilot fault (82), are removed in case of starting success of the heat engine (2) during the test with the nominal starting means (12). 5 - Hybrid vehicle comprising a heat engine (2) and a second independent motor (20), the heat engine having a first nominal starting means (12) during a rolling cycle, and a second means independent starting device (8), characterized in that it comprises means implementing a method of securing the starting of this heat engine, made according to any one of the preceding claims. 6 - hybrid vehicle according to claim 5, characterized in that the nominal starting means of the heat engine (2) comprises an alternator-starter (12) connected to the engine by a thermal belt. 7 - hybrid vehicle according to claim 6, characterized in that the independent starting means (8) comprises a conventional starter, or a reinforced starter for a large number of starts of the engine made during the rolling cycles. 8-hybrid vehicle according to claim 6 or 7, characterized in that the engine (2) drives the front wheels, and the second independent motor (20) drives the rear wheels.