EP1069299B1 - Injection device for internal combustion engine - Google Patents

Description

The present invention relates to a device fuel injection of an internal combustion engine, including common rail for diesel engine.

In US-A-5,636,618, there is described a fuel and air supply device combustion for internal combustion engines in which a separate controller is provided for each cylinder. Each controller performs the regulation of all mixing and ignition functions. It is mentioned in this state of the art the ability of each controller to perform a redundancy function for the other faulty controller.

Fuel injection devices are known with a working calculator, depending on the number of engine cylinders, with one or more control benches injectors. So, for example, for a four-engine cylinders, it is known to use either a single bench charged with ordering four injectors, two benches of control which each manages two injectors. The choice of the solution depends on different criteria among which, in particular, the strategies for reducing emissions of pollutants by the engine. To achieve this, the solution with two control benches presents the interest of able to ensure fuel injection simultaneously on two injectors from the same control bench.

Whatever solution is chosen, a failure of a control bench can lead to a risky failure, at the better, to be very badly perceived by the user of the vehicle, at worst, to create a dangerous situation. In indeed, if only one bench is provided for all injectors, the breakdown leads to the total immobilisation of the vehicle and if there are two, the engine will have a heavily degraded operation. In both cases, there is will have a major risk of accident if the failure occurs in "at risk" driving conditions (overtaking, taxiing in a dense and fast traffic).

The object of the invention is to provide a device injection without the disadvantages presented above.

It therefore relates to a device according to claim 1.

Thanks to these features, in the absence of a failure of a control bench, the device Injection can work with bench control distributed on the injectors in such a way that the fuel supply of the injectors is adapted to closer to the emission reduction requirements polluting.

On the other hand, in the event of a failure of one of control benches, the piloting of the injectors that was there connected is automatically picked up by another bank of command, which allows to keep at least temporarily engine performance to a degree such that security remains preserved even in case of taxi risk.

• lesdits signaux de défaillance sont spécifiques pour chaque banc de commande et en cas d'une défaillance d'un banc de commande, les signaux qui lui sont propres, sont appliqués uniquement aux inverseurs connectés aux injecteurs qui, avant la défaillance, étaient connectés au banc défaillant;
• le dispositif comprend également une mémoire connectée auxdits moyens de détection de défaillance, pour mémoriser lesdits signaux de défaillance jusqu'à un prochain démarrage dudit moteur à combustion interne, de manière à fournir des signaux de défaillance mémorisés qui, dès ce prochain démarrage, sont appliqués aux inverseurs dont les injecteurs étaient commandés par le banc défaillant, pour que ces injecteurs soient déconnectés de celui-ci, tout en étant connectés à un banc non défaillant;
• lesdits signaux de défaillance et lesdits signaux de défaillance mémorisés sont appliqués respectivement auxdits inverseurs par l'intermédiaire de fonctions OU.
• le dispositif comprend également des moyens pour limiter les performances dudit moteur, dès la production par lesdits moyens de détection de défaillance de l'un desdits signaux de défaillance;
• lesdits moyens de limitation sont agencés pour limiter la demande d'accélération appliquée audit moteur à une valeur inférieure à une valeur de demande maximale d'accélération imposée pendant le fonctionnement normal desdits bancs de commande;
• lesdits moyens de limitation comprennent des moyens de comptage temporel connectés auxdits moyens de détection de défaillance et des moyens cartographiques connectés auxdits moyens de comptage temporel et qui, en fonction de la position de ces derniers, déterminent une valeur variable réduite de demande maximale d'accélération destinée à être utilisée pendant ladite défaillance et maintenue inférieure à ladite valeur de demande maximale d'accélération imposée pendant le fonctionnement normal desdits bancs de commande;
• lesdits moyens cartographiques sont agencés pour ne faire intervenir ladite valeur réduite de demande maximale d'accélération qu'après écoulement d'un intervalle de temps prédéterminé depuis l'apparition d'une défaillance de banc de commande;
• ladite valeur variable réduite de demande maximale d'accélération est maintenue à une valeur zéro par lesdits moyens cartographiques pendant un court instant suivant immédiatement l'apparition d'une défaillance de banc de commande;
• lesdits moyens de limitation comprennent également un premier inverseur auquel sont appliquées ladite valeur de demande maximale d'accélération et ladite valeur variable réduite de demande maximale d'accélération fournie par lesdits moyens cartographiques, cet inverseur transmettant audit moteur l'une ou l'autre de ces valeurs en fonction des signaux de défaillance fournis par lesdits moyens de détection de défaillance;
• lesdits moyens de limitation comprennent des moyens, pour limiter à une valeur fixe les performances dudit moteur en présence d'un desdits signaux de défaillance mémorisés;
• lesdits moyens de limitation à une valeur fixe sont agencés pour, après redémarrage dudit moteur survenant après un fonctionnement durant lequel une défaillance est apparue, limiter la demande d'accélération à une valeur fixe inférieure à une valeur de demande maximale d'accélération imposée pendant le fonctionnement normal desdits bancs de commande;
• lesdits moyens de limitation à une valeur fixe comprennent un second inverseur auquel sont appliquées une valeur de demande d'accélération maximale de défaut mémorisée ainsi que ladite valeur de demande maximale d'accélération utilisée hors défaillance, ledit second inverseur transmettent l'une ou l'autre desdites valeurs audit moteur en fonction de l'état desdits signaux de défaillance mémorisés;
• il comprend également des moyens de signalisation visuelle connectés audit dispositif de détection de défaillance pour signaler l'apparition d'une défaillance.

According to other features of the invention:

• said failure signals are specific for each control bank and in the event of a failure of a control bank, the signals which are specific to it are applied only to the inverters connected to the injectors which, before the failure, were connected to the bench failing;
• the device also comprises a memory connected to said failure detection means, for storing said fault signals until a next start of said internal combustion engine, so as to provide stored fault signals which, from this next start, are applied inverters whose injectors were controlled by the failing bank, so that these injectors are disconnected from it, while being connected to a non-faulty bench;
• said failure signals and said stored failure signals are respectively applied to said inverters via OR functions.
• the device also comprises means for limiting the performance of said engine, from the production by said failure detection means of one of said failure signals;
• said limiting means are arranged to limit the acceleration demand applied to said motor to a value less than a maximum acceleration demand value imposed during normal operation of said control banks;
• said limiting means comprise time counting means connected to said failure detecting means and mapping means connected to said time counting means and which, depending on the position of the latter, determines a reduced variable value of maximum acceleration demand intended to be used during said failure and kept below said maximum acceleration demand value imposed during normal operation of said control banks;
• said map means are arranged to use said reduced maximum acceleration demand value only after a predetermined time interval has elapsed since the occurrence of a control bank failure;
• said reduced variable value of maximum acceleration demand is maintained at a zero value by said map means for a short time immediately following the occurrence of a control bank failure;
• said limiting means also comprises a first inverter to which said maximum acceleration demand value is applied and said reduced variable value of maximum acceleration demand provided by said mapping means, said inverter transmitting to said motor one or the other of these values as a function of the failure signals provided by said failure detection means;
• said limiting means comprises means for limiting to a fixed value the performance of said motor in the presence of one of said stored failure signals;
• said fixed-value limiting means are arranged to, after restarting said motor occurring after an operation during which a failure has occurred, limiting the acceleration request to a fixed value less than a maximum acceleration demand value imposed during the normal operation of said control benches;
• said fixed value limiting means comprises a second inverter to which a stored maximum error acceleration demand value is applied and said maximum acceleration demand value used out of failure, said second inverter transmitting one or the other other said values to said engine as a function of the state of said stored failure signals;
• it also comprises visual signaling means connected to said failure detection device to signal the occurrence of a failure.

• la figure unique est un schéma symbolique d'un exemple de réalisation d'un dispositif d'injection selon l'invention.

Other features and advantages of the invention will become apparent from the following description given purely by way of example and with reference to the appended drawing in which:

• the single figure is a symbolic diagram of an exemplary embodiment of an injection device according to the invention.

The embodiment shown in the single figure relates to a diesel engine with common rail comprising four cylinders. The specialists will understand that the invention can also be applied to injection engines other types with different numbers of cylinders injectors and control benches, but without depart from the scope of the invention.

That being so, we see schematically represented a fuel injection device with part of its CC control computer with two banks of command 1 and 2 each able to command the four injectors 3 to 6 at a time, regardless of the other bench control. For this, each injector, 3 to 6, is connected to an output of the same rank of each of the benches of control via an inverter member, respectively 7 to 10.

In the represented configuration, which corresponds to a normal situation, the bench 1 controls the injectors 3 and 6 and the bench 2, the injectors 4 and 5.

The control benches 1 and 2 are connected to a measuring module 11 which raises several parameters and which is connected to a monitoring module 12 loaded with detect malfunctions of the banks of command 1 and 2. This function can be executed according to known strategies for monitoring operating parameters of the benches. For example, we can control the voltage at the terminals of some of their components or the intensities of currents flowing through them.

In case of a failure of one of the benches 1 and 2, the monitoring module 12 provides respectively defect signals default_banc_1 or default_banc_2 formed by Boolean values indicating, when they are true (value 1 for example) that fault is present in the corresponding control bank. These signals are applied respectively to two blocks 13 and 14 with OR function, whose outputs control respectively the inverters 7, 10 or 8, 9.

The signals default_banc_1 and default_banc_2 are also applied to a fault memory 15 which stores the fault signals possibly during the taxi current vehicle, to be able to restore them at startup next engine. The inscription in this memory of default_banc_1 or default_banc_2 signals are preferred during the stop phase of the DC control computer. So, depending on the case, during the next start of it, the memory 15 makes available a signal default_banc_1_mem or a signal default_banc_2_mem, meaning that a defect occurred during a previous use of the engine, in one or other of the benches command 1 or 2.

The signals default_banc_1, default_banc_2, default_banc_1_mem and default_banc_2_mem are applied together at a block 16 with OR function whose output is connected to a fault signaling device 17. This last can be a light from the dashboard of the vehicle, shared or not with other signaling functions relating to other malfunctions of the vehicle.

The signals default_banc_1 and default_banc_2 are also applied to an OR function block 18 whose output is transmitted to a block 19 of deactivation of the bench 1 or 2 depending on whether one or the other signal corresponding is true.

The injection control device according to the invention also comprises means for, in case of failure of control benches 1 or 2, limiting the accelerating will of the driver of the vehicle. In this effect, the output of the OR function block 18 is connected to a counter 20 which, in the event of a defect of a bank of command, that is when default_banc_1 or default_banc_2 is 1, to total the elapsed time since the appearance of the defect. This counter 20 provides a signal time_def_banc and it is reset after each resetting the CC control computer.

The output of the counter 20 is connected to a block of mapping 21 which according to the position of the meter 20 allows to select a value to which will be limited the driver's "desire to accelerate" vehicle in the event of failure of one of the benches 1 or 2. The corresponding value is called here "reduced value of maximum demand for acceleration ".

The output of the mapping block 21 is applied to an inverter 22 which also receives a signal will_max which represents for the situations out of breakdown, a value calibrated maximum acceleration that the driver can impose. This value is called here "demand value maximum acceleration ".

The inverter 22 is normally placed on the terminal to which is applied the signal will_max. However, he is reversed under the command of the output of the block to OR function 18, that is to say in case of detection of a failure. The output of the inverter 22 is applied to a block 23 with OR function that can transmit, or the value resulting from the inverter 22, that provided by a another inverter 27 yet to be described. The exit of the block OR function 23 is connected to a first input of a block 24 says "minimum function" (MIN).

This block 24 also receives on another input a variable signal generated will, according to the engine control system, from a parameter translating the demand for current acceleration of the driver. This parameter can be a voltage detected in depending on the position of the accelerator pedal, a requested torque value, a quantity of fuel injected by injection, a percentage of charge or other.

The output signal vol_cond_lim from block 24 to MIN function is either the actual demand for acceleration of the driver, when it is less than the value from the mapping block 21, the latter value when the actual demand for acceleration of the driver exceeds it. This output signal is transmitted to application software 25 of the calculator CC responsible for managing the engine operation. This output signal thus translates the driver's desire to accelerate while driving with failure but it can not exceed the limit value imposed.

The software 25 also receives the signals default_banc_1 and default_banc_2 from the monitoring 12 in order to adapt the operation of the engine to the situation of failure.

The default_banc_1_mem and default_banc_2_mem signals are applied to an OR function block 26 whose output is applied to a second inverter 27. This receives on one of its terminals a signal will_max_def_mem which fixes the maximum demand value of acceleration in case of a driving after restarting the engine. The other terminal of the inverter receives the will_max signal used during the operation out of trouble. The output of the inverter 27 is applied to block 23 with OR function to be able, the case where appropriate, be transmitted to block 24 with MIN function.

The operation of the injection device that one just described is the following.

Without the presence of a fault on one of the two benches command 1 or 2, each of these pilot benches two injectors (3, 6 or 4,5, respectively), the inverters 7 to 10 being then in their position shown in the figure.

In the event of a failure of one of the benches (eg example the bank 1), the inverters 7 and 10 are toggled under the command of the signal default_banc_1 passing through the block OR 13. As a result, the injectors 3 and 6 are now also driven by non-faulty bank 2.

Similarly, when restarting the CC calculator after an engine shutdown following this failure, the same inverters 7 and 10 will switch under the command the signal default_banc_1_mem extracted from the memory 15 and also passing through the OR block 13.

Simultaneously with the switching of the inverters, the driver is alerted by the signaling device 17, while bank 1 is disabled via from block 19.

During normal operation, the signal will_max limits the demand for driver acceleration at the maximum value calibrated will_max. When the the fault appears, the inverter 22 switches under the command of the signal coming from the block OR 18. From this moment, the maximum demand value of acceleration is governed by time function by the mapping deposited in the block 21.

This particular characteristic of the invention in particular to warn the driver of the vehicle to way of an unusual reaction to the behavior of the vehicle. For example, it is possible to report a failure of benches 1 or 2 by a drastic reduction (possibly up to zero) but brief of value reduced maximum demand for acceleration, leading thus to a total or almost total cut of the injection for a brief period of a few milliseconds per example. This will result in a very smooth jerk noticeable for the driver, without compromising security, for example during a exceeded.

However, by properly mapping of Block 21, the law of modification of the reduced value of maximum acceleration demand can also be chosen from way to start limiting the performance of the engine after a sufficiently long time (10 seconds per example) so that the driver can bring the vehicle in good conditions of safety before any lapse engine performance. So thanks to the block 21, the invention offers great flexibility to calibrate over time the management of the mode of degraded operation of the engine.

The performance limitation in case of failure of one control benches will further encourage the driver to promptly have his vehicle repaired and in the immediate future adopt a prudent behavior so as to be able to mitigate more easily any failure of the other control bench.

In the case where the driver proceeds to a new starting the engine, the performance limitation is governed uniformly by the signal vol_max_def_mem on which switches the system under the command of one or the other signals default_banc_1_mem and default_banc_2_mem.

This feature of the present invention the advantage, besides those already mentioned, to avoid a return to normal performance of the vehicle which would in principle possible since the engine could run at full performance with a single control bench but which give the driver the impression that the breakdown would have disappeared and could lead to a situation dangerous if the only non-defective control also deteriorated.

Claims (13)

1. An injection apparatus for an internal combustion engine, in particular with a common rail, for a diesel engine, comprising a plurality of injectors (3 to 6) and a control computer (CC) of the engine for managing fuel injection by way of said injectors, said control computer (CC) comprising at least two control banks (1, 2) for the pilot control of said injectors (3 to 6) and which also comprises a plurality of inverter members (7 to 10) connected between said control banks (1, 2) and said injectors (3 to 6) in such a way that each injector can be connected selectively to each of said control banks,

   characterised in that there are also provided detection means (11, 12) for detecting a failure of any one of said control banks (1, 2) which are capable of producing a plurality of failure signals (fault_bank_1, fault_bank_2) thereof which can serve as control signals for said inverters in such a way that, as soon as failure is detected, the injectors which are pilot-controlled by the failing bank are disconnected therefrom, while being connected to a non-failing bank, and

   it also comprises means (21 to 24, 26, 27) for limiting the performances of the engine as soon as one of said failure signals (fault_bank_1, fault_bank_2) is produced by said failure detection means (11, 12).
2. An injection apparatus according to claim 1 characterised in that said failure signals (fault_ bank_1, fault_bank_2) are specific for each control bank (1, 2) and in the event of a failure of a control bank the signals which are appropriate thereto are applied solely to the inverters (7 to 10) connected to the injectors (3 to 6) which prior to the failure were connected to the failing bank.
3. An injection apparatus according to either one of claims 1 and 2 characterised in that it also comprises a memory (15) connected to said failure detection means (11, 12) for storing said failure signals (fault_bank_1, fault_bank_2) until a next start-up of said internal combustion engine so as to provide stored failure signals (fault_bank_1_mem, fault_bank_2-mem) which as from said next start-up are applied to the inverters of which the injectors were pilot-controlled by the failing bank so that said injectors are disconnected therefrom while being connected to a non-failing bank.
4. An injection apparatus according to claim 3 characterised in that said failure signals (fault_bank_1, fault_bank_2) and said stored failure signals are applied respectively to said inverters (7 to 10) by way of OR functions (13, 14).
5. An injection apparatus according to any one of the preceding claims characterised in that said limitation means (21 to 24, 26, 27) are arranged to limit the maximum demand for acceleration (wish_driver) applied to said engine to a value (wish_dr_limited) lower than a maximum acceleration demand value (wish_max) imposed during normal operation of said control banks (1, 2).
6. An injection apparatus according to claim 5 characterised in that said limitation means (20 to 24, 26, 27) comprise time counting means (20) connected to said failure detection means (11, 12) and mapping means (21) connected to said time counting means (20) and which in dependence on the position of the latter determine a reduced variable value in respect of maximum acceleration demand (wish_max_red), said value being intended to be used during said failure and kept below said maximum acceleration demand value (wish_max) imposed during normal operation of said control banks (1, 2).
7. An injection apparatus according to claim 6 characterised in that said mapping means (21) are arranged to involve said reduced maximum acceleration demand value (wish_max_red) only after the elapse of a predetermined time interval from the appearance of a control bank failure.
8. An injection apparatus according to either one of claims 6 and 7 characterised in that said reduced maximum acceleration demand value (wish_max_red) is maintained at a value zero by said mapping means (21) for a short instant immediately following the appearance of a control bank failure.
9. An injection apparatus according to any one of claims 6 to 8 characterised in that said limitation means also comprise a first inverter (22) to which are applied said maximum acceleration demand value (wish_max) and said reduced maximum acceleration demand value (wish_max_red) provided by said mapping means (21), said inverter (22) transmitting to said engine one or other of said values in dependence on the failure signals (fault_bank_1, fault_bank_2) provided by said failure detection means.
10. An injection apparatus according to any one of claims 1 and 6 to 9 when they are appendant to claim 3 characterised in that said limitation means comprise means (26, 27) for limiting to a fixed value the performances of said engine in the presence of one of said stored failure signals (fault_bank_1_mem, fault_bank_2_mem).
11. An injection apparatus according to claim 1 characterised in that said means for limitation to a fixed value (26, 27) are arranged in order after re-starting of said engine occurring after an operating situation during which a failure has appeared, to limit the acceleration demand to a fixed value (wish_max_def_mem) lower than a maximum acceleration demand value (wish_max) imposed during normal operation of said control banks (1, 2).
12. An injection apparatus according to claim 11 characterised in that said means for limitation to a fixed value comprise a second inverter (27) to which are applied a stored fault maximum acceleration demand value as well as said maximum acceleration demand value used in a non-fault situation, said second inverter transmitting one or other of said values to said engine in dependence on the state of said stored failure signals.
13. An injection apparatus according to any one of claims 1 to 11 characterised in that it also comprises visual signalling means (17) connected to said failure detection device for signalling the appearance of a failure.

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