EP1096113B1 - Method for driving an internal combustion engine during a temporary failure of an electromagnetic valve actuator - Google Patents

Abstract

The engine operating method responds to a detected function failure of the electromagnetic operating drive (7.1,7.2) for the gas changing valve of one of the engine cylinders (1), indicated by the electronic engine control, for supplying the electromagnets (8,9) of the failed gas changing valve with a current for bringing the valve armature (10) into a given end position, with control of the electromagnetic operating drive for movement from this end position for restoring the cylinder operating cycle. The fuel feed to the corresponding engine cylinder can be interrupted during the detected function failure.

Description

An electromagnetic valve train for actuating a gas exchange valve on a piston internal combustion engine consists in essentially of two spaced apart Electromagnets, between which one with the gas exchange valve related anchor corresponding to the alternate Current supply to the electromagnet is movable back and forth. In the respective end position, d. H. if the anchor on the pole face of the electromagnet, the corresponding one is located Gas exchange valve accordingly in its closed position or its open position. To catch the anchor, the one in question Electromagnet applied with an increased capture current. As soon as the armature reaches its end position on the electromagnet has reached, the energization of the electromagnet is on reduced a lower holding current.

Due to disturbances in the activation of the current supply, for example too low a catch current or too low regulated holding current, but also due to external influences the case may occur that the armature does not touch the pole face at all comes to the plant or moves away prematurely from the pole face solves and without further measures under the action of force the return spring assigned to the respective end position in moved back a middle position between the two electromagnets is, so that the gas exchange valve in question remains in a half-open position. Because such actuators work on the resonance principle, d. H. the full Restoring force of the spring and the timely switching on of the Catch current on the other electromagnet for a flawless Function is necessary, it is not possible to use the anchor the normal control of the energization of the electromagnets back in the working game. Apart from this, that the piston engine by the failure of this Gas exchange valve works with one cylinder less, leads this functional failure of a gas exchange valve with spark-ignited Piston internal combustion engines, usually with a catalytic exhaust gas cleaning device are provided, to considerable impairments of the company. One thing remains the gas exchange valves in the half-open position, then this always results in the course of the further working games Situation that both gas ducts, i.e. H. on the Gas inlet side and gas outlet side gas exchange valves opened are so that mixed with unburned fuel Air or at least air in the case of an injection shutdown reaches the exhaust tract and thus to incorrect values of the lambda control leads, in turn, to the operation of the piston internal combustion engine adverse changes in the Fuel supply and an insufficient conversion rate of the catalyst leads. They also change through the Failure of an actuator or cylinder the vibrations in the Intake or exhaust system.

EP 0 717 172 A describes a method for starting a piston internal combustion engine described, the gas exchange valves with electromagnetic valve trains are provided. The starting procedure is designed so that by triggering the start signal, for example by pressing an ignition key, the starting process cannot run immediately, but initially a timer is switched, which specifies a delay time and by which the starting process, d. H. the actuation of the Crankshaft is locked by a starter. During this Time the gas inlet valves and the gas outlet valves closed. The start process can only take place when It has been determined via a sensor that the gas inlet valves are closed and the lockout period has expired.

The invention has for its object in such Functional failures of electromagnetically actuated gas exchange valves on piston internal combustion engines one in progress Operation as soon as possible restarting a failed To effect gas exchange valve.

For operating a piston internal combustion engine with electromagnetic Valve drives for actuating the gas exchange valves, the one between two electromagnets against the Power from return springs movable and with a gas exchange valve have related anchors and the Can be controlled fully variably via an electronic motor control are, according to the invention to achieve the object suggested that the function in the engine control during operation the electromagnetic valve train of each cylinder is detected and that upon detection of a functional failure on a cylinder the electromagnet of the failed electromagnetic valve train with a catch current the armature in the end position on an electromagnet brings and that out of this end position electromagnetic valve train for the current work cycle of the cylinder is controlled.

To minimize the maximum current, a Piston engine the electromagents of each electromagnetic valve trains by alternating current supply in the resonance frequency of the armature, valve and return springs formed spring-mass system or by high current from the half-open described above Position brought into the fully open position so that the Starter crankshaft practically without compression resistance can turn until then in the corresponding sequence of Working cycle the individual gas exchange valves in the assigned Open or closed position by appropriate Control of the associated electromagnetic valve train be moved and then the fuel supply and possibly the ignition is switched on.

In the event of a functional failure during operation is, in contrast to the first start-up, already at the start the injection is activated and in the intake port is on Fuel wall film available. It is also located in the Cylinders of residual gas from the previous cycle and The tambour control is also activated, so that measures are taken here are to be affected by the operation of the engine due to the actuator failure affect little.

Since it does not matter during operation, electrical To save energy, but only one failure Eliminating the gas exchange valve as quickly as possible will be appropriate the invention via the engine control directly after detection of the failure of the next one Relevant electromagnet or when detecting a Defects the next but one fishing operation with a corresponding one driven high capture current, so that the armature in the shortest Time one in its end positions on one of the pole faces of the catching electromagnet comes into contact. Depending on the work cycle of the relevant cycle are the valves defined moved to the closed or open position, so that the cylinder is still operated in an emergency mode can be closed or partially closed Valves is no longer used for power delivery and one by switching the other valves of the cylinder minimal influence on engine and catalytic converter operation Has. From this end position it will then holding electromagnet so energized, that the gas exchange valve in question is again in the current working cycle moved or if a magnet is defective in the end position is held.

As a corresponding sensor system in the engine control the work cycle related to the time of failure can be recorded can also be adjusted to the piston movement Switch-on time for the catching current with appropriate programming the electronic engine control, so that in no time the anchor in the working game next opened or closed position can. The control of the gas exchange valves of the concerned Cylinder must be changed in the engine control so that the valves of the one gas feed side (gas inlet side) and the other gas feed side (Gas outlet side) not opened at the same time are.

In an advantageous embodiment it is provided that during a functional downtime determined at least the fuel supply is interrupted to the cylinder in question. Because of the failure of a gas exchange valve and that independently whether it's a gas inlet valve or a gas outlet valve fails, due to insufficient compression of the cylinder in question does not work, it is avoided that unburned Fuel is pushed out into the exhaust tract and here the catalyst is "overloaded" with hydrocarbons because, additionally and via the lambda control, this operating situation is detected as a "too lean" mixture, so that then the fuel supply to the rest of the properly working Cylinders is increased so that it becomes a there is significant over-greasing in these cylinders.

In an expedient embodiment of the invention, it is further provided that that during a determined downtime the lambda control is deactivated. Deactivating the Lambda control is also required when using the engine control the fuel supply to the cylinders in question is switched off, because then the moving on Pistons fed into the exhaust tract from the air intake tract Air is pushed out so that the oxygen content in the Exhaust gas is increased, which in turn would lead to the remaining, properly working cylinders the fuel supply would be increased and an optimal combustion process is not guaranteed in the working cylinders.

In a further embodiment of the method according to the invention it is provided that in the event of failure of an inlet-side gas exchange valve the gas exchange valve (s) on the outlet side kept closed or closed immediately until Initiation of normal operation of the failed gas exchange valve in the work cycle or an emergency operation for the failed Cylinder or engine. This avoids that an unburned fuel-air mixture in the exhaust tract or air is pushed out when the fuel supply is switched off can be.

In a modification, it is provided in the same way that in the event of failure an outlet-side gas exchange valve at least one inlet-side gas exchange valve upon detection of the malfunction with a piston movement to the top dead center position is opened and kept open or remains open and at Engines with at least two exhaust valves the other exhaust valves be closed or kept closed. The opening or closing process depends on the Downtime outside of the normal work cycle, so that both with a piston movement in the extension phase as well in the case of a piston movement in the compression phase, the intake side Gas exchange valve is opened so the extension of air-fuel mixture or air into the exhaust system minimize. Both gas inlet valves are expediently here opened so that due to the smaller free cross section of the half-open failed gas outlet valve the majority of the gas volume in the air intake tract pressed in and sucked back into the cylinder chamber becomes.

When the cylinder is switched on again in the normal working cycle the piston internal combustion engine, it is useful in the How much fuel to take into account Fuel from the work cycles before and during the downtime is present in the cylinder or in the suction system. This metering has to be done via the engine control and depending on whether a gas inlet or a gas outlet valve has failed and at what time one Working cycle the failure has occurred, d. H. whether the failure during the air intake and fuel injection phase or whether the failure occurs during the exhaust phase one work cycle or in the compression or expansion cycle is done. In addition, there is also the recording of the functional downtime in terms of the number of working games as well the detection of the time of switching off the fuel supply and the load and speed status of the engine in the event of failure and restart.

When switching on again, the motor control is next to the Fuel quantity the charge composition over the valve timing for the cylinder to be switched on. This adjustment depends on the extent to which burned exhaust gas is or could be present in the cylinder and to what extent, depending on the functional downtime Change in the temperature boundary conditions has occurred. In Dependency on these boundary conditions must then first to be decided whether to first push out the existing ones Cylinder charging takes place in the exhaust tract or whether the charge change can start with a suction process.

In a further embodiment of the invention it is provided that for the cylinder concerned, the time of failure in Working cycle recorded and stored for the purpose of fault diagnosis becomes.

At first, it cannot be determined via the engine control a detected failure of a gas exchange valve is due to a temporary disturbance, for example a fault in the current supply, larger impact influences etc., or whether it is permanent damage to the electromagnetic Valve train itself acts, such as one Cable break or the like. Such a permanent error can be recognized by the fact that when energizing the electromagnetic Valve train according to the inventive method It is determined via the existing sensors whether the concerned valve train is not working properly again or a proper function is available. To the valve control times must be recognized when the valve actuator failure and the valve actuator control parameters of the subject Cylinder can be adjusted. One is in particular Adjustment of the outlet capture flow level in the event of a failure higher load necessary to influence the load on the current parameters to consider. the changed intake manifold and exhaust gas dynamics can also depend on the operating state of the engine an adjustment of the valve actuator control parameters and Require valve timing of the other cylinders.

In an embodiment of the inventive method is therefore provided that after an ongoing failure after unsuccessful commissioning of a gas exchange valve on a Throttle duct side the other gas duct side kept closed and that the gas exchange valves via the engine control and the fuel supply to the other cylinders to maintain the total charge with a correspondingly higher Load specification can be controlled. This ensures that the load share of the failed cylinder is full of the other cylinders is taken over. To avoid excessive Rotational irregularities leading to deterioration of driving comfort can lead to a simultaneous increase in load the still fired cylinder one or more cylinders be switched off in a corresponding manner. This can in such a way that after switching off the fuel supply and ignition the gas exchange valves on a gas guide side be kept closed and on the other side of the gas duct are kept open or all are closed. The other cylinders can also be exchanged cyclically burn

The invention is illustrated by a schematic representation explained.

The drawing shows schematically a cylinder 1 of a piston internal combustion engine, in which a piston 2 is in the usual way Move up and down between top and bottom dead centers emotional. All cylinders 1 of the piston internal combustion engine are on a gas guide side with a gas inlet channel 3 and on it other gas supply side with a gas outlet channel 4, which each have a gas inlet valve 5 and a gas outlet valve 6 is assigned. At least one gas exchange valve 5 is each with an electromagnetic valve train 7.1 and 7.2 provided. The electromagnetic valve train 7 consists in essentially from a closing magnet 8 and an opening magnet 9, between which an anchor 10 against in a known manner the force of return springs, not shown here is movable back and forth. The anchor 10 is associated with the Gas exchange valve connected so that when the armature is applied 10 on the closing magnet 8 the gas exchange valve is closed is and when it is in contact with the opening magnet 9, the gas exchange valve is fully open. Are the two electromagnets de-energized, the armature 10 and, accordingly, the associated one Gas exchange valve without further mechanical locking measure a half-open intermediate position.

The energization of the magnets 8 and 9 of the electromagnetic Valve drives 7 are controlled via an engine control 11, which also the other functions of the piston internal combustion engine controls, such as the fuel supply here by a direct injection fuel nozzle 12 schematically is shown and the ignition, which is shown here by a corresponding Lightning symbol 13 is shown.

The two electromagnetic valve drives are sensors for detecting the valve movement or the armature movement assigned here, schematically by sensors 14.1 and 14.2 are shown, which are operatively connected to the gas exchange valve stand. The detection of the valve movement can also be done with other means, for example by recording the Current and / or voltage profiles on the electromagnets immediately be detected via the engine control system, as is known the current curve and also the voltage curve in one Coil changes when not in contact with one approaching, an adjoining or moving away Anchor changed the magnetic field.

The piston internal combustion engine shown here with only one cylinder stands with its exhaust tract 4 with a catalytic Exhaust gas purification device 15, for example one Three-way catalytic converter connected to a lambda sensor 16 is assigned to influence the fuel supply.

According to the procedure detailed above is now in the event of a functional failure, for example Gas inlet valve on the engine control 11 immediately in the Way reacts that, on the one hand, the fuel supply Close the fuel injector 12 to that cylinder is turned off and the gas outlet valve 6 is closed is held to prevent over opening itself Condition gas inlet valve immediately air or unburned air-fuel mixture from the cylinder compartment can be excavated into the exhaust tract.

As soon as the gas inlet valve 5 is in the appropriate position on his holding electromagnet 8 or 9 to the system has come, both electromagnetic valve trains 7.1 and 7.2 corresponding to that for the entire piston internal combustion engine next cycle for this cylinder controlled, then according to the assigned work cycle ignition and fuel supply also switched on again become. In the event of a defect in a magnet become dependent whether it is the opening or closing magnet, measures also taken to keep the engine running as possible little influence on the maintenance of the business continues to increase operate.

The in connection with the restart of a failed gas exchange valve further measures to be taken, too depend on whether a gas inlet valve or a gas outlet valve has failed, are described in detail above been so that, in order to avoid repetition, on a description of the different operating cases based on the schematic drawing is dispensed with.

Claims (13)

1. Method for operating a reciprocating internal combustion engine with electromagnetic valve gear units for actuating the gas exchange valves (5, 6), which units in each case comprise an armature (10), which can move between two electromagnets (8, 9) against the force of return springs and is connected to a gas exchange valve (5, 6), and can be controlled via an electronic engine control unit (11) in a fully variable manner, characterised in that the functioning of the electromagnetic valve gear units (7) of each cylinder (1) is detected in the engine control unit (11) during operation, and that, if a functional failure of an electromagnetic valve gear unit (7) at one cylinder (1) is detected, a pull-in current is applied to the electromagnet (8, 9) of the failed electromagnetic valve gear unit (7) to bring the armature (10) into the end position at one of the electromagnets (8, 9), and that the electromagnetic valve gear unit (7) is controlled from this end position for the current working stroke of the cylinder (1).
2. Method according to Claim 1, characterised in that, throughout a functional failure time of a gas exchange valve (7) at a cylinder (1) on one gas flow side, the control of the remaining gas exchange valves of this cylinder (1) is carried out such that one gas flow side (gas inlet side 3) and the other gas flow side (gas outlet side 4) are not open at the same time.
3. Method according to Claim 1 or 2, characterised in that at least the fuel supply to this cylinder (1) is interrupted throughout the functional failure time.
4. Method according to any one of Claims 1 to 3, for a reciprocating internal combustion engine with lambda control, characterised in that the lambda control is deactivated throughout the functional failure time.
5. Method for operating a reciprocating internal combustion engine with at least two gas exchange valves (5, 6) in each case on the gas inlet side (3) and the gas outlet side (4), according to any one of Claims 1 to 4, characterised in that, if a gas exchange valve (5) on the inlet side fails, the gas exchange valves (6) on the outlet side are held closed until the initiation of normal operation or emergency running operation of the failed gas exchange valve (5) in the working stroke.
6. Method according to any one of Claims 1 to 5, characterised in that, if a gas exchange valve (6) on the outlet side fails, at least one gas exchange valve (5) on the inlet side is opened upon a piston movement to the upper dead centre and held open.
7. Method according to any one of Claims 1 to 6, characterised in that, upon starting up the failed gas exchange valve (5, 6) again for the current working stroke, the instant of the failure in the working cycle, the load and the rotational speed as well as the duration or the working cycles of the failure are taken into account for controlling the fuel supply.
8. Method according to any one of Claims 1 to 7, characterised in that the instant of the failure in the working cycle is detected and stored for the purpose of fault diagnosis for the cylinder (1) concerned.
9. Method according to any one of Claims 1 to 8, characterised in that, in the case of a continuous functional failure after unsuccessfully starting up a gas exchange valve (5, 6) on one gas flow side (3, 4), the other gas flow side (3, 4) is held closed, and that the gas exchange valves (5, 6) and the fuel supply to the other cylinders (1) are controlled via the engine control unit (11) to obtain the total load delivery with a correspondingly higher load requirement.
10. Method according to any one of Claims 1 to 9, characterised in that the total load delivery remains constant by adapting the load of the cylinders (1).
11. Method according to any one of Claims 1 to 10, characterised in that the charge composition is adapted upon starting up the cylinder (1) again.
12. Method according to any one of Claims 5 to 11, characterised in that the gas exchange valve (5, 6) remains closed and the engine is operated further with one less gas exchange valve on the gas inlet side (3) or the gas outlet side (4).
13. Method according to any one of Claims 1 to 12, characterised in that at least one further cylinder (1) is shut off and the engine can thereby be operated with the same ignition interval, wherein the cylinders can be shut off alternately.

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