JP5865419B2 - Hydraulic valve control apparatus and method for controlling and monitoring the switching state of a valve of an internal combustion engine of an automobile - Google Patents

Description

  The present invention relates to a hydraulic valve control device and method for controlling and monitoring the switching state of a valve of an internal combustion engine of an automobile.

  An internal combustion engine that monitors the switching state of a valve of the internal combustion engine is known from Patent Document 1, for example. This patent document 1 discloses a variable valve control for operating and stopping a cylinder of an internal combustion engine. At that time, a large number of rocker arms are provided. The rocker arm has a plurality of hydraulic passages for applying hydraulic pressure to the respective valve trains for the purpose of operating or deactivating cylinders of the internal combustion engine. At that time, the oil pressure is monitored by an oil sensor.

European Patent Application Publication No. 1365115A2

  In light of this background, an object of the present invention is to provide improved monitoring of the switching state of a valve of an internal combustion engine of a motor vehicle.

  This object is solved by a hydraulic valve control device having the features of claim 1 and by a method having the features of claim 9.

  The present invention provides a hydraulic valve control device for controlling and monitoring a switching state of a valve of an internal combustion engine of an automobile, and in this case, the switching state of each valve causes a predetermined oil pressure to act on the valve. The valve is formed so as to be adjustable. In this case, the valve control device comprises a hydraulic line that connects the valves to be controlled and monitored with the internal combustion engine, and in order to switch the hydraulic pressure in the hydraulic line between different hydraulic pressures assigned to the switching state of the valve, A switching valve is provided in the hydraulic pipeline, and a hydraulic pressure sensor is provided in the hydraulic pipeline to measure the hydraulic pressure in the hydraulic pipeline. The valve control device further includes a control device that controls the switching valve so that the valve has a predetermined switching state. In this case, the control device compares the hydraulic pressure measured by the hydraulic pressure sensor with at least one first and second hydraulic pressure threshold value to monitor the valve, and at the time of the first hydraulic pressure threshold value, a predetermined switching state. The switching state of the valve to is changed, and when the second hydraulic pressure threshold is reached, the valve reaches a predetermined switching state.

  By providing at least two hydraulic pressure thresholds, the switching state of the valves of the internal combustion engine can be monitored more accurately. Based on the first oil pressure threshold, it can be determined whether a predetermined change in the switching state has been made, and whether the change in the switching state has been made correctly or incorrectly by means of the second oil pressure threshold. Can be determined. Thereby, fault diagnosis is improved and appropriate measures can be taken based on the determined fault.

  In an advantageous embodiment of the invention, the controller determines a failure when the oil pressure does not reach and exceed the respective oil pressure threshold or does not reach and exceed the predetermined time. Fault diagnosis is further improved by taking into account the change in hydraulic pressure over time. In this case, the failure can also be confirmed when the oil pressure reaches and exceeds the set oil pressure threshold. However, for that purpose, it is necessary to exceed the time longer than in the case of normal operation without failure, for example.

  In another advantageous embodiment, the first switching state of the valve is an empty lift (Leerhub) and the second switching state of the valve is a valve lift (Ventilhub). At that time, the valve lift can be further variably formed. For example, a camshaft with one cam having two different cams for each valve or two cam profiles different for each valve to produce different sized valve lifts for each valve; This is done by cooperating the valves.

  In another embodiment, the second hydraulic threshold is preferably the upper hydraulic threshold for the second switching state or valve lift. The controller determines a failure when the measured oil pressure does not reach and exceed the upper oil pressure threshold or does not reach or exceed the predetermined time. This can not only confirm whether the switching state has been changed, but can also confirm whether the desired switching state has occurred or whether a fault has occurred in this case.

  In another advantageous embodiment, the second hydraulic pressure threshold is the lower hydraulic threshold for the first switching state or empty lift. The controller determines a failure when the measured oil pressure does not reach and exceed the lower oil pressure threshold or does not reach or exceed the predetermined time. In the same way, it is possible not only to check whether the switching state has been changed, but also to check the switching state, here whether an empty lift is being performed. In a particularly advantageous embodiment, the lower and upper hydraulic thresholds are provided as second and third hydraulic thresholds in addition to the first hydraulic threshold.

  Preferably, each valve further comprises a switchable cup tappet for switching the valve between different switching states, the cup tappet being connected to the hydraulic line. In this case, the cup tappet is formed of at least two parts, for example comprising an inner tappet and an outer tappet, both tappets producing different valve lifts, the inner cam and the outer campet of one camshaft. It can be operated by a cam. Each cup tappet is lockable or the tappets are lockable to each other. Thereby, the cup tappet can reciprocate the associated valve between different switching states.

  In an advantageous embodiment, the control device closes the switching valve to unlock the cup tappet and opens the switching valve to lock the cup tappet. With the switching valve, the cup tappet and the valve connected thereto can be easily switched back and forth between different switching states.

  In another embodiment, the failure message is stored in the storage device after the controller has determined the failure. This failure message can be read from the storage device when necessary, and appropriate measures are taken based on the failure message, such as, for example, turning on an engine indicator lamp, disconnecting a valve having a failure or emergency operation of an internal combustion engine. be able to.

   An embodiment of the invention is shown in the figure. This embodiment will be described in detail in the following description.

1 schematically shows an internal combustion engine of a motor vehicle with a hydraulic valve control device according to an advantageous embodiment; The graph of the signal evaluation of the hydraulic sensor of the valve control device concerning FIG.

  FIG. 1 schematically shows an internal combustion engine 1 with two cylinder banks 2 having, for example, a large number of cylinders 3 in a greatly simplified manner and controls and monitors the switching states of the valves of the cylinders 3 in each cylinder bank 2. An embodiment of a hydraulic valve control device 10 for performing the above will be described.

  At that time, each cylinder bank 2 of the internal combustion engine 1 includes a cylinder block and a cylinder head. In this case, the cylinder head is provided with at least one intake valve 4 and at least one exhaust valve (not shown) for each cylinder 3. At that time, the intake valve 4 and the exhaust valve of the cylinder bank are operated by an intake camshaft (not shown) and an exhaust camshaft (not shown).

  For example, a switchable cup tappet (not shown) is arranged between the intake side camshaft and the intake valve 4 in order to perform at least variable valve control of the intake valve 4. This cup tappet can be switched or controlled by a switching valve of the hydraulic valve control device 10, for example, an electrohydraulic switching valve. With the switchable cup tappet, the lift of the intake valve 4 is variable or switchable.

  Therefore, for example, a different cam is attached to the intake side camshaft. In this case, the first cam generates a first lift of the intake valve 4 attached thereto, for example, a maximum lift. The second cam produces a second lift of the intake valve 4, for example, a lift shorter than the maximum lift. Instead of two cams, one cam with two different cam profiles can be provided. In this case, the first cam profile produces a first lift of the intake valve 4, for example a maximum lift, and the second cam profile produces a second lift of the intake valve 4, for example a lift shorter than the maximum lift.

  Such a variable valve control as used in the embodiment of FIG. 1 is known as the Porsche VarioCam-Plus-System (registered trademark VarioCam-Plus-System). At that time, a switchable cup tappet is provided between the intake camshaft and the intake valve. The cup tappet is controlled by a switching valve, such as an electrohydraulic switching valve. In this case, each cup tappet consists of two tappets that fit together and can be locked by pins. In this case, alternatively, the first cam or the large cam of the intake camshaft acts on the outer tappet, or the second cam or the small cam of the intake camshaft acts on the inner tappet. Such valve control is described, for example, in German Patent Application Publication No. 199595765A1 by Porsche.

  In order to produce different valve lifts for the intake valves 4, the hydraulic valve control device 10 connects the cup tappets of the cylinder banks 2 via a common hydraulic line 6. Each of the hydraulic lines 6 of both cylinder banks 2 in FIG. 1 further includes a switching valve 5, for example, an electrohydraulic switching valve, for controlling the hydraulic pressure in the hydraulic line 6. The switchable cup tappet can be switched back and forth between, for example, an empty lift as a switching state and a valve lift as another switching state by the hydraulic pressure P in the hydraulic line 6. At that time, both hydraulic pipelines 6 of the hydraulic valve control device 10 are connected to an oil sump of the vehicle via, for example, one oil pump.

  When the switching valve 5 is closed in the first switching state Z1 by the control device 8 of the hydraulic valve control device 10, the pressure P in the hydraulic line 6 is low and the tappets of the cup tappet are not locked to each other. In this case, the intake valve 4 is not opened by the intake camshaft, and an empty lift is performed.

  When the switching valve 5 is opened in the second switching state Z2 by the control device 8, for example, the engine control device, the hydraulic pressure P in the hydraulic line 6 rises, and both tappets of each cup tappet are locked to each other by pins, Thereby, the intake valve 4 can be operated by one of the two cams to produce the first or second valve lift.

Conventionally, the O ₂ sensor signal has been used to monitor the variable valve control of the cylinder on the intake side of the internal combustion engine. However, this solution is not appropriate for an internal combustion engine in which the exhaust gases of two or more cylinder banks are guided in one exhaust gas line.

  Therefore, in the present invention, in the hydraulic valve control device 10, a hydraulic sensor 7 for detecting the hydraulic pressure P is provided in each hydraulic line 6 of the cylinder bank 2 in order to monitor variable valve control. . Information of the hydraulic sensor 7 is supplied to the control device 8, and the control device 8 determines whether or not a failure exists based on a set hydraulic pressure threshold value and a time Δt that is arbitrarily set. When the control device 8 confirms that a failure exists based on the hydraulic pressure P measured by the hydraulic sensor 7, the control device stores, for example, an appropriate failure message in the attached storage device 9, for example, a non-volatile memory. At that time, the storage device 9 may be a part of the control device 8 or may be connected to this control device.

  An embodiment for evaluating information of the hydraulic sensor 7 by the control device 8 of the hydraulic valve control device 10 is shown in FIG.

  In this case, in the graph shown in FIG. 2, the change of the hydraulic pressure P is shown depending on the time t and the switching state Zi of the switching valve in each hydraulic pipe. At that time, at least the variable valve control on the intake side is monitored as described above with reference to FIG. However, the present invention is not limited to the variable valve control described above with reference to FIG. All other variable valve controls with a switchable cup tappet can be performed, in which case the cup tappet is switched back and forth between multiple lift states by the hydraulic pressure of one cylinder bank hydraulic line, Controlled and monitored by a hydraulic valve control device.

  A target switching state Zi of a valve of each cylinder bank of the internal combustion engine, for example, an intake valve, is set and stored in the control device or a storage device connected to the control device.

  In the first switching state Z1 in which the switching valve is closed, no hydraulic pressure is generated or low hydraulic pressure is generated in each hydraulic line of the cylinder bank. In the first switching state Z1, since the tappet portions of the cup tappet are not locked or not locked to each other, the intake side camshaft does not open the intake valve of either of the two cams. Therefore, an empty lift is performed in the first switching state Z1.

  In the second switching state Z2, the switching valve is opened, and a higher hydraulic pressure or higher hydraulic pressure is generated in the hydraulic line than when the valve is closed. In this second switching state Z2, the tappet portions of the cup tappet are locked together so that the cup tappet can be operated by the first cam or the second cam to produce the first valve lift or the second valve lift of the intake valve. The

  In order to monitor variable valve control by the hydraulic valve control device, a predetermined first or intermediate hydraulic pressure threshold A is provided. At this time, the first hydraulic pressure threshold is a threshold at which the cup tappet of each cylinder bank changes the lift state. At the first hydraulic pressure threshold A, the cup tappet switches between the empty lift and the first or second valve lift.

In order to monitor the variable valve control, another predetermined second threshold, for example a lower threshold A _unten, is provided. This lower threshold provides a lower diagnostic threshold. Furthermore, a predetermined third threshold value, for example, an upper threshold value _Aeven can be provided. This upper threshold provides, for example, an upper diagnostic threshold.

When the control device changes the switching state by switching the switching valve from the first switching state Z1 that is closed to the second switching state Z2 that is opened, the hydraulic pressure P in the hydraulic line rises and is usually predetermined. above the hydraulic threshold _{a oben} the predetermined upper time Δt _1.

However, the oil pressure sensor indicates that the detected oil pressure P is less than or equal to the oil pressure P _{obj of the} predetermined oil pressure threshold A _oveen without the oil pressure P in the oil pressure line reaching or exceeding the upper oil pressure threshold A _aven . If it is detected or if the oil pressure P does not reach or exceed a predetermined oil pressure threshold _Aoven within a predetermined time Δt ₁ , the presence of a fault is determined by the control device. In this case, the control device stores the fault message in a storage device, for example a non-volatile memory.

A second switching state Z2 the control device opens the switching valve, changing the first switching state Z1 closing the switching valve, pressure P is typically below the threshold A _Unten lower the predetermined time Δt within ₂ Decrease or fall below the lower threshold A _unten . However, the hydraulic pressure P in the hydraulic line does not exceed the lower threshold value A _unten and does not exceed it, or does not decrease below the lower threshold value A _unten within the predetermined time Δt ₂ , or the lower threshold value is not increased. If the excess is detected by a hydraulic sensor in the hydraulic line, the controller determines that a fault exists and stores a fault message in the storage device.

When the control device does not change the switching state Z1, for example, when the switching state Z1 in which the switching valve is closed occurs, the oil pressure P in the hydraulic line may change so as to exceed the upper threshold A _obj in the switching state Z1. Once confirmed by the hydraulic sensor, the controller determines the presence of a fault and stores the fault message in the storage device.

When a switching state Z2 occurs in which the switching valve opens, when the hydraulic pressure sensor detects that the hydraulic pressure falls below or falls below the lower threshold A _unten , Similarly, it is determined that a fault exists and the fault message is stored in the storage device.

  By measuring and evaluating the hydraulic pressure in each hydraulic pipe line, it is possible to reliably determine whether the switching of the internal combustion engine having the variable valve operating mechanism is correctly performed or not is normal.

  Based on the occurrence of a fault and reading of a corresponding fault message in the storage device, for example, an engine indicator lamp can be lit as a warning for the vehicle driver. Similarly, for example, on the basis of the respective failure messages stored in the storage device, the malfunctioning cylinder bank is disabled by the engine control device or the number of revolutions of the internal combustion engine is limited to perform emergency operation. be able to. This is just one example of a strategy that can be taken based on the failure identified by the hydraulic sensor. The present invention is not limited to this measure.

1 an internal combustion engine 4 valve 5 switched valve 6 hydraulic line 7 hydraulic pressure sensor 8 control unit 10 the valve control device A hydraulic threshold _{A oben,} A unten pressure threshold P hydraulic Z1, Z2 switching state

Claims (12)

A hydraulic valve control device (10) for controlling and monitoring a switching state (Z1, Z2) of a valve (4) of an internal combustion engine (1) of an automobile, the switching state of the valve (4) each time The valve (4) is formed such that the valve control device (10) should control the internal combustion engine (1) so that it can be adjusted by applying a predetermined oil pressure to the valve (4). A hydraulic line (6) for connecting the valves (4) to each other for switching the hydraulic pressure in the hydraulic line (6) between different hydraulic pressures assigned to the switching state of the valve (4); A switching valve (5) is provided in the hydraulic line (6), and a hydraulic pressure sensor (7) is provided in the hydraulic line (6) to measure the hydraulic pressure (P) in the hydraulic line (6). The valve control device is A control device (8) for controlling the switching valve (5) is provided so that the valve (4) has a predetermined switching state (Z1, Z2), and the control device (8) includes the hydraulic sensor (7). hydraulic (P) measured by comparing at least one of the first hydraulic threshold (a) and at least one second oil pressure threshold value _{(a oben, a} unten) and, based on said first hydraulic threshold (a) Then , it is determined whether or not the switching state of the valve (4) to the predetermined switching state (Z1, Z2) has been changed, and based on the second hydraulic pressure threshold (A _obj , A _unten ). A hydraulic valve control device in which it is determined whether or not the change of the switching state has been correctly performed . The hydraulic (P) is an oil pressure threshold _{(A oben, A} unten) when not in and exceed not reach within not reached and if not exceeded or the predetermined time (Delta] t), the control device (8) has failed The hydraulic valve control device according to claim 1, wherein:   The first switching state (Z1) of the valve (4) is an empty lift, and the second switching state (Z2) of the valve (4) is a valve lift. Hydraulic valve control device. _Whether the second hydraulic pressure threshold is the upper hydraulic pressure threshold (A) for the second switching state (Z2), and the measured hydraulic pressure (P) does not reach and exceed the upper hydraulic pressure threshold 4. The hydraulic valve control device according to claim 3, wherein the control device determines a failure when the time does not reach and does not exceed a predetermined time (Δt). The second hydraulic pressure threshold value (A _unten ) is a lower hydraulic pressure threshold value for the first switching state (Z1), and the measured hydraulic pressure (P) does not reach and exceeds the lower hydraulic pressure threshold value. The hydraulic valve control device according to claim 3 or 4, characterized in that the control device (8) determines a failure when it does not or does not reach and exceed a predetermined time (Δt).   Each said valve (4) is provided with a switchable cup tappet for switching said valve (4) between different switching states (Z1, Z2), and this cup tappet is connected to said hydraulic line (6) And is formed of at least two parts and is lockable so that the cup tappet causes the second switching state (Z2) of the valve (4) in the locked state and the valve (4) in the unlocked state. The hydraulic valve control device according to any one of claims 3 to 5, wherein the first switching state (Z1) is generated.   The control device (8) closes the switching valve (5) to unlock the cup tappet and opens the switching valve to lock the cup tappet. Hydraulic valve control device.   8. The hydraulic valve control device according to claim 1, wherein a failure message is stored in the storage device (9) after the control device (8) has determined a failure. A method for controlling and monitoring the switching state (Z1, Z2) of a valve (4) for an internal combustion engine (1) of a motor vehicle,
This method comprises the step of preparing an internal combustion engine (1) equipped with a valve (4), and the switching state (Z1, Z2) of the valve (4) for each time applies a predetermined oil pressure to the valve (4). The valve (4) is formed so that it can be adjusted by acting on
The method further comprises the step of providing a hydraulic line (6) connecting the valves (4) to be controlled of the internal combustion engine (1) to each other, the switching state (Z1, Z2 of the valves (4)) In order to switch the hydraulic pressure (P) in the hydraulic line (6) between the different hydraulic pressures assigned to (), a switching valve (5) is provided in the hydraulic line (6), In order to measure the hydraulic pressure of the hydraulic line (6), a hydraulic pressure sensor (7) is provided in the hydraulic line (6),
The method further comprises providing a control device (8) for controlling the switching valve (5) such that the valve (4) has a predetermined switching state (Z1, Z2);
The method further comprises the step of producing a predetermined switching state (Z1, Z2) of the valve (4) by the control device (8),
The method further measures the hydraulic pressure (P) in the hydraulic line (6) by the hydraulic sensor (7), and the measured hydraulic pressure (P) is measured by at least one first hydraulic threshold (A) and at least one one. the second oil pressure threshold value _{(a oben, a} unten) and comprises the step of comparing, on the basis of the first hydraulic threshold (a), the switching state (Z1 of the valve to the predetermined said switch condition (4) , Z2) is determined, and it is determined whether the change of the switching state is correctly performed based on the second hydraulic pressure threshold (A _obj , A _unten ). It said measured pressure (P) is pre-Symbol second oil pressure threshold value _{(A oben, A} unten) when not reach without and exceeded, and wherein the presence of a fault is determined by the control device (8) The method according to claim 9. Said measured pressure (P) is a predetermined time (Delta] t) the second oil pressure threshold before Symbol in _{(A oben, A} unten) when not reach without and exceeded, the presence of a fault is the control device (8 The method according to claim 9 or 10, characterized in that it is determined by:   12. Method according to any one of claims 9 to 11, characterized in that the control device (8) stores the fault in a storage device (9).

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