Patent Application
20190301378
The invention relates to a method for controlling an emergency device comprising at least one quick-closing valve for a combustion machine. The invention also relates to a valve control unit, and to a control device comprising an engine control unit and a valve control unit, and to a combustion machine, as per the preamble of claim 10 and of claim 11. The combustion machine has at least one quick-closing valve in an air path. In particular, the combustion machine is a combustion machine for use in explosive environments. The combustion machine is in particular a gas engine or a diesel engine.
This type of combustion machine is used for example on oil or gas platforms and as a fracking engine or as a combustion machine in which a reliable shut-down of the engine is necessary; this relates for example to a combustion machine which is utilized in the context of a rail vehicle drive—in all of these types of combustion machines, the use of quick-closing valves is advantageous. In the case of an engine which is operated in an explosive environment, such as for example a fracking engine, this may, in the event of damage, draw in combustible gas. This may give rise to an undesired increase in engine speed and thus cause a mechanical failure, posing a hazard to the surroundings.
It is known that, in the case of the abovementioned usage situation, an emergency device comprising at least one quick-closing valve must be provided which locks the air path in the event of an undesired increase in speed. Said quick-closing valve is typically arranged downstream of the compressor and of the EGR opening-in point, that is to say in the manifold pipe. Embodiments of such quick-closing valves are described for example in DE 43 10 901 A1.
Such quick-closing valves are, in systems known in the prior art, activated by an engine control unit ECU. It is desirable to minimize the risk of malfunctions in the case of such safety components.
It is this that is addressed by the invention, the object of which is to specify a method and devices by means of which the risk of malfunctions can be minimized.
Said object, relating to the method, is achieved by means of a method as claimed in claim 1. In particular, a method according to the invention for controlling an emergency device of a combustion machine, in particular of an engine, wherein the emergency device comprises at least one quick-closing valve, has the following the steps:
The invention is based on the realization that, through the use of a second speed sensor and the additional plausibility check of the second speed detected by said second speed sensor by means of a comparison with a first speed detected by a first speed sensor of an engine control unit, the safety of the system can be improved, because two independent values for the speed are present and, in addition to the speed-dependent activation of the emergency device, a further monitoring function is ensured by means of the required plausibility checking. Furthermore, a high level of process reliability is realized, because manipulations are prevented by means of the two independent measurement values for the speed.
The invention furthermore comprises the realization that such improved process reliability can, through the utilization of an additional valve control unit for the emergency device, be achieved functionally separately from the engine control unit. The object relating to the device is achieved by the invention by means of a valve control unit which is designed to carry out a method according to the invention, wherein the valve control unit is connectable to a second speed sensor. The object is furthermore achieved by means of the control device comprising an engine control unit and a valve control unit of said type, which is functionally separate from the engine control unit.
For the achievement of the object with regard to the device, the concept of the invention also leads to a combustion machine having an emergency device comprising at least one quick-closing valve in an air path of the combustion machine, wherein the combustion machine has a valve control unit designed to carry out a method according to the invention, and has a second speed sensor independent of a first speed sensor. The concept of the invention furthermore leads to a combustion machine having an emergency device, in particular an emergency device comprising at least one quick-closing valve in an air path of the combustion machine, wherein the combustion machine has a control device comprising a valve control unit according to the invention and an engine control unit and also a second speed sensor independent of a first speed sensor of the engine control unit.
Advantageous refinements of the invention emerge from the subclaims and specify, in detail, advantageous possibilities for realizing the above-discussed concept in the context of the stated object and with regard to further advantages.
In particular, it is advantageous if the threshold value for the overspeed is automatically read in upon an initial commencement of operation, and said threshold value is provided by the engine control unit. This permits an automatic transfer of system-relevant parameters without the need for manual input or setting.
The activation process of the emergency device preferably comprises the following steps:
In particular, it is advantageous if the second speed sensor comprises a measuring wheel or toothed wheel with a number of teeth z, by means of which the speed is detected. In the context of a preferred refinement, in addition to the threshold value for the overspeed, a number n of quick-closing valves and a number of teeth z of a measuring wheel of the second speed sensor are read in, and the read-in values are subsequently validated, in particular during the course of an initial commencement of operation. The reading-in and validation of these values, that is to say the check as regards whether a correct activation—that is to say an activation which ensures reliable operation—of the emergency device takes place on the basis of these values, further increases the process reliability, because it is ensured in this way that the activation process is initiated in the event, and only in the event, of a departure from the corresponding boundary conditions that are defined for reliable operation.
If the validation fails, a corresponding fault signal is output to the engine control unit ECU, and a commencement of operation of the valve control unit is terminated. The validation may be performed both as a measure of an initial commencement of operation and during the course of re-commencements of operation.
In particular, it is advantageous if the validation of the read-in values comprises the execution of an overspeed test, in the case of which—preferably by corresponding signal output or by corresponding operation of the combustion machine—a speed corresponding to a stored threshold value for the overspeed is simulated or generated. Preferably, a check is subsequently performed as regards whether the activation of the emergency device has correspondingly taken place. The correct activation of the emergency device in the event of damage is thus assured. It is thus established in particular that the activation takes place only if the threshold value is reached or overshot. It is advantageously furthermore the case that no activation of the emergency device takes place during operation below the threshold value.
In one advantageous refinement of the method, in the event of a failure of the plausibility check, in particular if the difference is greater than or equal to the threshold value for the difference, an alarm signal is output to the engine control unit (ECU). This step increases the reliability of the method and of the emergency device further, because faults can be logged, and can be initiated by means of corresponding measures.
Preferably, in the event of an emergency stop signal, in particular an emergency stop signal triggered by a user or by some other monitoring device of the combustion machine, being read in, an activation of the emergency device is performed, and an outputting as an emergency signal to the engine control unit (ECU) is performed. Thus, in the event of an emergency stop, it is ensured that the at least one quick-closing valve of the emergency device closes, and operationally critical states are avoided, even if the threshold value for the overspeed has not been overshot prior to this.
In particular, a refinement is advantageous which has the additional step whereby, upon the receipt of the emergency signal and/or of the alarm signal, an alarm is output, and/or an engine stoppage, in particular an injection stoppage, is triggered, by the engine control unit. In this way, it is ensured that, after activation of the emergency device, in particular after the closing of the at least one quick-closing valve, this is firstly logged and, secondly, it is also the case that the combustion machine is stopped in order to avoid damage.
In one advantageous refinement of the valve control unit and of the control device, the valve control unit is connectable and/or connected by means of a bus, in particular a CAN bus, to the engine control unit. Furthermore, the valve control unit is preferably designed to additionally output an availability signal, that is to say to transmit information to the effect that the emergency device is available and intact, in the event of successful validation and plausibility checking.
Embodiments of the invention will now be described below on the basis of the drawing. This is not necessarily intended to illustrate the embodiments to scale; rather, where expedient for explanatory purposes, the drawing is of schematic and/or slightly distorted form. With regard to additions to the teaching that emerges directly from the drawing, reference is made to the relevant prior art. It must be taken into consideration here that numerous modifications and changes may be made with regard to the form and the detail of an embodiment without departing from the general concept of the invention. The features of the invention disclosed in the description, in the drawing and in the claims may be essential to the refinement of the invention both individually and in any desired combination. Furthermore, the scope of the invention encompasses all combinations of at least two of the features disclosed in the description, in the drawing and/or in the claims. The general concept of the invention is not restricted to the exact form or the detail of the preferred embodiments shown and described below, or restricted to a subject matter that would be restricted in relation to the subject matter claimed in the claims. Where dimension ranges are specified, it is also the intention for values lying within the stated limits to be disclosed, and to be capable of being used and claimed as desired, as limit values. For the sake of simplicity, below, the same reference designations are used for identical or similar parts or parts with identical or similar function.
Further advantages, features and details of the invention will emerge from the following description of the preferred embodiments and on the basis of the drawing; in which:
In particular, the valve control unit SFB is designed to validate the values transmitted by the engine control unit ECU, wherein the validation of the read-in values comprises the execution of an overspeed test, in the case of which, by corresponding signal output or by corresponding operation of the combustion machine, a speed higher than the stored threshold value for the overspeed is simulated or generated, and subsequently, a check is performed as regards whether the activation of the emergency device has correspondingly taken place. Various scenarios of this overspeed test will be discussed in more detail with reference to
If the validation fails, the valve control unit SFB is designed to output a corresponding fault notification to the engine control unit ECU. The valve control unit SFB is likewise designed to output a corresponding fault notification or alarm signal to the engine control unit ECU in the event of a failure of the plausibility check, in particular if the difference between second speed nMOT2 and first speed nMOT1 is greater than or equal to the threshold value for the difference. Furthermore, the valve control unit SFB is designed such that, in the event a successful validation and plausibility checking, it additionally outputs an availability signal, that is to say transmits information to the effect that the emergency device is available and intact.
Upon receipt of an emergency stop signal, the valve control unit SFB is designed to activate your the emergency device with the two quick-closing valves QCV-A and QCV-B and output an emergency signal to the engine control unit ECU. The engine control unit is designed to trigger an engine stoppage, in particular an injection stoppage of the injectors of the combustion machine, both in response to an emergency signal of the valve control unit SFB and in response to an emergency stop signal a user or of some other monitoring device.
If the validation, in this case the initial commencement of operation, is successful, a plausibility check is performed. This comprises the detection of a second speed nMOT2 of the combustion machine by means of a second speed sensor 120 and the reading-in of a first speed nMOT1 detected by means of a first speed sensor 110 of the engine control unit ECU, and a calculation of a difference dn between the second speed nMOT2 and the first speed nMOT1. In the next step, the difference dn is then compared with a stored threshold value GW for the difference; in the present exemplary embodiment, it is checked whether the difference dn is smaller than the threshold value GW, and if the difference dn is smaller than the threshold value GW for the difference, a plausible signal is output. After receipt of the plausible signal, the method is continued correspondingly with the steps described below with reference to
The further method is illustrated in
In the second case, specifically the emergency stop control, an emergency stop signal is read in. In an optional further step, it is firstly checked whether an emergency stop is active, and if so, as described above, the emergency device is activated and the at least one quick-closing valve QCV is closed. If the emergency stop is not active, a “no” is read in, and the query as regards whether the emergency stop is active is performed once again. The method then continues correspondingly to that described above with reference to the overspeed control.
In scenario A, a signal is applied which indicates that the threshold value nMOT(MAX) has been reached or overshot (the overshooting is thus simulated). As soon as the signal is read in, the relay that switches the two quick-closing valves is activated, and an activation sequence with two activation intervals of x seconds is run through, between which there is an inactive phase of y seconds. In the situation shown, both quick-closing valves QCV-A and QCV-B are triggered within the first activation interval. At the end of the activation sequences, a signal is output to the effect that the read-in values are valid. Scenario B differs from A in that, here, the first quick-closing valve QCV-A closes only after the second activation interval. In this case, it is optionally possible, after the first activation interval, for a fault notification to be output to the effect that the values are not valid. At the end of the activation sequences, it is then the case, as in situation A, that the signal is output to the effect that the read-in values are valid. The scenarios C and D correspond, as regards the behavior of the quick-closing valves, to the scenarios A and B. They differ with regard to the triggering factor. Here, in the scenarios C and D, the speed is actually increased, and an attainment of the threshold value nMOT(MAX) is detected, whereupon the relay is activated. It is also the case in scenarios C and D that the values are evaluated as being valid after the completion of the activation sequence. In situation E, the quick-closing valve QCV-B closes without the relay having been activated. In this case, a fault notification is output.
The combustion machine 200 furthermore has a valve control unit SFB as described above, and an engine control unit ECU connected to the valve control unit. The valve control unit SFB is connected to a second speed sensor (not illustrated here), and the engine control unit ECU is connected to a first speed sensor (likewise not illustrated here).
| Number | Date | Country | Kind |
|---|---|---|---|
| 102016215125.8 | Aug 2016 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/000841 | 7/13/2017 | WO | 00 |
