DK177921B1

DK177921B1 - Control of operational events for an internal combustion engine

Info

Publication number: DK177921B1
Application number: DK201370728A
Authority: DK
Inventors: Erik Rosenlund; Niels Kristian Jensen; Christian Jon Veng Jensen; Morten Skov Rasmussen; Kristian Blidegn
Original assignee: Man Diesel & Turbo Deutschland
Priority date: 2013-11-28
Filing date: 2013-11-28
Publication date: 2015-01-05
Also published as: JP2016145578A; CN104675550B; JP6125483B2; JP2015121216A; JP6199427B2; KR101544933B1; KR20150062134A; CN104675550A

Description

The present invention relates to a method and / or system for controlling the execution of an operational event of an active member during each or some combustion cycle(s) for each cylinder of a multi-cylinder internal combustion engine in response to a control parameter varying in time during each revolution of the multi-cylinder internal combustion engine.

Exact timing and control of the execution of operational events of active members during each combustion cycle of each cylinder in a multicylinder internal combustion engine is very critical and relies on updated and exact information of the instantaneous angular position of the crankshaft which is directly linked to the piston position. The operational events to be controlled in time during each combustion cycle for instance comprise the instants of fuel injection, ignition and actuation of inlet and exhaust valves and supply of lubricant and compressed air to the cylinder.

Control methods and systems of the kind, to which the invention pertains, are well known in the art, e.g. from Japanese patent JP 5143939 B2 belonging to the applicant and disclosing a control system that captures values of a control parameter, transmits the captured values over a communication network, and compensates the captured values with a compensation factor generated by determining the transfer time in the network. The transfer time is determined by finding the difference between time of capture of the values and time of reception in a control unit.

It is however complicated to determine the time of reception in a control unit and it requires additional dedicated hardware.

The additional dedicated hardware further increases the risk of a malfunction in the system.

Thus it remains a problem to provide a simpler and more robust method and / or system for controlling operational events during each combustion cycle in each cylinder of a multi-cylinder internal combustion engine.

According to a first aspect the invention relates to a method for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine in response to a control parameter varying in time during each revolution of the multi-cylinder internal combustion engine, comprising the steps of: capturing a first instantaneous value of the control parameter at a first discrete instance during each combustion cycle by a first sensor unit, wherein said first sensor unit has an internal clock; generating a first data package comprising data indicative of said captured first instantaneous value of said control parameter and the value of said internal clock of said first sensor unit at said first discrete instance resulting in a first point in a time / parameter space; transmitting said first data package over a communication network to a first control unit wherein said first control unit has an internal clock synchronized with the internal clock of said first sensor unit; obtaining in said first control unit a first estimate of the temporal rate of change of said control parameter; wherein said method further comprises the steps of estimating in said first control unit either: the value of said control parameter at a first selected discrete instance, wherein said first selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing without being directly dependent on the time of reception of said first data package in said first control unit; or the value of the internal clock of the first control unit when the value of said control parameter reaches a predetermined target; wherein the value of said control parameter at said first selected discrete instance or the value of the internal clock of the first control unit is estimated by directly extrapolating said first point in the time / parameter space using the obtained first estimate of the temporal rate of change of said control parameter, and wherein the operational event is initiated when it is estimated that the value of said control parameter has reached or exceeded said predetermined target or the internal clock of the first control unit has reached or exceeded the estimated value.

Consequently, a method is provided whereby an operational event in the internal combustion engine may be controlled without the need of a de- terministic communication network or means for detecting time of reception in the first control unit.

The method further enables the use of non-deterministic processing units as control units, since a varying time lag between time of reception in the processing unit and time of processing has no effect on the precision of the method.

This allows the use of a single processing unit to perform a plurality of tasks e.g. the first control unit may comprise a single processing unit configured to control the operational event of all cylinders in the internal combustion engine.

The communication network may be a non deterministic communication network, i.e. a communication network where the transfer time in the network is stochastic such as an Ethernet based network.

The use of a non deterministic communication network allows standard components to be used and further lowers the installation costs as dedicated connections between all points in the network is not needed i.e. network switches may be used. The clock of the first sensor unit and the clock of the first control unit may be synchronized using the method disclosed in relation to Fig. 2 in JP 5143939 B2 or other methods, e.g. IEEE 1588

Any type of extrapolation may be used such as linear or a non linear model.

In some embodiments, the first data package is received in the first control unit in a manner whereby the time of reception is not determined.

The first control unit may have a non deterministic processing time i.e. the time lag of the processing unit between the time of reception of the first data package and the time processing of the data in the first data package may be non-deterministic, i.e. the first processing unit may comprise a queue with a varying length.

The first control unit may comprise a single processing unit. Alternatively the first control unit may comprise a plurality of processing units e.g. a de-central processing unit may be provided close to each cylinder communicatively coupled to a central processing unit, wherein the internal clock of the de-central processing units are synchronized with the internal clock of the central processing unit.

The first estimate of the temporal rate of change may be obtained by the first sensor unit and send to the first control unit in the first data package. Alternatively / additionally the first estimate of the temporal rate of change may be obtained by the first control unit e.g. by processing two or more points in the time / parameter space.

The first data package may be generated by the first sensor unit.

In a preferred embodiment, the instantaneous value of the control parameter comprises the instantaneous position of an engine crankshaft connected with piston members of each of said cylinders.

Consequently, the execution of the operational event may be initiated with great precision at a particular advantageous point in the combustion cycle.

The predetermined target may be a predetermined position of the engine crankshaft. There typically exists a control temporal lag between the instance the first control unit initiates the operational event, and the actual instance where the active element performs the operational event. Thus, the predetermined target may be selected so as to take this control temporal lag into consideration. As the control temporal lag typically is at least partly uncorrelated with the speed of the engine, the predetermined target may be selected dependent on the engine speed e.g. at high engine speeds the predetermined target may be slightly smaller compared to the predetermined target at low engine speeds (the control temporal lag result in a further rotation of the crankshaft, at high engine speed compared to at low engine speeds).

In some embodiments, the method further comprises the steps of capturing a second instantaneous value of the control parameter at a second discrete instance during each combustion cycle by said first sensor unit, said second discrete instance being after said first discrete instance; generating a second data package comprising data indicative of said captured second instantaneous value of said control parameter and the value of said internal clock of said first sensor unit at said second discrete instance resulting in a second point in the time / parameter space; transmitting said second data package over the communication network to said first control unit; wherein, if the second data package is processed for a particular combustion cycle after it is estimated that the value of said control parameter has reached said predetermined target or the internal clock of said first control unit has reached said estimated value, the operational event is controlled without the use of the data in the second data package, and if the second data package is processed for said particular combustion cycle before it is estimated that the value of said control parameter have reached said predetermined target or the internal clock of said first control unit has reached said estimated value, the operational event is controlled with the use of the data in the second data package.

Consequently, said operational event may be controlled even if said second data package is lost or reaches said first control unit late.

This allows the operational event to be controlled with both a high precision and a high reliability i.e. the first data package provides the high reliability and the second data package provides the high precision.

Furthermore, the operational event may be controlled even if the first data package or the second data package is damaged.

The operational event may be controlled with the use of the data in the second data package, by processing the data in the second data package in a corresponding manner as the data in the first data package is processed, i.e. by extrapolating the second point in the time / parameter space. The second point in the time / parameter space may be extrapolated using the first estimate of the temporal rate of change or a second estimate of the temporal rate of change. The second estimate of the temporal rate of change may be obtained using the following equation:

where pt2 is the second estimate of the temporal rate of change, Ap is the difference between the value of the control parameter at the first dis- crete instance and the second discrete instance, and At is the time between the first discrete instance and the second discrete instance.

In some embodiments, said second instantaneous value of the control parameter is captured in a manner whereby less than 99.9%, 99.5%, 99% or 95% of the time the first processing unit have time to process the second data package before the execution of the operational event is initiated.

This may be done be capturing the second instantaneous value very close to the predetermined target, i.e. the second instantaneous value may be predetermine and the second discrete instance may be varying between combustion cycles.

In some embodiments, said first instantaneous value of the control parameter is captured in a manner whereby at least 99.9%, 99.5%, or 99% of the time the first processing unit have time to process the first data package before the control parameter reaches the predetermined target.

This may be done be capturing the first instantaneous value with a large distance to the predetermined target i.e. the first instantaneous value may be predetermine and the first discrete instance may be varying between combustion cycles.

In some embodiments, the method further comprises the step of capturing a verification value of the control parameter at a particular instance during a combustion cycle by said first sensor unit, after said operation event has been initiated in said combustion cycle; generating a first verification data package comprising said verification value and the value of said internal clock of said first sensor unit at said particular instance resulting in a verification point in the time / parameter space; transmitting said verification data package over said communication network to said first control unit; estimating in said first control unit a verification estimate of the discrete instance where the value of said control parameter reached said predetermined target by interpolating between said first point and / or second point and the verification point in the time / parameter space; determining a discrepancy between said verification estimate and the estimate used for initiating the operational event, wherein the determined discrepancy is used to generate a correction factor for use in controlling said operation event in subsequent combustion cycles.

Consequently, as errors typically have a repeatable nature the precision of the method may be improved over time. This further allows the system to adapt to new sources of errors making the system more robust. This is especially important when the method is used in an internal combustion engine of a vessel, as the engine may need to run continuously for days and weeks at a time.

In some embodiments, the method further comprises the steps of measuring during a combustion cycle the discrete instance where said active element performs said operational event by an active element sensor unit positioned at said active element, wherein said active element sensor unit has an internal clock synchronized with the internal clock of said first control unit; generating a second verification data package comprising the measured discrete instance; transmitting said second verification data package to said first control unit over a communication network, wherein said first control unit generates a correction factor for use in subsequent combustion cycles by processing said second verification data package.

Consequently, the precision of the method may be further improved. This further allows the method to be at least partly self-calibrating, whereby the installation costs may be reduced.

In some embodiments, said first control unit generates said correction factor by estimating a control temporal lag from the initiation of the operational event by the first control unit to the operational event is actually performed by said active element.

The correction factor may be used to modify the predetermined target of the control parameter for subsequent combustion cycles e.g. if the control temporal lag increases the predetermined target is lowered, and if the control temporal lag decreases the predetermined target in increased.

In some embodiments, the predetermined target is selected dependent on both the speed of the engine and an estimate of the control temporal lag.

In some embodiments, a redundant second sensor unit additionally captures values of said control parameter and transmits said values to a control unit.

The redundant second sensor unit may communicate with a redundant second control unit through a communication network, wherein the redundant second sensor unit and the redundant second control unit performs the corresponding actions as the first sensor unit and the first control unit, whereby full redundancy is provided.

Consequently, a more robust method is provided as the operational events may be controlled even if one of the control units and /or sensor units malfunctions.

In some embodiments, the number of values of the control parameter captured for each combustion cycle is selected dependent on the length of the combustion cycles.

The number of values of the control parameter captured for each combustion cycle may be higher when the combustions cycles are long compared to when the combustion cycles are short.

Consequently, operational events may be controlled even at high motor speeds without overloading the processing capabilities of the first control unit.

According to a second aspect the invention relates to a system for controlling the execution of an operational event of an active member during each or some combustion cycle(s) for each cylinder of a multi-cylinder internal combustion engine in response to a control parameter varying in time during each revolution of the multi-cylinder internal combustion engine, said system comprising: a first sensor unit having an internal clock, wherein said first sensor unit is configured to capture a first instantaneous value of the control parame ter at a first discrete instance during each combustion cycle and generate a first data package comprising said captured first instantaneous value of said control parameter and the value of said internal clock of said first sensor unit at said first discrete instance resulting in a first point in a time / parameter space; and a first control unit having an internal clock configured to be synchronized with the internal clock of said first sensor unit, wherein said first control unit is connected to said first sensor unit through a communication network and is configured to obtain a first estimate of the temporal rate of change of said discrete parameter, and wherein said first sensor unit is configured to transmit said first data package through said communication network to said first control unit wherein said first control unit further is configured to in response to receiving said first data package estimate either: the value of said control parameter at a first selected discrete instance, wherein said first selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing without being directly dependent on the time of reception of said first data package in said first control unit; or the value of the internal clock of the first control unit when the value of said control parameter reaches a predetermined target; wherein the value of said control parameter at said first selected discrete instance or the value of the internal clock of the first control unit is estimated by directly extrapolating said first point in the time / parameter space using the obtained first estimate of the temporal rate of change of said control parameter, and wherein the first control unit is configured to initiate the operational event when the first control unit estimates that the value of said control parameter has reached or exceeded said predetermined target or the internal clock of the first control unit has reached or exceeded the estimated value.

Consequently, a simpler system is provided that can control an operational event in the internal combustion engine without the need of a deterministic communication network or means for detecting time of reception in the first control unit.

In some embodiments, the first sensor unit further is configured to capture a second instantaneous value of the control parameter at a second discrete instance during each combustion cycle said second discrete instance being after said first discrete instance, generate a second data package comprising said captured second instantaneous value of said control parameter and the value of said internal clock of said first sensor unit at said second discrete instance resulting in a second point in the time / parameter space, and transmit said second data package over a communication network to said first control unit; wherein said first control unit is configured to if the second data package is processed for a particular combustion cycle after it is estimated that the value of said control parameter has reached said predetermined target or the internal clock of said first control unit has reached said estimated value, control the execution of the operational event without the use of the data in the second data package, and if the second data package is processed for said particular combustion cycle before it is estimated that the value of said control parameter have reached said predetermined target or the internal clock of said first control unit has reached said estimated value, control the execution of the operational event with the use of the data in the second data package.

In some embodiments, said first sensor unit further is configured to capture a verification value of the control parameter at a particular instance during a combustion cycle, after said operation event has been initiated in said combustion cycle, generate a first verification data package comprising said verification value and the value of said internal clock of said first sensor unit at said particular instance resulting in a verification point in the time / parameter space, and transmit said first verification data package over said communication network to said first control unit; wherein said first control unit is configured to estimate a verification estimate of the discrete instance where the value of said control parameter reached said predetermined target by interpolating between said first point and / or second point and the verification point in the time / parameter space; and further determine a discrepancy between said verification estimate and the estimate used for initiating the operational event, wherein the determined discrepancy is used to generate a correction factor for use in controlling said operation event in subsequent combustion cycles.

In some embodiments, said system further comprises an active element sensor having an internal clock configured to be synchronized with the internal clock of said first control unit, said active element sensor is connected to said first control unit through said communication network wherein said active element sensor is configured to measure the discrete instance where said active element performs said operational event during a combustion cycle, generate a second verification data package comprising the measured discrete instance, and transmit said second verification data package to said first control unit, wherein said first control unit further is configured to generate a correction factor by processing said second verification data package for use in controlling said operation event in subsequent combustion cycles.

In some embodiments, said first control unit is configured to generate said correction factor by estimating the time lag from the initiation of the operational event by the first control unit to the operational event is actually performed by said active element.

The different aspects of the present invention can be implemented in different ways including as a method for controlling operational events and as a system for controlling operational events as described above and in the following, each yielding one or more of the benefits and advantages described in connection with at least one of the aspects described above, and each having one or more preferred embodiments corresponding to the preferred embodiments described in connection with at least one of the aspects described above and/or disclosed in the dependant claims. Furthermore, it will be ap- predated that embodiments described in connection with one of the aspects described herein may equally be applied to the other aspects.

The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

Fig. 1 shows a flow chart of a method and for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine, according to an embodiment of the present invention.

Fig. 2 illustrates how a control unit may use data from the first data package to estimate the value of the internal clock of the first control unit when the value of the control parameter reaches a predetermined target, according to an embodiment of the present invention.

Fig. 3 illustrates how a control unit may estimate the value of the control parameter at a first selected discrete instance, wherein the first selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing without being directly dependent on the time of reception of the first data package in the first control unit, according to an embodiment of the present invention.

Figs. 4 and 5 illustrate how a control unit may utilize data from two data packages according to embodiments of the present invention.

Fig. 6 shows a flowchart illustrating how the first control unit may use data from a plurality of data packages to control the execution of an operational event of an active member, according to an embodiment of the present invention.

Fig. 7 shows how data from a verification data package may be used to improve the precision, according to an embodiment of the present invention.

Figs 8 to 10 show schematic drawings of internal combustion engines comprising control systems according to embodiments of the present invention.

In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

Fig. 1 shows a flow chart 100 of a method for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine, according to an embodiment of the present invention. In the first step 101 a first instantaneous value of the control parameter at a first discrete instance is captured by a first sensor unit. Next, in step 102 a first data package is generated comprising data indicative of the captured first value of the control parameter and the value of the internal clock of the first sensor unit at the first discrete instance, resulting in a first point in a time / parameter space. The first data package is then in step 103 transmitted over a communication network to a first control unit wherein the first control unit has an internal clock synchronized with the internal clock of the first sensor unit. The first control unit then in step 104 obtains a first estimate of the temporal rate of change of the control parameter.

Next, in step 105, the first control unit estimates either: the value of the control parameter at a first selected discrete instance, wherein the first selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing without being directly dependent on the time of reception of the first data package in the first control unit(as explained in relation to Fig. 3); or the value of the internal clock of the first control unit when the value of said control parameter reaches a predetermined target (as explained in relation to Fig. 2).

Finally, in step 106 the operational event is initiated when it is estimated that the value of said control parameter has reaches said predetermined target or the internal clock of the first control unit has reaches the estimated value.

As mentioned previously, Fig. 2 illustrates how the first control unit may use data from the first data package to estimate the value of the internal clock of the first control unit, when the value of the control parameter reaches a predetermined target 204. Shown is a time / parameter space 200 compris ing a first axis 201 representing time and a second axis 202 representing values of the control parameter. The point p1 represents the first point in the time parameter space. Thus, 209 represent the captured first instantaneous value of the control parameter at the first discrete instance, and 208 represents the value of the internal clock of the first sensor unit (and the first control unit) at the first discrete instance. To estimate the value of the internal clock of the first control unit t1 where the value of the control parameter reaches the predetermined target 204, the first control unit firstly extrapolates the point p1 using the obtained first estimate of the rate of change of the control parameter, thereby generating the line 203, and secondly determine the intersection between the extrapolated line 203 and the line 204 representing the predetermined target. As the internal clock of the first control unit is synchronized with the internal clock of the first sensor unit, the first control unit may simply wait unit its internal clock reaches t1 and then initiate the operational event. Consequently, the exact transfer time of the first data package in the communication network does not influence the precision of the method. The only requirement is that the first data package must be processed by the first control unit before the internal clock of the first control unit reaches t1. This makes it possible to use a non-deterministic communication network without having to determine the time of transfer in the communication network.

As mentioned previously Fig. 3 illustrates how the first control unit may estimate the value of the control parameter at a first selected discrete instance, wherein the first selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing without being directly dependent on the time of reception of the first data package in the first control unit. In this approach the first control unit constantly keeps an estimate of the current value of the control parameter, and updates the estimate when a data package is received. Shown is a time / parameter space 300 comprising a first axis 301 representing time and a second axis 302 representing values of the control parameter. The point p1 represents the first point in the time parameter space. Thus, 309 represent the cap- tured first instantaneous value of the control parameter at the first discrete instance, and 308 represents the value of the internal clock of the first sensor unit (and the first control unit) at the first discrete instance. The line section 306 shows the estimates made by the first control unit of the value of the control parameter before the first data package is processed. At t_proc the first control unit process the first data package by extrapolating p1 using the obtained first estimate of the rate of change of the control parameter, and the estimate of the current value of the control parameter is updated by evaluating the extrapolated line in t_proc. The line section 307 shows the estimates made by the first control unit of the value of the control parameter after the first data package has been processed. When the first control unit estimates that the value of the control parameter has reaches the predetermined target 304, the operational event is initiated. The temporal difference between the first discrete instance 308 and t_proc 330 is the combination of the transfer time of the first data package in the communication network and the queue in the first control unit both of which may be stochastic.

Figs. 4 and 5 illustrate how the execution of an operational event may be controlled using data from a plurality of data packages according to embodiments of the present invention.

Fig. 4 illustrates how data from two data packages may be used to estimate the value of the internal clock of the first control unit when the value of the control parameter reaches a predetermined target 404. Shown is a time / parameter space 400 comprising a first axis 401 representing time and a second axis 402 representing values of the control parameter. The point p1 represents a first point in the time parameter space origin from data in a first data package, 409 represent a captured first instantaneous value of the control parameter at a first discrete instance, and 408 represents the value of the internal clock of the first sensor unit (and the first control unit) at the first discrete instance. To make a first estimate of the value of the internal clock of the first control unit t1 where the value of the control parameter reaches the predetermined target 404, the first control unit firstly extrapolates the point p1 using an obtained first estimate of the rate of change of the control parameter, thereby generating the line 403, and secondly determine the intersection between the extrapolated line 403 and the line 404 representing the predetermined target. To improve the precision of the method data from a second data package is additionally used. The point p2 represents a second point in the time parameter space origin from data in the second data package, 411 represent a captured second instantaneous value of the control parameter at a second discrete instance, and 412 represents the value of the internal clock of the first sensor unit (and the first control unit) at the second discrete instance. If the extrapolated line 403 correctly represented the control parameter, the point p2 would lay on 403. However due to varies sources of errors p2 will typically be slightly offset.

To make a second estimate of the value of the internal clock of the first control unit t2 where the value of the control parameter reaches the predetermined target 404, the first control unit firstly extrapolates the point p2 using an obtained second estimate of the rate of change of the control parameter, thereby generating the line 405, and secondly determine the intersection between the extrapolated line 405 and the line 404 representing the predetermined target

As the internal clock of the first control unit is synchronized with the internal clock of the first sensor unit, the first control unit may simply wait unit its internal clock reaches t2 and then initiate the operational event.

As the second data package comprise information related the control parameter closer to the predetermined target 404, t2 will be a more precise estimate than t1.

It should be noted that information from more than two data packages may be used e.g. information from at least 3, 4 or 5 data packages.

Fig. 5 illustrates how data from two data packages may be used to estimate the value of the control parameter at a first selected discrete instance and a second selected discrete instance, wherein the first and second selected discrete instance is selected dependent on the value of the internal clock of the first control unit at the time of processing the two data packages without being directly dependent on the time of reception of the two data package in the first control unit. In this approach the first control unit constantly keeps an estimate of the current value of the control parameter, and updates the estimate when a data package is processed. Shown is a time / parameter space 500 comprising a first axis 501 representing time and a second axis 502 representing values of the control parameter. The point p1 represents a first point in the time parameter space origin from a first data package, 509 represent a captured first instantaneous value of the control parameter at a first discrete instance, and 508 represents the value of the internal clock of the first sensor unit (and the first control unit) at the first discrete instance. The line section 506 shows the estimates made by the first control unit of the value of the control parameter before the first data package is processed. At t_proc the first control unit process the first data package by extrapolating p1 using an obtained first estimate of the rate of change of the control parameter, and the estimate of the current value of the control parameter is updated by evaluating the extrapolated line in t_proc. To improve the precision data from a second data package is additionally processed by the first control unit. The point p2 represents a second point in the time parameter space origin from the second data package, 511 represent a captured second instantaneous value of the control parameter at a second discrete instance, and 512 represents the value of the internal clock of the first sensor unit (and the first control unit) at the second discrete instance. At t_proc2 the first control unit process the second data package by extrapolating p2 using an obtained second estimate of the rate of change of the control parameter, and the estimate of the current value of the control parameter is updated by evaluating the extrapolated line in t_proc2. The line section 507 shows the estimates made by the first control unit of the value of the control parameter in the period between tproc and tproc 2 and the line section 505 shows the estimates made by the first control unit of the value of the control parameter after the second data package has been processed. When the first control unit estimates that the value of the control parameter has reaches the predetermined target 504, the operational event is initiated.

Fig. 6 shows a flowchart illustrating how the first control unit may use data from a plurality of data packages to control the execution of an operational event of an active member, according to an embodiment of the present invention. In the first step 601, the first control unit determines whether its internal clock t has reached or exceeded a previously determined value T where the first control unit estimates that the control parameter has reached a predetermined target. If the internal clock t has reached the determined value T, the operational event is initiated in step 602. Alternatively, the first control unit determines in step 603 whether a new data package has been received.

If a new data package has been received, the first control unit, in step 604, obtains an estimate of the temporal rate of change of the first control parameter. Using, the obtained estimate of the temporal rate of change, and the data in the data package (a point in the time parameter space) the first control unit in step 605 determines a new estimate of the value of its internal clock when the value of the control parameter reaches the predetermined target, as explained in relation to Fig. 2 and / or Fig. 4. Next, the first control unit returns to step 601 after a temporal lag Δ proc, defining the temporal resolution of the first control method. If, the first control unit in step 603 determines that no new data package has been received it directly returns to step 601 (after the temporal lag Δ proc). Thus if a first and a second data package is generated for each combustion cycle, the first control unit may control the execution of the operational event without using information from the data in the second data package if the second data package is processed for a particular combustion cycle after the first control unit has estimated that the value of said control parameter has reached said predetermined target (in step 601), and with the use of the data in the second data package if the second data package is processed before the first control unit estimates that the value of said control parameter have reached said predetermined target.

Consequently, the second data package may be recorded in a manner where it comprises information of the control parameter very close to the predetermined target as it is not a requirement that it reached the first control unit in time. Thus, the first data package may provide high reliability and the second data package may provide high precision.

It should be noted that the steps may be fully implemented in software or in a combination of software and hardware e.g. steps 601 602 relating to the initiation of the event may be implemented in hardware, whereas steps 603 604, and 605 may be implemented in software, Fig. 7 shows how data from a verification data package may be used to improve the precision, according to an embodiment of the present invention. Shown is a time / parameter space 700 comprising a first axis 701 representing time and a second axis 702 representing values of the control parameter. The point p1 represents a first point in the time parameter space origin from data in a first data package, 709 represent a captured first instantaneous value of the control parameter at a first discrete instance, and 708 represents the value of the internal clock of the first sensor unit (and the first control unit) at the first discrete instance. To make a first estimate of the value of the internal clock of the first control unit t1 where the value of the control parameter reaches the predetermined target 704, the first control unit firstly extrapolates the point p1 using an obtained first estimate of the rate of change of the control parameter, thereby generating the line 703, and secondly determine the intersection between the extrapolated line 703 and the line 704 representing the predetermined target. Thus, the first control unit initiates an operational event when its internal clock reaches t1. As explained above, to improve the precision for subsequent combustion cycles a first verification data package is received in the first control unit. The first verification data package comprises a verification value of the control parameter 720 captured at a particular instance after said operation event has been initiated in the combustion cycle, and the value of the internal clock 721 of the first sensor unit at said particular instance, resulting in a verification point vp in the time / parameter space. Next, the first control unit estimates a verification estimate ve of the discrete instance where the value of said control parameter reached said predetermined target by interpolating between said first point p1 and the verification point vp in the time / parameter space. Using this verification estimate ve a discrepancy 715 between said verification estimate ve and the estimate used for initiating the operational event t1 is determined. This discrepancy is then used by the first control unit to generate a correction factor for use in controlling said operation event in subsequent combustion cycles.

Fig. 8 shows a schematic drawing of internal combustion engine comprising a control system for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine, according to embodiments of the present invention. The internal combustion engine comprises four cylinders 2, each cylinder 2 having an active member 8 associated. The control system comprises a first sensor unit 3 communicatively coupled to a first control unit 4 through a communication network 10 11. The communication network comprises wired connections 10 and a switch 11. In this embodiment the first control unit comprises a single central processing unit 4.

Fig. 9 shows schematic drawings of internal combustion engine comprising a control system for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine, according to embodiments of the present invention. The internal combustion engine comprises four cylinders 2, each cylinder 2 having an active member 8 associated. The control system comprises a first sensor unit 3 communicatively coupled to a first control unit 4 5 through a communication network 10 11. The communication network comprises wired connections 10 and a switch 11. In this embodiment the first control unit comprises a single central processing unit 4 and four de-central processing units 5 positioned at the active element 8 of each cylinder 2.

Fig. 10 shows schematic drawings of internal combustion engine comprising a control system for controlling the execution of an operational event of an active member during each combustion cycle for each cylinder of a multi-cylinder internal combustion engine, according to embodiments of the present invention. The control system shown in Fig. 10 is similar to the control system shown in Fig. 9 with the difference that a redundant second sensor unit 3' and a redundant second control unit 4' are provided.

Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.

In system claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

1. Fremgangsmåde (100) til at styre udførelsen af en driftshændelse for et aktivt element (8) under hver driftscyklus eller nogle driftscykler for hver cylinder (2) i en flercylindret forbrændingsmotor som reaktion på en styreparameter, der varierer i tid under hver omdrejning af den flercylindrede forbrændingsmotor, omfattende: (101) at opsamle en første momentanværdi af styreparameteren (209, 309) på et første diskret tidspunkt (208, 308) under hver forbrændingscyklus med en første sensorenhed (3), hvor den første sensorenhed har en intern clock; (102) at generere en første datapakke, som omfatter data, der indikerer de opsamlede første momentanværdier af styreparameteren (209, 309) og værdien af den interne clock i den første sensorenhed (3) på det første diskrete tidspunkt (208, 308), resulterende i et første punkt (p1) i et tids/parameter-rum; at transmittere den første datapakke over et kommunikationsnetværk (10, 11) til en første styreenhed (4, 5), hvor den første styreenhed (4, 5) har en intern clock, der er synkroniseret med den interne clock i den første sensorenhed (3); at tilvejebringe et første estimat af den tidsmæssige ændringshastighed af styreparameteren i den første styreenhed (4, 5); hvor fremgangsmåden yderligere omfatter trinnene at der i den første styreenhed (4, 5) enten estimeres: værdien af den første styreparameter på et første udvalgt diskret tidspunkt (t proc), hvor det første udvalgte diskrete tidspunkt (t_proc) vælges i afhængighed af værdien af den interne clock i den første styreenhed (4, 5) på behandlingstidspunktet uden at være direkte afhængigt af modtagelsestidspunktet for den første datapakke i den første styreenhed (4, 5); eller værdien (t1) af den interne clock i den første styreenhed (4, 5), når værdien af styreparameteren når et forudbestemt mål (204, 304); hvor værdien af styreparameteren på det første udvalgte diskrete tidspunkt (t_proc) eller værdien (t1) af den interne clock af den første styreenhed (4, 5) estimeres ved direkte ekstrapolering af det første punkt (p1) i tids/parameter-rummet under brug af det tilvejebragte første estimat af den tidsmæssige ændringshastighed for styreparameteren, og hvor driftshændelsen igangsættes, når det estimeres, at værdien af styreparameteren har nået eller overskredet det forudbestemte mål (204, 304) eller den interne clock i den første styreenhed har nået eller overskredet den estimerede værdi (t1).

2. fremgangsmåde ifølge krav 1, hvor momentanværdien af styreparameteren omfatter den momentane position af en motorkrumptapaksel, som er forbundet med stempelorganer for hver af cylindrene (2).

3. Fremgangsmåde ifølge krav 1 eller 2, hvor fremgangsmåden yderligere omfatter trinnene at: opsamle en anden momentanværdi (411, 511) af styreparameteren på et andet diskret tidspunkt (412, 512) under hver forbrændingscyklus med den første sensorenhed (3), hvilket andet diskrete tidspunkt (412, 512) ligger efter det første diskrete tidspunkt (208, 308); at generere en anden datapakke, som omfatter data, der indikerer den opsamlede anden momentanværdi af styreparameteren (411, 511) og værdien af den interne clock i den første sensorenhed (3) på det andet diskrete tidspunkt (412, 512), resulterende i et andet punkt (p2) i tids/parameter-rummet; at transmittere den anden datapakke over kommunikationsnetværket (10, 11) til den første styreenhed (4, 5); hvor driftshændelsen styres uden brug af dataene i den anden datapakke, hvis den anden datapakke behandles for en specifik forbrændingscyklus efter, at det er blevet estimeret, at værdien af styreparameteren har nået det forudbestemte mål, eller den interne clock i den første styreenhed har nået den estimerede værdi (t1), og hvor driftshændelsen styres under brug af dataene i den anden datapakke, hvis den anden datapakke behandles for en specifik forbrændingscyklus før, at det er blevet estimeret, at værdien af styreparameteren har nået det forudbestemte mål (404, 504), eller den interne clock i den første styreen- hed har nået den estimerede værdi (t1).

4. Fremgangsmåde ifølge et hvilket som helst af kravene 1 til 3, hvor fremgangsmåden yderligere omfatter trinnene, at: opsamle en verifikationsværdi (720) af styreparameteren med den første sensorenhed (3) på et specifikt tidspunkt (721) under en forbrændingscyklus, efter at driftshændelsen er blevet igangsat i forbrændingscyklen; generere en første verifikationsdatapakke omfattende verifikationsværdien (720) og værdien af den interne clock i den første sensorenhed på det specifikke tidspunkt (721), resulterende i et verifikationspunkt (vp) i tids/parameter-rummet; transmittere verifikationsdatapakken over kommunikationsnetværket (10, 11) til den første styreenhed (4, 5); estimere et verifikationsestimat (ve) for det diskrete tidspunkt, hvor værdien af styreparameteren nåede det forudbestemte mål (704), i den første styreenhed ved at interpolere mellem det første punkt (p1) og/eller det andet punkt (p2) samt verifikationspunktet (vp) i tids/parameter-rummet; bestemme en diskrepans (715) mellem verifikationsestimatet (ve) og det esti mat, der blev benyttet til at igangsætte driftshændelsen, hvor den bestemte diskrepans benyttes til at generere en korrektionsfaktor til brug ved styringen af driftshændelsen i efterfølgende forbrændingscykler.

5. Fremgangsmåde ifølge et hvilket som helst af kravene 1 to 4, hvor fremgangsmåden yderligere omfatter trinnene, at måle det diskrete tidspunkt under en forbrændingscyklus, hvor det aktive element (8) udfører driftshændelsen, med en sensorenhed for det aktive element placeret ved det aktive element (8), hvor sensorenheden for det aktive element har en intern clock, der er synkroniseret med den interne clock i den første styreenhed (4, 5); generere en anden verifikationsdatapakke omfattende det målte diskrete tidspunkt; transmittere den anden verifikationsdatapakke til den første styreenhed (4, 5) over et kommunikationsnetværk (10, 11), hvor den første styreenhed (4, 5) genererer en korrektionsfaktor til brug i efterfølgende forbræn- dingscykler ved at behandle den anden verifikationsdatapakke.

6. Fremgangsmåde ifølge et hvilket som helst af kravene 1 til 5, hvor antallet af værdier af styreparameteren, der opsamles for hver forbrændingscyklus, vælges i afhængighed af længden af forbrændingscyklerne.

7. Fremgangsmåde ifølge et hvilket som helst af kravene 1 til 6, hvor en redundant anden sensorenhed (3’) yderligere opsamler værdier af styreparameteren og transmitterer disse værdier til en styreenhed (4’).

8. System til styringen af udførelsen af en driftshændelse for et aktivt element under hver driftscyklus eller nogle driftscykler for hver cylinder (2) i en flercylindret forbrændingsmotor som reaktion på en styreparameter, der varierer i tid under hver omdrejning af den flercylindrede forbrændingsmotor, hvilket system omfatter: en første sensorenhed (3) med en intern clock, hvor den første sensorenhed (3) er konfigureret til at opsamle en første momentanværdi af styreparameteren (209, 309) på et første diskret tidspunkt (208, 308) under hver forbrændingscyklus og generere en første datapakke omfattende den opsam-lede første momentanværdi af styreparameteren (209, 309) og værdien af den interne clock i den første sensorenhed på det første diskrete tidspunkt (208, 308), resulterende i et første punkt i et tids/parameter-rum; og en første styreenhed (4, 5) med en intern clock konfigureret til at være synkroniseret med den interne clock i den første sensorenhed (3), hvor den første styreenhed (4, 5) er forbundet med den første sensorenhed (3) via et kommunikationsnetværk (10, 11) og er konfigureret til at tilvejebringe et første estimat af den tidsmæssige ændringshastighed for den diskrete parameter, og hvor den første sensorenhed (3) er konfigureret til at transmittere den første datapakke via kommunikationsnetværket (10, 11) til den første styreenhed (4, 5), hvor den første styreenhed (4, 5) er konfigureret til som respons på modtagelse af den første datapakke at estimere enten: værdien af styreparameteren på et første udvalgt diskret tidspunkt (t_proc), hvor det første udvalgte diskrete tidspunkt vælges i afhængighed af værdien af den interne clock i den første styreenhed (4, 5) på behandlings- tidspunktet uden at være direkte afhængigt af modtagelsestidspunktet for den første datapakke i den første styreenhed (4, 5); eller værdien (t1) af den interne clock i den første styreenhed (4, 5), når værdien af styreparameteren når et forudbestemt mål (204, 304); hvor værdien af styreparameteren på det første udvalgte diskrete tidspunkt (t_proc) eller værdien (t1) af den interne clock i den første styreenhed (4, 5) estimeres ved direkte ekstrapolering af det første punkt (p1) i tids/parameter-rummet under brug af det tilvejebragte første estimat af den tidsmæssige ændringshastighed for styreparameteren, og hvor den første styreenhed (4, 5) er konfigureret til at igangsætte driftshændelsen, når den første styreenhed estimerer, at værdien af styreparameteren har nået eller overskredet det forudbestemte mål, eller den interne clock i den første styreenhed (4, 5) har nået eller overskredet den estimerede værdi (t1).

9. System ifølge krav 8, hvor momentanværdien af styreparameteren omfatter den momentane position af en motorkrumtapaksel, som er forbundet med stempelorganer for hver af cylindrene (2).

10. System ifølge krav 8 eller 9, hvor den første sensorenhed (3) yderligere er konfigureret til at opsamle en anden momentanværdi (411,511) af styreparameteren på et andet diskret tidspunkt (412, 512) under hver forbrændingscyklus, hvilket andet diskrete tidspunkt (412, 512) ligger efter det første diskrete tidspunkt (411, 511), at generere en anden datapakke, som omfatter den anden opsamlede momentanværdi af styreparameteren (411, 511) og værdien af den interne clock i den første sensorenhed (3) på det andet diskrete tidspunkt (412, 512), resulterende i et andet punkt (p2) i tids/parameter-rummet, og at transmittere den anden datapakke over et kommunikationsnetværk (10, 11) til den første styreenhed (4, 5); hvor den første styreenhed er konfigureret til, at styre udførelsen af driftshændelsen uden brug af dataene i den anden datapakke, hvis den anden datapakke for en specifik forbrændingscyklus behandles efter, at det er blevet estimeret, at værdien af styreparameteren har nået det forudbestemte mål (404, 504), eller den interne clock i den første styreenued (4, 5) har nået den estimerede værdi (t1), og styre udførelsen af driftshændelsen under brug af dataene i den anden datapakke, hvis den anden datapakke behandles for en specifik forbrændingscyklus før, at det er blevet estimeret, at værdien af styreparameteren har nået det forudbestemte mål (404, 504), eller den interne clock i den første styreenhed har nået den estimerede værdi (t1).

11. System ifølge et hvilket som helst af kravene 8 til 10, hvor den første sensorenhed (3) yderligere er konfigureret til at opsamle en verifikationsværdi (720) af styreparameteren på et specifikt tidspunkt (721) under en forbrændingscyklus, efter at driftshændelsen er blevet igangsat i forbrændingscyklen, at generere en første verifikationsdatapakke omfattende verifikationsværdien (720) og værdien af den interne clock i den første sensorenhed (3) på det specifikke tidspunkt (721), resulterende i et verifikationspunkt (vp) i tids/parameter-rummet, og at transmittere den første verifikationsdatapakke over kommunikationsnetværket (10, 11) til den første styreenhed (4, 5); hvor den første styreenhed (4, 5) er konfigureret til at estimere et ve-rifikationsestimat (ve) for det diskrete tidspunkt, hvor værdien af styreparameteren nåede det forudbestemte mål (704), ved at interpolere mellem det første punkt (p1) og/eller det andet punkt (p2) samt verifikationspunktet (vp) i tids/parameter-rummet; og yderligere at bestemme en diskrepans (715) mellem verifikationsestimatet (ve) og det estimat, der blev benyttet til at igangsætte driftshændelsen, hvor den bestemte diskrepans (715) benyttes til at generere en korrektionsfaktor til brug ved styringen af driftshændelsen i efterfølgende forbrændingscykler.

12. System ifølge et hvilket som helst af kravene 8 til 11, hvor systemet omfatter en sensorenhed for det aktive element som har en intern clock, der er konfigureret til at være synkroniseret med den interne clock i den første styreenhed (4, 5), hvilken sensor for det aktive element er forbundet med den første styrenhed (4, 5) via kommunikationsnetværket (10, 11), hvor sensoren for det aktive element er konfigureret til at måle det diskrete tidspunkt, hvor det aktive element (8) udfører driftshændelsen under en forbrændingscyklus, at generere en anden dataverifikationspakke omfattende det målte diskrete tidspunkt, og at transmittere den anden verifikations- datapakke til den første styreenhed (4, 5), hvor den første styreenhed (4, 5) yderligere er konfigureret til at generere en korrektionsfaktor til brug ved styringen af driftshændelsen i efterfølgende forbrændingscykler ved at behandle den anden verifikationsdatapakke.