Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
METHOD AND DEVICE FOR CONTROL OF OPERATION OF VALVES OF AN INTERNAL COMBUSTION ENGINE
Document Type and Number:
WIPO Patent Application WO/2015/195035
Kind Code:
A1
Abstract:
A method to control of the operation of at least one valve (10, 11) in at least one cylinder (61-66) in a combustion engine (1), com- prising the steps, at a movement of a piston (14) in said cylinder (61-66), planning control of the at least one valve (10, 11), based on at least one setpoint value of at least one operating parameter in the engine (1), detecting movements, caused by a positional change in the at least one valve (10, 11), propagating in at least one cylinder head (8) of the cylinder (61-66) or in parts adjacent thereto in the engine (1), comparing at least one actual value obtained through the detection step with said at least one setpoint value of the at least one operating parameter, and controlling the at least one valve (10, 11), based on the result of said comparison.

Inventors:
STENLÅÅS, Ola (Myntstigen 7, Södertälje, S-151 48, SE)
NORDIN, Mikael (Billstavägen 76, Järna, S-153 95, SE)
Application Number:
SE2015/050697
Publication Date:
December 23, 2015
Filing Date:
June 16, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SCANIA CV AB (S- Södertälje, 151 87, SE)
International Classes:
F02D35/02; F02B77/08; F02D13/02; G01M15/12
Foreign References:
US5797360A1998-08-25
GB2413850A2005-11-09
DE102004048599A12006-04-20
US6167852B12001-01-02
EP0577485A11994-01-05
US5179857A1993-01-19
DE102009053264A12011-05-19
Attorney, Agent or Firm:
GARDEMARK, Niklas (Scania CV AB, Södertälje, S-151 87, SE)
Download PDF:
Claims:
Claims

1 . Method for control of the operation of at least one valve (10, 1 1 ) in at least one cylinder (61 -66) of a combustion engine (1 ), characterised in that it comprises the steps, at a movement of a piston (14) in said cylinder (61 -66) planning control of the at least one valve (10, 1 1 ), based at least on a setpoint value of at least one operating parameter of the engine (1 ), detecting movements, caused by a positional change in the at least one valve (10, 1 1 ), propagating in at least one cylinder head (8) of the cylinder (10, 1 1 ) or in parts adjacent thereto in the engine (1 ), comparing at least one actual value obtained through step S2 with said at least one setpoint value of the at least one operating parameter, and controlling the at least one valve (10, 1 1 ), based on the result of said comparison. 2 Method according to claim 1 , characterised in that the detection is carried out in or on said cylinder head (8). 3. Method according to claim 1 , characterised in that the detection is carried out on the engine, in an area adjacent to the outlet of the exhaust channel from a cylinder. 4. Method according claim 1 , characterised in that the detection is carried out on the engine, in an area adjacent to the suction channel's inlet to a cylinder. 5. Method according to any of claims 1 - 4, characterised in that in step S2 movements caused by a turn of said piston (14) are also detected.

6. Method according to any of claims 1 - 4, characterised in that, in step S2 movements caused by a pressure change in a cylinder chamber (5) of said cylinder (61 -66) are also detected.

7. Method according to any of claims 1 - 6, characterised in that, in step S3 an actual value comprising information about a positional change of a valve (10, 1 1 ) at a specific crank angle is compared.

8. Method according to any of the previous claims, characterised in that, in step S2 a positional change in the form of opening and/or closing of said valve (10, 1 1 ) is detected.

9. Method according to any of the previous claims, characterised in that, in step S4 the opening and/or closing of said valve (10, 1 1 ) is controlled at a respective specific crank angle.

10. Method according to any of the previous claims, characterised in that, in step Si control of the at least one valve (10, 1 1 ), based at least on a setpoint value of the fuel injection pressure and/or start of fuel injection and/or exhaust back pressure and/or charge air pressure (turbo pressure) and/or exhaust temperature and/or efficiency for the supercharging system and/or EGR-level and engine speed of the engine (1 ) is planned.

1 1 . Method according to any of the previous claims, character- ised in that in step S3 an actual value in the form of fuel injection pressure and/or an actual value in the form of the engine speed in the engine (1 ) is compared.

12. Method according to any of the previous claims, character- ised in that the operation of at least two, at least three or at least four valves (10, 1 1 ) per cylinder (61 -66) in the combustion engine (1 ) are controlled.

13. Method according to any of the previous claims, character- ised in that in step S4 the period length of said valve (10, 1 1 ), i.e. the time during which the valve is open, is controlled.

14. Method according to any of the previous claims, characterised in that planning is carried out in step Si before a specific valve period, that step S2 is the starting point for said valve period which is detected, that comparison is carried out in step S3 during said valve period, and that in step S4 it is the end point of said valve period, which is controlled. 15. Method according to any of the previous claims, characterised in that planning is carried out in step Si during a valve period, that detection is carried out in step S2 during said valve period, that comparison is carried out in step S3 during said valve period, and that in step S4 the starting point of the subsequent valve period is controlled. 16. Method according to any of the previous claims, characterised in that it also comprises the following step evaluating a result of at least one of said steps S1 -4 and using the result of the evaluation as an input to the subsequent step Si .

17. Device (3) for control of the operation of at least one valve (10, 1 1 ) in at least one cylinder (61 -66) of a combustion engine (1 ), characterised in that it comprises at least one sensor element (7), arranged separately from a cylinder chamber (5) in said cylinder (61 -66) on a part of a cylinder head (8) or on parts adjacent thereto in the engine (1 ) and adapted to detect, at a movement of a piston (14) in said cylinder chamber (5), movements propagating in said cylinder head (8) or said parts.

18. Device according to claim 17, characterised in that said sensor element (7) is arranged in or on said cylinder head

(8).

19. Device according to claim 17, characterised in that said sensor element (7) is placed on the engine, in an area adja- cent to the outlet of the exhaust channel from a cylinder.

20. Device according to claim 17, characterised in that said sensor element (7) is placed on the engine, in an area adjacent to the inlet of the suction channel to a cylinder. 21 . Combustion engine (1 ), characterised in that it comprises a device (3) according to any of claims 17 - 20.

22. Computer program which may be downloaded directly into the internal memory of a computer, which computer program comprises a computer program code in order to make the computer control the steps according to any of claims 1 -16 when said computer program is executed in the computer. 23. A computer program product comprising a non-volatile data storage medium (20), which is readable by a computer, the computer program code of a computer program according to claim 22 being stored on the data storage medium (20). 24. Electronic control device (9) for a combustion engine (1 ), comprising an execution means (17), a memory (18) connected to the execution means (17) and an execution means (17) connected to the data storage medium (20), the computer program code in a computer program according to claim 22 being stored on said data storage medium (20).

25. Motor vehicle, characterised in that it comprises a combustion engine (1 ) according to claim 21 .

26. Motor vehicle according to claim 25, characterised in that it is a wheeled motor vehicle, such as a truck or a bus, or a boat or a crawler.

Description:
METHOD AND DEVICE FOR CONTROL OF OPERATION OF VALVES OF AN INTERNAL COMBUSTION ENGINE

FIELD OF THE INVENTION

The present invention relates to a method and a device for control of operation of at least one valve in at least one cylinder in a combustion engine.

BACKGROUND

There is a constant aspiration to achieve control of a combustion engine, in such a manner that fuel used therein is burned in the engine's cylinders, while generating a maximum amount of energy/fuel mass output from the engine and a minimum amount of emissions of environmentally hazardous pollutants. It is of deci- sive importance in such aspiration to have constant knowledge of the combustion engine's operating conditions, such as the operating condition of the in- and outlet valves of the engine's cylinders, and to be able to control the engine's processes according to said operating conditions during operation.

Flexible control of the engine's valves for inlet of air-gas-mixture and outlet of exhausts is a decisive factor for the engine to be operated with a high efficiency and with a minimum of hazardous emissions. Optimal control of said valves is, however, problem- atic to achieve and common valve control methods result in large expenditure.

In an effort to achieve such a control of the engine's valves, today expensive proximity switches are often used, for example one for the inlet valves and another for the outlet valves in each cylinder, in order to detect positional changes in said valves as a basis for deciding how these should be controlled. In addition to the relatively high cost, which purchase of such sensors results in, they must, in order to provide reliable results, also be diag- nosed and adjusted regularly.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a method and a device, which are improved in at least one respect in relation to prior art methods and devices.

This objective is achieved with the invention as defined in the enclosed claims. In one embodiment, a method for control of operation of at least one valve in at least one cylinder in a combustion engine is achieved. The method comprises the steps of, at a movement of a piston in said cylinder,

- planning control of the at least one valve, based on at least one setpoint value of at least one operating parameter in the engine,

- detecting propagating movements in at least one cylinder head of the cylinder or in parts adjacent thereto in the engine, caused by a positional change in the at least one valve,

- comparing at least one actual value obtained above with said at least one setpoint value of the at least one operating parameter, and

- controlling the at least one valve based on the result of said comparison. Thus, it is possible to control, in a simple and flexible manner and with reliable results, the operation of valves in cylinders of a combustion engine, at the same time as the latter is in operation, since regard may be had continuously to changes in the operating parameters of the engine. In addition to improvements relating to the control, cost savings may also be achieved since there is no need for expensive sensors or diag- nosis of these.

The movements that may be detected and used at control of said at least one valve may, for example, be vibrations, noise, i.e. gas movements, and various types of shape changes, such as protru- sions, in said cylinder head or in parts adjacent thereto in the engine.

According to one embodiment of the invention, movements caused by a turn of said piston are also detected. It has been shown that it is possible with the help of said detected movements to control said at least one valve in an advantageous manner.

According to another embodiment of the invention, movements caused by a pressure change in a cylinder chamber of said cylinder are also detected. It has been shown that it is possible with the help of said detected movements to control said at least one valve in an advantageous manner. According to another embodiment of the invention, an actual value is determined, comprising information about a positional change of a valve at a specific crank angle, which is compared. With the help of the result of a comparison of such an actual value with a corresponding setpoint value, control of the opera- tion of the at least one valve may be achieved, with a desirable result.

According to another embodiment of the invention, a positional change in the form of opening and/or closing of said valve is detected.

According to another embodiment of the invention, opening and/or closing of said valve at a respective determined crank an- gle is controlled. Through control of opening and/or closing of said valve at a determined crank angle, processes in the engine may be controlled for efficient operation of the latter.

According to another embodiment of the invention, control of the at least one valve, based at least on a setpoint value of the fuel injection pressure and/or start of fuel injection and/or exhaust back pressure and/or charge air pressure (turbo pressure) and/or exhaust temperature and/or efficiency for the supercharging system and/or EGR-level and engine speed of the engine, is planned. Said planning increases the possibility of controlling the at least one valve with a satisfactory result.

According to another embodiment of the invention, an actual value in the form of the fuel injection pressure and/or an actual value in the form of the engine speed of the engine are compared. With the help of the result of said comparison, control of the operation of the at least one valve may be achieved, with a desirable result. According to another embodiment of the invention, the operation of at least two, at least three or at least four valves per cylinder in the combustion engine are controlled. By way of a simultaneous control of said valves, the possibility of controlling the en- gine's processes with a satisfactory result increases.

According to another embodiment of the invention, the period length of said valve, i.e. the time during which the valve is open, is controlled. Control of the period length of the at least one valve has been shown to be an efficient manner of controlling the engine's processes with a satisfactory result.

According to another embodiment of the invention, planning is carried out before a determined valve period, the starting point of said valve period is detected, the comparison is carried out during said valve period, and the end point for said valve period is controlled. Thus, control of said at least one valve towards changes in the engine's operating parameters is achieved with a short reaction time.

According to another embodiment of the invention, is the planning is carried out during a valve period, detection is carried out during said valve period, comparison is carried out during said valve period, and the starting point for the subsequent valve pe- riod is controlled. Thus, control of said at least one valve is provided with advantageous planning, wherein regard is had to the current operating conditions in the engine.

According to another embodiment of the invention, the method also comprises the step of evaluating a result of at least one of said steps, and using the result of the evaluation as an input for the subsequent step. Through said step, the result of the control of the at least one valve is feedback in a certain manner, and future control of said valve may thus be improved continuously.

According to another embodiment of the invention, the at least one setpoint value and/or the at least one actual value comprises at least one setpoint and/or actual value for the pressure in the engine's inlet channel, the pressure in said cylinder chamber, the pressure in the engine's exhaust manifold, the temperature in the engine's inlet channel and/or the temperature in the engine's exhaust manifold.

According to another embodiment of the invention at least 2, 3, 5 or 7 setpoint values are used for planning of the control and/or at least 2, 3, 5 or 7 actual values are used for the comparison.

The invention also relates to a device for control of the operation of at least one valve in at least one cylinder of a combustion en- gine according to the enclosed independent device claims. The function of such a device and the possibilities it offers are described in the discussion above of the innovative method.

The invention also relates to a computer program, a computer program product, an electronic control device, a combustion engine and a motor vehicle.

The invention is not limited to any specific type of combustion engine, but encompasses Otto engines as well as compression ignited engines, nor to any specific fuel, non-exhaustive exam- pies of which may comprise fuel in the form of petrol, ethanol, diesel and gas.

Likewise, the invention comprises combustion engines intended for all types of use, such as in industrial applications, in crushing machines and various types of motor vehicles, wheeled motor vehicles as well as trucks and buses, and boats and crawlers or similar vehicles. Other advantageous features and advantages with the invention are set out in the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

Below are descriptions of example embodiments of the invention, with reference to the enclosed drawings, in which:

Fig. 1 a is a schematic view illustrating a part of a combustion engine according to one embodiment of the invention, Fig. 1 b shows a possible location of a sensor element,

Fig. 2 is a diagram showing on the one hand the pressure over time in the cylinder chamber of a cylinder in a combustion engine according to the invention, and on the other hand several signals generated over time by sensor elements according to Fig. 1 of the combustion engine, as a result of detection of movements in the cylinder head, Fig. 3 is a flow chart showing a method according to one embodiment of the invention, and

Fig. 4 is a fundamental diagram of an electronic control de- vice for implementation of one or several methods according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS ACCORDING TO THE INVENTION

Fig. 1 a illustrates very schematically a combustion engine 1 according to one embodiment of the invention, which is here arranged in an implied motor vehicle 2, for example a truck. The engine is equipped with a device 3, indicated with a dashed line, adapted to detect operating conditions in the engine, and such device has a schematically drawn device 4, which is adapted to detect e.g. pressure changes in the cylinder chambers 5 of the combustion engine's cylinders 61 -66, of which there are six in this case, but of which there may be any number.

The device 4 has, in order to be able to detect said pressure changes in the cylinder chambers, one sensor element 7 per cylinder 61 -66, and this is arranged separately from the associated cylinder chamber 5 on the respective cylinders' cylinder heads 8. The sensor elements in this case consist of piezo resistive sensors, adapted to detect pressure changes, for example in the form of vibrations, generated by movements propagated in the cylinder head, caused by the turns of a piston 14 in the respective cylinders 61 -66 or by positional changes in the valves 10, 1 1 , arranged in the respective cylinder heads 8. The fact that said at least one sensor element 7 is arranged separately from the cylinder chamber 5, i.e. the cylinder's 61 -66 combustion chambers, means that it does not come into direct contact with the inside volume of the cylinder chamber, but is completely separate therefrom. However, some form of external recess could be adapted in the wall of the cylinder chamber 5, in which a sensor element 7 could be arranged. The device 3 also comprises a unit 9, which may consist of the vehicle's 2 electronic control device, adapted to receive information about the detected movements from the sensor elements 7, and to compare such information, or information calculated based on such sensor information with stored values, and to de- liver measurings of the state of the engine 1 and its component parts and/or processes in the engine, such as positions in inlet- 10 and/or outlet valves 1 1 and the period length of a valve period in any of these. Thus, information about the engine's 1 operating conditions or divergences from these, which suitably provide the bases for control of various components in the combustion engine, such as for example fuel injection, or valves, or an indication of adjustment or service requirements, may be obtained based on the sensor elements' 7 detection. It has been shown that, by arranging such sensor elements in the manner described, so that they have the ability to detect movements propagating in the cylinder head 8 or in parts adjacent thereto in the engine 1 , derived from pressure changes in the cylinder chamber 5, turns of said piston 14 and/or positional changes in said valves 10, 1 1 , high quality signals may be ob- tained, which signals do not require filtering or further processing, or alternatively, which require a simple filtering or processing, in order to be used at the control of the operation of at least one valve 10, 1 1 in the at least one cylinder 61 -66 of the engine 1 .

Fig. 1 b shows another placement of the sensor element 7. The sensor element is here placed on a section adjacent to the cylinder head. In this example, the sensor element is placed on the engine, specifically on the engine block. The sensor element may here be placed on the engine, in an area adjacent to the outlet of the exhaust channel from a cylinder. For example, it may be placed on a surface on the engine block next to the outlet, on the engine, of the exhaust channel from a cylinder. The surface where the sensor 7 is placed may be substantially vertical. The sensor may be arranged to detect movements, which are perpendicular to the movements of the piston. The sensor may also be arranged to detect movements, which are perpendicular both in relation to the piston's direction of movement and in relation to the engine's longitudinal direction. In one embodiment, the sensor is located on the engine's long side. The sensor may be arranged to detect movements in a direction, which is perpendicular in relation to the surface on which it is placed. In another embodiment (not displayed) the sensor element 7 may be placed in a corresponding manner as when placed on the engine at the outlet of the exhaust channel from a cylinder, but instead placed in a corresponding location on the engine at the suction channel's inlet to a cylinder. The signal detected by the sensor element 7 may be treated in various ways. For example, the following signal treatment steps may be carried out. First the sensor's electrical signal is entered into a control device/signal treatment device. The signal is fil- tered with a bandpass filter in order to remove superfluous information, which does not belong to the frequency range around which information is required. The signal is evened out by way of filtering, averaging or by being replaced with one or several continuous function(s) with good likeness. Subsequently, the signal is scaled, e.g. with the help of the correlation between pressure and volume at compression. Subsequently, (a) suitable part(s) of the signal is/are transformed to the pressure domain. Supplemental modelling closes gaps in the signal's reliability, in order to form a pressure curve. The thus formed pressure curve is used to calculate different values at engine control. In some embodiments one or several of the steps above may be omitted.

Below is an example of a method according to the invention, for control of operation of four valves 10, 1 1 in a cylinder 61 of a combustion engine 1 , at movement of a piston 14 in said cylinder (see Fig. 3).

In a first step Si control is planned, i.e. opening and closing, of the cylinder's 61 valves, of which two are inlet valves 10 and two are outlet valves 1 1 , based on setpoint values of the operating parameters of the engine 1 . Such operating parameters may be fuel injection pressure, start of fuel injection, exhaust back pressure, charge air pressure (turbo pressure), exhaust temperature, efficiency for the supercharge system, EGR-level, engine speed, as well as additional parameters impacting the operation of the engine, such as the crank angle at which a specific valve should be opened or how long this should be kept open, or other parameters impacting combustion, gas exchange, efficiency and/or exhaust treatment. This planning may consist in that control of the valves 10, 1 1 is determined based on values determined at the production of the engine 1 , such as for example fuel injection pressure, or more current values measured during operation of the engine, such as for example engine speed. In a second step S 2 at least movements propagated in a cylinder head 8 of the cylinder 61 or in parts adjacent thereto in the engine 1 , caused by a positional change, i.e. an opening or closing in any one or several of the relevant valves 10, 1 1 are detected. The movements caused by said positional change consist of vi- brations spreading in the cylinder head as a consequence of a valve lid 12, 13 of a valve 10, 1 1 repelling or hitting against a valve seat 15, 16 in the cylinder head 8 at the opening and closing, respectively, of the valve, and are detected with the help of the sensor element 7.

In this step S 2 such vibrations caused by other events, such as pressure increases in the cylinder chamber 5, may also be detected with the sensor element 7. Other values as well, such as the prevailing crank angle and engine speed of the engine 1 , may be detected in this step, with the help of for example suitable sensors. Examples of movements that may be detected with the sensor element 7 are illustrated in Fig. 2, and the use of information from these, as well as from other said values, is explained in more detail below. In step S 3 one or several actual values obtained through step S 2 are compared with corresponding setpoint values of said operating parameters. Such an actual value may consist of an opening of the inlet valves 10 at a certain crank angle. When the inlet valves, in the example two in number, are opened, vibrations are created in the cylinder head 8, which are detected by the sensor element 7 and illustrated in Fig. 2 as noise IVO. The crank angle at which this opening occurs is detected by a crank angle sensor and all this information constitutes, jointly, an actual value, to be compared with the corresponding setpoint value.

In step S 4 the valves 10, 1 1 of cylinder 61 are controlled based on the result of the comparisons in step S 3 - For example, the timing, i.e. the crank angle, at which the outlet valves 1 1 are closed may be moved forward or backward, depending on the differences between the different actual values in relation to their corresponding setpoint values.

In this manner, the inlet valves 10 and/or outlet valves 1 1 of a cylinder 61 in the engine 1 may be controlled according to the prevailing operating conditions of the engine, in order for operation of the same with the best possible efficiency to be achieved.

The above mentioned steps S 1 -4 may be carried out at different points in time, depending on the manner in which one wishes to control the valves 10, 1 1 and the desired result. For example, planning at step Si may be carried out before a determined valve period, i.e. the time during which a valve 10, 1 1 is open. The crank angles, at which opening and closing, respectively, of the valve must be carried out, and accordingly the valve's period length, are determined. In step S 2 the valve period's starting point is detected, i.e. the opening of the valve 10, 1 1 , and potentially other values to be used as actual values in the subsequent step. In step S 3 actual values obtained from step S 2 are com- pared with corresponding setpoint values used instep and in step S 4 the valve period's end point, i.e. the closing of the relevant valve is controlled, based on the results of the comparisons in step S 3 . In another example, the control of the subsequent period is planned in step Si during a determined valve period, in step S 2 actual values are detected and generated during said determined valve period, which in step S 3 are compared with corresponding setpoint values during said valve period. Accordingly, in step S 4 , at least the starting point, i.e. the opening of a valve 10, 1 1 in the subsequent valve period is controlled, based on the result of the comparisons carried out during the previous one. The subsequent valve period may also have its starting point before the end point of the previous one, when for example the inlet valves 10 of a cylinder 61 may be opened before the outlet valves 1 1 are closed.

One or several valves may obviously be controlled to be opened and closed several times during a working cycle, described be- low.

In order to provide for the best possible result at the control of the valves 10, 1 1 , an additional step S 5 may be carried out. In this step, the results from one or several previous steps S 1 -4 are evaluated, and the result of this evaluation is then used as an input for the subsequent step In this manner, for example the result of the comparison in step S 3 may be used to adjust the setpoint values used in step S 1 , to try to reduce the difference between setpoint values and actual values, and thus to achieve a more correct planning. In this way, a manner of continuously improving the control of the valves 10, 1 1 in a cylinder 61 -66 of the engine 1 is provided.

Fig. 2 illustrates in a diagram the development of the pressure P over the time t during a working cycle in a cylinder chamber 5, without combustion in the engine 1 that uses diesel as fuel during operation and works in four strokes, which are referred to hereafter as the suction stroke, the compression stroke, the combustion stroke and the exhaust stroke, and jointly constitute one said working cycle.

The markings BDC1 , TDC1 , BDC2, TDC2 on the time axis show at what points the piston 14 of a cylinder 61 turns, i.e. is located at a top and bottom dead centre, respectively, where BDC1 re- fers to the piston's turn at a first bottom dead centre at the end of the suction stroke, DC1 refers to the piston's turn at a first top dead centre at the end of the compression stroke and the beginning of the combustion stroke, BDC2 refers to the piston's turn at a second bottom dead centre at the beginning of the exhaust stroke and TDC2 refers to the piston's turn at a second top dead centre at the end of the exhaust stroke and the beginning of the suction stroke.

The curve in the diagram shows clearly how the pressure in the cylinder chamber 5 increases between BDC1 and TDC1 , reduces between TDC1 and BDC2 and remains substantially constant between BDC2 and TDC2, and between TDC2 and BDC1 . At different points along the curve, there may also be noise in the form of noise IVO, IVC illustrating detected vibrations caused by the opening and closing, respectively, of the inlet valve 10, noise AVO, AVC illustrating detected vibrations caused by the opening and closing, respectively, of the outlet valve 1 1 , i.e. the exhaust valve, and noise a-d illustrating detected vibrations caused by a turn of said piston 14.

The noise IVO, IVC, AVO, AVC illustrating detected movements caused by a positional change of a valve 10, 1 1 will hereafter be referred to, for the sake of clarity, as valve noise and the noise a-d illustrating detected movements caused by a turn of said pis- ton 14 will, for the same reason, be referred to as piston noise.

The pressure as well as the respective noise in the diagram are examples of movements propagating in a cylinder head 8 of the cylinder 61 or in parts adjacent thereto in the engine 1 , detected by the sensor element 7. Attempts have shown that such a sensor element may be used both to detect the pressure and thus to generate signals which correspond, with great reliability, with signals generated by a conventional pressure sensor, and to detect other said movements, such as vibrations, which are illus- trated by way of said noise a-d, IVO, IVC, AVO, AVC.

The movements and noise IVO, IVC, AVO, AVC thus shown, deriving from positional changes in said valves 10, 1 1 , are caused by their valve lids 12, 13 hitting against or repelling parts, such as valve seats 15, 16 in the cylinder head 8 at closing and open- ing, respectively, of said valves, through which vibrations spreading in the cylinder head are created.

The movements, which are shown in the diagram as noise a-d and are derived from turns of said piston 14, are caused because parts of the piston, at turns, come into contact with parts of the cylinder 61 connecting the piston and the crankshaft 21 , so that vibrations spreading in the cylinder are created. The measuring values displayed in the above described diagram may be used in various ways with the help of the device 3, in order to control the operation of at least one valve 10, 1 1 in at least one cylinder 61 -66 of the engine 1 , according to one innovative method.

In step S 2 , for example, a valve noise AVO and a piston noise c may be detected. With the help of a value for the engine's 1 prevailing engine speed, obtained from a suitable speed sensor, the time and thus the distance between the valve noise and the pis- ton noise may be determined. When the piston noise c is detected at a determined crank angle, the crank angle at which the valve noise AVO is detected may thus be determined, and this information may constitute an actual value to be compared in step S 3 .

In another example, in step S 2 a valve noise IVO, IVC, AVO, AVC and the pressure in the cylinder chamber 5 may be detected. With the help of a value for the engine's 1 prevailing engine speed the time, and thus the distance between the valve noise and the top pressure in the cylinder chamber 5, i.e. the highest point of the pressure curve, may be determined. Since the top pressure should arise at a specific crank angle, the crank angle at which the relevant valve noise is detected may be determined, and this information may constitute an actual value to be com- pared in step S 3 -

The unit 9 in the device 3 may, through the frequency of a noise, determine whether this derives from a turn of said piston 14, which event results in noise a-d with a first frequency, or from a positional change of a valve 10, 1 1 , which event results in noise I VO, IVC, AVO, AVC with a second, higher frequency.

Another example of information that may constitute an actual value to be compared in step S 3 are movements detected by the sensor element 7, caused by a pressure change in the cylinder chamber 5 at a specific crank angle, which is determined with the help of, for example, a crank angle positional sensor.

Fig. 3 shows a flow chart illustrating an embodiment of a method according to the present invention, to control the operation of at least one valve in at least one cylinder of a combustion engine, when a piston in said cylinder moves. In a first step control of the at least one valve is planned, based on at least one setpoint value of at least one operational parameter of the engine, in a second step S 2 movements propagated in at least one cylinder head of the cylinder or in parts adjacent thereto in the engine, caused by a positional change in the at least one valve, are detected, in a third step S 3 at least one actual value obtained through step S 2 is compared with said at least one setpoint value of the at least one operational parameter, and in step S 4 the at least one valve is controlled, based on the result of said comparison.

A computer program code for the implementation of a method ac- cording to the invention is suitably included in a computer program, loadable into the internal memory of a computer, such as the internal memory of an electronic control device of a combustion engine. Such a computer program is suitably provided via a computer program product, comprising a data storage medium readable by an electronic control device, which data storage medium has the computer program stored thereon. Said data storage medium is e.g. an optical data storage medium in the form of a CD-ROM, a DVD, etc., a magnetic data storage medium in the form of a hard disk drive, a diskette, a cassette, etc., or a Flash memory or a ROM, PROM, EPROM or EEPROM type memory.

Fig. 4 very schematically illustrates an electronic control device 9 comprising execution means 17, such as a central processor unit (CPU), for the execution of computer software. The execution means 17 communicates with a memory 18, e.g. a RAM memory, via a data bus 19. The control device 9 also comprises a data storage medium 20, e.g. in the form of a Flash memory or a ROM, PROM, EPROM or EEPROM type memory. The execution means 17 communicates with the data storage means 20 via the data bus 19. A computer program comprising computer program code for the implementation of a method according to the invention is stored on the data storage medium 20.

The invention is obviously not limited in any way to the embodi- ments described above, but numerous possible modifications thereof should be obvious to a person skilled in the area, without such person departing from the spirit of the invention as defined by the appended claims. For example, the combustion engine could have another number of cylinders than displayed. A sensor element to detect movements derived from the cylinder chambers in all cylinders is also unnecessary, and it is even plausible that the device may have only one sensor element, intended to detect movements derived from pressure changes in only one of the engine's cylinders.

The number of valves per cylinder may vary from only one inlet valve and one outlet valve, respectively, up to three or four of such respective valve types, or even more. The valves in a cylin- der that may be controlled simultaneously with an innovative method may be one, several or all of said valves, and valves in different cylinders of the engine may also be controlled simultaneously. The sensor elements, e.g. piezo resistive elements or optical sensors, may be adapted to detect said movements when there is no combustion in the engine's cylinders, but when there are still changes in the pressure inside the cylinder chambers, for example when starting the combustion engine with a starting engine, or when combustion takes place in the engine's cylinder chambers.

The diagram displayed in Fig. 2 is prepared for illustrative purposes and thus the information that may be derived therefrom is not necessarily realistic with respect to scales etc. Correspond- ing diagrams for different types of engines may also differ in terms of appearance, as a consequence of, for example, different timing of opening and/or closing of a valve in these. Detection of movements caused by a pressure change also relates to comprising detection of the absence of such movements, in a sensor element adapted to detect such movements when pressure changes arise. This detected absence then indicates that the pressure is substantially unchanged during a certain time, which indicates that we are currently in, for example, the suction stroke or the exhaust stroke.

A piston which, at a turn, gives rise to movements, such as vibrations, relates to a piston which, when the engine is in operation, carries out a forward and backward movement in the cylinder and therefore operates a crankshaft connected with the piston.

A crank angle at which movements are detected by a said sensor element may be determined with some type of conventional crank angle sensor, such as an inductive crank angle positional sensor, but may also be calculated by the innovative device, based only on the movements detected by said sensor elements.

The described manners in which the innovative device may use movements detected by the sensor element to control the operation of at least one valve are examples thereof, and thus not intended to limit the area of use of the invention.

A setpoint value may be a value, for example, for a crank angle determined at the manufacture of the engine, at which a certain event should occur, or a value measured and determined previously during the operation of the engine, and also a combination of these. A valve period relates to the period which begins when the opening of a valve from a closed state takes place, and ends when the valve is in the closed state again. The period length of such a valve period accordingly relates to the distance between the beginning and the end of the period, i.e. the opening and closing of the valve, and is suitably provided as a number of crank angle degrees.

The operating parameters in which setpoint values are determined are not limited to consist of those described in this docu- ment, but may for example be more numerous and different from those provided as examples herein.