RU2583325C1 - Control device for internal combustion engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: present invention relates to device and method of controlling internal combustion engine with spark ignition, equipped with pressure sensor in cylinder. Device comprises electronic control unit (ECU) (20), which after beginning of cranking engine controls so that first combustion cycle run in cylinder equipped with pressure sensor (step 100). After that self-ignition occurs in first cycle and varying pressure in cylinder. ECU (20) detects change of pressure in cylinder with help of sensor (22) of pressure in cylinder and receives its maximum value in form of value Pmax (step 102). Then obtained value Pmax is corrected based on cooling liquid temperature and amount of air in cylinder (step 104). ECU (20) stores information on relationship between value of Pmax and octane number (RON) in form of card. ECU (20) determines octane number (RON) corresponding to derived value Pmax from this card (step 106).

EFFECT: technical result is determination of characteristics of fuel based on detected pressure change in cylinder prior to start.

14 cl, 6 dwg

Description

1. The technical field

[0001] The invention relates to a control device for an internal combustion engine and, more specifically, a control device for a spark ignition internal combustion engine equipped with a cylinder pressure sensor.

2. Description of the Related Art

[0002] Japanese Patent Application Publication No. 2009-74515 (JP 2009-74515 A) discloses a control device for an internal combustion engine capable of determining fuel characteristics at engine start. This control device, while cranking the engine’s crankshaft, forms such a small amount of air-fuel mixture that the engine will not start for spontaneous operation, and then causes this mixture to ignite by means of a spark at the set ignition time after top dead center. With respect to this combustion, the control device calculates the amount of heat produced per unit mass of fuel and determines the characteristics of the fuel based on this estimated amount of heat generation.

[0003] However, to ensure high accuracy in determining fuel characteristics, a control device is required to accurately calculate the amount of heat produced per unit mass of fuel. At the same time, the above-described control device is designed to calculate the amount of heat produced by the combustion of such a small amount of fuel that the engine does not start for spontaneous operation. Therefore, it can be assumed that in cases where the effect of temperature / pressure increase caused by compression is relatively large, the control device cannot accurately calculate the amount of heat produced by the combustion of fuel, and therefore the accuracy in determining the characteristics of the fuel may decrease.

SUMMARY OF THE INVENTION

[0004] The invention provides a control device for a spark ignition type internal combustion engine capable of accurately determining the characteristics of the fuel currently being used by the internal combustion engine.

[0005] A first aspect of the invention is a control device for a spark ignition type internal combustion engine; wherein the control device includes: means for measuring pressure in the cylinder for measuring pressure in the cylinder of one or more cylinders of the internal combustion engine and means for determining fuel characteristics for detecting a change in pressure in the cylinder caused by self-ignition after the start of the compression stroke and before performing spark ignition by using a means for measuring pressure in the cylinder during the first combustion cycle, during which spark ignition is performed for the first time after start cranking the crankshaft of an internal combustion engine, as well as to determine the characteristics of the fuel used by the internal combustion engine, based on a change in pressure in the cylinder.

[0006] According to a first aspect of the invention, during the first combustion cycle, during which spark ignition is performed for the first time after starting cranking the crankshaft of the internal combustion engine, the control device detects a change in cylinder pressure caused by self-ignition over a period of time from the start of the cycle compression before performing spark ignition. A change in cylinder pressure caused by self-ignition correlates with fuel characteristics. Therefore, according to the invention, it becomes possible to determine the characteristics of the fuel based on the detected change in pressure in the cylinder before starting the internal combustion engine.

[0007] In the above apparatus, the fuel characterization means may include means for determining a maximum value of the pressure change in the cylinder and may determine the characteristics of the fuel used by the internal combustion engine based on the maximum value.

[0008] From the point of view of the foregoing device, during the first combustion cycle after starting cranking the crankshaft of the internal combustion engine, a change in cylinder pressure caused by self-ignition is detected by the cylinder pressure measuring means, and then the maximum value of the cylinder pressure change (maximum pressure in top hat). Maximum cylinder pressure correlates with fuel performance. Therefore, it becomes possible to determine the characteristics of the fuel based on the information obtained about the maximum pressure in the cylinder before starting the internal combustion engine.

[0009] In addition, in the above device, the means for determining the characteristics of the fuel may include means for determining the rate of change when the pressure in the cylinder changes and may determine the characteristics of the fuel used by the internal combustion engine based on this rate of change. The rate of change with a change in pressure in the cylinder can be the amount of change in pressure in the cylinder per unit angle of rotation of the crankshaft (ΔP / ΔОА0).

[0010] In addition, from the point of view of the foregoing device, during the first combustion cycle, during which spark ignition is performed for the first time after starting cranking, the pressure change in the cylinder caused by self-ignition is detected by the cylinder pressure measuring means, and then the rate of change (rate of change of pressure in the cylinder) is determined. The rate of change of pressure in the cylinder correlates with the characteristics of the fuel. Therefore, it becomes possible to determine the characteristics of the fuel based on a certain rate of change of pressure in the cylinder before starting the internal combustion engine.

[0011] Furthermore, in the above apparatus, the cylinder pressure detecting means may be a cylinder pressure sensor mounted to a specific cylinder, which is one cylinder of one or more cylinders, and the control device may further include cylinder selection means for performing the first combustion cycle in a specific cylinder.

[0012] In addition, from the point of view of the foregoing device, a specific cylinder is equipped with a cylinder pressure sensor, and the cylinder is selected so that the first combustion cycle is performed in a specific cylinder. Therefore, a change in cylinder pressure in the first combustion cycle can be detected without the need for multiple pressure sensors in the cylinder.

[0013] Furthermore, in the above device, the control device may further include means for controlling the increase in compression ratio in the first combustion cycle. The control of increasing the compression ratio in the first combustion cycle can be a control that increases the degree of throttle opening or a time delay control that delays the closure time at which the inlet valve is closed by the valve timing control mechanism (valve timing mechanism).

[0014] From the point of view of the foregoing device, an increase in the compression ratio in the first combustion cycle is controlled. Therefore, with a high probability, a state can be achieved in which self-ignition occurs in the first combustion cycle so that it becomes possible to effectively increase the accuracy of determining the characteristics of the fuel.

[0015] Furthermore, in the above device, the control device may further include correction means for correcting a change in cylinder pressure detected by the cylinder pressure detecting means using the temperature of the coolant of the internal combustion engine or the amount of air in the cylinder of the internal combustion engine.

[0016] From the point of view of the above device, the detected change in pressure in the cylinder is corrected using either the temperature of the coolant or the amount of air in the cylinder. The pressure in the cylinder during autoignition varies with the temperature of the coolant and the amount of air in the cylinder. Therefore, it becomes possible to effectively improve the accuracy of determining the characteristics of the fuel by adjusting the resulting change in pressure in the cylinder depending on the aforementioned operating conditions.

[0017] In the above device, the fuel characterization tool may determine the octane number of the fuel used by the internal combustion engine.

[0018] From the point of view of the foregoing device, the octane number of the fuel is determined based on the detected change in pressure in the cylinder. Therefore, the octane number of the fuel can be effectively determined before starting the internal combustion engine.

[0019] Furthermore, in the above device, the control device may further include knock suppression means for controlling knock occurrence suppression if the octane number determined by the fuel characterization means is lower than a predetermined reference value.

[0020] From the point of view of the foregoing device, if the determined octane number is lower than the predetermined reference standard value, the knock suppression control is controlled. Thus, the occurrence of detonation can be effectively suppressed.

[0021] In addition, in the above device, the knock suppression means may include means for limiting the output of the internal combustion engine.

[0022] From the point of view of the foregoing device, the output of the internal combustion engine is limited if a certain octane number is lower than a predetermined standard value. Thus, the occurrence of detonation can be effectively avoided.

[0023] Furthermore, in the above apparatus, knock suppression means may include warning means for providing a warning to the user.

[0024] From the point of view of the foregoing device, the user is warned if a certain octane number is lower than a predetermined standard value. Thus, the user is effectively notified of a low octane fuel problem or similar problem so that detonation can be avoided.

[0025] A second aspect of the invention is a method for controlling a spark ignition type internal combustion engine; the method includes the step of determining the characteristics of the fuel used by the internal combustion engine, based on a change in cylinder pressure caused by self-ignition after the start of the compression stroke and before performing spark ignition during the first combustion cycle, during which spark ignition is performed for the first time after cranking engine crankshaft.

[0026] According to the second object, during the first combustion cycle, during which spark ignition is performed for the first time after cranking the engine shaft during its starting, fuel characteristics are determined based on a change in cylinder pressure caused by self-ignition, over a period of time from the start of the compression stroke before performing spark ignition. A change in cylinder pressure caused by self-ignition correlates with fuel characteristics. Therefore, it becomes possible to determine the characteristics of the fuel before starting the internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The features, advantages, technical and industrial significance of embodiments of the invention will be described below with reference to the accompanying drawings, in which identical numbers indicate identical elements, and in which:

in FIG. 1 is a diagram for describing a system device of a first embodiment of the invention;

in FIG. 2 is a timing chart showing changes in cylinder pressure and engine shaft speed for a cylinder equipped with a cylinder pressure sensor during engine start-up;

in FIG. 3 is a diagram showing the relationship between the maximum value Pmax of pressure change in the cylinder and the octane number (RON) for a given operating mode;

in FIG. 4A is a diagram showing a tendency for a maximum value of Pmax to change with respect to the amount of air in the cylinder;

in FIG. 4B is a diagram showing a tendency for a maximum value of Pmax to change with respect to engine coolant temperature;

in FIG. 5 is a flowchart of a first embodiment of the invention; and

in FIG. 6 is a flowchart of a second embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention will be described below with reference to the drawings. Identical or similar elements in the drawings are denoted by the same reference numerals and will not be re-described below.

It should also be noted that the following descriptions do not limit the invention.

FIRST EXAMPLE OF IMPLEMENTATION

[FIRST EXAMPLE OF IMPLEMENTATION OF THE DEVICE]

[0029] FIG. 1 is a diagram for describing a system device for a first embodiment of the invention. As shown in FIG. 1, a system according to this embodiment includes an internal combustion engine 10 (engine). The engine 10 is a spark ignition type internal combustion engine equipped with a supercharger. The design of the supercharger is disclosed in many documents and therefore is not illustrated in the drawing. The exhaust pipe 16 is connected to the exhaust system of the engine 10. In the exhaust pipe 16 there is an exhaust gas catalyst 18 for removing harmful substances from the exhaust gases. The exhaust gas catalyst 18 may be a known catalyst, such as a triple catalyst or the like.

[0030] The system according to this embodiment also includes a fuel tank 12 for storing gasoline supplied externally. The input of the fuel line 14 is connected to the fuel tank 12. The output of the fuel line 14 is connected to the fuel system of the engine 10. In addition, one of the cylinders of the engine 10 is equipped with a cylinder pressure sensor (hereinafter also referred to as “DDC”) 22 for measuring pressure in this cylinder. The cylinder that is equipped with DDC 22 will be called the “cylinder equipped with DDC”.

[0031] The system according to an embodiment includes an ECU (electronic control unit) 20, as shown in FIG. 1. The inputs of the ECU 20 are connected not only with the aforementioned DDC 22, but also with a crank angle sensor for determining the angular position of the crankshaft, a coolant temperature sensor for determining the temperature of the engine coolant and a knock sensor that detects the occurrence of knock in the engine 10. The outputs of the ECU 20 are connected to various actuators for controlling the throttle, spark plug and fuel injection nozzles. The ECU 20 controls the operating mode of the engine 10 based on various information components input to the ECU 20.

[ACTION ON THE FIRST EXAMPLE OF EMBODIMENTS OF THE INVENTION]

(Refers to the phenomenon of self-ignition during engine start)

[0032] Next, actions according to an embodiment of the invention will be described with reference to FIGS. 2-4V. In a spark ignition type internal combustion engine 10, self-ignition, in which the air-fuel mixture in the cylinder spontaneously ignites, can sometimes occur in the first combustion cycle while cranking the crankshaft upon starting engine 10. This self-ignition phenomenon will be explained more specifically. Since cranking of the crankshaft initiated by the starter motor is low speed rotation (e.g. 260 rpm), the mixture in the cylinder is very slowly compressed during the first combustion cycle.

Then, an oxidation reaction takes place in the cylinder for a long period of the compression stroke in such a way that the mixture spontaneously ignites near the top dead center (TDC) and the fuel immediately burns out in the cylinder.

[0033] FIG. 2 is a timing chart showing a change in pressure in a cylinder equipped with a cylinder pressure sensor and engine speed during engine start. The example shown in this diagram illustrates how self-ignition occurs in the first combustion cycle during cranking of the engine 10. As mentioned above, with self-ignition, fuel in the cylinder burns out immediately, unlike conventional combustion that occurs when the flame propagates. Therefore, as shown in FIG. 2, when self-ignition occurs, a peak signal appears, indicating a sharp increase in pressure in the cylinder. After the first combustion increases the rotational speed of the motor shaft, the compression stroke is shortened, and therefore combustion usually occurs without self-ignition.

[0034] Combustion starting with self-ignition and combustion starting with ignition may differ from each other by the degree of pressure increase in the cylinder, as indicated above, and may also differ in another way, for example, the value of the angle of rotation of the crankshaft at which combustion occurs. Thus, the ignition time in the first combustion cycle is usually set as the PVMT time (post-top dead center time), while self-ignition occurs near TDC. Therefore, when determining the angle of rotation of the crankshaft at which combustion occurs, the difference can be easily made.

(Regarding the relationship between autoignition and octane)

[0035] As indicated above, a change in cylinder pressure due to self-ignition occurs in the first combustion cycle of the engine 10 if low octane fuel is used. The authors of this patent application conducted intensive studies and studies of the relationship between the change in pressure in the cylinder due to self-ignition and the octane number (RON) of the fuel. As a result, the inventors found that there is a definite correlation between the maximum value Pmax of the pressure change in the cylinder due to self-ignition and the octane number (RON) of the fuel used. In FIG. 3 is a diagram showing the relationship between the maximum value Pmax of pressure change in the cylinder and the octane number (RON) for a given engine operating mode. As shown in the diagram, the Pmax value increases as the octane number decreases.

[0036] Therefore, in the system according to this embodiment, the relationship shown in FIG. 3 is used to determine the octane number (RON) of the fuel used. Specifically, the relationship between the Pmax value and the octane number (RON) is previously stored as a card in the ECU 20, and the octane number (RON), which corresponds to the obtained Pmax value, is determined from the card. It should be noted that the Pmax value varies depending not only on the octane number (RON), but also on other engine operating conditions, such as the amount of air in the cylinder (compression ratio), engine coolant temperature, etc. In FIG. 4A shows the tendency for the maximum value of Pmax to change relative to the amount of air in the cylinder. In FIG. 4B shows the tendency for the maximum value of Pmax to change with respect to the temperature of the coolant. As shown in FIG. 4A and 4B, the maximum Pmax value tends to increase as the amount of air in the cylinder increases or the temperature of the coolant increases. Therefore, the system according to this embodiment carries out an adjustment in which the influence of the amount of air in the cylinder and the temperature of the coolant is reflected in the obtained maximum value Pmax. Then the octane number (RON) corresponding to the Pmax value after adjustment is determined from the map. The specific procedure for determining the octane number (RON) of the fuel used will be described in detail below with reference to the flowchart.

DETAILED DESCRIPTION OF THE PROCEDURE FOR THE FIRST EXAMPLE OF CARRYING OUT THE INVENTION

[0037] FIG. 5 is a flowchart in which the ECU 20 performs a procedure for determining the octane number (RON) of the fuel used. As shown in this block diagram, the ECU 20, after starting to crank the crankshaft, firstly controls so that the first combustion cycle is carried out in a cylinder equipped with a diesel engine (step 100). As for the method of this control, it is sufficient, for example, so that after determining the cylinder by cranking the crankshaft, fuel injection starts from a cylinder equipped with a diesel engine. Then, during the first combustion cycle, self-ignition occurs, accompanied by a change in cylinder pressure, the ECU 20 detects a change in cylinder pressure using the cylinder pressure sensor 22 and obtains its maximum value in the form of a Pmax value (step 102). Then, the ECU 20 corrects the obtained value Pmax based on the temperature of the coolant and the amount of air in the cylinder (step 104). In ECU 20, information about the relationship between the value of Pmax and the octane number (RON) in the form of a map is pre-stored. The ECU 20 accurately determines the octane number (RON) corresponding to the obtained Pmax value from the card (step 106).

[0038] As described above, according to the system of this embodiment, the octane number (RON) of the fuel used can be determined using a change in cylinder pressure caused by self-ignition during the first combustion cycle during engine start-up. Therefore, it becomes possible to determine the octane number (RON) of the fuel used using the existing device system without the need for a separate sensor installation to determine fuel characteristics, etc. In addition, since the octane number (RON) of the fuel used is detected before complete combustion, it becomes possible to carry out various types of control in proportion to the octane number (RON), immediately after starting the engine.

[0039] Although in the above-described first embodiment, the operating mode for the first combustion cycle during engine start-up is not specifically limited, the accuracy in determining fuel quality can be increased by setting such an operating mode that self-ignition occurs with a sufficient degree of probability. More precisely, the probability of self-ignition in the first combustion cycle is the higher, the higher the compression ratio. Therefore, with an increase in the amount of air in the cylinder in the first combustion cycle, the compression ratio can be effectively increased to achieve a condition that is favorable for self-ignition. In this regard, possible examples of a method for increasing the amount of air in a cylinder include a method in which the degree of opening of the throttle valve is increased, and a method in which in a system equipped with an electric mechanism for controlling the moment of opening or closing a valve (VVT electromechanism - variable valve timing - mechanism valve timing), the timing of closing the intake valves (IVC time - intake valves closure) is delayed. In addition, a variable compression ratio (VCR) engine may be used as the engine 10 to increase the compression ratio.

[0040] Furthermore, regarding the operating mode for the first combustion cycle during engine start-up, the probability of self-ignition in the first combustion cycle is the higher, the higher the temperature of the engine coolant. Therefore, if the coolant temperature detected by the coolant temperature sensor is below a predetermined reference value, the determination regarding the fuel characteristics may be limited. This will effectively limit the erroneous determination in the event that self-ignition does not occur.

[0041] Furthermore, although in the above first embodiment, the maximum value Pmax detected by the DDC (cylinder pressure sensor) 22 is corrected taking into account the amount of air in the cylinder and the temperature of the coolant so that these operating conditions are reflected in characterization fuel, this does not limit this method. Thus, the determination of the fuel characteristics, in which the operating mode is reflected, can be performed using pre-stored maps in which the octane number (RON) corresponds to the maximum value of Pmax separately for each of the operating modes (mode parameters), such as the amount of air in cylinder, coolant temperature, etc., and subsequent selection of a card in accordance with the current operating mode. In addition, the operating mode parameters regarding the adjustment are not limited to the amount of air in the cylinder and the coolant temperature, but other operating mode parameters, such as the amount of injected fuel, atmospheric pressure, etc., can be additionally used as operating mode parameters, related to adjustment.

[0042] Furthermore, despite the fact that in the first embodiment, one of the cylinders is equipped with DDC 22, two or more cylinders can be equipped with DDC 22. In this case, it is sufficient that the first combustion cycle is called up in one of the cylinders equipped with DDC .

[0043] In addition, although in the first embodiment, the maximum value (Pmax) of the cylinder pressure change caused by self-ignition in the first combustion cycle is used to determine the octane number (RON) of the fuel used, the cylinder pressure changes that applicable to determine, not limited to the maximum value of the pressure change in the cylinder. Thus, since self-ignition is a phenomenon that is synchronous with the angle of rotation of the crankshaft, the rate of change of pressure in the cylinder to a maximum value of Pmax inevitably becomes the higher, the higher will be Pmax.

Therefore, as the rate of change when the pressure in the cylinder changes, for example, the degree of change in pressure in the cylinder per unit of crank angle (ΔP / Δ0Ao) is determined, and the degree of change in pressure in the cylinder can be used to determine the octane number (RON) of the fuel used.

[0044] In this regard, in the first embodiment, the DDC 22 corresponds to a means for measuring pressure in the cylinder, and the ECU 20 implements a means for determining fuel characteristics by performing the procedures in steps 102 and 106.

[0045] Furthermore, in the first embodiment, the ECU 20 implements the cylinder selection means by performing the procedure in step 100 and implements the adjustment means by performing the procedure in step 104.

SECOND EXAMPLE FOR CARRYING OUT THE INVENTION

[FEATURES OF THE SECOND EXAMPLE OF EMBODIMENTS OF THE INVENTION]

[0046] Next, a second embodiment of the invention will be described with reference to FIG. 6. The second embodiment may be implemented by performing the sequence of operations shown in FIG. 6, in the system shown in FIG. one.

[0047] The system according to this embodiment includes a knock control system (hereinafter, KCS - knocking control system). The KCS system is a system that prevents knocking, delaying the ignition time in the event that the occurrence of detonation or any sign of this occurrence is detected by the knock sensor. However, the operating range of the KCS system is limited. Thus, if refueling occurs with an octane number lower than the octane number (RON) assumed to be processed by the KCS system, it is possible that the KCS system will not be able to deal with this situation sufficiently, and detonation in some cases cannot be avoided.

[0048] As described above, the system according to this embodiment is capable of determining the octane number (RON) of the fuel used based on the maximum value Pmax of the pressure change in the cylinder caused by self-ignition in the first combustion cycle. Therefore, in the system of the second embodiment, if the determined octane number (RON) is lower than the operating range of the KCS system, then the output of the internal combustion engine 10 is limited to avoid detonation and a warning is given to the driver. Possible examples of limiting engine power output include emergency operation or breakdown protection. Possible warning examples include the inclusion of an IDL (malfunction indicator lamp), a warning sound, etc. Such a device can effectively avoid the occurrence of detonation even if low-quality fuel is supplied during refueling, the octane number of which is very low.

DETAILED DESCRIPTION OF PROCEDURES PERFORMED IN THE SECOND EXAMPLE OF IMPLEMENTATION

[0049] FIG. 6 is a flowchart in which the ECU 20 performs a knock prevention procedure. As shown in this block diagram, the ECU 20, after starting to crank the crankshaft, firstly controls so that the first combustion cycle is carried out in a cylinder equipped with a diesel engine (step 200). After this, self-ignition occurs in the first combustion cycle, accompanied by a change in pressure in the cylinder. The ECU 20 detects a change in cylinder pressure using the cylinder pressure sensor 22 and determines its maximum value in the form of a Pmax value (step 202). Then, the ECU 20 corrects the obtained value Pmax based on the temperature of the coolant and the amount of air in the cylinder (step 204). In block ECU 20, information on the relationship between the value of Pmax and the octane number (RON) in the form of a map is stored in advance. The ECU 20 accurately determines the octane number (RON), which corresponds to the obtained value Pmax from the card (step 206). In steps 200-206, the ECU 20 performs the same procedure as in steps 100-106.

[0050] Then, the ECU 20 determines whether the octane number (RON) determined in step 206 is less than a predetermined reference value (step 208). The set reference value is the value of the lower limit of the operating range of the KCS system, pre-stored in the ECU 20 and read from the ECU 20, as necessary. If at step 208 it is not determined that the octane number (RON) <control value, it is determined that knocking can be avoided by the KCS system, and this sequence of actions immediately ends. On the other hand, if it is determined at step 208 that the octane number (RON) <control value, it is determined that knocking cannot be avoided using the KCS system, and the procedure proceeds to the next step, where the output of the internal combustion engine 10 is limited and a warning is given to the driver (step 210).

[0051] As described above, according to the system of the second embodiment, if the octane number (RON) of the fuel used is lower than the operating range of the KCS system, the output of the internal combustion engine 10 is accordingly limited so that the occurrence of detonation can be effectively avoided.

[0052] In the second embodiment, the DDTs 22 corresponds to a "means for measuring pressure in the cylinder", and the ECU 20 implements "means for determining the fuel characteristics" by performing the procedure of steps 202 and 206.

[0053] Furthermore, in the second embodiment, the ECU 20 implements the “cylinder selection means” by performing the procedure of step 200 and implements the “correction means” by performing the procedure of step 204.

[0054] Also, in a second embodiment, the ECU 20 implements “knock suppression means” by performing the procedure of steps 208 and 210.

Claims (14)

1. The control device for an internal combustion engine with spark ignition, characterized in that it contains:
cylinder pressure measuring means for measuring pressure in one or more cylinders of an internal combustion engine; and
means for determining fuel characteristics for detecting a change in cylinder pressure caused by self-ignition after the start of a compression stroke and before performing spark ignition using means for measuring pressure in the cylinder during the first combustion cycle, during which spark ignition is performed for the first time after crankshaft cranking has begun internal combustion engine, as well as to determine the characteristics of the fuel used by the internal combustion engine, based on changes in detecting in the cylinder. 2. The control device according to claim 1, characterized in that the means for determining the characteristics of the fuel includes means for determining the maximum value of the pressure change in the cylinder and determines the characteristics of the fuel used by the internal combustion engine based on this maximum value. 3. The control device according to claim 1, characterized in that the means for determining the characteristics of the fuel includes means for determining the rate of change when the pressure in the cylinder changes and determines the characteristics of the fuel used by the internal combustion engine based on this rate of change. 4. The control device according to claim 3, characterized in that the rate of change with pressure in the cylinder is the degree of change in pressure in the cylinder per unit angle of rotation of the crankshaft. 5. The control device according to any one of paragraphs. 1-4, characterized in that the means for measuring the pressure in the cylinder is a cylinder pressure sensor installed for a specific cylinder, which is one cylinder of one or more cylinders, and further includes
means for selecting a cylinder for performing a first combustion cycle on that specific cylinder. 6. The control device according to claim 1, characterized in that it further includes
control means for controlling the increase in the compression ratio in the first combustion cycle. 7. The control device according to claim 6, characterized in that
control means for controlling the increase in the compression ratio in the first combustion cycle increases the throttle opening degree so as to increase the compression ratio in the first combustion cycle. 8. The control device according to claim 6, characterized in that
control means for controlling the increase in the compression ratio in the first combustion cycle delays the closing moment at which the inlet valve is closed by a valve for controlling the opening or closing moment of the valve so as to increase the compression ratio in the first combustion cycle. 9. The control device according to claim 1, characterized in that it further includes
correction means for correcting changes in cylinder pressure determined by cylinder pressure measuring means by using the temperature of the coolant of the internal combustion engine or the amount of air in the cylinder of the internal combustion engine. 10. The control device according to claim 1, characterized in that
means for determining the characteristics of the fuel determines the octane number of fuel used by the internal combustion engine. 11. The control device according to p. 10, characterized in that it further includes
knock suppression means for controlling suppression of knock occurrence if the octane determined by the fuel characterization means is less than a predetermined reference value. 12. The control device according to p. 11, characterized in that
knock suppression means includes means for limiting the output of the internal combustion engine. 13. The control device according to claim 11 or 12, characterized in that
knock suppression means includes warning means for providing a warning to the user. 14. A method for controlling an internal combustion engine with spark ignition, characterized in that it includes the step of determining the characteristics of the fuel used by the internal combustion engine, based on a change in cylinder pressure caused by self-ignition, after the start of the compression stroke and before performing spark ignition during the first combustion cycle, during which spark ignition is performed for the first time after starting cranking the crankshaft of the internal combustion engine.

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