JP6504045B2 - Throttle diagnostic device - Google Patents

Description

  The present invention relates to a throttle abnormality diagnosis apparatus that performs abnormality diagnosis on an electronically controlled throttle drive device, and in particular, performs abnormality diagnosis on an urging member that urges a throttle valve in either an opening or closing direction. The present invention relates to a throttle diagnostic device.

  There is known a throttle diagnosis device which diagnoses an abnormality of a biasing member with respect to an electronically controlled throttle drive device after the ignition is turned off (see, for example, Patent Document 1). The biasing member is a member for positioning the throttle valve, and for example, when the ignition is off, the biasing member causes the throttle valve to return to a predetermined opening degree. In the abnormality diagnosis, first, after the throttle valve is opened to a predetermined opening degree by the drive unit, the power supply of the drive unit is stopped. Then, the throttle valve is made to return to the determination position by the biasing force of the biasing member, and at this time, the time required for the constant opening change is measured, and is the biasing member functioning normally based on this measurement result? It judges whether or not.

JP-A-11-229943

  If the temperature around the throttle valve changes after the vehicle travels, condensation occurs on the throttle valve. At this time, if the throttle is below 0 ° C., dew condensation water formed on the surface of the throttle valve will freeze. For example, in the electronic control type throttle drive device, the thing of the type which eliminated the warm water passage is adopted for cost reduction. In a throttle drive system having no hot water path, the throttle valve is cooled after traveling at an extremely low temperature, and in that state, the combustion gas present downstream of the throttle after the engine is stopped is cooled by the throttle valve and the combustion gas is Water inside condenses and freezing occurs. In addition, even when the vehicle is stopped in a garage or the like where the ambient temperature is relatively high, the outside air is cooled by the throttle valve by intrusion of the outside air into the throttle valve, and moisture in the outside air is condensed and frozen. Furthermore, in the case of a throttle drive device having a hot water passage, when the vehicle is stopped in a garage or the like where the ambient temperature is relatively high before the water temperature rises under extremely low temperature, the outside air is throttled by the outside air entering the throttle portion There is a possibility that the phenomenon that the moisture in the outside air condenses and freezes may occur. If condensation water freezes, increase the drive resistance of the throttle valve. When the drive resistance of the throttle valve due to freezing increases, the time required for the throttle valve due to the biasing member to return to the determination position becomes long, and there is a possibility that an erroneous diagnosis will be made as an abnormality at the time of abnormality diagnosis.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a throttle diagnosis device capable of preventing a false diagnosis due to freezing in an abnormality diagnosis on a biasing member of a throttle drive device.

  In order to solve the above-mentioned problems, in the present invention, a throttle drive device having a throttle valve, a drive unit for opening and closing the throttle valve, and an urging member for urging the throttle valve to a predetermined reference opening. A throttle diagnosis device that performs abnormality diagnosis of the biasing member based on the time from the operating position to the determination position by the biasing member after the ignition is turned off. After that, the abnormality diagnosis is performed based on the number of times of the opening / closing operation stored in the operation frequency storage unit after the ignition is turned off, and the operation frequency storage unit that stores the opening / closing operation of the throttle valve by the drive unit. And a determination unit that switches between implementation and non-implementation.

  After the ignition is turned on, the opening and closing operation of the throttle valve by the drive unit is repeated, so that even if the throttle valve is frozen, the freezing is weakened and the operating resistance of the throttle valve which causes a misdiagnosis is reduced. it can. Therefore, in the present invention, after the ignition is turned on, the operation number storage unit stores the opening / closing operation of the throttle valve which is a factor that weakens the operation resistance due to freezing. Then, after the ignition is turned off, the determination unit determines, based on the number of opening and closing operations stored in the operation number storage unit, the weakening of the operation resistance due to the freezing described above, and determines whether to perform abnormality diagnosis or not. . For example, if the number of opening and closing operations of the throttle valve is equal to or more than a predetermined number, it is determined that the operation resistance due to the freezing of the throttle valve is weak and there is no fear of abnormality diagnosis. On the other hand, if the number of opening and closing operations of the throttle valve is less than a predetermined number, it is determined that there is a possibility of abnormality diagnosis. As a result, it is possible to prevent misdiagnosis due to freezing of the throttle valve.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the structure of the intake system 100 which concerns on this embodiment. FIG. 8 is a diagram for explaining processing that is performed in response to turning on and off of the IG switch 66. The flowchart explaining abnormality diagnosis. 7 is a flowchart illustrating storage of the number of opening and closing operations. FIG. 6 is a diagram for explaining a throttle opening to be stored. 5 is a flowchart showing determination of a diagnosis condition performed by the ECU 50. The figure explaining the relationship between environmental temperature DE and the threshold value TW. The figure explaining determination of the implementation conditions which concern on 2nd Embodiment.

  Embodiments according to the present invention will be described with reference to the drawings. In the following, as an example, a throttle drive unit incorporated in the middle of an intake passage of an engine (internal combustion engine) having a plurality of cylinders, and a throttle diagnosis unit (electronic control unit: ECU for performing abnormality diagnosis on the throttle drive unit) And an intake system comprising In the following embodiments, parts identical or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the parts having the same reference numerals is incorporated.

First Embodiment
FIG. 1 is a view showing the configuration of an intake system 100 according to the present embodiment. The intake system 100 mainly includes the throttle drive device 10, the ECU 50, and various sensors as described above.

  First, the configuration of the throttle drive device 10 will be described. The throttle drive device 10 mainly includes a throttle body 11, a throttle valve 20, a return spring 30, a reduction gear 40, and a drive motor 45. In this embodiment, the return spring 30 functions as a biasing member.

  The throttle body 11 is integrally formed with a cylindrical intake duct (cylindrical portion) 16 incorporated in the middle of an intake pipe of the engine. Further, inside the intake duct 16 is formed a throttle bore 17 having a circular cross section, which is an intake passage communicating with the combustion chamber of each cylinder of the engine and through which the intake air passing through the air cleaner flows.

  Further, the throttle body 11 is integrally formed with a gear case 13 and a motor case 12 which are accommodation portions in which members are accommodated. The throttle body 11 is formed in a predetermined shape by metal or synthetic resin.

  A throttle valve 20 is rotatably attached to the intake duct 16 of the throttle body 11. The throttle valve 20 has a valve body 21 for measuring the flow rate of intake air that has passed through the air cleaner, and a shaft portion 22 fixed to the valve body 21.

  The valve body 21 is in the form of a disk having an outer diameter slightly smaller than the inner diameter of the throttle bore 17, and the shaft portion 22 is fixed to the center in a state in which both end portions are protruded. Both ends of the valve body 21 are rotatably supported in the axial direction by bearings 23 and 23 which are press-fitted into the intake duct 16.

  The gear case 13 of the throttle body 11 mainly houses a return spring 30 and a reduction gear 40. Further, an end of the shaft portion 22 protrudes from the gear case 13.

  The return spring 30 applies a biasing force to bias the valve body 21 to a predetermined intermediate opening (reference opening). The return spring 30 is engaged with the shaft portion 22 of the valve body 21 via an opener member 31 accommodated in the gear case 13. In FIG. 1, the opener member 31 is a flange member coupled to an end of the shaft 22 projecting to the gear case 13, and is rotatable integrally with the shaft 22. Further, the opener member 31 is engaged with one end of the return spring 30 in a state where the cylindrical portion is inserted inside the return spring 30. In a steady state in which no drive force is generated by the drive motor 45, the throttle valve 20 is held at an intermediate opening in the throttle bore 17 by the biasing force of the return spring 30.

  The intermediate opening degree which is the reference opening degree is, for example, the position of the valve body 21 when the valve body 21 shields the throttle bore 17 as shown in FIG. 1. In addition to this, the reference opening may be a fully closed position or a fully open position of the valve 21.

  The reduction gear 40 is composed of a plurality of gears with different gear ratios, and transmits the rotational force of the drive motor 45 to the throttle valve 20. The reduction gear 40 is interposed between an output gear 41 integrated with the opener member 31, a pinion gear 42 attached to the output shaft of the drive motor 45, and the pinion gear 42 and the output gear 41. And an intermediate gear 43 for transmitting the rotation speed [rpm] to the output gear 41.

  The motor case 12 of the throttle body 11 houses a drive motor 45 that functions as a drive unit. By rotating the pinion gear 42, the drive motor 45 rotates the output gear 41 via the intermediate gear 43, and operates the position of the throttle valve 20 between the fully open position and the fully closed position. Further, the drive motor 45 is electrically connected to the battery 70 mounted on the vehicle via a motor drive circuit 55 electronically controlled by the ECU 50.

  Next, the ECU 50 and a sensor group connected to the ECU 50 will be described. The ECU 50 variably controls the throttle opening degree in accordance with the operating condition of the engine (for example, the depression amount of the accelerator pedal, the accelerator opening degree). The ECU 50 is a microcomputer of a known structure including functions of a CPU, a memory (ROM and RAM), an input circuit (input unit), an output circuit (output unit), a power supply circuit, a timer circuit and the like.

  Connected to the ECU 50 is a motor drive circuit 55 that controls energization of the drive motor 45. The motor drive circuit 55 variably controls the power supplied to the internal conductor (armature coil) of the drive motor 45 with respect to the control signal (for example, the duty ratio of the PWM signal) supplied from the ECU 50.

  Connected to the ECU 50 are a sensor group that detects the state of the vehicle and the throttle opening of the throttle valve 20. In FIG. 1, an air flow meter 61, a crank angle sensor 62, an accelerator opening sensor 63, a throttle opening sensor 64, a temperature sensor 65, and an IG switch (ignition switch) 66 are connected as a sensor group.

  The ECU 50 determines the operating state of the engine based on outputs from the air flow meter 61, the crank angle sensor 62, and the accelerator opening sensor, for example. Further, the ECU 50 calculates a target throttle opening based on an accelerator opening signal which is an output signal of the accelerator opening sensor 63, and the deviation between the actual throttle opening detected by the throttle opening sensor 64 and the target throttle opening The electric power supplied to the drive motor 45 is feedback controlled so that

  The throttle opening degree sensor 64 detects the rotation angle of the shaft portion 22 and outputs the detected rotation angle to the ECU 50. The throttle opening degree sensor 64 is configured of, for example, a magnetic sensor that detects a magnetic flux density that changes according to the rotation of the shaft portion 22. In FIG. 1, the throttle opening sensor 64 is installed in the cylindrical boss of the opener member 31 (output gear 41) in the gear case 13, and outputs to the ECU 50 the change in the magnetic field accompanying the rotation of the shaft 22. . The ECU 50 acquires the throttle opening degree corresponding to the rotation angle of the throttle valve 20 based on the output from the throttle opening degree sensor 64.

  The temperature sensor 65 outputs a value corresponding to the environmental temperature DE of the engine to the ECU 50. The environmental temperature DE acquired by the temperature sensor 65 is the outside air temperature, the temperature around the engine, the temperature of the main body air of the engine, the water temperature of the engine, and the like.

  The IG switch 66 switches power on and off of the battery 70 for the vehicle. The IG switch 66 is connected to a main relay 67 that connects the battery 70 and the load circuit including the ECU 50. For example, when the driver turns on the IG switch 66 (ignition is turned on), the main relay 67 is turned on, and the battery 70 conducts electricity to the ECU 50. On the other hand, when the driver turns the IG switch 66 OFF (ignition OFF), the main relay 67 is turned OFF after a predetermined period, and the current from the battery 70 to the ECU 50 is cut off.

  After the IG switch 66 is turned off, the ECU 50 carries out an abnormality diagnosis to diagnose the return spring 30. FIG. 2 is a diagram for explaining the process performed in response to the ON operation and the OFF operation of the IG switch 66.

  In the abnormality diagnosis, after the return spring 30 is operated to a predetermined target opening degree (operating position) by the drive motor 45, the energization of the drive motor 45 is cut off. Therefore, the throttle valve 20 operates from the target opening to the intermediate opening by the biasing force of the return spring 30. At this time, the ECU 50 acquires the time (acquisition time AT) required for the throttle valve 20 to operate from the target opening to the determination opening S / L (determination position). If the biasing force of the return spring 30 is normal, the acquisition time AT becomes shorter than a predetermined determination time. On the other hand, if the biasing force of the return spring 30 is abnormal, the acquisition time AT becomes longer than the determination time. Therefore, the ECU 50 compares the acquisition time AT with the determination time to diagnose the biasing force of the return spring 30.

  In FIG. 2, the determination opening is set as a value between the target opening and the intermediate opening. In addition to this, the determination opening may be set to an intermediate opening.

  In the abnormality diagnosis shown in FIG. 2 described above, there is a possibility that the return spring 30 may be erroneously determined to be abnormal due to the freezing of the throttle valve 20. For example, when the engine changes from high temperature to low temperature due to IG off, condensation occurs in the throttle valve 20, but when condensed water freezes due to the open air, the operating resistance of the throttle valve 20 is increased. As the operating resistance of the throttle valve 20 increases, the acquisition time AT required for the throttle valve 20 to operate up to the judgment opening degree S / L is lengthened by the biasing force of the return spring 30, and the return spring 30 functions normally. May also be misdiagnosed as abnormal. Further, at the time of abnormality diagnosis, since the drive motor 45 can change the throttle valve 20 to the target opening degree by the torque by the power supply, it is difficult to determine the erroneous diagnosis.

  Therefore, in this embodiment, the ECU 50 predicts the possibility of an erroneous determination due to the freezing of the throttle valve 20, and avoids the execution of the abnormality diagnosis when the possibility of an erroneous determination is high. Thereby, it can prevent that the return spring 30 which freezing generate | occur | produced is misjudged.

  Next, an abnormality diagnosis method implemented by the intake system 100 will be described. FIG. 3 is a flow chart for explaining the process involved in the abnormality diagnosis. The process shown in FIG. 3 is a process performed by the ECU 50 after the operation of the IG switch 66 (IG off).

  In step S11, it is determined whether or not the IG switch 66 has been turned on after being turned on. If the IG switch 66 is ON (step S11: NO), the process proceeds to step S12, and the drive motor 45 is normally controlled such that the throttle opening of the throttle valve 20 becomes an opening corresponding to the opening of the accelerator pedal. Control is performed.

  On the other hand, when ON of the IG switch 66 is continued (step S11: YES), in step S13, it is determined whether a diagnosis condition for performing abnormality diagnosis is established. The diagnosis conditions are conditions under which the ECU 50 determines whether or not to perform an abnormality diagnosis. The details of step S13 will be described later.

  If the diagnosis condition is not satisfied (step S13: NO), the process ends without performing the abnormality diagnosis. On the other hand, when the diagnosis condition is satisfied (step S13: YES), the process proceeds to step S14 to perform abnormality diagnosis on the return spring 30. In the abnormality diagnosis, as shown in FIG. 2, after operating the throttle valve 20 to the target opening degree, it is determined the time required for the throttle valve 20 to return to the judgment opening degree S / L by the biasing force of the return spring 30 .

  If it is determined that the return spring 30 is normal (step S15: NO), the process is ended. On the other hand, when the return spring 30 is diagnosed as abnormal (step S15: YES), an abnormality is stored in step S16. Then, the process ends. The abnormality determination stored in step S16 may be notified next when the IG switch 66 is turned on.

  Next, prior to describing the determination of the diagnosis condition in step S13 of FIG. 2, a method of acquiring the number of opening / closing operations used in the determination of the diagnosis condition will be described. FIG. 4 is a flowchart for explaining the storage of the number of opening and closing operations of the throttle valve 20. The process shown in FIG. 4 is, for example, a process performed by the ECU 50 every time the driver operates the accelerator pedal in step S12 after the IG is turned on. By the process shown in FIG. 4, the ECU 50 functions as an operation number storage unit. FIG. 5 is a diagram for explaining the throttle opening to be stored.

  In step S21, the magnitude of the change in the throttle opening is determined. For example, the ECU 50 determines, based on time-series changes in the output from the throttle opening degree sensor 64, the throttle operation in which a predetermined opening degree change occurs. For example, the ECU 50 determines that the throttle opening degree is large, that is, the throttle operation that produces a predetermined amount of opening degree change (throttle opening degree change SVA) from the intermediate opening degree. The throttle opening degree change SVA is a value capable of sufficiently reducing the operation resistance associated with the freezing of the throttle valve 20 by ensuring that the shaft portion 22 of the throttle valve 20 slides by a predetermined amount.

  If the change in the throttle opening degree is large (step S21: YES), the number of operations WC is stored in step S22, and the process is ended. In this embodiment, the ECU 50 has a history for storing the number of operations WC, and updates the history according to the determination result in step S21. Therefore, each time the accelerator pedal is operated in the period from IG on to IG off, the ECU 50 performs the determination shown in FIG. 4 and stores the operation count WC according to the determination result.

  Next, determination of a diagnosis condition using the number of operations WC stored by the ECU 50 will be described. FIG. 6 is a flowchart showing the determination of the diagnosis condition performed by the ECU 50, and is a process performed in step S13 of FIG. The ECU 50 functions as a determination unit by the process shown in FIG.

  In step S31, it is determined that the execution condition is met. The implementation conditions are conditions for performing abnormality diagnosis, and are conditions for indirectly determining that the throttle valve 20 is not frozen. In the first embodiment, the ECU 50 acquires the environmental temperature DE based on the output from the temperature sensor 65, and determines whether the acquired environmental temperature DE is higher than the threshold value TD. The threshold value TD is a temperature at which condensation water freezes, and for example, a value of 0 ° C. or less can be used. Therefore, the ECU 50 implements the detection unit by the process of step S31.

  If the execution condition is satisfied (step S31: YES), the process proceeds to step S34, and condition satisfaction determination is performed. That is, since the ECU 50 can determine from the environmental temperature DE that freezing of the throttle valve 20 has not occurred, the abnormality diagnosis is permitted.

  On the other hand, if the implementation condition is not satisfied (step S31: NO), the process proceeds to step S32, and the determination threshold value TW for determining the operation count WC is set based on the environmental temperature DE. FIG. 7 is a diagram for explaining the relationship between the environmental temperature DE and the determination threshold value TW. In this embodiment, when the environmental temperature DE becomes equal to or less than a threshold value TD (for example, 0 [° C.]), the determination threshold value TW is changed so that the number of operations WC increases as the environmental temperature DE decreases.

  In FIG. 7, when the environmental temperature DE becomes lower than the determination threshold TD, the determination threshold is monotonously increased. However, the present invention is not limited to this, and may be increased stepwise. .

  Returning to FIG. 6, in step S33, the stored number of operations WC is determined. The ECU 50 compares the operation count WC stored in the history with the determination threshold value TW set in step S32 to determine whether the operation resistance due to freezing is reduced.

  If the operation count WC is equal to or greater than the determination threshold TW (step S33: YES), the process proceeds to step S34, and condition satisfaction determination is performed. That is, the ECU 50 determines that the operation resistance due to the freezing of the throttle valve 20 is reduced by IG off, and permits the abnormality diagnosis.

  If the number of times of operation WC is less than the determination threshold value TW (step S33: NO), the process proceeds to step S35, and condition non-establishment determination is performed. That is, it is determined that the operation resistance due to the freezing of the throttle valve 20 is not reduced by IG off, and the abnormality diagnosis is not permitted.

  Then, in step S14 of FIG. 3, abnormality diagnosis is performed or not performed according to the determination result of steps S34 and S35 of FIG. 6 described above.

  As described above, in this embodiment, the ECU 50 (the number-of-operations storage unit) stores the opening / closing operation of the throttle valve 20 which is a factor that weakens the operation resistance of the throttle valve 20 due to freezing. Then, the ECU 50 (determination unit) determines the weakening of the freezing of the throttle valve 20 based on the stored number of opening / closing operations after IG is turned off, and switches whether to perform abnormality diagnosis or not. As a result, it becomes possible to prevent a misdiagnosis of the throttle valve 20 due to freezing.

  The ECU 50 (operation number storage unit) stores an open / close operation in which the amount of change in the throttle opening is equal to or greater than a predetermined amount. The opening and closing operation where the amount of change in the throttle opening becomes equal to or more than the predetermined amount has a high degree of weakening the operation resistance due to freezing, and whether to perform or not perform abnormality diagnosis by using the number of such opening and closing operations for determination. As a result, the determination accuracy of the establishment of the diagnosis condition can be enhanced.

  -A detection unit (S31) for detecting the environmental temperature of the engine, and the ECU 50 (determination unit) performs abnormality diagnosis based on the stored number of opening / closing operations when the environmental temperature is equal to or lower than a predetermined temperature Decide whether to implement or not. It is desirable to carry out an abnormality diagnosis as much as possible since it diagnoses an abnormality in the return spring 30, but it is desirable that no misdiagnosis due to freezing also occur. Here, if the temperature of the engine is high, the possibility that the throttle valve 20 is freezing is reduced. Therefore, if the environmental temperature DE of the engine is equal to or higher than the predetermined temperature, it is possible to increase the opportunity to carry out the abnormality diagnosis by carrying out the abnormality diagnosis.

  The ECU 50 (determination unit) changes the number of open / close operations to be referred to as a case where abnormality diagnosis is not performed based on the detected environmental temperature DE of the engine. By changing the number of open / close operations referred to by the ECU 50 according to the environmental temperature DE, priority is given to not carrying out an abnormality diagnosis in the environmental temperature DE where an erroneous diagnosis easily occurs, and an environmental temperature DE where an erroneous diagnosis hardly occurs In this case, priority can be given to implementation of abnormality diagnosis. As a result, the ECU 50 can properly balance the execution of the abnormality diagnosis and the prevention of the occurrence of the erroneous diagnosis.

Second Embodiment
The implementation condition in step S31 of FIG. 6 may use the length of the period when the engine is stopped. FIG. 8 is a diagram for explaining the determination of the implementation condition according to the second embodiment.

  If the period during which the engine is stopped (for example, the soak time) is long, the environmental temperature DE decreases, and the possibility that the condensed water generated in the throttle valve 20 freezes increases. On the other hand, if the period during which the engine is stopped is short, the amount of decrease in the environmental temperature DE becomes low, and it becomes difficult for the dew condensation water produced on the throttle valve 20 to freeze. Therefore, in addition to the condition that the environmental temperature DE becomes a predetermined temperature (for example, 0 ° C.) in step S31 of FIG. 6, the establishment condition is determined by adding the period in which the engine is stopped to the determination condition. For example, the ECU 50 receives an output from a known soak timer and determines a period in which the engine is stopped.

  -With the above configuration, the number of times the abnormality diagnosis is performed increases by adding the time during which the engine is stopped at the time of IG on to the determination condition of whether to perform the abnormality diagnosis, and the reliability of the throttle drive device 10 Can be enhanced.

(Other embodiments)
The use of the change amount of the throttle opening as the condition of the opening and closing operation stored in the ECU 50 is merely an example. For example, the ECU 50 may monitor the throttle opening at a predetermined cycle, and determine a change in the throttle opening based on the maximum value of the throttle opening.

  The use of the return spring 30 as the biasing member is merely an example, and any member may be used as long as it applies a biasing force to the throttle valve 20.

  20 ... throttle valve, 30 ... return spring, 45 ... drive motor, 50 ... ECU.

Claims (5)

A throttle drive system (10) comprising a throttle valve (20), a drive unit (45) for opening and closing the throttle valve, and an urging member (30) for urging the throttle valve to a predetermined reference opening. A throttle diagnosis device (50) for performing an abnormality diagnosis of the biasing member based on a time until the throttle valve changes from the operating position to the determination position by the biasing member after the ignition is turned off. ,
An operation number storage unit (S25) for storing the number of times of the opening / closing operation of the throttle valve by the drive unit after the ignition is turned on;
A throttle having a determination unit (S33, S34, S35) for determining whether to perform the abnormality diagnosis or not based on the number of times of the opening / closing operation stored in the operation number storage unit after the ignition is turned off. Diagnostic device.   2. The throttle diagnosis device according to claim 1, wherein the operation number storage unit stores the number of times of the opening / closing operation in which the change amount of the throttle opening in the throttle valve is equal to or more than a predetermined amount. A detection unit (S31) for detecting the environmental temperature of the internal combustion engine;
The determination unit is configured to determine whether the abnormality diagnosis is to be performed or not based on the number of times of the opening / closing operation stored in the operation number storage unit when the environmental temperature is equal to or lower than a predetermined temperature. The throttle diagnostic device according to claim 1 or 2.   The throttle diagnosis device according to claim 3, wherein a determination value of the number of times of determining whether to perform the abnormality diagnosis is changed based on the detected environmental temperature.   When the stop period of the internal combustion engine after the ignition is on is a predetermined time or more, the determination unit may or may not perform the abnormality diagnosis based on the number of opening / closing operations stored in the operation number storage unit. The throttle diagnosis device according to any one of claims 1 to 4, which determines

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