JP2006009784A - Number of idle revolution controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a number of idle revolution controller capable of speedily returning the number of idle revolutions to target number of idle revolutions when the number of idle revolutions is abruptly changed due to large load fluctuation. <P>SOLUTION: An electronically controlled throttle device 13 is controlled by a control unit 21 so that actual number of idle revolutions of the internal combustion engine 11 agrees with a target value to feedback-control air amount. When change amount ΔNE of the number of idle revolutions is larger than a previously determined reference value XNE, the control unit compensates air amount by air amount ΔQN being proportional to the change amount. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an idle speed control device for an internal combustion engine.

In conventional idle speed control, loads that can be predicted in advance, such as electrical systems and air conditioners, are handled with appropriate air volume correction, and the rotation speed is monitored for other unpredictable load fluctuations due to other disturbance factors. The target idle speed is maintained by the feedback control.
JP-A-9-68084

  In feedback control, as a general characteristic, it is known that hunting or overshooting occurs when the gain is excessive, and convergence to the target value is delayed when the gain is excessive. In an internal combustion engine mounted on a vehicle, normally, the idling speed does not change suddenly, and therefore, gain setting is made with emphasis on stability. For this reason, there arises a problem that convergence is delayed or the rotational speed becomes unstable when a large load that cannot be predicted is applied and the idle rotational speed is greatly reduced. As a condition for generating such an unpredictable load, for example, when the release of the lockup clutch of the automatic transmission is delayed due to sudden braking, a large load cannot be detected due to a failure of the power steering switch or hydraulic switch. There are times when acted on.

  An object of the present invention is to provide an idle speed control device that can quickly return to a target idle speed when the idling speed suddenly changes due to such a large load fluctuation.

  In the present invention, as a basic configuration of the idle speed control device, an air amount control means for adjusting the intake air amount of the internal combustion engine, an idle operation detection means for detecting an idling operation state, and an engine speed during idling operation. And a control for feedback-controlling the air amount control device based on a deviation between the target value of the idle speed and the detected value so that the actual idle speed of the internal combustion engine matches the target value. Means.

  Further, in the present invention, in order to achieve the above object, there is provided a rotation speed change detecting means for detecting a change amount of the idle rotation speed, and the control means is provided with a change amount of the idle rotation speed larger than a predetermined reference value. In this case, the air amount is corrected in an amount proportional to the idle speed deviation until the actual idle speed returns to the target value.

  According to the present invention, when the idling engine speed greatly changes to a certain reference value or more, the engine speed is corrected by the air amount proportional to the engine speed deviation from the target value at that time. The idling speed can be quickly returned to the vicinity of the target value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an idle speed control device for an internal combustion engine to which the present invention is applicable. In the figure, 11 is an internal combustion engine, 12 is its intake passage, 13 is an electronically controlled throttle device interposed in the middle of the intake passage 12, 14 and 15 are its throttle valve and throttle opening sensor, 16 is an intake air amount sensor, 17 is an engine speed sensor, 18 is an accelerator pedal switch, and 21 is a control unit. In relation to the present invention, the electronic control throttle device 13 adjusts the intake air amount of the internal combustion engine, the rotation speed sensor 17 is the rotation speed detection means, the accelerator pedal switch 18 is the idle operation detection means, and the control unit 21. Corresponds to the control means and the rotational speed change detecting means, respectively.

  The control unit 21 is composed of a microcomputer comprising a CPU and its peripheral devices. The control unit 21 determines the operating state of the internal combustion engine based on inputs from the various sensors so that the idle speed matches a predetermined target value. The idle air amount is adjusted by the electronic control throttle device 13.

  In this embodiment, the idle operation state is determined by the accelerator pedal switch 18, and in the idle operation state, the air amount is adjusted by a signal from the rotation speed sensor 17 to feedback control the idle rotation speed. In this case, the air amount is also feedback-controlled based on the signal from the intake air amount sensor 16.

  Basic feedback control of the idle speed is based on integral control. In the present invention, when the rotational speed deviation is further large, the engine speed is quickly returned to the target idle speed by correcting the intake air amount regardless of the feedback control amount.

  Next, an intake air amount correction routine executed by the control unit 21 for this control will be described with reference to FIG. The control unit 21 executes this routine periodically while the internal combustion engine 11 is operating. In the following description or drawings, the number with the symbol S represents the step number of the processing routine.

  When the internal combustion engine 11 is in the idle operation state, as described above, feedback control of the engine speed to the target idle speed is performed by another idle speed feedback control routine. The routine shown in this figure corrects the target intake air amount under a predetermined condition, and prioritizes the control of the opening degree of the electronically controlled throttle device 13 performed in the idle speed feedback control routine. The opening degree of the electronically controlled throttle device 13 is controlled based on the air amount.

  First, in S201, the control unit 21 determines whether or not the internal combustion engine 11 is in an idle operation state. Specifically, based on the signal from the accelerator pedal switch 18, when the accelerator pedal is released, it is determined that the internal combustion engine 11 is in the idling operation state.

  If the determination in S201 is negative, the control unit 21 immediately terminates the routine without executing the subsequent processes. If the determination in S201 is affirmative, the control unit 21 executes the processes after S202.

  In S202, the control unit 21 calculates the rotational speed deviation ΔNE of the internal combustion engine 11 by the following equation (1).

ΔNE = tNE-NE… (1)
Where tNE = target idle speed
NE = actual rotational speed of the internal combustion engine 11.

  The actual rotational speed NE is a detection speed of the rotational speed sensor 17. As shown in the equation, the rotational speed deviation ΔNE takes a positive value when the actual rotational speed of the internal combustion engine 11 is lower than the target idle rotational speed.

  The control unit 21 further calculates a feedback correction amount QFB of the intake air amount by basic feedback control by the following equation (2).

When ΔNE ≥ Y: QFB = QFBZ + ΔI, and when ΔNE ≤ -Y: QFB = QFBZ-ΔI… (2)
Y = boundary value that defines the dead zone
QFBZ = QFB calculated during the previous routine execution
ΔI = change amount.

  The feedback correction amount QFB calculated using the equation (2) gradually changes, and an environment in which hunting is unlikely to occur in the idle rotation speed is realized. Under normal control conditions, the feedback control of the opening degree of the electronically controlled throttle device 13 based on the rotational speed deviation ΔNE of the internal combustion engine 11 causes the internal combustion engine 11 to absorb a certain amount of load fluctuations and set the actual rotational speed to the target idle speed. Keep near the number.

  The method of calculating the feedback correction amount QFB in S202 is not limited to Equation (2). Any calculation method may be used as long as the feedback correction amount QFB gradually changes in accordance with the deviation ΔNE every time the routine is executed. For example, a proportional / integral control calculation method in which the proportional gain is set to a small value can also be applied to the calculation of the feedback correction amount QFB in S202.

  In next step S204, the control unit 21 obtains the intake air amount increase ΔQN with reference to the characteristic map shown in the figure stored in advance in the internal memory based on the rotational speed deviation ΔNE. The intake air amount increase ΔQN has the following characteristics.

  That is, as the rotational speed deviation ΔNE increases, the intake air amount increase ΔQN increases. When the rotational speed deviation ΔNE is smaller than the predetermined deviation W and when the rotational speed deviation ΔNE is a negative value, the intake air amount increase ΔQN is zero. When ΔQN is zero, the intake air amount is controlled depending on the feedback control based on the rotational speed deviation ΔNE in S202.

  In next S205, the control unit 21 determines whether or not the rotational speed deviation ΔNE is equal to or greater than a predetermined value XNE. Here, the predetermined value XNE is set to zero. The predetermined value XNE is a value for determining that the rotational speed NE of the internal combustion engine 11 has substantially returned to the target idle rotational speed tNE, and is not necessarily limited to zero, and may be a value close to zero.

  If the determination in S205 is affirmative, the control unit 21 sets a final increase ΔQNMAX of the intake air amount in S206. Specifically, the larger of the intake air amount increase ΔQN obtained by referring to the map in S204 and the previous increase value ΔQNMAXZ of the final increase amount ΔQNMAX of the intake air amount obtained during the previous routine execution is the final increase amount ΔQNMAX. And

  If the rotational speed deviation ΔNE is greater than or equal to the predetermined value XNE in S205 and the rotational speed deviation ΔNE increases with each execution of the routine, therefore, the intake air amount obtained from the map in S204 is added to the final increase amount ΔQNMAX of the intake air amount. The air amount increase ΔQN is applied. As a result, the final increase ΔQNMAX increases.

  On the other hand, when the rotational speed deviation ΔNE is greater than or equal to the predetermined value XNE in S205, but the rotational speed deviation ΔNE is decreasing every time the routine is executed, the previous value ΔQNMAXZ is always applied to the final increase ΔQNMAX of the intake air amount. The That is, the final increment ΔQNMAX maintains a constant value.

  In next S207, the control unit 21 calculates the total intake air amount QTOTAL supplied to the internal combustion engine 11 by the following equation (3).

QTOTAL = QCAL + QFB + ΔQNMAX… (3)
Where QCAL = basic intake air amount when the internal combustion engine 11 is idling
QFB = feedback correction amount of intake air amount calculated in S201.

  The basic intake air amount QCAL is set in advance according to the cooling water temperature of the internal combustion engine 11 and the operating state of auxiliary equipment such as an air conditioner.

  On the other hand, if the determination in S205 is negative, that is, after the rotational speed NE of the internal combustion engine 11 exceeds the target idle rotational speed tNE, the control unit 21 determines in S208 that the previous value QFBZ of the feedback correction amount for the intake air amount. And the previous value ΔQNMAXZ for the final increase is set as the feedback correction amount QFB for the intake air amount. Here, the previous value means the QFB calculated in S201 during the previous routine execution and the final increase ΔQNMAX calculated in S206. The previous value ΔQNMAXZ for the final increase corresponds to the increase correction amount equivalent value when the predetermined end condition is satisfied.

  Further, the control unit 21 sets the final increase amount ΔQNMAX to zero. By setting the final increase ΔQNMAX to zero, the value of ΔQNMAX used for the calculation performed in the next S207 becomes zero.

  In S208, ΔQNMAX is reset to zero for the following reason. In S208, the feedback correction amount QFB is calculated by adding the previous value ΔQNMAXZ corresponding to the final increase to the previous value QFBZ of the feedback correction amount. The feedback correction amount QFB increased by the final increase amount ΔQNMAXZ is used as the previous value QFBZ at the next execution of S208. That is, the previous value QFBZ used in the next execution of S208 is a value for which the increase correction has already been added. Therefore, ΔQNMAX is reset to zero so that the increase correction is not performed repeatedly in the subsequent S208.

  After the process of S206, the control unit 21 performs the process of S207 described above to determine the total intake air amount QTOTAL. When the process of S207 is performed subsequent to S205, ΔQNMAX in Expression (3) is zero.

  After the process of S207, the control unit 21 ends the routine.

  The control unit 21 adjusts the opening degree of the electronic control throttle device 13 based on the total intake air amount QTOTAL determined in this way.

  Next, the function performed by the above routine execution with respect to the load fluctuation of the internal combustion engine will be described with reference to FIG. As shown in (a) of the figure, when an unexpected load fluctuation occurs at time P during the idling operation of the internal combustion engine 11, the rotational speed NE of the internal combustion engine 11 correspondingly decreases rapidly.

  If a general feedback control represented by equation (1) is only performed for a sudden decrease in the rotational speed NE, it takes a long time for the rotational speed NE to return to the target idle rotational speed tNE as shown in the figure. Cost. This is because, as shown in (c) and (d) of the figure, in the feedback control, the intake air amount increases only by a predetermined integral amount (ΔI) by one control.

  On the other hand, when the intake air amount correction routine of FIG. 2 is executed, the final increase of the intake air amount calculated in S206 is performed until the rotational speed NE of the internal combustion engine 11 completely returns to the idle target rotational speed tNE after time P. Using the minute ΔQNMAX, the feedback correction amount QFB for the intake air amount is increased in S207. Therefore, immediately after the time P at which the decrease in the rotational speed of the internal combustion engine 11 is detected, the total intake air amount QTOTAL significantly increases as shown in (c) of the figure, and is shown in (a) and (b) of the figure. Thus, the rotational speed NE quickly approaches the target value tNE.

  As a result of this control, the rotational speed deviation ΔNE is already substantially zero at time R shown in FIG. However, since the rotational speed deviation ΔNE is not a negative value, the determination result of S205 in the routine of FIG. 2 is still positive at this stage. Therefore, as shown in (c) and (d) of the figure, the final increase ΔQNMAX of the intake air amount and the total intake air amount QTOTAL both maintain high levels.

  When time Q is reached, as shown in (b) of the figure, the rotational speed deviation ΔNE becomes a negative value, and the determination in S205 is negatively changed. As a result, the final increase ΔQNMAX is reset to zero in S208, and only the feedback correction amount QFB is applied to the total intake air amount QTOTAL in the subsequent routine execution. That is, the normal feedback control by the integral control of the intake air amount is restored. However, the previous value QFBZ of the feedback correction amount applied in S208 in the next routine execution is a value to which the increase correction has been added as described above.

  In summary, as shown in (e) of the figure, the feedback correction amount QFB of the intake air amount is gradually increased by ΔI of the equation (2) after being increased by a value corresponding to the final increase ΔQNMAXZ at time Q. Change.

  As described above, even when the rotational speed NE of the internal combustion engine 11 during idling suddenly decreases due to a large load fluctuation, the rotational speed NE is quickly returned to the target value tNE by executing the routine of FIG. Can do.

  Further, as shown in (b) of the figure, as a result of the increase correction, the rotational speed NE of the internal combustion engine 11 has already returned to the vicinity of the idle target rotational speed tNE at time R long before time Q. However, in the routine of FIG. 2, the increase correction by the final increase ΔQNMAX is not immediately stopped at time Q, and until the deviation ΔNE changes to a negative value (rotation increasing direction) at time Q, (c) and ( Maintain the increase correction as shown in d). Therefore, it is possible to reliably prevent a problem that the rotational speed NE that has returned to the vicinity of the idle target rotational speed tNE decreases again due to the stop of the increase correction, thereby realizing stable control of the intake air amount.

  If you only want to speed up the response to return to the target idle speed tNE of the internal combustion engine 11 that has decreased during idle operation, apply proportional / integral control to the feedback control of the intake air amount, and set a large proportional gain. This is also possible. However, when such control is applied, after the rotational speed NE returns to near the idle target rotational speed tNE at time R in (c) in the figure, the proportional component becomes zero or a value close to zero. The effect of suppressing the lowering of the rotational speed NE cannot be obtained, and the control of the idle rotational speed is not stable.

  As in the present invention, by combining the highly stable integral control or similar control with the increase correction of the intake air amount corresponding to the sudden decrease in the rotational speed NE of the internal combustion engine 11, the sudden decrease in the internal combustion engine 11 The engine speed NE can be restored to the idle target engine speed tNE at an early stage and the engine speed NE can be stabilized after the engine return.

  In the above embodiment, in the calculation of S204, the intake air amount increase ΔQN is set to zero until the rotational speed deviation ΔNE reaches the predetermined deviation W. Further, the predetermined value XNE used in S205 is set to zero.

  However, various variations are possible for setting the predetermined deviation W and the predetermined value XNE.

  Based on FIG. 4, a second embodiment of the present invention will be described in which the predetermined deviation W is set to zero and the predetermined value XNE is set to a positive value. The processing content of each step of the intake air amount correction routine executed by the control unit 21 is the same as that of the first embodiment (FIG. 2).

  According to this embodiment, when the rotational speed deviation ΔNE becomes equal to or greater than the predetermined value XNE in S205, the intake air amount increase correction by the final increase amount ΔQNMAX of the intake air amount is applied in S206. Also, as shown in (b) of the figure, when the rotational speed deviation ΔNE falls below the predetermined value XNE at time R, the increase correction of the intake air amount by the final increase ΔQNMAX is immediately ended, and the subsequent control of the intake air amount is performed. This is done by normal feedback control. However, by incorporating the final increase ΔQNMAXZ into the feedback correction amount QFB in S208, the feedback correction amount QFB is greatly increased as shown in FIG. As a result, the feedback correction amount QFB is maintained at a high level until the rotational speed deviation ΔNE greatly fluctuates in the negative direction at time Q, that is, until the rotational speed NE of the internal combustion engine 11 greatly exceeds the idle target rotational speed tNE.

  According to this embodiment, the correction of the intake air amount by the final increase ΔQNMAX is completed at time R, while the final increase ΔQNMAX at the end is incorporated into the feedback correction amount QFB. Is substantially continued until time T. Therefore, as in the first embodiment, even when the rotational speed NE of the internal combustion engine 11 during idling suddenly decreases due to a large load fluctuation, the rotational speed NE is quickly and reliably returned to the target value tNE. A decrease in the rotational speed NE after the return can also be prevented.

  In this embodiment, since the predetermined deviation W is set to zero, there is no dead zone relating to the calculation of the intake air amount increase ΔQN. However, by setting the predetermined value XNE to a positive value, as a result, a result equivalent to that of the first embodiment can be obtained regarding the control characteristic of the intake air amount.

  Next, a third embodiment of the present invention will be described based on FIG. 5 and FIG. In this embodiment, the control unit 21 executes an intake air amount correction routine shown in FIG. 5 instead of the routine of FIG. 2 of the first embodiment.

  In this routine, S303 and S304 are provided instead of S204 in the routine of FIG. The processing contents of the other steps are the same as those in FIG. The control unit 21 executes this routine periodically while the internal combustion engine 11 is operating.

  In S303, the control unit 21 calculates the decrease rate ΔNR of the rotational speed NE of the internal combustion engine 11 by the following equation (4).

ΔNR = NEZ-NE… (4)
However, NEZ = the previous value of the rotational speed NE of the internal combustion engine 11.

  If the routine is executed, for example, at intervals of 10 milliseconds, the reduction rate ΔNR obtained by the equation (4) corresponds to a change per 10 milliseconds of the rotational speed NE.

  In next step S304, the control unit 21 obtains the intake air amount correction amount ΔQR by referring to a map stored in advance in the memory from the rotational speed deviation ΔNE and the rotational speed reduction rate ΔNR.

  Here, the characteristics of the map will be described. As shown in the diagram on the right side of S304, the intake air amount correction amount ΔQR increases as the rotational speed deviation ΔNE increases and as the rotational speed decrease rate ΔNR increases.

  This map is set by experimentally determining in advance the amount of increase in the intake air amount necessary to compensate for a decrease in torque due to a change in the rotational speed, and regarding the increase as the intake air amount correction amount ΔQR. The

  The processing of the other steps of the routine is the same as the routine of FIG. 2 except for the value of the predetermined value XNE. In the first embodiment, the predetermined value XNE for determining whether or not the engine speed NE has returned to the idle target speed tNE is set to zero, but in this embodiment, the second embodiment (FIG. 4) is used. ), The predetermined value XNE is set to a positive value.

  Therefore, the difference between this embodiment and the second embodiment is that the calculation of the intake air amount correction amount ΔQR is performed depending on the rotation speed decrease rate ΔNR in addition to the rotation speed deviation ΔNE. That is, even when the rotational speed deviation ΔNE is the same as in the second embodiment, if the rotational speed reduction rate ΔNR is large, the intake air amount correction amount ΔQR calculated in S304 becomes a larger value than in the second embodiment.

  As a result, as shown in FIG. 6, as compared with the second embodiment, it is possible to reduce the time required for returning the rapidly decreasing engine speed NE of the internal combustion engine 11 to the idle target engine speed tNE. On the other hand, with respect to the rotational speed NE after returning to the idle target rotational speed tNE, preferable stability is maintained as in the second embodiment.

  In the first and second embodiments, the intake air amount increase ΔQN is calculated from the deviation ΔNE of the engine speed NE. In the third embodiment, the intake air amount increase ΔQN is calculated using both the deviation ΔNE and the decrease rate ΔNR. However, the intake air amount increase ΔQN can be calculated based only on the decrease rate ΔNR of the engine speed NE.

1 is a schematic configuration diagram of an idle speed control device according to the present invention. The flowchart showing 1st Embodiment of the idle speed control which concerns on this invention. The timing diagram by the said idle speed control. The timing diagram by 2nd Embodiment of idle speed control which concerns on this invention. The flowchart showing 3rd Embodiment of idle speed control which concerns on this invention. The timing diagram which showed the execution result of the said 3rd Embodiment in the comparison with the execution result of the said 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Internal combustion engine 12 Intake passage 13 Electronically controlled throttle device 14 Throttle valve 15 Throttle opening sensor 16 Intake air amount sensor 17 Rotational speed sensor 18 Accelerator pedal switch 21 Control unit

Claims (14)

An air amount control means for adjusting the intake air amount of the internal combustion engine;
Idle operation detecting means for detecting an idle operation state;
Engine speed detecting means for detecting the engine speed during idling operation;
Idle of an internal combustion engine comprising control means for feedback-controlling the air amount control device so that the actual idle speed of the internal combustion engine matches the target value based on a deviation between the target value of the idle speed and the detected value In the rotation speed control device,
While providing a rotation speed change detecting means for detecting the amount of change in the idle rotation speed,
The control means;
When the amount of change in the idle speed is larger than a predetermined reference value, the air amount correction proportional to the amount of change is performed until the actual idle speed returns to the target value. An idle speed control device for an internal combustion engine.   The idling engine speed control device for an internal combustion engine according to claim 1, wherein the engine speed change amount detecting means detects a deviation of the idle engine speed as a change amount.   2. The idle speed control device for an internal combustion engine according to claim 1, wherein the rotation speed change amount detecting means detects a change rate of the idle speed as a change amount.   2. The internal combustion engine according to claim 1, wherein the control means feedback-controls the idle rotational speed by an integral based on a deviation of the idle rotational speed at least initially when the idle rotational speed returns to the target value by the air amount correction. Engine idle speed control device.   The control means according to claim 1, wherein when the amount of change in the idle speed is equal to or less than a predetermined reference value, the idle speed is feedback controlled by proportional-integral control based on the deviation of the idle speed. An idle speed control device for an internal combustion engine. An air amount control means for adjusting the intake air amount of the internal combustion engine;
A rotational speed detecting means for detecting the engine rotational speed of the internal combustion engine;
When the engine speed is different from the idle target speed, the feedback correction amount is calculated so as to gradually change the intake air amount in the direction in which the engine speed approaches the idle target speed,
Calculate the amount of increase correction for intake air based on the engine speed,
When the engine speed falls below the idle target speed, the air amount control means is controlled based on the sum of the feedback correction amount and the increase correction amount,
It is determined whether or not the engine speed is satisfied with a preset increase correction end condition,
When the engine speed satisfies the increase correction end condition, the sum of the feedback correction amount and the increase correction amount equivalent value when the end condition is satisfied is set as a new feedback correction amount, and the subsequent increase correction amount And an idling engine speed control device for an internal combustion engine.   The idle speed control device for an internal combustion engine according to claim 6, wherein the control means increases the increase correction amount as the deviation of the engine speed from the idle target speed is larger.   8. The idle speed control device for an internal combustion engine according to claim 7, wherein when the deviation of the engine speed from the idle target speed is less than a predetermined deviation, the control device sets the increase correction amount to zero.   The idle speed control device for an internal combustion engine according to any one of claims 6 to 8, wherein the control device increases the increase correction amount as the decrease rate of the engine speed is larger.   The control device repeatedly calculates the increase correction amount at a predetermined interval, and calculates the sum of the increase correction amount calculated based on the engine speed and the larger one of the previously calculated increase correction amount and the feedback correction amount. 10. The idle speed control device for an internal combustion engine according to claim 6, wherein the air amount control means is controlled based on the control.   The internal combustion engine idle according to any one of claims 6 to 10, wherein the control device determines that the engine rotational speed satisfies an increase correction end condition when the engine rotational speed exceeds an idle target rotational speed. Rotational speed control device.   The control device does not control the air amount control means based on the sum of the feedback correction amount and the increase correction amount until the deviation between the engine speed and the idle target speed becomes a positive positive value or more. An idle speed control device for an internal combustion engine according to any one of claims 1 to 11.   The controller according to any one of claims 6 to 12, wherein the controller determines that the engine speed satisfies an increase correction end condition when a deviation of the engine speed from the idle target speed is less than a predetermined positive value. An idle speed control device for an internal combustion engine according to any one of the above.   7. The control device according to claim 6, wherein the control device repeatedly calculates the feedback correction amount at a predetermined interval, and calculates a current feedback correction amount by adding a certain amount of positive or negative to the previously calculated feedback correction amount. The idle speed control device for an internal combustion engine according to any one of claims 13 to 14.

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