JP6699373B2 - Engine controller - Google Patents

Description

  The present invention relates to an engine control device.

  In general, in a vehicle such as an automobile, fuel cut control may be executed to stop the fuel supply to the engine (combustion chamber) at the time of deceleration when the depressed accelerator pedal is released. This fuel cut control improves fuel efficiency and exhaust gas purification performance.

  Patent Document 1 discloses a technique for preventing vehicle body vibration by setting a fuel cut delay time between when the fuel cut condition is satisfied and when the execution of the fuel cut is instructed.

JP 2002-322931 A

  However, according to the earnest research of the present inventor, a power train including an engine may oscillate from a shock caused by a torque fluctuation (torque step) before and after fuel cut. For this reason, even if the fuel cut delay time is set as in Patent Document 1, if the timing of executing the fuel cut is bad, not only the torque fluctuation of the engine but also the fluctuation cannot be suppressed, but rather these are increased. It can happen. If the torque fluctuation of the engine, and thus the rocking becomes large, the ride comfort of the occupant deteriorates due to the vibration of the vehicle body.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine control device capable of suppressing the torque fluctuation of the engine and hence the swing while suitably exhibiting the fuel cut function. One

In one aspect thereof, an engine control device of the present invention is an engine control device that can be driven in either a fuel supply state or a fuel supply stop state, wherein the engine rotation speed and the wheel of a vehicle equipped with the engine are provided. An engine swing angular velocity calculation unit that calculates the swing angular velocity of the engine in the fuel supply state, and a differential process is performed on the swing angular velocity of the engine based on the difference between the rotation speed of the engine and the total reduction ratio. According to the engine swing angular acceleration calculation unit that calculates the swing angular acceleration of the engine in the fuel supply state, and after the fuel cut condition is satisfied, the swing angular acceleration of the engine is equal to or greater than a predetermined threshold value. And a fuel cut control unit that executes fuel cut control for switching the engine from the fuel supply state to the fuel supply stop state.

  According to the present invention, it is possible to provide an engine control device capable of suppressing the torque fluctuation of the engine and hence the swing while suitably exhibiting the fuel cut function.

It is a conceptual diagram which shows the structure of the power train containing the engine which concerns on this embodiment. It is a functional block diagram which shows the internal structure of a fuel-injection control part. FIG. 6 is a process diagram showing calculation of an engine swing angular velocity by an engine swing angular velocity calculation unit and calculation of an engine swing angular acceleration by an engine swing angular acceleration calculation unit. It is a conceptual diagram which shows the rocking|fluctuation direction of an engine at the time of a fuel cut, and a fuel cut return. FIG. 5 is a waveform diagram showing engine rotation behavior, wheel rotation behavior, powertrain swing angular velocity, and powertrain swing angular acceleration during engine swing. FIG. 6A is a waveform diagram showing the engine rotation behavior at the time of deceleration of the engine swing, FIG. 6B is a waveform diagram showing the case where the fuel cut control is performed at the timing of promoting the engine swing in FIG. 6A, and FIG. FIG. 6B is a waveform diagram showing a case where fuel cut control is performed at a timing of suppressing engine swing in FIG. 6A. Engine speed, powertrain swing angular velocity, powertrain swing angular acceleration, throttle when fuel cut control is executed triggered by the fact that the engine swing angular acceleration exceeds a predetermined threshold after the fuel cut conditions are satisfied FIG. 6 is a waveform diagram showing an opening degree, a fuel cut condition establishment state, an angular acceleration condition establishment state, and an injector drive state. When the fuel cut control is executed triggered by the lapse of a predetermined time after the fuel cut condition is satisfied, the engine speed, the power train swing angular velocity, the power train swing angular acceleration, the throttle opening, and the fuel cut condition are satisfied. FIG. 3 is a waveform diagram showing a state, a state of measuring a predetermined time by a timer, a state of satisfying an angular acceleration condition, and a driving state of an injector. 3 is a flowchart showing the operation of the engine control device according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. An example in which the engine control device according to the present embodiment is applied to a four-wheeled vehicle will be described below, but the application target is not limited to this and can be changed. For example, the engine control device according to the present embodiment may be applied to another type of vehicle (for example, a motorcycle or a motorcycle).

  An engine control system according to the present embodiment will be described with reference to FIG. It should be noted that the power train including the engine 10, even though not shown in FIG. 1, is assumed to have the components that are normally included in a four-wheeled motor vehicle, and a description thereof will be omitted. The engine 10 is, for example, a direct-acting DOHC (Double OverHead Camshaft) engine, and has the following basic configuration. The engine 10 includes a crankshaft 11, a cylinder 12, a cylinder head 13 and the like inside a crankcase.

  A piston 14 is housed in the cylinder 12 so as to be vertically reciprocable. The crankshaft 11 and the piston 14 are connected by a connecting rod 15. In the engine 10, the piston 14 reciprocates in the vertical direction, so that the crankshaft 11 is rotated via the connecting rod 15. The internal space of the cylinder head 13 constitutes a combustion chamber 16. Further, the cylinder head 13 is provided with an intake valve 19 and an exhaust valve 20 corresponding to the intake port 17 and the exhaust port 18.

  Further, a pair of cam shafts 21 are provided corresponding to the intake valve 19 and the exhaust valve 20. A cam chain (not shown) spans the crankshaft 11 and the pair of camshafts 21. The rotation of the crankshaft 11 is transmitted to the pair of camshafts 21 via the cam chain. By rotating the pair of cam shafts 21, the intake valve 19 and the exhaust valve 20 are reciprocated toward the combustion chamber 16. In this way, the opening/closing timing of each of the intake valve 19 and the exhaust valve 20 is adjusted.

  An intake pipe 26 communicates with an intake port 17 of the engine 10, and the intake pipe 26 is provided with a throttle valve 27 which is an intake control valve. The throttle valve 27 opens and closes in conjunction with an accelerator pedal (not shown) operated by the driver. The intake pipe 26 is provided with a throttle opening sensor 28 for detecting the opening state of the throttle valve 27 and an air flow meter 29 for detecting the flow rate of air flowing through the intake pipe 26. The opening state of the throttle valve 27 detected by the throttle opening sensor 28 and the flow rate of air flowing through the intake pipe 26 detected by the air flow meter 29 are input to a control unit (ECU: Electronic Control Unit) 50.

  The intake port 17 between the throttle valve 27 and the intake valve 19 is provided with an injector 22 for injecting fuel. The injector 22 has its fuel injection hole exposed inside the intake port 17, and injects fuel into the intake port 17. A spark plug 23 is provided above the combustion chamber 16. The spark plug 23 generates a spark at a predetermined timing according to an instruction from the ignition timing control unit 51 of the control unit 50. As a result, the air-fuel mixture in the combustion chamber 16 is ignited.

  The engine 10 is provided with a crank pulley 24 to which the rotation of the crankshaft 11 is transmitted and a crank angle sensor 25 for detecting the rotation angle of the crank pulley 24. The rotation angle of the crank pulley 24 detected by the crank angle sensor 25 is input to the control unit 50.

  A power train including the engine 10 has a final gear 30 that constitutes a part of a driving force transmission mechanism that transmits a driving force to wheels of a vehicle equipped with the engine 10. The final gear 30 is provided with a vehicle speed sensor 31 that detects the rotational speed (vehicle speed) of the wheels of the vehicle equipped with the engine 10. The rotation speed (vehicle speed) detected by the vehicle speed sensor 31 is input to the control unit 50.

  The rotation speed of the engine 10 configured as described above is constantly monitored and input to the control unit 50.

  The engine 10 can be driven in either a fuel supply state in which fuel is supplied from the injector 22 to the combustion chamber 16 or a fuel supply stop state in which fuel is not supplied from the injector 22 to the combustion chamber 16. The control unit 50 has a fuel injection control unit 52 for executing fuel injection control from the injector 22 to the combustion chamber 16, and in particular, fuel cut control for switching the engine 10 from a fuel supply state to a fuel supply stop state.

  Next, various functions inside the fuel injection control unit 52 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, the fuel injection control unit 52 includes an engine swing angular velocity calculation unit 52X, an engine swing angular acceleration calculation unit 52Y, and a fuel cut control unit 52Z.

  As shown in FIGS. 2 and 3, the engine swing angular velocity calculation unit 52X determines the engine in the fuel supply state based on the rotation speed of the engine 10 and the rotation speed (vehicle speed) of the wheels of the vehicle on which the engine 10 is mounted. The rocking angular velocity of 10 is calculated. More specifically, the engine swing angular velocity calculation unit 52X supplies the fuel based on the difference between the rotation speed of the engine 10 and the rotation speed (vehicle speed) of the wheels of the vehicle equipped with the engine 10 multiplied by the total reduction ratio. The swing angular velocity of the engine 10 in the state is calculated.

  The engine swing angular acceleration calculation unit 52Y calculates the swing angular acceleration of the engine 10 in the fuel supply state based on the swing angular velocity of the engine 10 calculated by the engine swing angular velocity calculation unit 52X. More specifically, the engine swing angular acceleration calculation unit 52Y performs a differentiation process on the swing angular velocity of the engine 10 calculated by the engine swing angular velocity calculation unit 52X to obtain the swing angular acceleration of the engine 10 in the fuel supply state. To calculate.

  When the swing angular acceleration of the engine 10 in the fuel supply state calculated by the engine swing angular acceleration calculation unit 52Y becomes equal to or higher than a predetermined threshold value after the fuel cut condition is satisfied, the fuel cut control unit 52Z causes the engine 10 to burn the fuel. The fuel cut control for switching from the supply state to the fuel supply stop state is executed.

  The "fuel cut condition" of the present embodiment is assumed to be, for example, a situation in which the driver coasts by returning the accelerator pedal while the vehicle is traveling. The valve 27 can be closed." The "fuel cut condition" is one of the conditions for executing the fuel cut control for switching the engine 10 from the fuel supply state to the fuel supply stop state. Immediately when the "fuel cut condition" is satisfied, It does not execute fuel cut control.

  The “fuel cut recovery condition” of the present embodiment can be set to, for example, “the number of revolutions of the engine 10 has become equal to or lower than a predetermined value (or less than the predetermined value) during execution of the fuel cut control”. The "fuel cut return condition" is one of the conditions for executing the fuel cut return control for switching the engine 10 from the fuel supply stop state to the fuel supply state, and is only provided when the "fuel cut return condition" is satisfied. Therefore, the fuel cut recovery control is not executed immediately.

  The fuel cut control unit 52Z determines that the swing angular acceleration of the engine 10 in the fuel supply state calculated by the engine swing angular acceleration calculation unit 52Y is a predetermined threshold value when a predetermined time (timeout time) has elapsed after the fuel cut condition is satisfied. Even if it is less than the limit, the fuel cut control for switching the engine 10 from the fuel supply state to the fuel supply stop state is executed.

  The fuel cut control unit 52Z sets the predetermined time (timeout time) to different values according to the reduction ratio. More specifically, the fuel cut control unit 52Z sets the predetermined time (timeout time) to be relatively long as the reduction ratio becomes relatively large, and sets the predetermined time as the reduction ratio becomes relatively small. Set (Timeout time) relatively short. The fuel cut control unit 52Z sets a predetermined time (timeout time) so as to be longer than one swing cycle of the engine 10. The fuel cut control unit 52Z can calculate the speed reduction ratio based on the rotation speed of the engine 10 and the speed (vehicle speed) of the vehicle on which the engine 10 is mounted.

  Since the swing cycle of the engine 10 varies depending on the reduction ratio, by changing the predetermined time (time-out time) according to the magnitude of the reduction ratio, the torque fluctuation of the engine 10 and thus the swing can be achieved while the fuel cut function is suitably exerted. Can be suppressed.

  In a low-speed gear state in which the reduction ratio is relatively large, the swing of the engine 10 is large, and the swing cycle of the power train including the engine 10 is long. In this case, a predetermined time (timeout time) is secured for a long time and waits for the swing angular acceleration of the engine 10 to become equal to or more than a predetermined threshold (the predetermined time (timeout time) elapses before the swing cycle of the engine 10). To prevent). As a result, the fuel cut control can be executed after the timing when the swing of the engine 10 is reduced.

  In a high speed gear state in which the reduction ratio is relatively small, the swing of the engine 10 is small, and the swing cycle of the power train including the engine 10 is short. In this case, it is difficult for the swing angular acceleration of the engine 10 to become equal to or higher than the predetermined threshold value, and therefore it may take a long time to execute the fuel cut control or the fuel cut control may not be executed. Therefore, by setting the predetermined time (timeout time) to be short and executing the fuel cut control early and surely, it is possible to improve fuel efficiency and exhaust gas purification performance. Further, since the swing of the engine 10 is originally small, the ride comfort (feeling) of the occupant is not deteriorated by the vehicle body vibration (the vehicle body vibration can be limited to an occupant allowable level).

  Next, the manner of rocking of the engine 10 when the engine is driven will be described with reference to FIGS. 4 to 6. As shown in FIG. 4, the engine 10 is swingable in the vehicle front-rear direction about a swing support portion (not shown) inside the vehicle body (strictly speaking, the vehicle vertical direction and the vehicle Although it swings in the left and right directions, it is negligible compared to the swing in the vehicle front-rear direction). The engine 10 swings forward of the vehicle (the traveling direction) when the fuel is cut, and swings rearward (the backward direction) of the vehicle when the fuel cut is restored.

  In the present embodiment, the swing angular velocity and the swing angular acceleration of the engine 10 as shown in FIG. 4 are constantly monitored, and the fuel cut and the fuel cut return are set by optimally setting the timing of the fuel cut and the fuel cut return. The torque fluctuation of the engine 10 and the swing due to the above are suppressed. In the example of FIG. 4, if the fuel cut return is performed while the engine 10 is swinging forward (the traveling direction), the torque fluctuation of the engine 10 due to the fuel cut return and thus the swing can be suppressed. If the fuel cut is performed while the 10 is swinging backward (backward direction), the torque fluctuation of the engine 10 due to the fuel cut and thus the swing can be suppressed.

  When the engine 10 is not swinging at all, in FIG. 3, the value obtained by multiplying the rotation speed (vehicle speed) of the wheels of the vehicle equipped with the engine 10 by the total reduction ratio has the same value as the rotation speed of the engine 10. . On the other hand, when the engine 10 is swinging to some extent, the value obtained by multiplying the rotation speed (vehicle speed) of the wheels of the vehicle equipped with the engine 10 by the total reduction ratio is different from the rotation speed of the engine 10. Become. Therefore, the swing angular acceleration of the engine 10 in the fuel supply state calculated by the engine swing angular acceleration calculator 52Y is a parameter indicating the swing direction and the swing amount of the engine 10.

  As shown in FIG. 5, the region where the power train swing angular acceleration (the swing angular acceleration of the engine 10) has a positive value is the region where the torque fluctuation of the engine is small even if the fuel is cut. When the fuel cut control is executed in this region, the axial torque of the engine 10 reduced by the fuel cut acts in the direction of canceling the swing of the engine 10.

  In FIG. 6, as is apparent from FIGS. 6B and 6C, depending on the timing of fuel cut control, the torque fluctuation of the engine 10 and thus the rocking can be promoted and this can be effectively suppressed (cancelled). There are cases. This is the same even when the fuel cut delay time is set as in Patent Document 1 described above. In the present embodiment, the fuel cut control unit 52Z always sets the fuel cut timing optimally so as to effectively suppress (cancel) the torque fluctuation and thus the swing of the engine 10 as shown in FIG. 6C. is there.

  In the control device for the engine 10 of the present embodiment, the fuel cut control unit 52Z causes the swing angular acceleration of the engine 10 to become equal to or higher than a predetermined threshold value after the fuel cut condition is satisfied, or after the fuel cut condition is satisfied. The fuel cut control is executed by using a lapse of a predetermined time (timeout time) as a trigger.

  Further, as shown in FIG. 7, since the swing of the engine 10 is large and the swing cycle of the power train including the engine 10 is long, the fuel cut control is waited for when the angular acceleration condition is switched from the non-established state to the established state. By executing the above, the priority is given to suppressing the torque fluctuation of the engine 10 and thus the fluctuation.

  As shown in FIG. 8, when the swing of the engine 10 is small and the swing cycle of the power train including the engine 10 is short, the riding comfort (feeling) of the occupant is not deteriorated due to the vehicle body vibration (the occupant is not tolerable). You can keep the car body vibration as much as you can). For this reason, priority is given to executing fuel cut control as soon as possible.

  Next, the control flow of this embodiment will be described with reference to FIG.

  As shown in FIG. 9, in step S1, the fuel cut control unit 52Z determines whether or not the fuel cut condition is satisfied. When the fuel cut condition is not satisfied (step S1: No), the fuel cut control unit 52Z executes the timer reset in step S2 and ends the process without executing the fuel cut in step S3. When the fuel cut condition is satisfied (step S1: Yes), the process proceeds to step S4.

  In step S4, the fuel cut control unit 52Z determines whether the fuel cut is being performed. When the fuel cut is being executed (step S4: Yes), the process is ended. When the fuel cut is not being executed (step S4: No), the process proceeds to step S5.

  In step S5, the fuel cut control unit 52Z starts a timer countdown for measuring the elapsed time after the fuel cut condition is satisfied. That is, although it is drawn in different process steps for the sake of convenience of description, the process of step S5 is executed at the same time as the process of step S1.

  In step S6, the fuel cut control unit 52Z determines whether the swing angular acceleration of the engine 10 is equal to or greater than a predetermined threshold value. When the swing angular acceleration of the engine 10 is less than the predetermined threshold value (step S6: No), the process proceeds to step S7. When the swing angular acceleration of the engine 10 is equal to or greater than the predetermined threshold value (step S6: Yes), the process proceeds to step S8.

  In step S7, the fuel cut control unit 52Z determines whether or not the elapsed time after the fuel cut condition is satisfied reaches a predetermined time (timeout time). When the elapsed time after the fuel cut condition is satisfied has not reached the predetermined time (timeout time) (step S7: No), the fuel cut control unit 52Z repeats the processing loop of step S6 and step S7. When the elapsed time after the fuel cut condition is satisfied reaches the predetermined time (timeout time) (step S7: Yes), the process proceeds to step S8.

  In step S8, the fuel cut control unit 52Z executes the fuel cut control and ends the processing. In the fuel cut control of step S8, the swing angular acceleration of the engine 10 becomes equal to or higher than a predetermined threshold value after the fuel cut condition is satisfied (step S6: Yes), or a predetermined time (timeout is reached after the fuel cut condition is satisfied. The execution is triggered by the elapse of time (step S7: Yes).

  As described above, according to the control device for the engine 10 of the present embodiment, the engine swing angular velocity calculation unit 52X calculates the swing angular velocity of the engine 10 in the fuel supply state, and the engine swing angular acceleration calculation unit 52Y The swing angular acceleration of the engine 10 in the fuel supply state is calculated based on the swing angular velocity of the engine 10, and the fuel cut control unit 52Z sets the swing angular acceleration of the engine 10 to a predetermined threshold after the fuel cut condition is satisfied. When the above is reached, the fuel cut control for switching the engine 10 from the fuel supply state to the fuel supply stop state is executed. Therefore, the axial torque of the engine 10 reduced by the fuel cut control acts in a direction of canceling (or canceling) the swing of the engine 10, so that the torque fluctuation of the engine 10 and thus the swing can be achieved while the fuel cut function is suitably exerted. Can be suppressed.

  In the above embodiment, the function, size, shape, etc. of each configuration illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within the range where the effect of the present invention is exerted. is there. In addition, the present invention can be appropriately modified and implemented without departing from the scope of the object.

  For example, instead of swinging the power train including the engine 10, the timing for executing the fuel cut control may be determined based on the change in the rotation of the engine 10. In this case, the differential value of the engine speed of the engine 10 is calculated, and the fuel cut control can be executed because the engine speed of the engine 10 is increasing.

  Further, in the above-described embodiment, the fuel is injected into the intake port 17, but the configuration is not limited to this. For example, the fuel may be directly injected into the cylinder.

  The engine control device of the present invention is suitable for application to various vehicles such as a four-wheeled motor vehicle and a two-wheeled motor vehicle.

10 Engine 50 Control Unit (ECU: Engine Control Unit)
52 Fuel Injection Control Section 52X Engine Swing Angular Velocity Calculation Section 52Y Engine Swing Angular Acceleration Calculation Section 52Z Fuel Cut Control Section

Claims (1)

In an engine control device that can be driven in either the fuel supply state or the fuel supply stop state,
Engine swing angular velocity calculation for calculating the swing angular velocity of the engine in the fuel supply state by the difference between the rotation speed of the engine and the rotation speed of the wheels of the vehicle equipped with the engine multiplied by the total reduction ratio Department,
An engine swing angular acceleration calculation unit that calculates a swing angular acceleration of the engine in the fuel supply state by applying a differentiation process to the swing angular velocity of the engine;
After the fuel cut condition is satisfied, when the swing angular acceleration of the engine is equal to or higher than a predetermined threshold value is a positive value, the fuel to perform fuel cut control for switching the engine from the fuel supply state to the fuel supply stop state A cut control unit,
An engine control device comprising:

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