JP2011226385A - Controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of internal combustion engine that stabilizes rotation speed and improves fuel efficiency performance at all times during engine operation.SOLUTION: The controller of internal combustion engine calculates a retard amount Rtd of the ignition time of an internal combustion engine based on a target output torque Pit and, in accordance with the retard amount Rtd, controls the ignition time Sact. An ignition coefficient operating block B52 calculates an ignition coefficient K corresponding to a reflection ratio to the ignition time Sact of the retard amount Rtd based on a rotation speed Ne and a load of an engine. A target ignition time operating block B56 increases or reduces the retard amount Rtd based on the ignition coefficient K.

Description

  The present invention relates to control of ignition timing of an internal combustion engine.

In order to stabilize the engine rotation speed, control is performed to control the output of the engine in accordance with fluctuations in the engine rotation speed and to maintain the desired rotation speed.
As a method for controlling the output of the engine, there are controls such as a throttle valve and a fuel injection amount. A method for controlling the ignition timing has been proposed in order to respond quickly to fluctuations in the engine speed.

  For example, during idle operation, the position that is retarded by a predetermined angle from MBT (Minimum advance for Best Torque) is used as the basic ignition timing, and if the engine speed falls below the set value, it advances from the basic ignition timing. The angle is made close to MBT to increase the output torque and increase the engine speed. Further, when the engine speed increases from a set value, the engine torque is retarded by retarding the basic ignition timing to reduce the output torque. As a result, the engine speed can be maintained at the set value.

  In addition, a technique has been developed that stabilizes the rotational speed of the engine during idle operation by correcting and controlling both the throttle valve and the ignition timing (see Patent Document 1).

Japanese Patent No. 3876609

However, in the above-mentioned patent document 1, the stabilization of the engine rotation speed and the improvement of the fuel consumption during the idling operation are achieved by controlling the ignition timing and the like, but the ignition timing is appropriately controlled even during the idling operation. Therefore, it is desirable to achieve both stable engine operation and improved fuel efficiency. Except during idling, the variable range of the load and engine rotation speed is large, and if the ignition timing is set by one map, a huge map capacity is required. Further, the ignition timing is set differently according to various requests such as when returning from a fuel cut at the time of deceleration or when requesting a reduction in output torque from the outside of the transmission or the like, and the map becomes complicated.

  The present invention has been made to solve such a problem, and controls an internal combustion engine capable of appropriately controlling ignition timing during engine operation and always achieving both stabilization of engine operation and improvement of fuel efficiency. To provide an apparatus.

  In order to achieve the above object, the invention according to claim 1 is an internal combustion engine comprising a torque control means for calculating a retard amount of the ignition timing of the internal combustion engine based on the target output torque and controlling the ignition timing in accordance with the retard amount. In the engine control device, an ignition operation coefficient calculating means for calculating an ignition operation coefficient corresponding to a reflection rate of the retard amount calculated in the torque control means on the ignition timing based on the rotational speed and load of the internal combustion engine; And a retard amount setting means for increasing / decreasing a retard amount to be applied to the ignition timing in the torque control means based on the ignition operation coefficient calculated by the operation coefficient calculating means.

According to a second aspect of the present invention, there is provided a control device for an internal combustion engine according to the first aspect, wherein the ignition operation coefficient is set between 0 and 1 such that the ignition operation coefficient increases as the load and the engine speed decrease. Features.
According to a third aspect of the present invention, there is provided a control device for an internal combustion engine according to the first or second aspect, wherein the ignition operation coefficient is related to a load and an engine speed in a predetermined operation state that requires a stable engine operation in response to an external request. It is characterized by being set to 1.

  According to a fourth aspect of the present invention, there is provided a control device for an internal combustion engine according to the third aspect, wherein the predetermined operation state is a request for torque reduction from an external device other than the engine when returning from a fuel cut, during feedback control of the engine speed. It is time.

According to the control apparatus for an internal combustion engine of the first aspect of the present invention, the retard amount of the ignition timing set based on the target torque is increased or decreased according to the ignition operation coefficient calculated based on the engine speed and the load. Therefore, at the time of engine operation, the control of the ignition timing in the torque control is always reflected, so that it is possible to achieve both the stabilization of the engine rotation speed and the improvement of the fuel consumption performance.
According to the control apparatus for an internal combustion engine of claim 2 of the present invention, the ignition operation coefficient becomes 1 at the time of low load and low rotation, and the reflection of the torque control to the ignition timing becomes large, so that the engine operation is reliably stabilized. be able to. In addition, the ignition operation coefficient becomes 0 at high load and high rotation, and torque control is not reflected in the ignition timing, so the retard amount becomes 0, the combustion efficiency of the engine increases, and the fuel efficiency and output performance can be improved. .

According to the control apparatus for an internal combustion engine of claim 3 of the present invention, since the ignition operation coefficient is set to 1 regardless of the load and the engine speed in a predetermined operation state, the ignition timing is controlled based on the target output torque. Thus, the engine speed can be quickly stabilized in response to an external request.
According to the control device for an internal combustion engine of claim 4 of the present invention, the load and the engine rotation speed are adjusted when returning from the fuel cut, at the time of feedback control of the engine rotation speed, or when torque reduction is requested from an external device other than the engine. Regardless, since the ignition operation coefficient is set to 1, stable engine operation can be realized quickly.

It is a schematic block diagram which shows the output control apparatus of the internal combustion engine which concerns on this invention. It is a block diagram of an ignition timing calculating part. It is a map which calculates | requires an ignition operation coefficient.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A control device for an internal combustion engine according to an embodiment of the present invention controls ignition timing of an engine (internal combustion engine) mounted on a vehicle, and is employed in, for example, an output control device of a gasoline engine. The output control apparatus includes an intake system called, for example, a drive-by-wire (DBW).

This intake system called DBW is configured to independently control the opening degree of an electronically controlled throttle valve by an electronic control unit in accordance with accelerator pedal operation information and the like.
FIG. 1 is a control block diagram showing the overall configuration of an output control device for an internal combustion engine according to the present invention, which is executed in an electronic control unit (ECU) 10.

  As shown in the figure, on the input side of the ECU 10, an accelerator position sensor 20 for detecting the degree of operation of the accelerator pedal by the driver of the vehicle, a throttle position sensor 30 for detecting the opening degree of the electronically controlled throttle valve 70, and an intake air flow rate are shown. In addition to sensors such as an air flow sensor 40 to detect, a crank angle sensor 50 (actual rotational speed detecting means) for detecting an engine crank angle and thus an engine rotational speed Ne, for example, a continuously variable transmission (CVT), a vehicle attitude control system, etc. Signal lines of various external system elements 60 are electrically connected, and an electronic control throttle valve 70 and an ignition device 80 are electrically connected to the output side.

  As shown in the figure, the ECU 10 indicates the indicated mean effective pressure Pi (accelerator request) as an index of the required torque based on the accelerator request from the accelerator position sensor 20 and the engine rotational speed Ne detected by the crank angle sensor 50. Accel) Pi calculation block B10 for calculating Pia), external request Pi calculation block B12 for calculating the indicated mean effective pressure Pi (external request Pio) based on the external request from the external system element 60, accelerator request Pi and external request Pi The target Pi calculation block B14 for calculating the target value (target Pi) of the indicated mean effective pressure Pi as an index of the target torque based on the above, and the target Ec calculation block B16 for calculating the target value (target Ec) of the charging efficiency based on the target Pi. , The target value of the intake air flow rate passing through the electronic control throttle valve 70 based on the target Ec (target intake Target intake flow rate Qt calculation block B18 for calculating the amount Qt), a target value (target throttle valve opening) of the electronic control throttle valve 70 is calculated based on the target intake flow rate Qt, and an output signal is sent to the electronic control throttle valve 70. Target throttle valve opening calculation block B20 to be supplied, throttle valve opening adjustment block B22 for adjusting the opening of the electronic control throttle valve 70 based on the opening information of the electronic control throttle valve 70 from the throttle position sensor 30, and the air flow sensor 40 The actual intake air flow rate Qr calculation block B24 for calculating the actual intake air flow rate (actual intake air flow rate Qr) at the adjusted opening degree of the electronically controlled throttle valve 70 based on the information from the actual intake air flow rate Qr. Based on the real Ec calculation block B26 for calculating (real Ec), real Ec The actual Pi calculation block B28 for calculating the actual indicated mean effective pressure Pi (actual Pi). When the engine is in the idling state, the engine rotational speed Ne detected by the crank angle sensor 50 based on the actual Pi is the target idle rotational speed. An F / B control block B30 for performing feedback control of the electronic control throttle valve 70 while performing engine rotational speed feedback control (Ne-F / B) so as to become is included, and a control program is configured according to the control block diagram Has been.

  That is, in the output control device for an internal combustion engine according to the present invention, the ECU 10 performs so-called torque-based control based on the output torque of the engine, obtains the target torque index from the required torque index, and based on the target torque index. Thus, the electronic control throttle valve 70 is adjusted to an appropriate opening degree so as to obtain a desired output torque in the engine. Thus, the control of the electronically controlled throttle valve 70 can be accurately controlled based on the target torque index, and a desired output torque can be reliably obtained in the engine.

  Further, when the actual Pi is calculated in the actual Pi calculation block B28, the thermal efficiency coefficient is multiplied. Specifically, in the MBT ignition timing calculation block B40, the MBT ignition timing Smbt (maximum torque ignition timing), which is the ignition timing for generating the maximum torque with the actual EC calculated in the actual EC calculation block B26, is calculated. Then, in the thermal efficiency coefficient calculation block B41, the retard amount of the ignition timing is obtained based on the MBT ignition timing Smbt and the basic target ignition timing Smain, and the ignition timing with respect to the indicated mean effective pressure Pi at the MBT ignition timing is retarded. An ignition efficiency coefficient that is a ratio of the indicated mean effective pressure Pi is calculated, and the thermal efficiency coefficient is calculated by multiplying the ignition efficiency coefficient by a coefficient of an air-fuel ratio or an EGR rate. The thermal efficiency coefficient is 1 at stoichiometric and MBT.

In the present embodiment, the effective ignition timing Sact that is the actual control value of the ignition timing is calculated in the effective ignition timing calculation unit B45. FIG. 2 is a block diagram of the effective ignition timing calculation unit B45. Hereinafter, the calculation procedure of the effective ignition timing Sact will be described with reference to FIG. Note that the calculation of the actual ignition timing Sact is repeatedly performed at predetermined intervals during engine operation.
The accelerator opening signal Raps from the accelerator position sensor 20 and the engine rotational speed Ne detected by the crank angle sensor 50 are input to the required load factor calculation block B50, and the required load factor Zpi is calculated in the required load factor calculation block B50. . The required load factor Zpi is a value that is interpolated based on the accelerator opening signal Raps and the engine speed Ne, assuming that the load at which the engine is in an idling state is 0% and the load capable of generating the maximum torque is 100%. It is read from a map having the accelerator opening signal Raps and the engine speed Ne as parameters.

  In the ignition operation coefficient calculation block B52 (ignition operation coefficient calculation means), based on the required load factor Zpi calculated in the required load factor calculation block B50 and the engine speed Ne, the ignition operation is performed based on the ignition operation coefficient map stored in advance. Read the coefficient K. For example, as shown in FIG. 3, the ignition operation coefficient map has an ignition operation coefficient K of 1 when the engine rotation speed Ne and the required load factor Zpi are relatively low and the low load low rotation (shaded area in FIG. 3). The ignition operation coefficient K is set to 0 at the time of high load or high rotation at which the speed Ne and the required load factor are relatively large. An area that is set to a value that complements between 0 and 1 (for example, 0.5 or is continuously variable between 1 and 0) between the 1 area and the 0 area Is provided (dot portion in FIG. 3).

Further, a fuel cut return limit Pi (Pif), which is a limit value of Pi for preventing a shock at the time of fuel cut return, and a target Pi (Pit) calculated in the target Pi calculation block B14 are input, and the following equation ( As shown in 1), the smaller value is divided by the MBT Pi value Paf to calculate the target ignition efficiency coefficient Kst.
Kst = MIN [Pif, Pit] / Paf (1)
The MBT-time Pi value Paf is an MBT condition actual Pi (Pmbt) that is an actual Pi at MBT when the number of IGs after F / C return (Cfig), which is the number of ignitions after fuel cut return, is smaller than a predetermined value Xig. Is divided by a predetermined value. When the number of IGs Cfig after F / C return is equal to or greater than the predetermined value Xig, the MBT condition actual Pi (Pmbt) is set as the MBT Pi value Paf as it is.

When there is an ignition retard external request Prtd, as shown in the following equation (2), a value obtained by subtracting the ignition retard external request Prtd from the target SA condition actual Pi (Piaf) is the Pi value Paf at MBT. The target ignition efficiency coefficient Kst may be calculated by dividing.
Kst = (Piaf−Prtd) / Paf (when Prtd> 0) (2)
Next, in the retard amount calculation block B54, the retard amount Rtd from the MBT is calculated based on the target ignition efficiency coefficient Kst obtained as described above, using the map for converting the ignition efficiency coefficient into the retard amount. To do.

Note that torque control that calculates the retard amount Rtd based on the target Pi and the like and applies the retard amount Rtd to the ignition timing as described above corresponds to the torque control means of the present invention.
Next, the target ignition timing a during torque control is calculated. The target ignition timing a during torque control is an ignition timing to which the retard amount Rtd calculated based on the target Pi or the like is applied. Specifically, as shown in the following equation (3), the retard amount Rtd is ignited. A value obtained by multiplying the retardation Ne correction coefficient Kne is obtained by subtracting it from the MBT ignition timing Smbt calculated in the MBT ignition timing calculation block B40.

a = Smbt−Rtd × Kne (3)
Next, the target ignition timing St is calculated in the target ignition timing calculation block B56. Specifically, at the time of ignition request at the time of return from the fuel cut, at the time of rotation feedback control (Ne-FB) by the F / B control block B30, or at the time of rotation speed limitation (at the time of torque limitation request from an external device such as a transmission) Regardless of the ignition operation coefficient K, the target ignition timing St is set to the torque control ignition timing a.

During normal operation other than the ignition request, rotation feedback control, and rotation speed limit, the target ignition timing St is calculated as shown in the following equation (4).
St = K × a + (1−K) × b (4)
However, b is the basic target ignition timing Smain at which the torque control is not performed.
The target ignition timing calculation block B56 increases or decreases the retard amount from the basic target ignition timing Smain by calculating the target ignition timing St, and corresponds to the retard amount setting means of the present invention.

  Next, the target ignition timing St calculated in the target ignition timing calculation block B56 is limited as necessary, and is output as the final effective ignition timing Sact. Specifically, a value obtained by subtracting the retard amount ΔSk for preventing knocking from the basic ignition timing Sfb after the air-fuel ratio feedback retardation correction, the actual EC time MBT ignition timing Smbt, and the target ignition timing calculation block B56 are calculated. Of the target ignition timings St, the smallest (advanced) value is selected, and the selected value is compared with the retard setting minimum value Smin, and the larger (retarded) value is selected. The final effective ignition timing Sact is output. The retard setting minimum value Smin is appropriately set so that an extremely small retard is regulated in order to achieve control stability.

Then, the ignition device 80 is controlled based on the output execution ignition timing Sact.
Further, the smallest value is selected from the target ignition timing St, the basic target ignition timing Smain and the actual EC time MBT ignition timing Smbt calculated in the target ignition timing calculation block B56, and this selected value and the retard setting minimum The larger value is compared with the value Smin, and the larger value is output as the effective ignition timing Sact1 without knocking correction. The effective ignition timing Sact1 is used as a parameter in opening control of the electronically controlled throttle valve 70, for example, during other torque correction calculations.

  By controlling as described above, in this embodiment, the ignition operation coefficient k is 1 at low load and low rotation, the ignition operation coefficient k is 0 at high load and high rotation, and the ignition operation coefficient k is 0 in the intermediate range. Set to a number between 1. During normal operation except when ignition is requested, during rotation feedback control, or when rotation speed is limited, torque control ignition timing a and basic target ignition timing b reflecting the retard amount Rtd calculated to achieve the target Pi and the like. The target ignition timing St is set based on the ignition operation coefficient k.

When the ignition operation coefficient k is 1, that is, at low rotation and low load, the target ignition timing St is set to the torque control ignition timing a. That is, since the ignition timing reflecting the torque control for realizing the target Pi is set, the engine speed can be reliably stabilized.
When the ignition operation coefficient k is 0, that is, at high load or high rotation, the target ignition timing St is set to the basic target ignition timing b. Therefore, the retard amount is suppressed, the engine can be operated efficiently, and the output and fuel consumption can be improved.

In the intermediate range, the target ignition timing St is set to a value between the torque control ignition timing a and the basic target ignition timing b in accordance with the ignition operation coefficient k. The improvement can be appropriately realized according to the setting of the ignition operation coefficient k.
Further, at the time of ignition request, at the time of rotation feedback, or at the time of rotation speed limitation, the target ignition timing St is set to the torque control ignition timing a regardless of the ignition operation coefficient. Therefore, the target Pi can be quickly and reliably realized according to various external requirements.

  That is, in this embodiment, the engine operation is controlled by increasing or decreasing the retard amount Rtd of the ignition timing set in the torque control for realizing the target Pi using the ignition operation coefficient k based on the load and the engine speed. Stabilizes engine operation at low load and low rotation, which tends to be unstable, and improves output and fuel efficiency by suppressing retard amount Rtd at high rotation, where engine operation is relatively stable or at high output. Plan. In addition, when there is a request for torque control, such as when ignition is requested, when rotation feedback is applied, or when the rotation speed is limited, the ignition timing is reliably set according to the request, and torque control is reliably reflected to stabilize engine operation. Can be realized reliably. Further, by performing these controls by calculation using the ignition operation coefficient k, it is possible to suppress the complication of the map and simplify the complicated control, and to stabilize engine operation and achieve both fuel efficiency. It becomes possible.

10 ECU
B45 Execution Ignition Timing Calculation Unit B52 Ignition Operation Coefficient Calculation Block B54 Delay Angle Calculation Block B56 Target Ignition Timing Calculation Block

Claims (4)

In a control device for an internal combustion engine comprising a torque control means for calculating a retard amount of the ignition timing of the internal combustion engine based on the target output torque and controlling the ignition timing according to the retard amount,
Ignition operation coefficient calculation means for calculating an ignition operation coefficient corresponding to a reflection rate of the retard amount calculated in the torque control means on the ignition timing based on the rotational speed and load of the internal combustion engine;
Retard amount setting means for increasing or decreasing the retard amount to be given to the ignition timing in the torque control means based on the ignition operation coefficient calculated by the ignition operation coefficient calculating means;
A control apparatus for an internal combustion engine, comprising:   2. The control device for an internal combustion engine according to claim 1, wherein the ignition operation coefficient is set between 0 and 1 so as to increase as the load and the engine speed decrease.   3. The ignition activation coefficient is set to 1 regardless of the load and the engine speed in a predetermined operation state that requires stable engine operation in response to an external request. Control device for internal combustion engine.   4. The internal combustion engine according to claim 3, wherein the predetermined operating state is a time of return from a fuel cut, a feedback control of an engine speed, or a torque reduction request from an external device other than the engine. Control device.

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