JP7058048B2 - Engine control unit - Google Patents

Description

The present invention relates to an engine control device.

In the engine, feedback control for correcting the fuel injection amount may be performed so that the actual air-fuel ratio approaches the target air-fuel ratio (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-025878

By the way, when the engine is manufactured, oil is applied to the engine parts and the assembly work is performed. Therefore, the oil applied in the assembly work may remain in the engine after the manufacture. The oil applied during this assembly and remaining in the engine burns with the fuel when the engine is used, which may affect the air-fuel ratio. In addition, in the case of an engine immediately after the start of use, engine oil may flow into the combustion chamber from the crankcase side until the sliding parts become familiar enough, and the engine oil burns together with the fuel. May also affect the air-fuel ratio.

An object of the present invention is to provide an engine control device capable of appropriately maintaining an air-fuel ratio even at the initial stage of use of an engine.

In order to solve the above problems, the engine control device of the present invention has an index derivation unit that derives an index value based on the cumulative number of times the engine piston has been slid after the start of use of the engine, and when the index value is equal to or higher than a threshold value. The index derivation unit includes an injection control unit that executes the first fuel injection control and executes the second fuel injection control in which the fuel injection amount is smaller than that of the first fuel injection control when the index value is less than the threshold value. The index value is derived by deriving the instantaneous value including the cumulative number of sliding times of the engine and the intake pressure and integrating the instantaneous values .

The index derivation unit may derive an index value based on the cumulative air amount obtained by multiplying the cumulative number of slides by the intake air amount per slide.

In the second fuel injection control, the injection control unit may make a correction to reduce the fuel injection amount as the index value becomes smaller.

The injection control unit performs feedback control of the air-fuel ratio in the second fuel injection control, and in the feedback control, the target of the air-fuel ratio is higher than the first fuel injection control by the first correction term not included in the first fuel injection control. The value may be increased.

In the second fuel injection control, the injection control unit performs feed forward control of the fuel injection amount, and in the feed forward control, the fuel is more fuel than the first fuel injection control by the second correction term not included in the first fuel injection control. The injection amount may be reduced.

According to the present invention, it is possible to appropriately maintain the air-fuel ratio even at the initial stage of using the engine.

It is a schematic diagram which shows the structure of an engine system. It is a flowchart explaining the flow of the 1st fuel injection control process. It is a flowchart explaining the flow of the 2nd fuel injection control processing. It is a flowchart explaining the flow of a control determination process. It is a figure which shows the relationship between the index value and the 1st correction term.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, other specific numerical values, etc. shown in the embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are not shown. do.

FIG. 1 is a schematic view showing the configuration of the engine system 100. In FIG. 1, the signal flow is indicated by a broken line arrow. As shown in FIG. 1, the engine system 100 includes an ECU 110 (Engine Control Unit) including a central processing unit (CPU), a ROM in which a program or the like is stored, a RAM as a work area, and the like. Is provided, and the entire engine 120 is collectively controlled by the ECU 110. However, in the following, the configurations and processes related to the present embodiment will be described in detail, and the description of the configurations and processes unrelated to the present embodiment will be omitted.

The engine 120 is a multi-cylinder engine having a plurality of cylinders 122a, and the intake manifold 126 is communicated with the intake port 124 of each cylinder 122a formed in the cylinder block 122. The intake passage 130 is communicated with the gathering portion of the intake manifold 126 via the air chamber 128. An air cleaner 132 is provided on the upstream side of the intake passage 130. A throttle valve 134 is provided on the downstream side of the air cleaner 132.

Further, the exhaust manifold 138 is communicated with the exhaust port 136 of each cylinder 122a formed in the cylinder block 122 of the engine 120. The muffler 142 communicates with the collecting portion of the exhaust manifold 138 via the exhaust passage 140. The exhaust passage 140 is provided with a catalyst device 144 such as a three-way catalyst. The exhaust gas is purified by the catalyst device 144 and discharged from the muffler 142.

The spark plug 146 and the injector 148 are provided for each cylinder 122a so that the tip is located in the combustion chamber 150.

Further, the engine 120 is provided with an intake air amount sensor 160, a pressure sensor 162, a throttle opening degree sensor 164, a crank angle sensor 166, an accelerator opening degree sensor 168, and an air-fuel ratio sensor 170.

The intake air amount sensor 160 and the pressure sensor 162 are provided between the air cleaner 132 and the throttle valve 134 in the intake passage 130. The intake air amount sensor 160 detects the amount of intake air flowing into the engine 120. The pressure sensor 162 detects the pressure (intake pressure) of the air flowing into the engine 120. The throttle opening sensor 164 detects the opening degree of the throttle valve 134. The crank angle sensor 166 detects the crank angle of the crankshaft. The accelerator opening sensor 168 detects the opening of the accelerator (not shown). The air-fuel ratio sensor 170 is provided, for example, downstream of the catalyst device 144 in the exhaust passage 140. The air-fuel ratio sensor 170 detects, for example, the oxygen concentration in the exhaust gas. The air-fuel ratio sensor 170 may be provided, for example, upstream of the catalyst device 144.

Each of the sensors 160 to 170 is connected to the ECU 110, and outputs a signal indicating a detected value to the ECU 110.

The ECU 110 controls the engine 120 by acquiring the signals output from the sensors 160 to 170. When controlling the engine 120, the ECU 110 functions as a signal acquisition unit 180, a target value derivation unit 182, an air amount control unit 184, an index derivation unit 186, an injection control unit 188, and an ignition control unit 190.

The signal acquisition unit 180 acquires a signal indicating a value detected by each of the sensors 160 to 170. The target value derivation unit 182 derives the current engine speed based on the signal indicating the crank angle acquired from the crank angle sensor 166. Further, the target value derivation unit 182 refers to the target torque and the target engine rotation speed with reference to the map stored in advance based on the derived engine rotation speed and the signal indicating the accelerator opening degree acquired from the accelerator opening sensor 168. Is derived.

The air amount control unit 184 determines the target air amount to be supplied to each cylinder 122a based on the target engine speed and the target torque derived by the target value derivation unit 182. The air amount control unit 184 derives the total amount of the determined target air amounts of each cylinder 122a, and determines the target throttle opening for sucking the total amount of air from the outside. Then, the air amount control unit 184 drives the throttle valve actuator (not shown) so that the throttle valve 134 opens at the determined target throttle opening degree.

The index derivation unit 186 derives an index value based on the cumulative number of slidings of the piston. The index value will be described in detail later.

The injection control unit 188 determines a target value (hereinafter referred to as a target injection amount) of the fuel injection amount of each cylinder 122a based on the target air amount of each cylinder 122a determined by the air amount control unit 184. The target injection amount will be described in detail later. Further, the injection control unit 188 is based on a signal indicating the crank angle detected by the crank angle sensor 166 in order to inject the determined target injection amount of fuel from the injector 148 in the intake stroke or the compression stroke of the engine 120. The target injection timing and target injection period of each injector 148 are determined.

Then, the injection control unit 188 drives the injector 148 at the determined target injection timing and target injection period, so that the injector 148 injects the fuel of the target injection amount.

The ignition control unit 190 determines the target ignition of the spark plug 146 in each cylinder 122a based on the target engine speed derived by the target value derivation unit 182 and the signal indicating the crank angle detected by the crank angle sensor 166. Decide when. Then, the ignition control unit 190 ignites the spark plug 146 at the determined target ignition timing.

Subsequently, the processing of the injection control unit 188 will be described in detail. The injection control unit 188 executes the first fuel injection control and the second fuel injection control. When the engine 120 is under the same operating conditions, the second fuel injection control is set to have a smaller target injection amount than the first fuel injection control. Here, the first fuel injection control will be described first, and then the second fuel injection control in which the correction for reducing the fuel injection amount is performed with respect to the first fuel injection control will be described.

FIG. 2 is a flowchart illustrating a flow of the first fuel injection control process.

(S200)
The injection control unit 188 derives (acquires) the actual air-fuel ratio from the detected value of the air-fuel ratio sensor 170.

(S202)
The injection control unit 188 derives a feedback term based on the actual air-fuel ratio and the previously derived target air-fuel ratio.

…（数式１） (S204)
As shown in the following formula 1, the injection control unit 188 multiplies the intake air amount V _Air by the fuel basic injection amount Y to derive the fuel basic injection amount X _base . The intake air amount V _Air is the volume of air sucked in one stroke derived from the detection value of the intake air amount sensor 160. The basic injection amount Y is the basic injection amount of fuel injected per unit volume of air.

… (Formula 1)

…（数式２） Then, the injection control unit 188 derives the target injection amount X _imp by multiplying the basic injection amount X _base by the injection amount correction coefficient C _total , as shown in the following mathematical formula 2.

… (Formula 2)

…（数式３） The correction coefficient C _total is obtained by adding the correction term _Cother to the feedback term C _back as shown in the following mathematical formula 3. The feedback term C _back is derived in step S202 above. The correction term _Cother is a correction term other than the feedback term C _back among the correction terms of the injection amount. The correction term _Cother includes, for example, a correction term for increasing the target injection amount _Ximp at the start of the engine 120, a correction term derived by learning, and the like.

… (Formula 3)

…（数式４） As described above, the feedback term C _back is derived based on the actual air-fuel ratio and the target air-fuel ratio TA _{/ F.} The target air-fuel ratio TA _{/ F} is obtained by multiplying the basic air-fuel ratio _{T base} by the air-fuel ratio correction term Ct, as shown in the following formula 4.

… (Formula 4)

(S206)
The injection control unit 188 injects fuel having a target injection amount of X _imp from the injector 148.

In this way, the injection control unit 188 executes feedback control for correcting the basic injection amount X _base by the feedback term C _back . Further, the injection control unit 188 executes feedforward control for correcting the basic injection amount X _base by the correction term _Cother .

FIG. 3 is a flowchart illustrating a flow of the second fuel injection control process. Here, the steps S200 and S206, which perform the same processing as the first fuel injection control processing, are designated by the same reference numerals and the description thereof will be omitted.

(S220)
After step S200, the injection control unit 188 derives the first correction term. The first correction term will be described in detail later.

…（数式４’） (S222)
The injection control unit 188 derives the feedback term C _back . As described above, the feedback term C _back is derived based on the actual air-fuel ratio and the previously derived target air-fuel ratio TA _{/ F.} In the second fuel injection control process, the target air-fuel ratio TA _{/ F} is derived by the following formula 4'instead of the above formula 4.

… (Formula 4')

In the formula 4', the _first correction term C1 is added to the formula 4. Here, the first correction term C ₁ has a positive value. In the formula 4', the target air-fuel ratio TA _{/ F} is derived as a large value with respect to the formula 4. Therefore, in the second fuel injection control process, the target injection amount X _imp is smaller than that in the first fuel injection control.

As described above, the injection control unit 188 performs feedback control of the air-fuel ratio in the second fuel injection control, and in the feedback control, the first fuel injection is performed by the _first correction term C1 not included in the first fuel injection control. Increase the target air-fuel ratio TA _{/ F} rather than control.

(S224)
Subsequently, the injection control unit 188 derives the second correction term. The second amendment will be described in detail later.

…（数式３’） (S226)
As shown in the above formula 2, the injection control unit 188 derives the target injection amount X _imp by multiplying the basic injection amount X _base by the injection amount correction coefficient C _total . However, in the second fuel injection control, the following formula 3'is used instead of the above formula 3 for deriving the correction coefficient C _total .

… (Formula 3')

In the formula 3', the second correction term C ₂ is added to the formula 3. Here, the second correction term C ₂ has a negative value. In the formula 3', the correction coefficient C _total is derived as a small value with respect to the formula 3. Therefore, in the second fuel injection control process, the target injection amount X _imp is smaller than that in the first fuel injection control.

As described above, the injection control unit 188 performs feedback control of the target injection amount and feedforward control of the air-fuel ratio in the second fuel injection control as well as the first fuel injection control. In the feedback control, the injection control unit 188 increases the target value of the air-fuel ratio more than the _first fuel injection control by the first correction term C1 not included in the first fuel injection control. In the feedforward control, the injection control unit 188 reduces the fuel injection amount as compared with the first fuel injection control by the _second correction term C2 not included in the first fuel injection control.

The reason why the injection control unit 188 performs the second fuel injection control in which the target injection amount X _imp becomes small is as follows. That is, the oil applied in the assembly work (hereinafter referred to as work oil) remains in the engine 120 immediately after production. Therefore, until the use of the engine 120 is started and the working oil is burned out, the fuel injection amount is increased.

Further, in the engine 120 immediately after production, the sealing property is temporarily deteriorated until the sliding parts and the like are sufficiently familiar. If the sealing property of the piston ring is low, for example, the amount of engine oil (lubricating oil) flowing into the combustion chamber 150 from the crankcase side increases. Therefore, until the engine 120 is used and the piston ring and the cylinder liner are sufficiently familiar, the fuel injection amount is increased.

In the second fuel injection control, the target injection amount X _imp becomes smaller by this increase. As a result, an appropriate air-fuel ratio is maintained even at the initial stage of use of the engine 120, which leads to an effect of suppressing an increase in particulate matter in the exhaust gas.

The working oil burns with the fuel and decreases with the use of the engine 120. Further, the lack of familiarity between the piston ring and the cylinder liner is eliminated with the use of the engine 120. Therefore, it is desirable to perform the second fuel injection control and then perform the first fuel injection control until the working oil is burned out and the lack of familiarity is resolved. However, it is not possible to directly measure the remaining amount of working oil and the degree of familiarity. Therefore, in the present invention, index values that can be used for these determinations are used. Here, the index derivation unit 186 derives the index value.

…（数式５） Specifically, as shown in the following formula 5, the index derivation unit 186 has the rotation speed R of the engine 120, the intake air amount GN (g / rev) per rotation (rev), the elapsed time T, and the intake air. By multiplying the pressure P, the instantaneous value I of the index value Isum is derived. Here, the elapsed time T is the calculation cycle of the ECU 110 (for example, 32 msec, 1024 msec, etc.).

… (Formula 5)

…（数式６） The index derivation unit 186 derives the index value I by integrating the instantaneous value I of the index value Isum. Here, the index value Iso when the calculation cycle of the ECU 110 has elapsed n times is defined as the index value Iso _(n) . As shown in Equation 6, the index value Isum _(n) is obtained by adding the instantaneous value I derived this time to the previously derived index value Isum _(n-1) . The index value Iso is, for example, integrated after the start of use of the engine 120.

… (Formula 6)

The product of the rotation speed R and the elapsed time T is the cumulative number of sliding times of the piston. Here, for example, the number of slidings per rotation is counted as one. That is, the index value Isum is a value based on (for example, proportional) the cumulative number of times the piston has been slid.

The remaining amount of working oil decreases with the use of the engine 120. In addition, the influence of engine oil due to lack of familiarity disappears with the use of the engine 120. Since the instantaneous value I and the index value Iso, which is an integrated value thereof, are values based on the cumulative number of times the piston has been slid (that is, the number of times of combustion), they indicate the degree of the remaining amount of working oil that decreases with combustion. Can be done. Further, since the index value Isum is a value based on the cumulative number of times the piston has been slid, it is possible to indicate the degree of familiarity between the piston ring and the cylinder liner.

Further, the product of the cumulative number of slidings and the intake air amount GN per one sliding (as described above, when one rotation is counted as one sliding) is the cumulative air amount. Here, the cumulative amount of air is the cumulative value of the amount of air taken in after the start of use of the engine 120. That is, the instantaneous value I and the index value Isom are values based on (for example, proportional) the cumulative air volume. Therefore, since the index value Isom also takes into account the influence of the load of the engine 120, it is possible to indicate the remaining amount of working oil and the degree of familiarity with higher accuracy.

Further, in the formula 5, the instantaneous value I is the cumulative amount of air multiplied by the intake pressure P. The intake pressure P shall be expressed as an absolute pressure. Generally, the higher the load of the engine 120, the larger the intake pressure P, so that the instantaneous value I and the index value Isum become larger. Therefore, since the index value Isum also takes into account the influence of the load of the engine 120 expressed as the intake pressure P, the remaining amount of working oil and the degree of familiarity can be indicated with higher accuracy.

In this way, the index derivation unit 186 derives the index value Iso. The injection control unit 188 determines whether to execute the first fuel injection control or the second fuel injection control based on the derived index value Isom.

FIG. 4 is a flowchart illustrating the flow of the control determination process.

(S240)
The index derivation unit 186 derives the index value Iso.

(S242)
The injection control unit 188 determines whether or not the index value Iso is equal to or higher than a preset threshold value. If the index value Iso is equal to or greater than the threshold value, the process proceeds to step S244. If the index value Iso is less than the threshold value, the process proceeds to step S246.

(S244)
The injection control unit 188 performs the first fuel injection control.

(S246)
The injection control unit 188 performs the second fuel injection control.

Further, the injection control unit 188 makes a correction in the second fuel injection control to reduce the target injection amount as the index value Isom becomes smaller.

FIG. 5 is a diagram showing the relationship between the index value Isum and the _first correction term C1. As shown in FIG. 5, the first correction term C ₁ is set according to the index value Isum. If the index value Ism is 0 or more and less than 1000, the first correction term C ₁ is 0.1, and if the index value Isum is 1000 or more and less than 2000, the first correction term C ₁ is 0.08 or the like. ..

Here, the relationship between the index value Iso and the first correction term C ₁ has been shown, but the second correction term C ₂ is also set according to the index value Ism as in the case of the first correction term C ₁ . In the first correction term C ₁ , the larger the index value Isom, the smaller (closer to 0) the positive value is taken. In the second correction term _C2 , the larger the index value Isom, the larger (closer to 0) the negative value is taken.

If the index value Isom is equal to or greater than the threshold value, both the first correction term C ₁ and the second correction term C ₂ become 0. That is, the transition from the second fuel injection control to the first fuel injection control.

As described above, in the second fuel injection control, the injection control unit 188 reduces the target injection amount as the index value Isom becomes smaller, so that an appropriate amount of fuel is used according to the remaining amount of working oil and the degree of familiarity. And oil will burn.

The value of the first correction term C ₁ and the positive / negative of the first correction term C ₁ and the second correction term C ₂ mentioned here are only examples. For example, a function having the index value Isum as a variable may be defined, and the first correction term C ₁ and the second correction term C ₂ may be derived by the function.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. Will be done.

For example, in the above-described embodiment, the case where the index value Iso is derived based on the cumulative air amount has been described. However, the index value Isom may be a value not related to the cumulative air volume.

Further, in the above-described embodiment, the case where the index value Iso is derived based on the intake pressure P has been described. However, the index value Isom may be a value not related to the intake pressure P.

Further, in the above-described embodiment, the injection control unit 188 has described the case where the injection control unit 188 makes a correction for reducing the target injection amount as the index value Isom becomes smaller in the second fuel injection control. However, the injection control unit 188 may determine the target injection amount in the second fuel injection control regardless of the value of the index value Iso. At least, in the second fuel injection control, the fuel injection amount may be smaller than that in the first fuel injection control.

Further, in the above-described embodiment, in the feedback control of the second fuel injection control, the injection control unit 188 has an air-fuel ratio higher than that of the _first fuel injection control by the first correction term C1 not included in the first fuel injection control. The case of increasing the target value of is explained. Further, in the feedforward control of the second fuel injection control, the injection control unit 188 reduces the fuel injection amount as compared with the first fuel injection control by the _second correction term C2 not included in the first fuel injection control. Explained. However, it is not an essential configuration to incorporate the first correction term C ₁ and the second correction term C ₂ into the calculation formula. At least, in the second fuel injection control, the fuel injection amount may be smaller than that in the first fuel injection control.

The present invention can be used for an engine control device.

110 ECU (engine control unit)
186 Index derivation unit 188 Injection control unit

Claims (5)

An index derivation unit that derives an index value based on the cumulative number of slidings of the piston of the engine after the start of use of the engine, and an index derivation unit.
When the index value is equal to or higher than the threshold value, the first fuel injection control is executed, and when the index value is less than the threshold value, the second fuel injection control in which the fuel injection amount is smaller than that of the first fuel injection control is executed. Control unit and
Equipped with
The index derivation unit derives the instantaneous value including the cumulative number of sliding times and the intake pressure of the engine, and derives the index value by integrating the instantaneous values.
Engine control device. The engine control device according to claim 1, wherein the index derivation unit derives the index value based on the cumulative air amount obtained by multiplying the cumulative number of slides by the intake air amount per slide. The engine control device according to claim 1 or 2 , wherein the injection control unit makes a correction to reduce the fuel injection amount as the index value becomes smaller in the second fuel injection control. The injection control unit performs feedback control of the air-fuel ratio in the second fuel injection control, and in the feedback control, according to the first correction term not included in the first fuel injection control, the first fuel injection control The engine control device according to any one of claims 1 to 3 , which also increases the target value of the air-fuel ratio. The injection control unit performs feed-forward control of the fuel injection amount in the second fuel injection control, and in the feed-forward control, the first correction term according to a second correction term not included in the first fuel injection control. The engine control device according to any one of claims 1 to 4 , wherein the fuel injection amount is reduced more than the fuel injection control.

Images