JP2015068334A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device which further properly performs throttle valve opening control, and can smoothly and quickly perform switching when switching usable fuel capable of operating an internal combustion engine by using two kinds of fuel.SOLUTION: When switching an operation mode to a second operation mode for injecting CNG by a second fuel injection valve 5 from a first operation mode for injecting gasoline by a first fuel injection valve 4, or vice versa, there is performed control for gradually transiting a throttle valve opening TH toward a post-switching target opening THTGT at a change speed VCG. The change speed VCG is corrected according to an engine operation state (engine rotation number NE, intake air pressure PBA, and a cooling water temperature TW), and the post-switching target opening THTGT is set so that an engine output torque difference caused by the switching of the usable fuel is suppressed.

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device that performs fuel switching control and output torque control of an internal combustion engine that can be operated with two types of fuel.

  Patent Document 1 discloses a fuel injection control device for an internal combustion engine that can be operated by two types of fuel, that is, liquid fuel (for example, gasoline) and gas fuel (for example, compressed natural gas (CNG)). According to this device, the target torque is set according to the accelerator opening, and the throttle valve opening and the ignition timing are controlled so that the target torque is realized. When the fuel used is switched from gas fuel to liquid fuel, the throttle valve opening and ignition timing corresponding to the gas fuel are gradually changed from the throttle valve opening and ignition timing corresponding to the liquid fuel. When the fuel used is switched from liquid fuel to gas fuel, the throttle valve opening and ignition timing corresponding to the liquid fuel are gradually changed from the throttle valve opening and ignition timing corresponding to the gas fuel. Such control at the time of switching prevents sudden change in engine output torque.

JP 2007-285121 A

  In Patent Document 1, there is no specific description about the speed at which the throttle valve opening is changed when the fuel is used, and it is assumed that the speed is changed at a preset speed. However, since the optimum change speed of the throttle valve opening changes depending on the engine operating state, there is room for improvement in the control at the time of fuel switching disclosed in Patent Document 1.

  The present invention has been made paying attention to the above points, and when switching the fuel used in an internal combustion engine that can be operated by two types of fuel, the throttle valve opening degree control is performed more appropriately, and the switching is performed smoothly and quickly. It is an object of the present invention to provide a control apparatus that can perform the above.

  In order to achieve the above object, the invention described in claim 1 includes a first fuel injection valve (4) for injecting a first fuel and a second fuel injection valve for injecting a second fuel different from the first fuel ( 5), the engine using the second fuel injection valve (5) from the first operation mode in which fuel is supplied to the engine using the first fuel injection valve (4). And switching means for switching from the second operating mode to the first operating mode, and when the operating mode is switched by the switching means, the throttle valve of the engine Throttle valve control means for gradually shifting the opening (TH) of the engine toward the target opening (THTGT) at a set speed (VCG), and a speed for correcting the set speed (VCG) according to the operating state of the engine Correction means Target opening (THtgt) is characterized in that change in the output torque of the engine according to the operation mode switching is set to be inhibited.

  According to this configuration, switching from the first operation mode in which fuel is supplied to the engine using the first fuel injection valve to the second operation mode in which fuel is supplied to the engine using the second fuel injection valve, or vice versa. When the operation mode is switched, the engine throttle valve opening is gradually shifted to the target opening at the set speed, and the set speed is corrected according to the engine operating state. Is done. Here, the target opening is set so that the change in engine output torque due to operation mode switching is suppressed. Therefore, by making the transition speed to the target opening suitable for the engine operating state, it is possible to suppress torque shock and realize smoother and quicker switching.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the speed correction means is configured to rotate the engine at a predetermined rotation speed (NE) at which the engine output torque takes a peak value. The speed-dependent correction that decreases the set speed (VCG) as the distance from the number (NETM) decreases, the load-dependent correction that increases the set speed (VCG) as the engine load (PBA) increases, and the engine It is characterized in that at least one of temperature-dependent correction for increasing the set speed (VCG) as the temperature (TW) becomes higher is executed.

  According to this configuration, the engine speed increases as the engine output torque deviates from the predetermined speed at which the engine output torque takes a peak value, and the speed dependent correction that decreases the set speed, and the set speed increases as the engine load increases. At least one of a load-dependent correction and a temperature-dependent correction that decreases the set speed as the engine temperature decreases is executed. Thus, by performing the set speed correction according to the engine operating state, the throttle valve opening degree suitable for the engine operating state can be changed, and the change in the output torque accompanying the switching can be suppressed and quick switching can be performed. .

  The invention according to claim 3 is the control apparatus for an internal combustion engine according to claim 1 or 2, wherein the maximum output torque of the engine in the second operation mode is the maximum output torque of the engine in the first operation mode. The switching means has a determination means for determining whether or not to execute switching when a request for switching from the first operation mode to the second operation mode is made, and according to a determination result by the determination means. And the determination means is based on a relative relationship between the output torque (TRQCNG) when the second fuel is used and the output torque (TRQGAS) when the first fuel is used. The determination is performed.

  According to this configuration, when a switching request is made from the first operation mode having a large maximum output torque to the second operation mode having a small maximum output torque, it is determined whether or not the switching can be performed, and the switching is performed according to the determination result. Is executed. The determination of whether or not to execute the switching is performed based on a relative relationship between the output torque when the second fuel is used and the output torque when the first fuel is used. Since the maximum output torque in the second operation mode is smaller than the maximum output torque in the first operation mode, the torque difference may not be eliminated even if the throttle valve opening is changed in a high load operation state. In such a case, the occurrence of torque shock can be prevented by not performing the switching.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to the third aspect, the throttle valve control means can be executed when a request for switching the operation mode is made or by the determination means. When the determination is made, a transition of the throttle valve opening (TH) toward the target opening (THTGT) is started.

  According to this configuration, when the operation mode switching request is made, or when the determination means determines that execution is possible, the transition of the throttle valve opening toward the target opening is started. The Since the change in the intake air amount is delayed from the change in the throttle valve opening, the switching operation can be performed smoothly and quickly by immediately starting the change in the throttle valve opening.

It is a figure which shows the structure of the internal combustion engine and its control apparatus concerning one Embodiment of this invention. It is a figure which shows the maximum output torque characteristic when using gasoline, and the maximum output torque characteristic when using CNG. It is a flowchart of the 1st switching control process which switches from the 1st operation mode which uses gasoline to the 2nd operation mode which uses CNG. It is a figure which shows the table referred by the process of FIG. It is a time chart for demonstrating the process of FIG. It is a flowchart of the 2nd switching control process which switches from the 2nd operation mode which uses CNG to the 1st operation mode which uses gasoline. It is a time chart for demonstrating the process of FIG.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention.
An internal combustion engine (hereinafter referred to as “engine”) 1 is a so-called bi-fuel engine that uses gasoline and CNG (compressed natural gas) as fuel. In the present embodiment, operation control of the engine 1, specifically, fuel injection amount control and ignition timing control are performed using two electronic control units (ECUs) 21 and 22. In the following description, the two ECUs are referred to as a first ECU 21 and a second ECU 22.

  The engine 1 has four cylinders # 1 to # 4, and each cylinder is provided with a spark plug (not shown). The intake passage 2 branches into four intake manifolds 2a corresponding to the four cylinders. A throttle valve 3 is disposed in the intake passage 2, and a first fuel injection valve 4 for injecting gasoline and CNG are injected slightly upstream (intake port) of an intake valve (not shown) of the intake manifold 2a. A second fuel injection valve 5 is attached. As shown in FIG. 1, the first fuel injection valve 4 is disposed on the downstream side of the second fuel injection valve 5.

  The first fuel injection valve 4 is connected to a fuel pump unit 7 in the gasoline tank 6 through a fuel passage 8. The fuel pump unit 7 includes a fuel pump and a pressure regulator, and gasoline adjusted to a predetermined fuel pressure is supplied to the first fuel injection valve 4.

  The second fuel injection valve 5 is connected to the CNG cylinder 10 via the fuel passage 11, and a shutoff valve 12 and a pressure regulator 13 are provided in the middle of the fuel passage 11. The pressure-adjusted CNG is supplied to the second fuel injection valve 5 through the fuel passage 11.

  An actuator 15 for changing the opening of the throttle valve 3 is attached to the throttle valve 3, and the operation of the actuator 15 is controlled by the first ECU 21.

  The first ECU 21 includes an engine speed sensor 31 that detects the speed NE of the engine 1, an intake air flow rate sensor 32 that detects the intake air flow rate GAIR, an intake pressure of the engine 1 (the pressure in the intake passage on the downstream side of the throttle valve 3). ) An intake pressure sensor 33 that detects PBA, a throttle valve opening sensor 34 that detects the opening TH of the throttle valve 3, a cooling water temperature sensor 35 that detects the cooling water temperature TW of the engine 1, and an intake air temperature sensor that detects the intake air temperature TA 36. An accelerator sensor 37 for detecting an accelerator pedal depression amount (hereinafter referred to as “accelerator pedal operation amount”) AP of a vehicle driven by the engine 1 is connected to other sensors (not shown), and detection of these sensors is performed. A signal is supplied to the ECU 21.

  A fuel changeover switch 38 is further connected to the first ECU 21 so that the fuel to be used can be selected by the operation of the driver. The fuel selector switch 38 is configured to be switchable between a first position for selecting gasoline, a second position for selecting CNG, and a third position for selecting automatic switching, and when set to the third position. The switching of the used fuel (switching of the operation mode) is performed by the first ECU 21 according to the operating state of the engine 1, the traveling state of the vehicle driven by the engine 1, and the remaining fuel amounts of CNG and gasoline.

  The first ECU 21 is connected to the ignition plugs IG # 1 to IG # 4 of each cylinder, and performs ignition control by the ignition plugs IG # 1 to IG # 4. Further, the target opening THCMD of the throttle valve opening TH is set according to the accelerator pedal operation amount AP, and the drive control of the actuator 15 is performed so that the throttle valve opening TH coincides with the target opening THCMD.

  The second ECU 22 is connected to the first ECU 21 via the data bus 23, and the two ECUs 21 and 22 transmit detection data and control data from the sensors to each other via the data bus 23. The second ECU 22 is connected to the first fuel injection valve 4 and the second fuel injection valve 5 corresponding to each cylinder, and performs fuel injection by driving the fuel injection valve corresponding to the selected used fuel. In FIG. 1, the first fuel injection valves 4 corresponding to the # 2 to # 4 cylinders are indicated as 4 (# 2), 4 (# 3), and 4 (# 4), respectively, and the # 2 to # 4 cylinders The second fuel injection valves 5 corresponding to are indicated by 5 (# 2), 5 (# 3), and 5 (# 4), respectively, to indicate the connection relationship.

  The first ECU 21 calculates the fuel injection time TINJ1 when using gasoline in accordance with the detection signals of various sensors, calculates the ignition timing IGLOG of the ignition plug of each cylinder, and calculates the calculated fuel injection time TINJ1 (hereinafter “first fuel”). Injection time TINJ1 ”) and a fuel use command signal SFUEL are transmitted to the second ECU 22, and an ignition command signal based on the ignition timing IGLOG is supplied to the ignition plugs IG # 1 to IG # 4 of each cylinder.

  The second ECU 22 calculates a fuel injection time TINJ2 when CNG is used (hereinafter referred to as “second fuel injection time TINJ1”) according to the first fuel injection time TINJ1. When the opening times of the first and second fuel injection valves 4 and 5 are the same, the output torque of the engine 1 becomes larger when gasoline is used. Therefore, the second fuel injection time TINJ2 is calculated so as to obtain the same engine output as the first fuel injection time TINJ1 by correcting the first fuel injection time TINJ1 in the increasing direction.

  FIG. 2 is a diagram showing the relationship between the engine speed NE and the maximum output torque of the engine 1. The solid line shows the first maximum output torque TMAXGAS when gasoline is used, and the broken line shows the case where CNG is used. The second maximum torque TMAXCNG is shown (output torque when the throttle valve 3 is fully opened and the ignition timing IGLOG is optimally set). As is apparent from this figure, the first maximum output torque TMAXGAS is greater than the second maximum output torque TMAXCNG over the entire range of the engine speed NE. Specifically, the second maximum output torque TMAXCNG corresponds to the output torque when gasoline is used and the throttle valve opening TH is about 80% of the fully opened state.

  Therefore, it is desirable to minimize the difference in output torque before and after switching when using fuel. As described above, a method of gradually changing the throttle valve opening TH in order to change the intake air amount in accordance with the switching of the fuel has been conventionally known. However, in the present embodiment, the throttle valve opening TH is further reduced. By changing the change speed according to the engine operating condition, the intake air amount is changed according to the engine operating condition, and torque switching is suppressed to realize smoother switching.

  FIG. 3 is a flowchart of a first switching control process for switching from the first operation mode using gasoline to the second operation mode using CNG. This process is executed in the first ECU 21.

  In step S11, it is determined whether or not the first switching request flag FCNGREQ is “1”. The first switching request flag FCNGREQ is displayed when the fuel switching switch 38 is switched to the second position or when the first ECU 21 determines that switching from gasoline to CNG is necessary with the fuel switching switch 38 switched to the third position. 1 ”.

  If the answer to step S11 is negative (NO), the process immediately ends. If the answer is affirmative (YES), step S12 and subsequent steps are executed. In step S12, an engine output torque (hereinafter referred to as “CNG output torque”) TRQCNG when CNG is used is calculated according to the detected engine speed NE and the intake air flow rate GAIR. In step S13, the detected engine The output torque (hereinafter referred to as “GAS output torque”) TRQGAS, that is, the current engine output torque when gasoline is used is calculated according to the rotational speed NE and the intake air flow rate GAIR.

  In step S14, a target opening after switching (hereinafter referred to as "target opening after switching") THTGT is calculated according to the GAS output torque TRQGAS and CNG output torque TRQCNG and the current throttle valve opening TH, and the switching is performed. Whether or not to execute is determined. The post-switching target opening THTGT is set so that the difference in engine output torque due to switching is suppressed. Specifically, for example, if the current throttle valve opening TH is 40% of the fully opened opening, the post-switch target opening THTGT is an opening equivalent to 50% of the fully opened opening, and it is determined that switching can be performed. The On the other hand, if the current throttle valve opening TH is 90% of the fully opened opening, the post-switching target opening THTGT is larger than the fully opened opening. Therefore, since switching without torque difference cannot be performed, it is determined that switching cannot be performed. When it is determined that switching can be performed, the switching execution permission flag FSWPT is set to “1”, and when it is determined that switching cannot be performed, the switching execution permission flag FSWPT is set to “0”.

  In step S15, it is determined whether or not the switching execution permission flag FSWPT is “1”. If the answer to step S15 is negative (NO), the processing is immediately terminated. When the switching execution permission flag FSWPT is “1”, the process proceeds to step S16, where the KNE table shown in FIG. 4A is searched according to the engine speed NE to calculate the speed correction coefficient KNE, and the intake pressure The KPB table shown in FIG. 4B is searched according to the PBA to calculate the load correction coefficient KPB, and the KTW table shown in FIG. 4C is searched according to the engine cooling water temperature TW to find the cooling water temperature correction coefficient. KTW is calculated.

  The NETM in the KNE table is the engine speed at which the output torque of the engine 1 is maximized (hereinafter referred to as “maximum torque speed”), and the KNE table is when the engine speed NE is the maximum torque speed NETM. The rotational speed correction coefficient KNE takes a maximum value KNEH (for example, 4.0), and the rotational speed correction coefficient KNE is set to decrease as the engine rotational speed NE departs from the maximum torque rotational speed NETM, and the engine rotational speed NE is low. (For example, at 800 rpm or less), “1.0” is set. Since the maximum output torque of the engine 1 varies depending on the engine speed NE as shown in FIG. 2, it is switched by setting the speed correction coefficient KNE as shown in FIG. Torque shock (torque change speed) can be suppressed.

  In the KPB table, when the intake pressure PBA is low (for example, 21.3 kPa (160 mmHg) or less), the load correction coefficient KPB takes “1.0”, and the load correction coefficient KPB increases as the intake pressure PBA increases. Is set. The maximum value KPBH is set to 4.0, for example. As the intake pressure PBA increases, the engine load increases and the intake air flow rate increases. Therefore, by setting a load correction coefficient KPB as shown in FIG. Can do.

  The KTW is set so that the cooling water temperature correction coefficient KTW takes “1.0” after the warm-up of the engine 1 is completed, and the cooling water temperature correction coefficient KTW decreases as the cooling water temperature TW decreases. The minimum value KTWL is set to 0.01, for example, and the predetermined cooling water temperatures TWL and TWH are set to 40 ° C. and 80 ° C., respectively. Since the intake air charging amount changes in response to the change in engine temperature indicated by the cooling water temperature TW, by setting the cooling water temperature correction coefficient KTW as shown in FIG. Can be suppressed.

  In step S17, the correction coefficient KNE, KPB, KTW is applied to the following equation (1) to calculate the throttle valve opening changing speed VCG. VCGR in the equation (1) is a reference change speed calculated by applying the current value TH0 of the post-switch target opening THTGT and the throttle valve opening TH to the equation (2). The change speed VCG is defined by the change amount of the throttle valve opening TH per unit time (for example, 1 msec).

VCG = VCGR × KNE × KPB × KTW (1)
VCGR = (THTGT−TH0) / TREF (2)
Here, TREF is a time corresponding to a 4TDC period (that is, a period corresponding to one combustion cycle), and is expressed as 120,000 / NE [msec] when NE [rpm] is used.

  In step S18, the throttle valve opening TH is changed at the changing speed VCG toward the target opening THTGT after switching. In step S28, the injected fuel is switched from gasoline to CNG at the switching timing CASW corresponding to the change speed VCG.

  FIG. 5 is a time chart for explaining the processing of FIG. 4. FIGS. 5A to 5C show the first switching request flag FCNGREQ, the throttle valve opening TH, and the # 1 to # 4 cylinders, respectively. The fuel injection timing (INJGAS, INGCNG) and ignition timing (IG) are shown.

  The operation example shown in FIG. 5 corresponds to a reference state (low rotation / low load operation state after completion of warm-up) in which the correction coefficients KNE, KPB, and KTW are all “1.0”. The degree TH is controlled so as to change from the initial value TH0 to the target opening degree THTGT after switching in the 4TDC period from time t0 to t1, and the switching timing CASW is set after the elapse of 1TDC period.

  FIG. 6 is a flowchart of a second switching control process for switching from the second operation mode using CNG to the first operation mode using gasoline, contrary to the process of FIG. 3. This process is executed in the first ECU 21.

  In step S21, it is determined whether or not the second switching request flag FGASREQ is “1”. The second switching request flag FGASREQ is displayed when the fuel selector switch 38 is switched to the first position or when the first ECU 21 determines that switching from CNG to gasoline is necessary in the state where the fuel switching switch 38 is switched to the third position. 1 ”.

  If the answer to step S21 is negative (NO), the process immediately ends. If the answer is affirmative (YES), step S22 and subsequent steps are executed. In step S22, the CNG output torque TRQCNG, that is, the current engine output torque, is calculated according to the detected engine speed NE and the intake air flow rate GAIR. In step S23, the detected engine speed NE and the intake air flow rate GAIR are calculated. The GAS output torque TRQGAS is calculated accordingly.

  In step S24, the post-switching target opening THTGT is calculated so that the output torque difference before and after switching is suppressed according to the GAS output torque TRQGAS and the CNG output torque TRQCNG and the current throttle valve opening TH0. When switching from CNG to gasoline, the throttle valve opening TH is changed in the valve closing direction, so it is not necessary to determine whether or not to perform switching. That is, the post-switching target opening THTGT is set to a value smaller than the current throttle valve opening TH0.

  In steps S25 to S28, processing similar to the processing in steps S16 to S19 in FIG. 3 is performed. That is, the change speed VCG is calculated, and the operation of gradually decreasing the throttle valve opening TH toward the target opening THTGT after switching is immediately started at the change speed VCG, and the injection is performed at the switching timing CASW corresponding to the change speed VCG. Change the fuel.

  FIG. 7 is a time chart for explaining the processing of FIG. 6. FIGS. 7A to 7C show the second switching request flag FGASREQ, the throttle valve opening TH, and the # 1 to # 4 cylinders, respectively. The fuel injection timing (INJGAS, INGCNG) and ignition timing (IG) are shown.

  The operation example shown in FIG. 7 corresponds to a reference state where the correction coefficients KNE, KPB, and KTW are all “1.0” (low-rotation low-load operation state after completion of warm-up), and the throttle valve is opened. The degree TH is controlled so as to change from the initial value TH0 to the target opening degree THTGT after switching in the 4TDC period from time t10 to t11, and the switching timing CASW is set after the elapse of 1 TDC period.

  As described above, in the present embodiment, switching from the first operation mode in which gasoline is injected by the first fuel injection valve 4 to the second operation mode in which CNG is injected by the second fuel injection valve 5 or vice versa is performed. When the operation mode is switched, control is performed to gradually shift the throttle valve opening TH toward the target opening THTGT at the changed speed VCG toward the target opening THTGT, and the engine operating state, specifically, the engine speed NE. The change speed VCG is corrected according to the intake pressure PBA and the coolant temperature TW. The post-switch target opening THTGT is set such that the engine output torque difference due to operation mode switching, that is, switching of the fuel used is suppressed. Therefore, by making the transition speed to the target opening degree THTGT after switching suitable for the engine operating state, torque shock can be suppressed and smoother and quicker switching can be realized.

  That is, as the engine rotational speed NE is further away from the maximum torque rotational speed NETM at which the engine output torque becomes maximum, the rotational speed correction coefficient KNE is calculated so as to decrease the change speed VCG, and the intake pressure PBA indicating the engine load increases. The load correction coefficient KPB is calculated so as to increase the change speed VCG as the engine speed increases, and the cooling water temperature correction coefficient KTW that decreases the change speed VCG is calculated as the cooling water temperature TW indicating the engine temperature decreases, and these correction coefficients are used. Thus, the change speed VCG is corrected. In this way, by correcting the change speed VCG according to the engine state, the throttle valve opening TH suitable for the engine operating state is changed, and the change in the output torque accompanying the switching is suppressed, and the quick switching is performed. be able to.

  Further, when a request for switching from the first operation mode in which the maximum output torque is large to the second operation mode in which the maximum output torque is small (when the first switch request flag FCNGREQ is set to “1”), FIG. In step S14 in FIG. 3, it is determined whether or not switching can be performed, and switching is performed when a switching request flag FSWPT indicating the determination result is “1”. The determination of whether or not to execute the switching is performed based on the relative relationship between the output torque when using CNG and the output torque when using gasoline, and the maximum output torque in the second operation mode using CNG is gasoline. Since it is smaller than the maximum output torque of the first operation mode to be used, the torque difference may not be eliminated even if the throttle valve opening TH is changed in a high load operation state. Thus, the occurrence of torque shock can be prevented.

  Further, when a switching request for the operation mode is made in the second switching control process, and when it is determined that the operation can be executed in the first switching control process, the target opening degree THTGT after switching of the throttle valve opening TH is made. The transition towards is started. Since the change in the intake air amount is delayed from the change in the throttle valve opening TH, the switching operation can be performed smoothly and quickly by immediately starting the change in the throttle valve opening TH.

  In the present embodiment, the first ECU 21 constitutes switching means, throttle valve control means, speed correction means, and determination means. Specifically, steps S15 and S19 in FIG. 3 and step S28 in FIG. 6 correspond to switching means, step S18 in FIG. 3 and step S27 in FIG. 6 correspond to throttle valve means, and step S16 in FIG. , S17 and steps S25 and S26 in FIG. 6 correspond to speed correction means, and step S14 in FIG. 3 corresponds to determination means.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, in the above-described embodiment, an internal combustion engine using CNG as the second fuel is shown. However, the present invention uses an alcohol or other gaseous fuel such as liquefied natural gas or hydrogen as the second fuel. The present invention can also be applied to other control devices.

  In the above-described embodiment, the change speed VCG of the throttle valve opening TH is corrected using all the three correction factors KNE, KPB, and KTW. However, any one or a combination of any two is used. You may make it correct | amend using.

  In the embodiment described above, each table shown in FIG. 4 is set with the low-rotation low-load operation state after completion of warming-up of the engine 1 as the reference state, but the reference state is not limited to this. It is good also as another driving | running state. Further, in the above-described embodiment, the reference value of the change period (the period from the start to the end of the change) of the throttle valve opening TH is set to 4 TDC period. However, the reference value is not limited to this. It is good.

  The present invention can also be applied to control of a marine vessel propulsion engine such as an outboard motor having a crankshaft as a vertical direction.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 4 1st fuel injection valve 5 2nd fuel injection valve 21 Electronic control unit (switching means, throttle valve control means, speed correction means, determination means)

Claims (4)

In a control device for an internal combustion engine comprising: a first fuel injection valve that injects a first fuel; and a second fuel injection valve that injects a second fuel different from the first fuel.
From the first operation mode in which fuel is supplied to the engine using the first fuel injection valve to the second operation mode in which fuel is supplied to the engine using the second fuel injection valve, or from the second operation mode Switching means for switching to the first operation mode;
Throttle valve control means for gradually shifting the throttle valve opening of the engine to a target opening at a set speed when performing operation mode switching by the switching means;
Speed correction means for correcting the set speed according to the operating state of the engine,
The control apparatus for an internal combustion engine, wherein the target opening is set so that a change in output torque of the engine due to the operation mode switching is suppressed.   The speed correction means is a speed-dependent correction that decreases the set speed as the engine speed deviates from a predetermined speed at which the output torque of the engine takes a peak value, and the engine load increases as the engine load increases. 2. The control device for an internal combustion engine according to claim 1, wherein at least one of a load-dependent correction for increasing a set speed and a temperature-dependent correction for decreasing the set speed as the temperature of the engine becomes lower is executed. The maximum output torque of the engine in the second operation mode is smaller than the maximum output torque of the engine in the first operation mode,
The switching means has a determination means for determining whether or not to execute switching when a request for switching from the first operation mode to the second operation mode is made, and the switching according to a determination result by the determination means. Run
2. The determination unit according to claim 1, wherein the determination unit performs the determination based on a relative relationship between the output torque when the second fuel is used and the output torque when the first fuel is used. 3. The control device for an internal combustion engine according to 2. The throttle valve control means is configured to turn the throttle valve opening toward the target opening when a request for switching the operation mode is made or when the judgment means judges that execution is possible. 4. The control apparatus for an internal combustion engine according to claim 3, wherein the shift is started.

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