Engine equipment

Abstract

To inhibit a second-time fuel injection amount from exceeding the maximum fuel injection amount in the partial injection when performing fuel injections including a first-time full injection and second- and third-times partial injections.SOLUTION: When performing three times of injections in which fuel injection is performed three times, a first-time fuel injection is performed as full injection and second- and third-times fuel injections are performed as partial injections. At that time, a total fuel injection amount and a third-time fuel injection amount are set, and a first-time fuel injection amount and a second-time fuel injection amount are set by multiplying a value obtained by subtracting the third-time fuel injection amount from the total fuel injection amount by a division rate. In this case, the first-time fuel injection amount and the second-time fuel injection amount are set so that the second-time fuel injection amount is equal to or smaller than the maximum fuel injection amount in the partial injection.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an engine device, and more particularly to an engine device including an engine having an in-cylinder injection valve that injects fuel into a combustion chamber. [Background technology]

[0002] A conventional engine system of this type has been proposed in which, when three fuel injections are performed, the first and second fuel injections are full-open injections (full lift injections) in which the direct-cylinder injection valve is fully opened, and the third fuel injection is a partial lift injection in which the direct-cylinder injection valve is not fully opened (see, for example, Patent Document 1). In this engine system, if the fuel injection amount for the third injection falls below the lower limit of partial lift injection, the second fuel injection is switched to partial lift injection. This prevents the fuel injection amount for the third injection from falling below the lower limit of partial lift injection. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-017160 Summary of the Invention [Problem to be solved by the invention]

[0004] When performing three fuel injections, with the first and second fuel injections performed as full lift injections and the third fuel injection performed as partial lift injection, it is possible to set the fuel injection amounts for the first and second injections after setting the third fuel injection amount so that it does not fall below the minimum fuel injection amount for partial lift injection. In this case, there may be cases where the first or second fuel injection amount falls below the minimum fuel injection amount for full lift injection, and the second fuel injection may be switched to partial lift injection. In this case, if the second fuel injection amount exceeds the maximum fuel injection amount for partial lift injection, the injection amount will be set in the bounce range.

[0005] The main purpose of the engine device of the present invention is to prevent the amount of fuel injected in the second injection from exceeding the maximum amount of fuel injected in the partial injection when the first fuel injection is performed by full injection and the second and third fuel injections are performed by partial injection. [Means for solving the problem]

[0006] The engine device of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The engine device of the present invention comprises: An engine device including an engine having an in-cylinder injection valve that injects fuel into a combustion chamber, and a control device that controls fuel injection of the in-cylinder injection valve, the in-cylinder injection valve is an injection valve capable of full injection in which fuel is injected with the valve in a fully open state and partial injection in which fuel is injected with the valve in a state that is not fully open, The control device sets a total fuel injection amount and a third fuel injection amount during a predetermined three-injection period in which fuel is injected three times in the range from the intake stroke to the expansion stroke, with the first fuel injection being full injection and the second and third fuel injections being partial injections, and sets the first fuel injection amount and the second fuel injection amount by multiplying the value obtained by subtracting the third fuel injection amount from the total fuel injection amount by a division ratio, insetting the first fuel injection amount and the second fuel injection amount so as to be equal to or less than a maximum fuel injection amount; It is characterized by:

[0008] In the engine device of the present invention, in a three-injection system in which fuel is injected three times in the range from the intake stroke to the expansion stroke, the first fuel injection is performed as a full-open injection (full lift injection) in which the in-cylinder injection valve is fully opened, and the second and third fuel injections are performed as partial injections (partial lift injection) in which the in-cylinder injection valve is not fully opened. During this three-injection system, the total fuel injection amount and the third fuel injection amount are set, and the first fuel injection amount and the second fuel injection amount are set by multiplying the value obtained by subtracting the third fuel injection amount from the total fuel injection amount by a division ratio. In this case, the second fuel injection amount is set as the partial injection (partial lift injection). in The first fuel injection amount and the second fuel injection amount are set so that they are equal to or less than the maximum fuel injection amount, thereby preventing the second fuel injection amount from exceeding the maximum fuel injection amount in partial injection.

[0009] In the engine system of the present invention, when setting the first fuel injection amount and the second fuel injection amount during the predetermined three injections, the control device may set the first fuel injection amount and the second fuel injection amount so that the second fuel injection amount is equal to or greater than the minimum fuel injection amount for the partial injection. This makes it possible to prevent the second fuel injection amount from falling below the minimum fuel injection amount for the partial injection.

[0010] In this case, when setting the first fuel injection amount and the second fuel injection amount during the predetermined three injections, the control device may set the first fuel injection amount and the second fuel injection amount by limiting the first fuel injection amount to an upper and lower limit using an upper limit value obtained by subtracting the third fuel injection amount and the minimum fuel injection amount from the total fuel injection amount and a lower limit value obtained by subtracting the third fuel injection amount and the maximum fuel injection amount from the total fuel injection amount. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an outline of the configuration of an engine device 10 according to an embodiment of the present invention. [Figure 2] 4 is a flowchart showing an example of a fuel injection amount setting process executed by an electronic control unit 70. [Figure 3] FIG. 10 is an explanatory diagram showing an example of the injection timing and the fuel injection amount when the first and second fuel injection amounts Q1 and Q2 are below the minimum fuel injection amount Qfmin. [Figure 4] FIG. 10 is an explanatory diagram showing an example of the injection timing and the fuel injection amount when the second fuel injection amount Q2 by partial injection is limited to the maximum fuel injection amount Qpmax. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, a mode for carrying out the present invention will be described using examples. [Example]

[0013] 1 is a diagram showing the outline of the configuration of an engine system 10 according to one embodiment of the present invention. As shown in the figure, the engine system 10 of the embodiment includes an engine 12 and an electronic control unit 70 that controls the engine 12. The engine system 10 is installed in an automobile that runs using only power from the engine 12, a hybrid automobile that has a motor in addition to the engine 12, construction equipment that operates using power from the engine 12, and the like. In the embodiment, the description will be made assuming that the engine system 10 is installed in an automobile.

[0014] The engine 12 is an internal combustion engine that uses fuel such as gasoline or diesel to output power through four strokes: intake, compression, expansion, and exhaust. The engine 12 has an in-cylinder injection valve 26 that injects fuel into a cylinder and a spark plug 30. The in-cylinder injection valve 26 is located approximately at the center of the top of a combustion chamber 29 and injects the fuel in a spray form. The spark plug 30 is located near the in-cylinder injection valve 26 so that it can ignite the fuel sprayed from the in-cylinder injection valve 26. The engine 12 draws air purified by an air cleaner 22 into the combustion chamber 29 through an intake pipe 25. The in-cylinder injection valve 26 injects fuel one or more times during the intake stroke and compression stroke. The fuel is then explosively combusted by an electric spark generated by the spark plug 30, and the reciprocating motion of a piston 32, which is pushed down by the resulting energy, is converted into rotational motion of the crankshaft 16.

[0015] The exhaust gas discharged from the combustion chamber 29 of the engine 12 into the exhaust pipe 33 is discharged into the outside air via a purification device 34 having a purification catalyst (three-way catalyst) 34a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

[0016] Although not shown, the electronic control unit 70 is configured as a microprocessor centered around a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, and input / output ports. Signals from various sensors required for controlling the engine 12 are input to the electronic control unit 70 via the input ports. Examples of signals input to the electronic control unit 70 include the crank angle θcr from a crank position sensor 40 that detects the rotational position of the crankshaft 16, the coolant temperature Tw from a water temperature sensor 42 that detects the temperature of the coolant for the engine 12, and the cam angles θci and θco from a cam position sensor 44 that detects the rotational positions of the intake camshaft that opens and closes the intake valve 28 and the exhaust camshaft that opens and closes the exhaust valve 31. Other examples include the throttle opening TH from a throttle valve position sensor 46 that detects the position of the throttle valve 24 provided in the intake pipe 25, the intake air amount Qa from an air flow meter 48 attached to the intake pipe 25, the intake air temperature Ta from a temperature sensor 49 attached to the intake pipe 25, and the intake pressure Pin from an intake pressure sensor 58 that detects the pressure inside the intake pipe 25. Further examples include the catalyst temperature Tc from a temperature sensor 34b that detects the temperature of the purification catalyst 34a of the purification device 34, the air-fuel ratio AF from an air-fuel ratio sensor 35a attached to the exhaust pipe 33, the oxygen signal O2 from an oxygen sensor 35b attached to the exhaust pipe 33, and a knock signal Ks from a knock sensor 59 attached to the cylinder block that detects vibrations caused by the occurrence of knocking.

[0017] Various control signals for controlling the engine 12 are output from the electronic control unit 70 via an output port. Examples of signals output from the electronic control unit 70 include a drive control signal for the throttle motor 36 that adjusts the position of the throttle valve 24, a drive control signal for the in-cylinder injection valve 26, and a drive control signal for the spark plug 30.

[0018] The electronic control unit 70 calculates the rotation speed of the crankshaft 16, i.e., the rotation speed Ne of the engine 12, based on the crank angle θcr from the crank position sensor 40. The electronic control unit 70 also calculates the volumetric efficiency KL of the engine 12 as a load (the ratio of the volume of air actually taken in during one cycle to the stroke volume per cycle of the engine 12) based on the intake air amount Qa from the air flow meter 48 and the rotation speed Ne of the engine 12.

[0019] In the engine system 10 configured as described above, the electronic control unit 70 controls the intake air amount, fuel injection, and ignition of the engine 12 so that the engine 12 is operated based on the target rotational speed Ne* and the target torque Te*. In the intake air amount control, the electronic control unit 70 sets a target air amount Qa* based on the target torque Te* of the engine 12, sets a target throttle opening TH* so that the intake air amount Qa becomes the target air amount Qa*, and controls the throttle motor 36 so that the throttle opening TH of the throttle valve 24 becomes the target throttle opening TH*. In the fuel injection control, the electronic control unit 70 basically sets a target fuel injection amount Qfd* of the direct injection valve 26 based on the rotational speed Ne and volumetric efficiency KL of the engine 12 so that the air-fuel ratio AF becomes the target air-fuel ratio AF* (e.g., the stoichiometric air-fuel ratio), and controls the direct injection valve 26 so that fuel at the target fuel injection amount Qfd* is injected from the direct injection valve 26 one or more times. In the ignition control, the electronic control unit 70 sets the target ignition timing Tp* based on the rotation speed Ne and the load factor KL of the engine 12, and controls the ignition of the spark plug 30.

[0020] Next, the operation of the engine system 10 of this embodiment configured as described above will be described, particularly the operation during triple injection, in which the target fuel injection amount Qfd* is injected three times from the in-cylinder injection valve 26 within the range from the intake stroke to the expansion stroke. In triple injection, for example, when rapidly warming up the purification catalyst (three-way catalyst) 34a of the purification device 34, the first fuel injection may be performed during the intake stroke, the second fuel injection may be performed during the compression stroke, and the third fuel injection may be performed during the expansion stroke. In this case, the first and second fuel injections are basically performed by full-lift injection, in which fuel is injected with the in-cylinder injection valve 26 fully open, and the third fuel injection is performed by partial lift injection, in which fuel is injected with the in-cylinder injection valve 26 not fully open. The reason why the third fuel injection (fuel injection during the expansion stroke) is performed by partial lift injection is that it is preferable to spray fuel particles as small as possible so as to induce a discharge when ignition is performed in synchronization with the third fuel injection. Note that partial lift injection means that fuel is injected with the direct injection valve 26 not fully opened, and includes openings of 5%, 10%, 20%, etc. When the direct injection valve 26 injects fuel by partial lift injection, in this embodiment, the direct injection valve 26 is opened to an opening that is determined in advance through experiments or the like.

[0021] 2 is a flowchart showing an example of a fuel injection amount setting process executed by the electronic control unit 70. This process is performed to set the fuel injection amount when the third fuel injection is performed by partial lift injection.

[0022] When the fuel injection amount setting process is executed, the electronic control unit 70 first sets the target fuel injection amount Qfd* as the total fuel injection amount of the direct injection valve 26 (step S100). As described above, the target fuel injection amount Qfd* is basically set based on the rotation speed Ne and volumetric efficiency KL of the engine 12 so that the air-fuel ratio AF becomes the target air-fuel ratio AF* (for example, the stoichiometric air-fuel ratio), but is also set using a feedback correction coefficient in air-fuel ratio feedback control, a learning value for correcting variations in the direct injection valve 26, and the like.

[0023] Next, set the third fuel injection amount Q3 ( Step S110 ) The third fuel injection amount Q3 is basically set based on the coolant temperature (start-up water temperature) Tws when the engine 12 is started, the time elapsed since the engine 12 is started (time after start-up) Taft, the volumetric efficiency KL, and the like. In this embodiment, the third fuel injection amount Q3 is set to tend to increase as the start-up water temperature Tws increases, to tend to decrease as the time after start-up Taft increases, and to tend to increase as the volumetric efficiency KL increases. Note that it is also preferable to use a learned value for correcting variations in the direct injection valve 26 for the third fuel injection amount Q3.

[0024] Next, the first fuel injection amount Q1 and the second fuel injection amount Q2 are set ( Step S120 ). The first fuel injection amount Q1 and the second fuel injection amount Q2 can be calculated by multiplying the value obtained by subtracting the third fuel injection amount Q3 from the target fuel injection amount Qfd* as the total fuel injection amount by the division ratios k1 and k2. The sum of the first division ratio k1 and the second division ratio k2 is 1, and the division ratios k1 and k2 are adjusted based on the water temperature at start Tws, the time after start Taft, the shift position SP, and other factors. In this embodiment, the relationships between the water temperature at start Tws, the time after start Taft, the shift position SP, and the division ratios k1 and k2 are determined in advance through experiments or the like and stored as a division ratio setting map. When the water temperature at start Tws, the time after start Taft, and the shift position SP are given, the corresponding division ratios are derived from the map and used.

[0025] Then, it is determined whether or not one or both of the first fuel injection amount Q1 and the second fuel injection amount Q2 is less than the minimum fuel injection amount Qfmin in full lift injection of the direct injection valve 26 ( Step S130 ). The minimum fuel injection amount Qfmin for full lift injection is calculated based on the fuel pressure Pf and the minimum injection time for full lift injection of the direct injection valve 26. In this embodiment, the relationship between the fuel pressure Pf, the minimum injection time for full lift injection of the direct injection valve 26, and the minimum fuel injection amount Qfmin is determined in advance through experiments, machine learning, or the like, and stored as a full lift minimum fuel injection amount setting map. When the fuel pressure Pf and the minimum injection time for full lift injection of the direct injection valve 26 are given, the corresponding minimum fuel injection amount Qfmin is derived from the map and used. If it is determined that both the first fuel injection amount Q1 and the second fuel injection amount Q2 are equal to or greater than the minimum fuel injection amount Qfmin for full lift injection, the fuel injection amount setting process is terminated. In this case, the first fuel injection is performed by full lift injection during the intake stroke, the second fuel injection is performed by full lift injection during the compression stroke, and the third fuel injection is performed by partial lift injection during the expansion stroke.

[0026] If it is determined in step S130 that either or both of the first fuel injection amount Q1 and the second fuel injection amount Q2 is less than the minimum fuel injection amount Qfmin for full lift injection of the in-cylinder injection valve 26, the second fuel injection is set to partial lift injection (step S140).

[0027] Next, an upper limit value Q1max and a lower limit value Q1min for the first fuel injection are set (step S150). The upper limit value Q1max is set as a value (Q1max=Qfd*-Q3-Qpmin) obtained by subtracting the third fuel injection amount Q3 and the minimum fuel injection amount Qpmin for partial lift injection by the direct injection valve 26 from the target fuel injection amount Qfd* as the total fuel injection amount. The minimum fuel injection amount Qpmin for partial lift injection is the lower limit value (Qpmin) of the second fuel injection amount Q2 by partial lift injection, and is found based on the fuel pressure Pf and the minimum injection time for partial lift injection by the direct injection valve 26. In this embodiment, the minimum injection time for partial lift injection by the direct injection valve 26 is calculated based on the fuel pressure Pf and the minimum injection time for partial lift injection by the direct injection valve 26. Minimum fuel injection amount Qpmin The relationship between the above is determined in advance through experiments, machine learning, etc. and stored as a map for setting the partial lift minimum fuel injection quantity, and when the fuel pressure Pf and the minimum injection time for partial lift injection of the direct injection valve 26 are given, the corresponding minimum fuel injection quantity Qpmin is derived from the map and used. The minimum injection time for partial lift injection of the direct injection valve 26 is determined in advance as the minimum time during control during which fuel can be injected by the direct injection valve 26 as partial lift injection. The minimum fuel injection quantity Qpmin increases as the fuel pressure Pf increases.

[0028] The lower limit value Q1min is set as the target fuel injection amount Qfd* as the total fuel injection amount minus the third fuel injection amount Q3 and the maximum fuel injection amount Qpmax in the partial lift injection of the direct injection valve 26 (Q1min=Qfd*-Q3-Qpmax). The maximum fuel injection amount Qpmax in partial lift injection is the upper limit (Qpmax) of the second fuel injection amount Q2 by partial lift injection, and is calculated based on the fuel pressure Pf and the maximum injection time in partial lift injection of the direct injection valve 26. In this embodiment, the maximum injection time in partial lift injection of the direct injection valve 26 is calculated based on the fuel pressure Pf and the maximum injection time in partial lift injection of the direct injection valve 26. Maximum fuel injection amount QpmaxThe relationship between the maximum injection time and the fuel pressure Pf is determined in advance through experiments, machine learning, or the like and stored as a partial lift maximum fuel injection quantity setting map. When the fuel pressure Pf and the maximum injection time for partial lift injection of the direct injection valve 26 are given, the corresponding maximum fuel injection quantity Qpmax is derived from the map and used. The maximum injection time for partial lift injection of the direct injection valve 26 is the time from when the direct injection valve 26 opens to when it can close during the compression stroke, and can be determined based on the engine speed Ne of the engine 12. In this embodiment, the relationship between the engine speed Ne of the engine 12 and the maximum injection time for partial lift injection of the direct injection valve 26 is determined in advance through experiments or the like and stored as a partial lift maximum injection time setting map. When the engine speed Ne of the engine 12 is given, the corresponding maximum injection time is derived and used. Note that the maximum fuel injection quantity Qpmax increases as the fuel pressure Pf increases and decreases as the engine speed Ne of the engine 12 increases.

[0029] After the upper limit Q1max and lower limit Q1min for the first fuel injection are set in this manner, it is determined whether the first fuel injection amount Q1 is within a range from the lower limit Q1min to the upper limit Q1max (step S160). If it is determined that the first fuel injection amount Q1 is within a range from the lower limit Q1min to the upper limit Q1max, the fuel injection amount setting process ends. In this case, the first fuel injection is performed by full lift injection during the intake stroke with the fuel injection amount Q1; the second fuel injection is performed by partial lift injection during the compression stroke with the fuel injection amount Q2; and the third fuel injection is performed by partial lift injection during the expansion stroke with the fuel injection amount Q3.

[0030] If it is determined in step S160 that the first fuel injection amount Q1 is less than the lower limit value Q1min, the first fuel injection amount Q1 and the second fuel injection amount Q2 are reset (step S170), and the fuel injection amount setting process ends. In resetting, the first fuel injection amount Q1 is set to the lower limit value Q1min. The second fuel injection amount Q2 is set to a value obtained by subtracting the third fuel injection amount Q3 and the newly set first fuel injection amount Q1 from the target fuel injection amount Qfd*, which is the total fuel injection amount. The lower limit Q1min is the target fuel injection quantity Qfd* minus the third fuel injection quantity Q3 and the maximum fuel injection quantity Qpmax for partial lift injection of the direct injection valve 26. The maximum fuel injection quantity Qpmax for partial lift injection of the direct injection valve 26 is the maximum value of the second fuel injection quantity Q2. Therefore, the processing of steps S160 and S170 is equivalent to limiting the second fuel injection quantity Q2 to the maximum fuel injection quantity Qpmax when the second fuel injection quantity Q2 exceeds the maximum fuel injection quantity Qpmax. In this case, the first fuel injection is performed during the intake stroke with the fuel injection quantity Q1 (Q1min) reset by full lift injection, the second fuel injection is performed during the compression stroke with the fuel injection quantity Q2 (Qpmax) reset by partial lift injection, and the third fuel injection is performed during the expansion stroke with the fuel injection quantity Q3 by partial lift injection.

[0031] FIG. 3 is an explanatory diagram showing an example of the injection timing and fuel injection amount when the first fuel injection amount Q1 and the second fuel injection amount Q2 are both below the minimum fuel injection amount Qfmin for full lift injection of the direct injection valve 26 when the split ratios k1 and k2 are set to 0.5. FIG. 4 is an explanatory diagram showing an example of the injection timing and fuel injection amount when the second fuel injection amount Q2 exceeds the maximum fuel injection amount Qpmax when partial lift injection is set for the second fuel injection and is therefore limited to the maximum fuel injection amount Qpmax. In the embodiment, as shown in FIG. 3, when the first fuel injection amount Q1 and the second fuel injection amount Q2 are both below the minimum fuel injection amount Qfmin for full lift injection of the direct injection valve 26, partial lift injection is set for the second fuel injection. In this case, when the second fuel injection amount Q2 exceeds the maximum fuel injection amount Qpmax, the second fuel injection amount Q2 is limited to the maximum fuel injection amount Qpmax, as shown in FIG. In this way, the second fuel injection amount Q2 by partial lift injection can be prevented from exceeding the maximum fuel injection amount Qpmax.

[0032] If it is determined in step S160 that the first fuel injection amount Q1 exceeds the upper limit value Q1max, the first fuel injection amount Q1 and the second fuel injection amount Q2 are reset (step S180), and the fuel injection amount setting process ends. In resetting, the first fuel injection amount Q1 is set to the upper limit value Q1max. The second fuel injection amount Q2 is set to a value obtained by subtracting the third fuel injection amount Q3 and the newly set first fuel injection amount Q1 from the target fuel injection amount Qfd*, which is the total fuel injection amount. The upper limit value Q1max is the target fuel injection quantity Qfd* minus the third fuel injection quantity Q3 and the minimum fuel injection quantity Qpmin for partial lift injection of the direct injection valve 26. The minimum fuel injection quantity Qpmin for partial lift injection of the direct injection valve 26 is the minimum value of the second fuel injection quantity Q2. Therefore, the processing of steps S160 and S180 is equivalent to processing that limits the second fuel injection quantity Q2 to the minimum fuel injection quantity Qpmin when the second fuel injection quantity Q2 is below the minimum fuel injection quantity Qpmin. In this case, the first fuel injection is performed during the intake stroke with the fuel injection quantity Q1 (Q1max) reset by full lift injection, the second fuel injection is performed during the compression stroke with the fuel injection quantity Q2 (Qpmin) reset by partial lift injection, and the third fuel injection is performed during the expansion stroke with the fuel injection quantity Q3 by partial lift injection. By resetting the second fuel injection amount Q2 by partial lift injection in this manner, it is possible to prevent the second fuel injection amount Q2 from falling below the minimum fuel injection amount Qpmin.

[0033] In the engine system 10 of the embodiment described above, during triple injection in which the total fuel injection amount is injected three times, a target fuel injection amount Qfd* as the total fuel injection amount and a third fuel injection amount Q3 by partial lift injection are set, and the first fuel injection amount Q1 and the second fuel injection amount Q2 are set by multiplying the value obtained by subtracting the third fuel injection amount Q3 from the target fuel injection amount Qfd* by division ratios k1 and k2. If one or both of the first fuel injection amount Q1 and the second fuel injection amount Q2 are below the minimum fuel injection amount Qfmin for full lift injection of the direct injection valve 26, the second fuel injection is switched to partial lift injection. When the first fuel injection amount Q1 is below a lower limit Q1min obtained by subtracting the third fuel injection amount Q3 and the maximum fuel injection amount Qpmax in partial lift injection of the direct injection valve 26 from the target fuel injection amount Qfd*, the lower limit Q1min is set as the first fuel injection amount Q1, and a value obtained by subtracting the third fuel injection amount Q3 and the newly set first fuel injection amount Q1 from the target fuel injection amount Qfd* is set as the second fuel injection amount Q2. The lower limit Q1min is the value obtained by subtracting the third fuel injection amount Q3 and the maximum fuel injection amount Qpmax in partial lift injection of the direct injection valve 26 from the target fuel injection amount Qfd*, and the maximum fuel injection amount Qpmax is the maximum value of the second fuel injection amount Q2. Therefore, when the second fuel injection amount Q2 exceeds the maximum fuel injection amount Qpmax, the second fuel injection amount Q2 can be limited to the maximum fuel injection amount Qpmax. That is, the second fuel injection amount Q2 by partial lift injection can be prevented from exceeding the maximum fuel injection amount Qpmax in partial lift injection.

[0034] Furthermore, when the second fuel injection is switched to partial lift injection, if the first fuel injection amount Q1 exceeds an upper limit value Q1max obtained by subtracting the third fuel injection amount Q3 and the minimum fuel injection amount Qpmin for partial lift injection of the direct injection valve 26 from the target fuel injection amount Qfd*, the upper limit value Q1max is set as the first fuel injection amount Q1, and a value obtained by subtracting the third fuel injection amount Q3 and the newly set first fuel injection amount Q1 from the target fuel injection amount Qfd* is set as the second fuel injection amount Q2. The upper limit value Q1max is the value obtained by subtracting the third fuel injection amount Q3 and the minimum fuel injection amount Qpmin for partial lift injection of the direct injection valve 26 from the target fuel injection amount Qfd*, and the minimum fuel injection amount Qpmin is the minimum value of the second fuel injection amount Q2. Therefore, if the second fuel injection amount Q2 is below the minimum fuel injection amount Qpmin, the second fuel injection amount Q2 can be limited to the minimum fuel injection amount Qpmin. That is, the second fuel injection amount Q2 by partial lift injection can be prevented from exceeding the minimum fuel injection amount Qpmin in partial lift injection.

[0035] The engine device 10 of the embodiment may be mounted on an automobile equipped with an automatic transmission at the rear, or may be mounted on a hybrid automobile together with a motor that outputs power for running.

[0036] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the direct injection valve 26 corresponds to the "direct injection valve," the engine 12 corresponds to the "engine," and the electronic control unit 70 corresponds to the "controller."

[0037] The correspondence between the main elements of the Examples and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the Examples are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section. The examples are merely specific examples of the invention described in the Summary of the Invention section.

[0038] The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0039] The present invention can be used in the engine device manufacturing industry and the like. [Explanation of symbols]

[0040] 10 engine device, 12 engine, 16 crankshaft, 22 air cleaner, 24 throttle valve, 25 intake pipe, 26 in-cylinder injection valve, 34b temperature sensor, 28 intake valve, 29 combustion chamber, 30 spark plug, 31 exhaust valve, 32 piston, 33 exhaust pipe, 34 purification device, 34a purification catalyst, 35a air-fuel ratio sensor, 35b oxygen sensor, 36 throttle motor, 38 ignition coil, 40 crank position sensor, 42 water temperature sensor, 44 cam position sensor, 46 throttle valve position sensor, 48 air flow meter, 49 temperature sensor, 58 intake pressure sensor, 59 knock sensor, 70 electronic control unit.

Claims

[Claim 1] An engine device including an engine having an in-cylinder injection valve that injects fuel into a combustion chamber, and a control device that controls fuel injection of the in-cylinder injection valve, the in-cylinder injection valve is an injection valve capable of full injection in which fuel is injected with the valve in a fully open state and partial injection in which fuel is injected with the valve in a state that is not fully open, the control device, in a predetermined three-injection in which fuel is injected three times within a range from the intake stroke to the expansion stroke, the first fuel injection is performed by the full injection and the second and third fuel injections are performed by the partial injection, sets a total fuel injection amount and a third fuel injection amount, and sets the first fuel injection amount and the second fuel injection amount by multiplying a value obtained by subtracting the third fuel injection amount from the total fuel injection amount by a division ratio, so that the second fuel injection amount is equal to or greater than a minimum fuel injection amount and equal to or less than a maximum fuel injection amount in the partial injection, and so that the first fuel injection amount is limited between an upper limit value obtained by subtracting the third fuel injection amount and the minimum fuel injection amount from the total fuel injection amount and a lower limit value obtained by subtracting the third fuel injection amount and the maximum fuel injection amount from the total fuel injection amount. An engine device characterized by:

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