JP7363667B2 - engine equipment - Google Patents

Description

The present invention relates to an engine device.

Conventionally, as this type of engine device, one has been proposed that includes an engine having an in-cylinder injection valve that injects fuel into the inside of the combustion chamber and a spark plug installed near the top of the combustion chamber (for example, (See Patent Document 1). In this engine system, if knocking is detected during combustion mode operation in which fuel is injected from the in-cylinder injection valve during the compression stroke and stratified combustion is performed by forming a stratified mixture near the spark plug, the ignition timing is delayed. make a corner Further, when the amount of retardation of the fuel injection timing according to the ignition timing is smaller than the reference amount, fuel injection in the compression stroke is performed at the injection timing retarded according to the amount of retardation.

Japanese Patent Application Publication No. 2018-131948

In the above-mentioned engine devices, when warming up a purification device that has a catalyst that purifies exhaust gas, the ignition timing is generally retarded to supply more heat to the purification device, and the ignition timing is An expansion stroke may also be selected. In this case, expansion stroke injection, in which fuel is injected in synchronization with ignition, is also being considered to ensure more reliable ignition. In such expansion stroke injection, the majority of the target fuel injection amount, which is determined based on the engine load factor, is injected once or in multiple times during the intake stroke, and is performed as the last fuel injection during the expansion stroke. Therefore, the timing to determine expansion stroke injection as the fuel injection mode is before the first fuel injection, for example, 180 degrees or more before compression top dead center (TDC: Top Dead Center) (for example, BTDC 270 (Before TDC 270 degrees)). On the other hand, in the case of ignition during the expansion stroke, the timing for determining the ignition timing may be before compression top dead center (for example, BTDC90).In such a case, the timing for determining the fuel injection mode and If the end of expansion stroke injection is commanded between the timing of determining the ignition timing, fuel injection will be performed in the expansion stroke, and ignition may not be performed in the expansion stroke.In this case, the engine combustion It lacks stability.

The main purpose of the engine device of the present invention is to suppress lack of combustion stability in the engine when ending expansion stroke injection.

The engine device of the present invention employs the following means to achieve the above-mentioned main purpose.

The engine device of the present invention includes:
An engine having an in-cylinder injection valve that sprays fuel into a combustion chamber and a spark plug that can ignite the fuel sprayed from the in-cylinder injection valve;
a purification device having a purification catalyst that purifies the exhaust gas of the engine;
a control device that controls fuel injection by the in-cylinder injection valve and ignition by the spark plug;
An engine device comprising:
The control device includes an expansion stroke injection in which the last fuel injection from the in-cylinder fuel injection valve is performed during the expansion stroke and an expansion stroke injection in which the fuel injection is ignited by the spark plug in synchronization with the fuel injection in the expansion stroke to warm up the purification device. When performing expansion stroke injection warm-up using stroke ignition, the fuel injection mode is determined to be the expansion stroke injection at a predetermined timing, and the ignition timing is determined at a subsequent timing. ,
When the expansion stroke injection warm-up is completed, the control device maintains the previous ignition timing as the ignition timing if the fuel injection mode has already been determined as expansion stroke injection at the timing of determining the ignition timing.
It is characterized by

In the engine device of the present invention, as warm-up of the purification device, the last fuel injection from the in-cylinder fuel injection valve is performed in the expansion stroke, and the expansion stroke is performed in which the fuel injection is ignited by the spark plug in synchronization with the fuel injection in the expansion stroke. When performing expansion stroke injection warm-up using ignition, it is determined at a predetermined timing that the fuel injection mode is expansion stroke injection, and the ignition timing is determined at a subsequent timing. When the expansion stroke injection warm-up is completed, if the fuel injection mode has already been determined as expansion stroke injection at the timing of determining the ignition timing, the previous ignition timing is held as the ignition timing. As a result, even if the expansion stroke injection warm-up is completed between the timing when the fuel injection mode is determined as expansion stroke injection and the timing when the ignition timing is determined, the ignition timing when the fuel injection mode is expansion stroke injection is Since this is maintained, it is possible to prevent the timing of expansion stroke injection and ignition from shifting. As a result, it is possible to suppress the lack of combustion stability in the engine when the expansion stroke injection ends.

1 is a configuration diagram schematically showing the configuration of an engine device 10 as an example of the present invention. It is a flowchart which shows an example of rapid warm-up ignition timing control performed by ECU70. An example of fuel injection and ignition with respect to crank angles in a target cylinder and the cylinder immediately before it is shown. FIG. 2 is an explanatory diagram illustrating an example of temporal changes in the rotational speed Ne of the engine 12 and the ignition timing Tf during rapid warm-up.

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

FIG. 1 is a block diagram schematically showing the structure of an engine device 10 as an embodiment of the present invention. As illustrated, the engine device 10 of the embodiment includes an engine 12 and an electronic control unit (hereinafter referred to as "ECU") 70 that controls the engine 12. Note that this engine device 10 is installed in a car that runs using only the power from the engine 12, a hybrid car that includes a motor in addition to the engine 12, construction equipment that operates using the power from the engine 12, etc. . The embodiment will be described assuming that the engine device 10 is installed in an automobile.

The engine 12 is configured as an internal combustion engine that uses fuel such as gasoline or light oil to output power through four strokes: intake, compression, expansion, and exhaust. This engine 12 includes an in-cylinder injection valve 26 that injects fuel into a cylinder, and a spark plug 30. The in-cylinder injection valve 26 is disposed approximately at the center of the top of the combustion chamber 29, and injects fuel in a spray form. The spark plug 30 is arranged near the in-cylinder injection valve 26 so as to ignite the fuel sprayed from the in-cylinder injection valve 26. The engine 12 sucks air purified by the air cleaner 22 into the combustion chamber 29 through the intake pipe 25, and injects fuel from the in-cylinder injection valve 26 once or multiple times during the intake stroke or compression stroke. The electric spark from the ignition plug 30 causes explosive combustion, and the reciprocating motion of the piston 32 pushed down by the energy is converted into rotational motion of the crankshaft 16.

Exhaust gas discharged from the combustion chamber 29 of the engine 12 to the exhaust pipe 33 is purified by a purification catalyst (three-way catalyst) 34a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). It is discharged to the outside air through a purification device 34 having a

Although not shown, the ECU 70 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, and an input/output port. Signals from various sensors necessary to control the engine 12 are input to the ECU 70 via input ports. Signals input to the ECU 70 include, for example, the crank angle θcr from the crank position sensor 40 that detects the rotational position of the crankshaft 16, the cooling water temperature Tw from the water temperature sensor 42 that detects the temperature of the cooling water of the engine 12, Examples include cam angles θci and θco from the cam position sensor 44 that detects the rotational position of the intake camshaft that opens and closes the intake valve 28 and the rotational position of the exhaust camshaft that opens and closes the exhaust valve 31. In addition, 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 the temperature sensor 49 attached to the air intake pipe 25 and the intake pressure Pin from the intake pressure sensor 58 which detects the pressure inside the intake pipe 25 can also be mentioned. Further, the catalyst temperature Tc from the temperature sensor 34b that detects the temperature of the purification catalyst 34a of the purification device 34, the air-fuel ratio AF from the air-fuel ratio sensor 35a attached to the exhaust pipe 33, and the oxygen sensor attached to the exhaust pipe 33 are detected. The oxygen signal O2 from the cylinder block 35b and the knock signal Ks from the knock sensor 59 which is attached to the cylinder block and detects vibrations caused by the occurrence of knocking can also be mentioned.

Various control signals for controlling the engine 12 are output from the ECU 70 via an output port. Examples of the signals output from the ECU 70 include a drive control signal to the throttle motor 36 that adjusts the position of the throttle valve 24, a drive control signal to the in-cylinder injection valve 26, and a drive control signal to the spark plug 30. You can also do that.

The ECU 70 calculates the rotation speed Ne of the crankshaft 16, that is, the rotation speed Ne of the engine 12, based on the crank angle θcr from the crank position sensor 40. Further, the ECU 70 determines the volumetric efficiency as a load of the engine 12 (actually in one cycle with respect 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. The ratio of the volume of air taken in) KL is also calculated.

In the engine device 10 configured in this manner, the ECU 70 controls intake air amount control, fuel injection control, and ignition control of the engine 12 so that the engine 12 is operated based on the target rotational speed Ne* and the target torque Te*. Let's do it. In the intake air amount control, the ECU 70 sets the target air amount Qa* based on the target torque Te* of the engine 12, and sets the target throttle opening TH* so that the intake air amount Qa becomes the target air amount Qa*. Then, the throttle motor 36 is controlled so that the throttle opening TH of the throttle valve 24 becomes the target throttle opening TH*. In the fuel injection control, the ECU 70 controls the target fuel injection of the in-cylinder injection valve 26 so that the air-fuel ratio AF becomes the target air-fuel ratio AF* (for example, the stoichiometric air-fuel ratio) based on the rotational speed Ne of the engine 12 and the volumetric efficiency KL. The amount Qfd* is set, and the in-cylinder injection valve 26 is controlled so that the target fuel injection amount Qfd* of fuel is injected from the in-cylinder injection valve 26 once or multiple times. In the ignition control, the ECU 70 sets a target ignition timing Tf* based on the rotational speed Ne of the engine 12 and the load factor KL, and controls the ignition coil 38 so that ignition is performed at the target ignition timing Tf*.

Next, the operation of the engine device 10 of the embodiment configured as described above, particularly the operation when rapidly warming up the purification catalyst (three-way catalyst) 34a of the purification device 34, will be described. Rapid warm-up of the purifying device 34 is performed when the condition that the catalyst temperature Tc is below a predetermined temperature below the activation temperature or the condition that the accelerator is turned off are satisfied. In rapid warm-up, when the water temperature Tw at the time of starting the engine 12 is lower than the first predetermined temperature (for example, 35 degrees or 45 degrees), fuel is injected 1 to 3 times during the intake stroke to warm up the catalyst more quickly. The final fuel injection is performed during the expansion stroke in order to improve the engine's performance and improve emissions, and is performed by expansion stroke injection warm-up, which is ignited in synchronization with the fuel injection during the expansion stroke. On the other hand, when the water temperature at the time of starting the engine 12 is higher than the first predetermined temperature, the final fuel injection is performed in the compression stroke and ignited in the expansion stroke to maintain good emissions. During the expansion stroke injection warm-up, the ignition timing Tf is controlled to be delayed as much as possible. If the ignition timing Tf is retarded, the combustion efficiency will decrease, so the rotational speed Ne of the engine 12 is maintained by increasing the amount of intake air. As a result, since the amount of combustion gas increases, the absolute amount of emission components also increases, but catalyst warm-up is accelerated. In the compression stroke injection warm-up, the catalyst is warmed up while maintaining good emissions, so the amount of retardation of the ignition timing Tf is smaller than in the expansion stroke injection warm-up. In the embodiment, depending on whether expansion stroke injection warm-up or compression stroke injection warm-up is selected, the base ignition timing Tfbase as the base value of the ignition timing Tf and the rotation speed Ne of the engine 12 are set for warm-up. In order to maintain the rotational speed Neset (for example, 1300 rpm, 1500 rpm, etc.), the feedback correction value Tk for correcting the amount of retardation of the ignition timing Tf and the retard side guard value Tfgrd are changed. Therefore, the base ignition timing Tfb1 and retard side guard value Tfg1 during expansion stroke injection warm-up and the base ignition timing Tfb2 and retard side guard value Tfg2 during compression stroke injection warm-up are determined in advance and stored as a map. However, when expansion stroke injection warm-up is selected, base ignition timing Tfb1 and retard side guard value Tfg1 are set and used as base ignition timing Tfbase and retard side guard value Tfgrd from the map, and compression stroke injection warm-up is selected. When the base ignition timing Tfb2 and the retard side guard value Tfg2 are set as the base ignition timing Tfbase and the retard side guard value Tfgrd from the map, the base ignition timing Tfb2 and the retard side guard value Tfgrd are used. Note that ATDC20 (After TDC (Top Dead Center) 20 degrees) or ATDC18 can be used as the base ignition timing Tfb1 during expansion stroke injection warm-up, and 3 as the retard side guard value Tfg1. Degrees, fifth degrees, etc. can be used. In addition, the base ignition timing Tfb2 during compression stroke injection warm-up is on the advanced side compared to the base ignition timing Tfb1 during expansion stroke injection warm-up, and for example, ATDC10 or ATDC15 can be used. As the value Tfg2, 3 degrees, 5 degrees, etc. can be used.

Further, rapid warm-up is performed when the shift position is the neutral position (N position) and when the shift position is the drive position (D position). In the embodiment, the above-mentioned first predetermined temperature is switched depending on the shift position. That is, the water temperature Tw at the time of starting the engine 12, which determines whether expansion stroke injection warm-up or compression stroke injection warm-up is selected depending on the shift position, switches the first predetermined temperature. For example, in the N position, 45 degrees is used as the first predetermined temperature, and in the D position, 35 degrees is used as the first predetermined temperature. Warming up may be made easier to select.

When rapid warm-up is performed at high altitudes, the output torque of the engine 12 decreases due to the lower air density. Correct Tfbase to the advance side.

Next, the ignition timing during rapid warm-up will be explained. FIG. 2 is a flowchart illustrating an example of rapid warm-up ignition timing control executed by the ECU 70 during rapid warm-up of the purification device 34. The following description assumes that expansion stroke injection warm-up is selected.

When the rapid warm-up ignition timing control is executed, the ECU 70 first inputs the rotation speed Ne of the engine 12 (step S100), and sets the value obtained by adding the first rate value Trt1 from the ignition timing Tf to the new ignition timing control. The process of calculating (determining) the time Tf (step S110) is repeated until the rotation speed Ne of the engine 12 reaches a predetermined rotation speed Neref or higher (step S120). In rapid warm-up, first, the amount of intake air is increased to raise the rotation speed Ne of the engine 12 to the warm-up rotation speed Neset (for example, 1300 rpm or 1500 rpm), and at the same time, the ignition timing is slowly retarded. Therefore, it is preferable to use a value for the first rate value Trt1 that does not inhibit the increase in the rotational speed Ne of the engine 12. Further, the predetermined rotation speed Neref may be a value slightly smaller than the warm-up rotation speed Neset. In addition, the repetition frequency is the frequency at which the calculation (determination) of the ignition timing Tf is repeated. For example, in the case of a 4-cylinder engine, it is every 180 degrees of crank angle, and in the case of a 6-cylinder engine, it is every 120 degrees of crank angle. The frequency of The same applies to the following repeated processing.

When the rotational speed Ne of the engine 12 reaches a predetermined rotational speed Neref or higher and reaches a warm-up rotational speed Neset (for example, 1300 rpm or 1500 rpm), the new ignition timing Tf is set by adding the second rate value Trt2 from the ignition timing Tf. The process of calculating (determining) (step S130) is repeated until the difference between the ignition timing Tf and the base ignition timing Tfbase becomes equal to or less than the threshold value Tfref1. This process is a process in which the ignition timing Tf is set to the base ignition timing Tfbase while keeping the rotational speed Ne of the engine 12 at the warm-up rotational speed Neset. The second rate value Trt2 is a value that can maintain the rotational speed Ne of the engine 12 at the warm-up rotational speed Neset, and can be a value larger than the first rate value Trt1. The second rate value Trt2 or a value slightly smaller than this can be used as the threshold value Tfref1. As the base ignition timing Tbase, as described above, the base ignition timing Tfb1 is used when the expansion stroke injection warm-up is selected, and the base ignition timing Tfb2 is used when the compression stroke injection warm-up is selected.

If an affirmative determination is made in step S140, expansion stroke injection warm-up (or compression stroke injection warm-up) is started. In the expansion stroke injection warm-up, fuel is injected in the form of a spray from the in-cylinder injection valve 26 just before the crank angle of the target cylinder reaches the ignition timing Tf, and when the ignition timing Tf is reached, the fuel is ignited from the ignition plug 30. Ru. Note that the calculation of the ignition timing Tf is started at BTDC90 (Before TDC 90 degrees) or the like.

When the expansion stroke injection warm-up (or compression stroke injection warm-up) is started in this way, feedback control of the ignition timing Tf based on the engine speed Ne of the engine 12 is repeated until the warm-up end transition condition is satisfied (steps S150 to S190). ). Warm-up completion transition conditions include conditions where the catalyst temperature Tc is equal to or higher than the activation temperature, conditions where the cooling water temperature Tw of the engine 12 is equal to or higher than a second predetermined temperature (for example, 70 degrees, etc.), and the cumulative intake air amount is equal to or higher than a predetermined amount. This may be the case when one or more of the above conditions, the condition that the accelerator is turned on, etc. are satisfied. The feedback control repetition frequency is the frequency at which the calculation (determination) of the ignition timing Tf is repeated, as described above. In the feedback control, first, the rotation speed Ne of the engine 12 is input (step S150), and a proportional term and an integral term are calculated for the difference (Ne-Neset) between the rotation speed Ne of the engine 12 and the warm-up rotation speed Neset. A feedback correction value Tk is calculated (step S160), and the correction value Tk is guarded by a retard side guard value Tfgrd (step S170). The target rotation speed Ne* is a warm-up rotation speed Neset (for example, 1300 rpm or 1500 rpm). As for the retard side guard value Tfgrd, the retard side guard value Tfg1 is used when the expansion stroke injection warm-up is selected, and the retard side guard value Tfg2 is used when the compression stroke injection warm-up is selected. . Then, the correction value Tk is added to the base ignition timing Tfbase to calculate (determine) the ignition timing Tf (step S180). For example, if the base ignition timing Tfbase is ATDC20 and the retard side guard value Tfgrd is 5 degrees, the ignition timing Tf is calculated (determined) within the range up to ATDC25.

When it is determined in step S190 that the warm-up end transition condition is satisfied, the process (step S200) of calculating (determining) the value obtained by subtracting the third rate value Trt3 from the ignition timing Tf as the new ignition timing Tf is performed. The process is repeated until the timing Tf reaches the end determination ignition timing Tfend (step S210). That is, while the rotational speed Ne of the engine 12 is maintained at the warm-up rotational speed Neset, the ignition timing Tf is advanced relatively quickly so as to reach the end determination ignition timing Tfref2. As the third rate value Trt3 needs to be advanced relatively quickly, it is preferable to use a value larger than the second rate value Trt2. For the end determination ignition timing Tfend, for example, TDC or a value near TDC can be used. Note that the feedback correction value Tk is cleared to the value 0.

When the ignition timing Tf reaches the end determination ignition timing Tfend, the expansion stroke injection (or compression stroke injection) is ended. Next, it is determined whether the fuel injection mode has been determined to be expansion stroke injection (step S220), and when it is determined that the fuel injection mode has been determined to be expansion stroke injection, the previous ignition timing Tf is set as the ignition timing Tf. is held (step S230). The fuel injection mode is determined at a timing before the first fuel injection in the intake stroke (for example, BDTC270, etc.), and the ignition timing Tf is calculated (determined) at a timing slightly before compression top dead center (TDC) (for example, BTDC90, etc.). ) to be done. Therefore, if the ignition timing Tf reaches the end determination ignition timing Tfref2 and the expansion stroke injection ends between the timing at which the fuel injection mode is determined and the timing at which the ignition timing Tf is calculated (determined), the expansion Ignition may not occur in synchronization with stroke injection. In this case, in the embodiment, since the previous ignition timing Tf is maintained, ignition can be performed in synchronization with expansion stroke injection. FIG. 3 shows an example of fuel injection and ignition with respect to crank angles in a target cylinder and the cylinder immediately before it. In addition, in FIG. 3, BTDC90 etc. are abbreviated as B90 etc., and ATDC90 etc. are abbreviated as A90 etc. Further, in FIG. 3, a hatched square means fuel injection, and a thick downward arrow above the hatched square means ignition. In this example, it is assumed that the engine 12 is a four-cylinder engine, and BDTC270 is used to start the intake stroke as the timing for determining the fuel injection mode, BTDC90 is used as the timing for calculating (determining) the ignition timing Tf, and expansion stroke injection is performed. TDC was used as the timing for calculating the start time. Further, in this example, the first fuel injection is performed in the intake stroke, the second fuel injection is performed in the compression stroke, and the third fuel injection (final fuel injection) is performed in the expansion stroke. As shown in the figure, the end of the expansion stroke injection is performed after BTDC270, which is the fuel injection determination timing for the target cylinder, and before BTDC90, which is the ignition timing calculation (determination) timing (between BTDC270 and BTDC90). If we consider the case where the cylinder is ignited, it can be seen that by setting the ignition timing Tf to the ignition timing Tf (previous value) of the previous cylinder, ignition can be performed in synchronization with the expansion stroke injection.

Next, a process (step S240) of calculating (determining) a value obtained by subtracting the fourth rate value Trt4 from the ignition timing Tf as a new ignition timing Tf is performed to calculate the ignition timing Tf and the target ignition set after the end of the rapid warm-up. This process is repeated until the difference from the time Tf* becomes less than the threshold value Tfref2 (step S250). That is, while the rotational speed Ne of the engine 12 is maintained at the warm-up rotational speed Neset, the ignition timing Tf is advanced so as to reach the target ignition timing Tf* by deviation. The fourth rate value Trt4 is a value smaller than the third rate value Trt3 because it is necessary to advance the angle by deviation.

When it is determined in step S220 that the fuel injection mode has not been determined to be expansion stroke injection, that is, it has been determined to be normal injection, etc., the previous ignition timing Tf is not held and the fourth rate value is changed from the ignition timing Tf. The process (step S240) of calculating (determining) the value obtained by subtracting Trt4 as the new ignition timing Tf is performed until the difference between the ignition timing Tf and the target ignition timing Tf* set after the end of rapid warm-up is less than the threshold value Tfref2. The process is repeated until the process is completed (step S250).

FIG. 4 is an explanatory diagram showing an example of temporal changes in the rotational speed Ne of the engine 12 and the ignition timing Tf during rapid warm-up. In the ignition timing Tf of FIG. 4, the lower side is shown as a retard side and the upper side is shown as an advance side. At time T1 when the conditions for executing rapid warm-up are satisfied, the rotation speed Ne of the engine 12 is increased to the warm-up rotation speed Neset, and at the same time, the ignition timing Tf is retarded by rate processing using the first rate value Trt1. Start. At time T2 when the rotational speed Ne of the engine 12 reaches the warm-up rotational speed Neset, the ignition timing Tf is adjusted to the rate using the second rate value Trt2 while maintaining the rotational speed Ne of the engine 12 at the warm-up rotational speed Neset. Starts the process of retarding the process relatively quickly. Feedback control of the ignition timing Tf based on the rotational speed Ne of the engine 12 is performed from time T3 when the ignition timing Tf is retarded to the base ignition timing Tfbase until time T4 when the warm-up end transition condition is satisfied. At time T4 when the warm-up end transition condition is satisfied, the ignition timing Tf is relatively quickly advanced by rate processing using the third rate value Trt3 while maintaining the engine 12 rotation speed Ne at the warm-up rotation speed Neset. Start the process. Then, at time T5 when the ignition timing Tf reaches the end determination ignition timing Tfref2, the expansion stroke injection (or compression stroke injection) is ended, and the ignition timing Tf is gradually changed by rate processing using the fourth rate value Trt4. Processing to set the target ignition timing Tf* after the end of rapid warm-up is started. At this time, the rotation speed Ne of the engine 12 is adjusted to the target rotation speed Ne* that is set after the rapid warm-up is completed. In FIG. 3, the rotation speed Ne of the engine 12 is set to the idle rotation speed, assuming a case where the warm-up of the purification device 34 is completed. Rapid warming is completely completed at time T6 when the ignition timing Tf reaches the target ignition timing Tf*, and the normal ignition timing Tf is reached at which the engine 12 outputs torque according to the accelerator opening.

In the engine device 10 of the embodiment described above, when the expansion stroke injection is completed and it is determined that the fuel injection mode is determined to be the expansion stroke injection, the previous ignition timing Tf is held as the ignition timing Tf. This makes it possible to ignite in synchronization with the last expansion stroke injection. As a result, when the expansion stroke injection ends, it is possible to suppress the occurrence of an event in which combustion stability in the engine is lacked, which may occur due to not being ignited in synchronization with the expansion stroke injection.

Of course, after the engine 12 rotation speed Ne reaches the warm-up rotation speed Neset, the feedback correction value Tk obtained using the difference between the engine 12 rotation speed Ne and the warm-up rotation speed Neset is used as the base ignition timing. Since the ignition timing Tf is calculated in addition to Tfbase, it is possible to maintain the retarded state of the ignition timing Tf while stabilizing the rotational speed Ne of the engine 12 even when performing expansion stroke injection warm-up. Furthermore, since the ignition timing Tf can be retarded from the base ignition timing Tfbase, the purifier 34 can be warmed up more quickly. Moreover, since the ignition timing Tf is guarded by the retard side guard value Tfgrd, it is possible to prevent the ignition timing Tf from being retarded more than necessary.

Furthermore, in the engine device 10 of the embodiment, when ending the expansion stroke injection warm-up, the ignition timing Tf is changed relatively quickly so as to reach the end judgment ignition timing Tfend, and then the ignition timing Tf is changed relatively slowly. The target ignition timing Tf* is set after the rapid warm-up is completed. Thereby, expansion stroke injection warm-up can be ended smoothly, and sudden changes in ignition timing Tf can be suppressed when setting ignition timing Tf to target ignition timing Tf* after the end of rapid warm-up.

In the engine device 10 of the embodiment, when it is determined that the fuel injection mode is expansion stroke injection upon completion of rapid warm-up, the previous ignition timing Tf is held as the ignition timing Tf. However, when it is determined that the fuel injection mode is fixed as expansion stroke injection when ending expansion stroke injection warm-up to switch from expansion stroke injection warm-up to compression stroke injection warm-up, the ignition timing Tf is set to the previous ignition timing. It is also possible to hold the timing Tf.

The engine device 10 of the embodiment may be mounted, for example, in an automobile equipped with an automatic transmission in the rear stage, or may be mounted in a hybrid automobile together with a motor that outputs driving power.

The correspondence between the main elements of the embodiments and the main elements of the invention described in the column of means for solving the problems will be explained. In the embodiment, the engine 12 corresponds to an "engine," the purification device 34 corresponds to a "purification device," and the ECU 70 corresponds to a "control device."

The correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem is that the example implements the invention described in the column of means for solving the problem. Since this is an example for specifically explaining a form for solving the problem, it is not intended to limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem should be based on the description in that column, and the examples are based on the description of the invention described in the column of means for solving the problem. This is just one specific example.

Although the embodiments of the present invention have been described above using examples, the present invention is not limited to these examples in any way, and may be modified in various forms without departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing industry of an engine device, etc.

Reference Signs List 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 (1)

An engine having an in-cylinder injection valve that sprays fuel into a combustion chamber and a spark plug that can ignite the fuel sprayed from the in-cylinder injection valve;
a purification device having a purification catalyst that purifies the exhaust gas of the engine;
a control device that controls fuel injection by the in-cylinder injection valve and ignition by the spark plug;
An engine device comprising:
The control device includes an expansion stroke injection in which the last fuel injection from the in-cylinder fuel injection valve is performed during the expansion stroke and an expansion stroke injection in which the fuel injection is ignited by the spark plug in synchronization with the fuel injection in the expansion stroke to warm up the purification device. When performing expansion stroke injection warm-up using stroke ignition, the fuel injection mode is determined to be the expansion stroke injection at a predetermined timing, and the ignition timing is determined at a subsequent timing. ,
When the expansion stroke injection warm-up is completed, the control device maintains the previous ignition timing as the ignition timing if the fuel injection mode has already been determined as expansion stroke injection at the timing of determining the ignition timing.
An engine device characterized by:

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