JP7639604B2 - Engine equipment - Google Patents

Description

The present invention relates to an engine device, and more particularly to an engine device equipped with an engine having an in-cylinder injection valve that sprays fuel into a combustion chamber and an ignition plug that can ignite the fuel sprayed from the in-cylinder injection valve.

Conventionally, engine devices of this type have been proposed in which, when the final fuel injection is performed during the expansion stroke, the injection start timing of the final injection is set based on the engine speed and the target torque of the engine, and the ignition timing is calculated based on the final injection start timing and injection period (see, for example, Patent Document 1). In this device, stratified combustion is performed by the above-mentioned fuel injection and ignition.

International Publication No. 2016/194184

When starting an engine, the timing of each of the multiple fuel injections, in which the final injection is performed during the expansion stroke, is usually performed at a predetermined timing before the first injection. For example, when the first injection is performed at BTDC220 (Before TDC 220 degrees), which is 220 degrees before the compression top dead center (TDC), the timing of each injection is set at BTDC240, which is just before the first injection, among the timings every 30 degrees of crank angle. On the other hand, the ignition timing is set at a timing before the final injection, for example, at BTDC30. The injection timing and ignition timing are set using the engine speed, cooling water temperature, and other parameters. Since the engine speed and cooling water temperature change significantly when the engine is started, the values when the injection timing is set and when the ignition timing is set are different, and the injection timing and ignition timing of the final injection are not synchronized, and there are cases in which good ignition cannot be performed.

The main purpose of the engine device of the present invention is to improve ignition of the final injection during the expansion stroke when starting the engine.

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

The engine device of the present invention comprises:
an engine having an in-cylinder injection valve that sprays fuel into a combustion chamber and an ignition plug that can ignite the fuel sprayed from the in-cylinder injection valve;
a purification device having a purification catalyst for purifying exhaust gas from the engine;
a control device for controlling fuel injection by the in-cylinder injection valve and ignition by the spark plug;
An engine device comprising:
When starting the engine by multiple injections including a final injection in the expansion stroke of fuel and ignition in the expansion stroke, the control device determines the injection timing of the multiple injections based on predetermined parameters at a first predetermined timing before the first injection, and sets a timing guarded by a guard value using the ignition timing obtained based on the parameters at the first predetermined timing with respect to the ignition timing obtained based on the predetermined parameters at a second predetermined timing before the injection timing of the final injection as an execution ignition timing.
It is characterized by:

In the engine device of the present invention, when starting the engine with multiple injections including the final injection during the expansion stroke of the fuel and ignition during the expansion stroke, the injection timing of the multiple injections is determined based on the specified parameters at a first specified timing before the first injection. Then, the timing guarded with a guard value using the ignition timing obtained based on the specified parameters at the first specified timing for the ignition timing obtained based on the specified parameters at a second specified timing before the injection timing of the final injection is set as the execution ignition timing. By guarding the ignition timing with a guard value using the ignition timing obtained based on the specified parameters at the first specified timing, it is possible to ignite at a better timing for the final injection. In other words, it is possible to perform better ignition for the final injection during the expansion stroke when the engine is started.

The guard values here have an advance guard value and a retard guard value, and for example, for the ignition timing obtained based on the specified parameters at the first specified timing (ignition timing based on the parameters at the time of injection confirmation), 0 degrees in crank angle can be used as the advance guard value, and 2 degrees in crank angle can be used as the retard guard value. This is because ignition for the final injection is required to ignite a spray-like injection, and it is preferable for it to be after the start of injection.

The predetermined parameters may include at least one of the coolant temperature for each cylinder, the number of fuel injections, and the rotation speed for determining low rotation. In addition, the predetermined parameters used to determine the injection timing of multiple injections and the predetermined parameters used to set the execution ignition timing may be completely the same, or may be partially the same.

In the engine device of the present invention, the control device may hold the previous value for the ignition timing when the injection mode is changed between the timing for determining the injection timing of the final injection and the timing for determining the ignition timing. When the injection mode is changed between the timing for determining the injection timing of the final injection and the timing for determining the ignition timing, if the injection timing of the final injection is determined in the injection mode before the change and the ignition timing is determined in the injection mode after the change, there may be cases where ignition cannot be performed satisfactorily for the final injection. However, by holding the previous value for the ignition timing (the timing determined in the injection mode before the change), ignition can be performed satisfactorily for the final injection.

1 is a configuration diagram showing an outline of the configuration of an engine device 10 according to an embodiment of the present invention. 4 is a flowchart showing an example of a fuel injection timing determination process executed by an ECU 70. 4 is a flowchart showing an example of an ignition timing determination process executed by an ECU 70. 4 is an explanatory diagram showing an example of three fuel injection timings, a fuel injection timing determination timing, and an ignition timing determination timing when the engine 12 is started. FIG.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of an engine device 10 according to one embodiment of the present invention. As shown in the figure, 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. The engine device 10 is mounted on 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 given assuming that the engine device 10 is mounted on an automobile.

The engine 12 is configured as a four-cylinder 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 the cylinder, and an ignition plug 30. The in-cylinder injection valve 26 is located approximately in the center of the top of the combustion chamber 29 and injects fuel in a spray. The ignition plug 30 is located near the in-cylinder injection valve 26 so that it can ignite the fuel sprayed in a spray from the in-cylinder injection valve 26. The engine 12 draws air cleaned by the air cleaner 22 into the combustion chamber 29 through the intake pipe 25, injects fuel from the in-cylinder injection valve 26 once or multiple times during the intake stroke and compression stroke, and explodes and burns the fuel with an electric spark from the ignition plug 30, converting the reciprocating motion of the piston 32, which is pushed down by the energy, into the rotational motion of the crankshaft 16.

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).

Although not shown, the ECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, and an input/output port. Signals from various sensors necessary for controlling the engine 12 are input to the ECU 70 via the input port. Examples of signals input to the ECU 70 include 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 for each cylinder of the engine 12, and the 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. Other examples include the throttle opening TH from the 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 the air flow meter 48 attached to the intake pipe 25, the intake air temperature Ta from the temperature sensor 49 attached to the intake pipe 25, and the intake pressure Pin from the intake pressure sensor 58 that detects the pressure inside the intake pipe 25. Further examples include 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, the oxygen signal O2 from the oxygen sensor 35b attached to the exhaust pipe 33, and the knock signal Ks from the knock sensor 59 attached to the cylinder block to detect vibrations caused by the occurrence of knocking.

Various control signals for controlling the engine 12 are output from the ECU 70 via an output port. Examples of 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.

The ECU 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 ECU 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.

In the engine device 10 thus configured, the ECU 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 rotation speed Ne* and the target torque Te*. 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, sets the 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 ECU 70 sets the target fuel injection amount Qfd* of the in-cylinder injection valve 26 so that the air-fuel ratio AF becomes the target air-fuel ratio AF* (e.g., theoretical air-fuel ratio) based on the rotation speed Ne and volumetric efficiency KL of the engine 12, and controls the in-cylinder injection valve 26 so that the target fuel injection amount Qfd* of fuel is injected from the in-cylinder injection valve 26 once or multiple times. In ignition control, the ECU 70 sets the target ignition timing Tp* based on the engine 12 rotation speed Ne and load factor KL, and controls the ignition of the spark plug 30.

Next, the operation of the engine device 10 of the embodiment thus configured, particularly the operation when starting the engine 12 by performing the final injection and ignition during the expansion stroke, will be described. Fuel injection during the start of the engine 12 is performed by multiple injections, with the final injection being performed during the expansion stroke. FIG. 2 is a flow chart showing an example of a fuel injection timing determination process, and FIG. 3 is a flow chart showing an example of an ignition timing determination process. FIG. 4 is an explanatory diagram showing an example of three fuel injection timings, fuel injection timing determination timing, and ignition timing determination timing during the start of the engine 12. In FIG. 4, the hatched parts indicate the first injection, second injection, and third injection (last injection), and the thick arrow shown at the final injection indicates ignition. Also, in FIG. 4, BTDC30 (Before TDC 30 degrees) and the like are simply indicated as B30, and ATDC30 (After TDC 30 degrees) and the like are simply indicated as A30.

The fuel injection timing determination process in FIG. 2 is executed at a first predetermined timing every 30 degrees of crank angle before the injection timing of the normal first injection, for example, at BTDC240 (Before TDC 240 degrees), which is 240 degrees before the compression top dead center (TDC) as shown in FIG. 4 (fuel injection timing determination timing). In the fuel injection timing determination process, first, parameters for setting the injection timing are input (step S100), and the input parameters are stored as injection timing determination parameters (step S110). The parameters include, for example, the cooling water temperature Tw for each cylinder, the number of fuel injections, and the rotation speed for low rotation determination. Then, the injection timing for each injection is set based on the input parameters (step S120), and the process ends.

The ignition timing determination process in FIG. 3 is executed at a second predetermined timing every 30 degrees of crank angle before the final injection (third injection), for example, at the timing of BTDC30 30 degrees before the compression top dead center TDC as shown in FIG. 4 (ignition timing determination timing). In the ignition timing determination process, first, parameters for setting the ignition timing are input (step S200), and the tentative ignition timing Tptmp is set based on the input parameters (step S210). The parameters are the same as the parameters for setting the injection timing, and include the cooling water temperature Tw for each cylinder, the number of fuel injections, and the rotation speed for low rotation determination. Next, the injection timing determination parameters are input (step S220), and an advance side guard value α is set by advancing the ignition timing set based on the input injection timing determination parameters by a first predetermined angle, and a retard side guard value β is set by retarding the ignition timing set by a second predetermined angle (step S230). For example, a crank angle of 0 degrees can be used as the first predetermined angle, and a crank angle of 2 degrees can be used as the second predetermined angle. This is to prevent ignition before the final injection and to prevent ignition later than necessary after the final injection.

After setting the advance guard value α and the retard guard value β in this way, the tentative ignition timing Tptmp is guarded by the advance guard value α and the retard guard value β to set the execution ignition timing Tp* (target ignition timing Tp*) (step S240). Then, it is determined whether the injection mode has been changed from the fuel injection timing determination timing to the ignition timing determination timing (step S260). If it is determined that the injection mode has not been changed from the fuel injection timing determination timing to the ignition timing determination timing, this process ends. In this case, ignition is performed at the execution ignition timing Tp* set in step S240. This allows ignition to be performed better for the final injection. On the other hand, if it is determined that the injection mode has been changed from the fuel injection timing determination timing to the ignition timing determination timing, the execution ignition timing Tp* set when this process was performed last time is set as the execution ignition timing Tp* for this time (step S260), and this process ends. In this case, the execution ignition timing Tp* is held at the previous value. This allows for good ignition for the final injection even if the injection mode is changed.

In the engine device 10 of the embodiment described above, when the engine 12 is started, the parameters used to determine the timing of multiple injections, including the final injection during the expansion stroke, are stored as injection timing determination parameters, and the advance guard value α and the retard guard value β are set based on the ignition timing based on the injection timing determination parameters. Then, the tentative ignition timing Tptmp obtained based on the ignition timing determination timing parameters is guarded by the advance guard value α and the retard guard value β to determine the actual ignition timing Tp*. This allows for better ignition for the final injection. At this time, by using the advance guard value α advanced by a first predetermined angle (0 degrees in crank angle) and the retard guard value β retarded by a second predetermined angle (2 degrees in crank angle) relative to the ignition timing based on the injection timing determination parameters, it is possible to prevent ignition before the final injection and to prevent ignition from occurring unnecessarily later than the final injection.

In the engine device 10 of the embodiment, when it is determined that the injection mode has changed between the fuel injection timing determination timing and the ignition timing determination timing, the execution ignition timing Tp* that was set the last time this process was executed is maintained. This allows for good ignition for the final injection even if the injection mode has changed.

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 power for driving.

The following explains the relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem. In the embodiment, the engine 12 corresponds to the "engine", the purification device 34 corresponds to the "purification device", and the ECU 70 corresponds to the "control device".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Means for Solving the Problem column.

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 without departing from the scope of the invention.

The present invention can be used in the engine equipment manufacturing industry, etc.

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 attached to a top of a combustion chamber for spraying fuel into the combustion chamber in a spray form , and an ignition plug attached near the in-cylinder injection valve for igniting the fuel sprayed from the in-cylinder injection valve ;
a purification device having a purification catalyst for purifying exhaust gas from the engine;
a control device for controlling fuel injection by the in-cylinder injection valve and ignition by the spark plug;
An engine device comprising:
When starting the engine by multiple injections including a final injection in the expansion stroke of fuel and ignition in the expansion stroke, the control device determines the injection timing of the multiple injections based on predetermined parameters at a first predetermined timing before the first injection, and sets a guard value set so that ignition for the final injection ignites a spray-like injection using an ignition timing obtained based on the predetermined parameters at a second predetermined timing before the injection timing of the final injection, as an execution ignition timing.
An engine device characterized by:

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