Drive control device for internal combustion engine

Abstract

Drive control device (50) for an internal combustion machine (20), the internal combustion machine comprising a fuel injector (21) configured to inject fuel, an intake timing variation mechanism (22) configured to control the opening / closing of an intake valve provided at an intake port, and an exhaust timing variation mechanism (24) configured to control the opening / closing of an exhaust valve provided at an exhaust port, wherein the drive control device comprises: a valve timing control unit (56) configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is a quantity of fuel adhering to a wall surface of the internal combustion machine facing an injection field in which the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce the fuel wetting quantity during a start of the internal combustion machine, wherein the valve timing control unit is configured to to execute no control other than the wetting reduction control in order to avoid advancing the intake valve opening timing before top dead center of the internal combustion engine's exhaust point during the first stroke after the internal combustion engine's start-up, and to implement the control as the wetting reduction control in order to advance the valve opening timing of the intake valve before the top dead center of the exhaust of the internal combustion engine during a second and later stroke after the start of the internal combustion engine.

Description

Technical field

[0001] The present disclosure relates to a drive control device for a machine with internal combustion. State of the art

[0002] Literature 1, which describes the prior art, outlines a technology in which, to improve emissions contained in exhaust gases from an internal combustion engine, the required injection quantity in a cycle or stroke is divided into an asynchronous intake injection and a synchronous intake injection under a predetermined condition, and multiple injections are performed in this sequence. Synchronous intake injection is the injection of fuel synchronously with the valve opening timing of an intake valve, while asynchronous intake injection is the injection of fuel with timing on the side of the advance angle relative to a synchronous intake injection.

[0003] DE 11 2019 005 678 T5 discloses that when the machine is started, an ECU determines whether the interior of a cylinder is in a state where wetting is a concern, where there are concerns regarding fuel wetting, or whether the interior of the cylinder is in a droplet suspension state, in which a large volume of suspended fuel droplets is present. If it is determined that the interior is in a state where wetting is a concern, the ECU performs a first control action to reduce the intake air volume by controlling the opening and closing times using the variable valve device. If it is determined that the interior is in a suspended droplet state, the ECU performs a second control action to increase the temperature in the cylinder by controlling the opening and closing times using the variable valve device. Literature on the state of the art Patent literature

[0004] Patent literature 1: JP 2019 - 44 760 A Summary of the invention

[0005] In a multi-injection process, as described in literature 1 of the prior art, and based on the finding that it becomes difficult to reduce or increase the quantity of generated fine particulate matter (PN) or similar particles when the synchronous intake injection accounts for a large proportion, a supplementary synchronous intake injection is performed. This means that the injection quantity during a synchronous intake injection is adjusted so that it does not exceed the injection quantity during an asynchronous intake injection.

[0006] However, with an increased injection quantity in an asynchronous intake injection system, a condition (fuel wetting) in which a droplet of fuel adheres to an inner wall surface of a combustion chamber of an internal combustion engine or the like tends to occur when the temperature in the combustion chamber is low, or on other similar occasions, and this causes a deterioration in terms of emissions or a deterioration in terms of fuel economy.

[0007] Taking into account the foregoing, it is an objective of the present disclosure to provide a technology that reduces fuel wetting in an internal combustion machine in order to improve emissions.

[0008] This problem is solved by the drive control device with the features of claims 1, 2, 3 and 6. Further advantageous embodiments are the subject of the subsequent claims.

[0009] The present disclosure provides a drive control device for an internal combustion engine. The internal combustion engine includes a fuel injection valve configured to inject fuel, an intake timing variation mechanism configured to control the opening / closing of an intake valve located at an intake port, and an exhaust timing variation mechanism configured to control the opening / closing of an exhaust valve located at an exhaust port.The drive control device includes a valve timing control unit configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is an amount of fuel adhering to a wall surface of the internal combustion engine facing an injection port where the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce a fuel wetting quantity at the time of starting the internal combustion engine.

[0010] The drive control device according to the present disclosure is provided with the valve timing control unit. When a requirement is made to reduce the amount of fuel wetting at the time of starting the internal combustion engine, which is the amount of fuel adhering to the wall surface of the internal combustion engine facing the injection field, due to a low injection field temperature or other similar reasons, the valve timing control unit performs wetting reduction control. In wetting reduction control, the valve timing control unit controls at least one of the intake timing variation mechanism and one of the exhaust timing variation mechanism to reduce the amount of fuel wetting by means of a counterflow that is blown back towards the intake port.According to the wetting reduction control system, an increased temperature effect on the injection field and other similar effects are achieved by utilizing the counterflow that is blown back towards the intake port, and additionally, a reduced amount of fuel is achieved. As a result, fuel wetting in the internal combustion engine can be reduced to improve emissions. Brief description of the drawings

[0011] The foregoing and other tasks, features, and advantages of the present disclosure will become clear from the following detailed description with reference to the accompanying drawings. These show: Fig. 1 a schematic diagram of a drive system of a machine with internal combustion according to one embodiment; Fig. 2 a drawing illustrating an exhaust / intake timing; Fig. 3 a drawing illustrating a relationship between an ambient temperature and a phase angle; Fig. 4 a drawing illustrating a relationship between an ambient temperature and a phase angle; Fig. 5 a drawing illustrating a relationship between exhaust / intake timing and fuel injection timing; Fig. 6 a drawing illustrating a forward displacement angle in an intake timing; Fig. 7 a drawing illustrating a relationship between a fuel wetting quantity and an injection quantity; Fig. 8 a drawing illustrating a relationship between a fuel wetting quantity and a water temperature or an intake air temperature; Fig. 9 a drawing illustrating a relationship between fuel wetting quantity and rotational speed of an internal combustion machine; Fig. 10 a flowchart of a drive control processing for a machine with internal combustion according to a first embodiment; and Fig. 11 a flow diagram of a drive control processing for a machine with internal combustion according to a second embodiment. Description of the embodiments: First embodiment

[0012] As in Fig. Figure 1 shows a drive system of a machine 20 with internal combustion of a vehicle comprising an intake manifold 10, an intake manifold 12, the machine 20 with internal combustion, an exhaust manifold 32, an exhaust pipe 30 and an ECU 50.

[0013] The internal combustion engine 20 is a four-stroke engine powered by the combustion of a fuel such as gasoline, repeatedly performing an intake, compression, expansion, and exhaust stroke. The internal combustion engine 20 is a four-cylinder engine, with one piston housed in each cylinder. The intake manifold 12 and the exhaust manifold 32 each branch into four cylinders, corresponding to the number of cylinders in the internal combustion engine 20. In the description of the present embodiment, a four-cylinder engine is used as an example of the internal combustion engine 20, but any number of cylinders is acceptable. The internal combustion engine 20 is not limited to a gasoline engine but can also be a diesel engine.

[0014] An air purifier 11 and a throttle valve 13 are installed in the intake pipe 10 in this order, starting from the upstream side. An airflow sensor 15, which detects the intake air volume, is installed downstream of the air purifier 11 and upstream of the throttle valve 13. The intake manifold 12 is connected to the downstream side of the throttle valve 13. An intake pressure sensor 16 is installed downstream of the throttle valve 13 and upstream of the intake manifold 12. Air is supplied to each cylinder of the internal combustion engine 20 from the intake manifold 12. An exhaust emission control catalyst layer 31 is installed in the exhaust pipe 30 to clean the exhaust gases from the internal combustion engine 20.

[0015] The internal combustion engine 20 includes a fuel injector 21, an intake timing variable mechanism 22, a variable valve lift mechanism 23, an exhaust timing variable mechanism 24, and an igniter 28. The fuel injector 21 injects fuel into each cylinder of the internal combustion engine 20. The intake timing variable mechanism 22 controls the opening / closing timing of an intake valve of the internal combustion engine 20. The variable valve lift mechanism 23 controls the lift amount of an intake valve. The exhaust timing variable mechanism 24 controls the opening / closing timing of an exhaust valve of the internal combustion engine 20. The igniter 28 is a spark plug and ignites fuel in a combustion chamber of the internal combustion engine 20 by excitation.

[0016] The internal combustion engine 20 is configured such that power from a crankshaft (drive shaft, not shown) is transmitted to a camshaft 25 on the intake side and a camshaft 26 on the exhaust side. The intake timing variation mechanism 22 is installed on the camshaft 25 on the intake side and adjusts the advance angle of the camshaft 25 on the intake side relative to the crankshaft. The exhaust timing variation mechanism 24 is installed on the camshaft 26 on the exhaust side and adjusts the advance angle of the camshaft 26 on the exhaust side relative to the crankshaft.

[0017] A sensor group 40 includes an ignition (IG) sensor 41, a crankshaft sensor 42, a camshaft sensor 43, a water temperature sensor 44, an intake air temperature sensor 45, an ambient air temperature sensor 46, an oil temperature sensor 47, a fuel temperature sensor 48, and the like. Sensor group 40 may further include: an accelerator pedal sensor that detects the amount of accelerator pedal depressurization (accelerator pedal opening); a vehicle speed sensor that detects vehicle speed; a brake sensor that detects the amount of brake pedal depressurization; an internal cylinder pressure sensor that detects the internal pressure in a cylinder; a battery sensor that detects a voltage between terminals, a charging / discharging current, or the like of a battery; and the like. A signal from sensor group 40 is sequentially input to the ECU 50.

[0018] The IG sensor 41 detects the switching on / off of the ignition of machine 20 with internal combustion. A start of machine 20 with internal combustion can be detected with the IG sensor 41.

[0019] The crankshaft sensor 42 detects the rotational position of the crankshaft relative to a reference position and a rotational speed NE of the internal combustion engine 20. The crankshaft sensor 42 outputs a pulse signal each time it detects a plurality of teeth arranged at predetermined intervals around a rotor that rotates together with the crankshaft of the internal combustion engine 20. A section is provided on the periphery of the rotor where a predetermined number of teeth are missing. Therefore, a section (signal section with missing teeth) where a predetermined number of pulse signals are generated is defined as the number of pulse signals that originate from the crankshaft sensor 42.

[0020] The cam sensor 43 is a sensor that outputs a pulse signal each time it detects one or more teeth formed on the rotor that rotates with the camshaft. The cam sensor 43 outputs a pulsed detection signal according to the rotation of the camshaft 25 on the intake side and the camshaft 26 on the exhaust side. The current crankshaft position can be determined from a signal segment with missing teeth in a detection signal originating from the crankshaft sensor 42 and a detection signal originating from the cam sensor 43.

[0021] The water temperature sensor 44 detects the temperature of the cooling water that cools the internal combustion engine 20. The intake air temperature sensor 45 detects the temperature of the intake air that is supplied from an intake valve into a combustion chamber of the internal combustion engine 20. The ambient air temperature sensor 46 detects the temperature of the ambient air outside the vehicle on which the internal combustion engine 20 is mounted. The oil temperature sensor 47 detects the temperature of the lubricating oil of the internal combustion engine 20. The fuel temperature sensor 48 detects the temperature of the fuel that is injected into the internal combustion engine 20.

[0022] The ECU 50 is an electronic control device comprising a microcomputer and the like, including a publicly known CPU, ROM, RAM, and the like. It functions as a drive control device, exercising drive control on the internal combustion engine 20 and each actuator used on the internal combustion engine 20, based on the results of observations from various sensors provided in the system. More specifically, the ECU 50 performs drive control of the throttle valve 13, control of the timing and stroke of the intake timing variation mechanism 22, the variable valve lift mechanism 23, and the exhaust timing variation mechanism 24, control of fuel injection by each fuel injector 21, and the like.

[0023] Based on a signal from the crankshaft sensor 42, the ECU 50 calculates the number of revolutions per unit of time of the crankshaft, i.e., the rotational speed NE of the internal combustion engine. Based on signals from the crankshaft sensor 42 and the camshaft sensor 43, the ECU 50 determines the number of cylinders.

[0024] The ECU 50 includes a start determination unit 51, a rotational speed calculation unit 52, a wetting calculation unit 53, a load calculation unit 54, an injection control unit 55 and a VT (valve timing) control unit 56.

[0025] The start determination unit 51 determines, based on a detection value from the IG sensor 41, that the machine 20 has been started with internal combustion. A certain number of cycles after a start can be obtained by ensuring that the machine 20 has been started with internal combustion.

[0026] The rotational speed calculation unit 52 calculates a rotational speed NE of the internal combustion machine 20 based on a detection signal from the crank sensor 42. The rotational speed calculation unit 52 determines the number of cylinders based on detection signals from the crank sensor 42 and the cam sensor 43.

[0027] The wetting calculation unit 53 calculates the quantity of fuel wetting that adheres to a wall surface of the internal combustion machine 20, which is oriented towards an injection field. The injection field refers to a field (space) in which fuel is injected in the internal combustion machine 20, and more precisely refers to the interior of a combustion chamber, the interior of an intake port, and the like.A wall surface of the internal combustion machine 20, facing an injection field, is a concept that can include a wall surface of any configuration element of the internal combustion machine 20 where injected fuel can arrive. Specific examples of a wall surface of the internal combustion machine 20 facing an injection field include an inner wall surface of an intake port, an inner wall surface of an intake valve, a combustion chamber, or the like. The wetting calculation unit 53 is preferably configured to calculate a fuel wetting quantity based on at least one of the required fuel injection quantity, temperature information of the internal combustion machine 20, and a number of revolutions of the internal combustion machine 20.The wetting calculation unit 53 further determines, based on a calculated fuel wetting quantity, whether a reduction of a fuel wetting quantity is necessary.

[0028] The load calculation unit 54 calculates the load of the machine 20 with internal combustion. Based on measured values ​​from an intake air temperature sensor 14 and a crankshaft angle sensor 29, the load calculation unit calculates, for example, the operating load of the machine 20 with internal combustion.

[0029] The injection control unit 55 controls a fuel injector 21 to control the injection of fuel into the internal combustion engine 20. More precisely, the injection control unit controls the excitation of a fuel injector 21 to control the timing and duration of the fuel injection.

[0030] The injection control unit 55 determines the counterflow generation duration and the required fuel injection quantity. The counterflow generation duration is the time during which a counterflow is generated in an injection field of the internal combustion engine 20. The required injection quantity is the total amount of fuel injected into the internal combustion engine 20 within one combustion cycle.

[0031] If a required injection quantity cannot be injected during a counterflow generation period, the injection control unit 55 injects this excess quantity of fuel when an intake valve is closed. That is, when fuel is injected, the injection control unit 55 splits an injection into an injection with the intake valve closed, which is made on the side of the forward displacement angle relative to a counterflow generation period, and an injection during generated counterflow, which is made during the counterflow generation period. The injection control unit 55 can further split or divide both an injection with the intake valve closed and an injection during generated counterflow.

[0032] The VT control unit 56 controls the intake timing variation mechanism 22 and the exhaust timing variation mechanism 24 to control an intake timing at which air is taken into a combustion chamber of the machine 20 with internal combustion, and an exhaust timing at which exhaust air is expelled from a combustion chamber.

[0033] When the wetting calculation unit 53 requests that a fuel wetting quantity be reduced at the time of a start of the machine 20 with internal combustion, the VT control unit 56 executes a wetting reduction control to control at least either the intake timing variation mechanism 22 or the exhaust timing variation mechanism 24 in order to reduce a fuel wetting quantity by means of a backflow. The VT control unit 56 preferably executes at least one advance angle control with the exhaust valve closed or one advance angle control with the intake valve open as a wetting reduction control. In the advance angle control with the exhaust valve closed, the exhaust valve closing timing is advanced to a top dead center of the exhaust.In the case of advance angle control with an open intake valve, the intake valve opening timing is advanced before the top dead center of the exhaust.

[0034] The VT control unit 56 controls at least either the intake timing variation mechanism 22 or the exhaust timing variation mechanism 24 to extend the counterflow generation time. The VT control unit thereby reduces a shortage of the actual counterflow generation time relative to the counterflow generation time (required counterflow generation time) needed to vaporize fuel and thus reduce the amount of fuel wetted.

[0035] With reference to the Fig. 2 and Fig. 3 will be given a description of how a counterflow generation time is extended by controlling the intake timing variation mechanism 22 or the exhaust timing variation mechanism 24. Fig. Figure 2 shows one phase of valve timing; the curves indicated by "EX" show exhaust timing; and the curves indicated by "IN" show intake timing. Fig. Figure 3 shows the ambient temperature of an injection field of machine 20 with internal combustion on the vertical axes and a phase angle on the horizontal axes. A temperature A, which on the vertical axes in Fig. Figure 3 shows a counterflow generation temperature, and a duration during which an ambient temperature is equal to or higher than the counterflow generation temperature A is equivalent to a counterflow generation duration.

[0036] For example, during the first stroke after the start of machine 20 with internal combustion, a pre-displacement angle control with the exhaust valve closed is preferably implemented as a wetting reduction control. With this control, the valve closing timing of an exhaust valve is set before the top dead center of the exhaust stroke (which is in Fig. 2 is indicated by TDC) shifted forward, as in (a) in Fig. 2 is shown. By implementing a forward displacement angle control with the discharge valve closed, as in (a) in Fig. As shown in Figure 3, air in a combustion chamber is compressed more strongly, and at a subsequent time of an intake valve opening, a counterflow can be effectively formed; therefore, the counterflow generation time can be extended.

[0037] During the second and subsequent strokes after the start of machine 20 with internal combustion, as in (b) in Fig. As shown in Figure 2, a wetting reduction control is preferably implemented as a pre-displacement angle control with the intake valve open in order to advance the valve opening timing of an intake valve before the top dead center of the exhaust of the machine 20 with internal combustion. By implementing a pre-displacement angle control with the intake valve open, as shown in (b) in Fig. As shown in Figure 3, the counterflow generation time can be extended.

[0038] Furthermore, the present invention can be configured, for example, to implement both a forward displacement angle control with the exhaust valve closed and a forward displacement angle control with the intake valve open as a wetting reduction control during the second and subsequent cycles after the start of the machine 20 with internal combustion, as shown in (c) in Fig. Figure 2 shows that by implementing both a forward displacement angle control with the exhaust valve closed and a forward displacement angle control with the intake valve open, to control respective forward displacement angle amounts, an overlap duration during which both an exhaust valve and an intake valve are open can be controlled. By controlling an overlap duration, a combustion state of the machine 20 with internal combustion can be maintained stably, and furthermore, a counterflow generation duration can be extended to reduce the amount of fuel wetting. For this reason, depending on a combustion state of the machine 20 with internal combustion, as shown in (c) in Fig. As shown in Figure 3, the counterflow generation time can be extended further than in cases where only the intake valve opening timing is advanced.

[0039] In cases where a deterioration in the combustion state of the internal combustion machine 20 needs to be further improved by controlling the ignition timing on the delay side or by other similar means, overlap duration control is limited, and a sufficiently long overlap duration cannot be ensured. In cases where a timing variation mechanism with good response, capable of being quickly initiated or actuated after the start of the internal combustion machine 20 with good response, is not used as an intake timing variation mechanism 22 or an exhaust timing variation mechanism 24, overlap duration control may be delayed, and a sufficiently long overlap duration cannot be ensured.For example, there are cases where a timing variation mechanism with good response is used as an intake timing variation mechanism 22, but a timing variation mechanism with poor response is used as an exhaust timing variation mechanism 24.

[0040] In cases where a sufficiently long overlap period cannot be ensured, as explained above, as in Fig. As shown in Figure 4, an injection duration T1 (represented as the duration from phase angle P1 to phase angle P3) to complete an injection of fuel in a required injection quantity can be so long that it exceeds a counterflow generation duration (represented as the duration from phase angle P2 to phase angle P3). Fig. Figure 4 shows an ambient temperature in an injection field of machine 20 with internal combustion on the vertical axis, and a phase angle is shown on the horizontal axis.

[0041] If an injection duration T1 is longer than a counterflow generation duration, as in Fig. As shown in Figure 4, the injection duration T1 includes a superfluid duration T2, which is an injection duration not included in a counterflow generation duration. Fuel injected during this superfluid duration T2 can adhere as a fuel coating to an intake port or the like of the internal combustion machine 20. However, during subsequent counterflow generation durations, fuel that once adheres as a fuel coating to an intake port or the like is separated from the intake port by a counterflow blown back to the intake port if the length of a superfluid duration T2 is equal to or shorter than a predetermined threshold Xt2.This means that even if the injection duration T1 required to complete a fuel injection of the necessary quantity is so long that it exceeds the counterflow generation duration, the fuel injection can be completed without increasing the fuel wetting quantity in the following cases: cases where its excess duration T2 is equal to or shorter than a predetermined threshold Xt2, and can be set on one side of the forward displacement angle relative to the counterflow generation duration. The threshold Xt2 can, for example, be set according to the length of a counterflow generation duration.

[0042] The ECU 50 can be configured to reduce the amount of fuel sprayed by splitting a closed-injection injection via the injection control unit 55. If the total amount of fuel injected into the internal combustion engine 20 cannot be injected during a counterflow generation period, the injection control unit 55 can be configured to perform split injection control to control the fuel injector 21 to divide a closed-injection injection into multiple injections. By performing split injection, the penetration force during a fuel injection can be reduced; therefore, the amount of fuel sprayed can be reduced.

[0043] Fig. Figure 5 illustrates an example of a split injection control system. (a) to (d) in Fig. Figure 5 shows the opening / closing timing of an exhaust valve, an intake valve, and a fuel injector.

[0044] The dashed line in (a) in Fig. Figure 5 shows a case where the valve closing timing of the ejection valve occurs at top dead center of the ejection, and the solid line shows a case where the valve closing timing of the ejection valve is advanced to top dead center of the ejection by a pre-advance angle control when the ejection valve is closed. The dashed line in (b) in Fig. Figure 5 indicates a case where the intake valve opening timing occurs at top dead center of the exhaust stroke, and the solid line indicates a case where the intake valve opening timing is advanced to top dead center of the exhaust stroke by an advance angle control with the intake valve open. If only an advance angle control with the intake valve open is implemented, the overlap duration is as indicated by B2, but if both an advance angle control with the exhaust valve closed and an advance angle control with the intake valve open are implemented, the overlap duration can be reduced, as indicated by B1.

[0045] (c) in Fig. 5 indicates the open / closed state of the fuel injector 21, which is achieved when an injection is not split with the intake valve closed. The dashed line in (c) in Fig. Figure 5 indicates a case where neither a pre-displacement angle control with the exhaust valve closed nor a pre-displacement angle control with the intake valve open is implemented, and the solid line indicates a case where both a pre-displacement angle control with the exhaust valve closed and a pre-displacement angle control with the intake valve open are implemented. By implementing both a pre-displacement angle control with the exhaust valve closed and a pre-displacement angle control with the intake valve open, the counterflow generation duration is extended from that indicated by TR1 to that indicated by TR2. As a result, the injection duration for injection with the intake valve closed is shortened, and the injection duration for injection with generated counterflow is lengthened, as indicated by the solid line.As a result of the counterflow generation duration being extended by a wetting reduction control by the VT control unit 56, the injection control unit 55 controls a fuel injection valve 21, so that fuel injected during injection with the intake valve closed is reduced, and fuel injected during injection with generated counterflow is increased; therefore, a fuel wetting quantity is reduced.

[0046] Compare to (c) in Fig. 5 shows (d) in Fig. 5 the open / closed state of a fuel injector 21, which is achieved when an injection with the intake valve closed is split. A total quantity of fuel injected in an injection with the intake valve closed, which is in (d) in Fig. 5 divided into two is identical to a total amount of fuel that would be injected in a single injection with the intake valve closed into (c) in Fig. 5 is injected. However, the penetration force of an injected fuel can be reduced if an injection is split with the intake valve closed, as in (d) in Fig. 5 is shown; therefore, this contributes to a reduction in the amount of fuel wetting.

[0047] The ECU 50 does not necessarily have to execute split injection control by the injection control unit 55 or wetting reduction control by the VT control unit 56 in every cycle from the first cycle after the start of the internal combustion engine 20. For example, while only a forward angle control with the exhaust valve closed is executed in the first cycle after start, no forward angle control with the intake valve closed needs to be executed in the second and subsequent cycles. While a forward angle control with the exhaust valve closed is executed in the first cycle after start, no forward angle control with the intake valve closed needs to be executed in the second and subsequent cycles after start.

[0048] A control operation that is executed at each stroke can be started or completed at any time during a duration from the start until the completion of the stroke. A description will be given with a case in which a forward displacement angle control is executed with the intake valve open at the second stroke, which is used as an example. As in (a) and (b) in Fig. As shown in Figure 6, a pre-shift angle control can be started before the start of J1 of the second clock cycle and the pre-shift angle control can be completed at the start of J1 of the second clock cycle. Or, as in (a) and (b) in Fig. As shown in Figure 6, a forward shift angle control can be started at the start J1 of the second clock cycle and the forward shift angle control can be completed at the end J2 of the second clock cycle.

[0049] The ECU 50 can be configured to determine, based on the operating state of the internal combustion machine 20 or the like, which is preferably to be implemented: split injection control by the injection control unit 55 or wetting reduction control by the VT control unit 56. The present invention can, for example, be configured such that split injection control by the injection control unit 55 has a higher priority than wetting reduction control by the VT control unit 56 when the rotational speed NE of the internal combustion machine 20 is greater than or equal to a predetermined rotational speed threshold NX. When the rotational speed NE is high, the time per combustion cycle is short, and the phase angle required to complete fuel injection in the required quantity is increased.For this reason, a rotational speed threshold NX is set based on a rotational speed at which an injection duration sufficient to complete fuel injection of the required quantity can be ensured. For example, if the combustion state of the engine 20 with internal combustion is not in a predefined stable state, the ECU 50 can further be configured such that split injection control by the injection control unit 55 has a higher priority than wetting reduction control by the VT control unit 56. The predefined stable state referred to herein is a combustion state in which an EGR ratio at which combustion becomes unstable is not exceeded, even if an internal EGR ratio is increased by wetting reduction control by the VT control unit 56.

[0050] The ECU 50 can contain a table or mathematical expression that specifies relationships between a fuel wetting quantity and each parameter, as in Fig. 7 to Fig. 9 is shown, it will be saved. Fig. Figure 7 shows a relationship between a fuel wetting quantity and an injection quantity per injection, and a fuel wetting quantity is increased when there is an increase in the injection quantity per injection. Fig. Figure 8 shows a relationship between a fuel wetting quantity and a cooling water temperature or an intake air temperature of the internal combustion machine 20, and a fuel wetting quantity is reduced when there is an increase in cooling water temperature or intake air temperature. Fig. Figure 9 shows a relationship between a fuel wetting quantity and a rotational speed NE of the internal combustion machine 20, and a fuel wetting quantity is increased with an increase in rotational speed NE. The wetting calculation unit 53 can be configured to reference tables that specify a fuel wetting quantity and each parameter that is in Fig. 7 to Fig. Figure 9 is shown to calculate a fuel wetting quantity.

[0051] Fig. Figure 10 shows a flowchart of a drive control processing operation for the internal combustion engine 20, performed by the ECU 50. This processing is repeated at a predetermined cycle. In step S101, a required injection quantity is first calculated, which is the amount of fuel injected into the internal combustion engine 20 during one combustion cycle, and the processing then proceeds to step S102.

[0052] Step S102 determines whether a wetting reduction control should be executed. More precisely, it determines whether a wetting reduction control should be executed when a request is made to reduce the amount of fuel wetting. This determination is based, for example, on a wetting amount calculated by the wetting calculation unit 53. Specifically, it determines whether a wetting reduction control should be executed if, for example, a calculated wetting amount is greater than or equal to a predefined threshold. If a calculated wetting amount is less than the predefined threshold, it determines whether a wetting reduction control should be executed.

[0053] It can be determined, based on various parameters such as the readings from the intake air temperature sensor 45 and the outside air temperature sensor 46, which influence the amount of wetting, whether a wetting reduction control should be implemented. More precisely, it can be determined that a wetting reduction control should be implemented if various parameters are determined based on the relationships described in Fig. 7 to Fig. Figure 9 indicates that a wetting quantity is greater than or equal to a predefined threshold. Furthermore, it can be determined, for example, based on a number of cycles since the start of machine 20 with internal combustion, whether a wetting reduction control should be executed. For example, it can be determined that a wetting reduction control should be executed during the first and subsequent cycles after a predefined number of cycles following the start of machine 20 with internal combustion.

[0054] If step S102 specifies that a wetting reduction control should be executed, processing proceeds to step S103. The control in steps S103 to S112 is the processing performed when a wetting reduction control is applied. If it specifies that a wetting reduction control should not be applied, processing proceeds to step S113. In this step, it is specified that normal control without a wetting reduction control should be applied, and processing terminates.

[0055] In step S103, as in the first step of a wetting reduction control, steps S103 to S112 determine whether the current cycle is the first cycle after the start of machine 20 with internal combustion. If the current cycle is the first cycle, processing proceeds to step S104. In step S104, it is determined that the discharge valve closing timing of machine 20 with internal combustion should be advanced, and then processing proceeds to step S108.

[0056] If the current cycle is the second or a later cycle, processing proceeds to step S105. In step S105, it is determined that an intake valve opening timing of the internal combustion engine 20 should be advanced, and an advance angle magnitude of the intake valve opening timing is calculated. Processing then proceeds to step S106. In step S106, it is determined whether a combustion state of the internal combustion engine 20 is unstable. For example, in cases where an internal EGR ratio in the internal combustion engine 20 becomes so high that it exceeds an EGR ratio at which fuel becomes unstable, advancing the intake valve closing timing based on the relationships established in [reference missing] will determine whether the combustion state of the internal combustion engine 20 is unstable. Fig. Step 5 is shown to determine that a combustion state is unstable. If step S106 determines that a combustion state is unstable, processing proceeds to step S107. In this step, it is determined that an exhaust valve closing timing of machine 20 with internal combustion should be advanced, and such an advance angle of an exhaust valve closing timing is calculated at which an internal EGR ratio does not exceed an EGR ratio at which fuel becomes unstable. Processing then proceeds to step S108. If step S106 determines that a combustion state is not unstable, processing proceeds to step S108.

[0057] Step S108 determines whether the injection duration TN is equal to or shorter than the actual counterflow generation duration TR. If TN ≥ TR, processing proceeds to step S111. This step determines whether a split injection should be performed when the valve is closed, and processing terminates. If TN < TR, processing proceeds to step S112, which determines whether a split injection should not be performed when the valve is closed, and processing terminates.

[0058] According to the first embodiment, the wetting reduction control, as shown in steps S103 to S112 above, is implemented when, in step S102, it is determined that a request has been made to reduce the amount of fuel wetting, which is the amount of fuel adhering to a wall surface of the internal combustion machine 20 facing an injection field. In a wetting reduction control, at least one of the intake timing variation mechanism 22 and the exhaust timing variation mechanism 24 are controlled to reduce the amount of fuel wetting by a counterflow that is blown back towards the intake port. A more specific description will be given.As shown in steps S104 to S107, the counterflow generation time TR can be extended by implementing control to advance the exhaust valve closing timing or the intake valve opening timing. Therefore, effects such as increased injection field temperature can be achieved by actively utilizing counterflow, resulting in a reduced fuel wetting effect. Consequently, fuel wetting in the internal combustion engine 20 can be reduced to improve emissions.

[0059] According to the first embodiment, during the first stroke after the start of the internal combustion machine 20, a control operation is performed to advance the timing of the exhaust valve closing in order to compress air in a combustion chamber of the internal combustion machine 20, as shown in steps S103 and S104. As a result, a counterflow can be effectively formed during the subsequent intake valve opening operations.

[0060] As shown in steps S103 and S105, during the second and subsequent cycles after the start of the internal combustion engine 20, control is performed to advance the intake valve opening timing, thereby extending the backflow generation duration. As shown in steps S106 and S107, the exhaust valve closing timing is advanced to prevent the internal EGR ratio in the internal combustion engine 20 from becoming so high that it exceeds an EGR ratio at which fuel becomes unstable. This would occur if the combustion state became unstable as a result of advancing the intake valve opening timing. Therefore, the fuel wetting quantity can be reduced while maintaining a stable combustion state in the internal combustion engine 20.

[0061] According to the first embodiment, a fuel injection occurring at the time of intake valve closing can be split, as shown in steps S108, S111, and S112, if the injection duration TN is equal to or longer than the actual counterflow generation duration TR. By performing a split injection, the penetration force during a fuel injection can be reduced; therefore, the amount of fuel wetting can be reduced. Second embodiment

[0062] Fig. Figure 11 shows a flowchart of a drive control processing operation for the machine 20 with internal combustion, which is carried out by the ECU 50 in the second embodiment. This processing is performed repeatedly at a predetermined cycle time.

[0063] In step S201, as in step S101, a required injection quantity is calculated, and processing proceeds to step S202. In step S202, as in step S102, it is determined whether a wetting reduction control should be executed. If a wetting reduction control is executed, processing proceeds to step S203. If a wetting reduction control is not executed, processing proceeds to step S213. In this step, as in step S113, it is determined that normal control without a wetting reduction control should be executed, and processing terminates.

[0064] Step S203 determines whether the rotational speed NE of the internal combustion machine 20 is lower than a predetermined rotational speed threshold NX. The rotational speed threshold NX is set according to a required injection quantity. For example, a rotational speed threshold NX is set to a lower limit of a rotational speed at which it is difficult to ensure an injection duration sufficient to complete a fuel injection of the required quantity. If NE ≥ NX, processing proceeds to step S204. In this step, as in step S111, it is determined that a split injection should be performed for injection with the valve closed, and processing is terminated. If NE < NX, processing proceeds to step S205.In this step, as in step S112, it is determined that a split injection should be carried out when the valve is closed, and then the processing proceeds to step S206.

[0065] In step S206, as in step S103, it is determined whether the current cycle is the first cycle after the start of machine 20 with internal combustion. If the current cycle is the first cycle after a start, processing proceeds to step S207. In this step, as in step S104, it is determined that the exhaust valve closing timing of machine 20 with internal combustion should be advanced, and then processing is terminated. If in step S206 it is determined that the current cycle is the second or a later cycle, processing proceeds to step S208. In this step, it is determined that the intake valve opening timing of machine 20 with internal combustion should be advanced, and its exhaust valve closing timing should also be advanced. The respective advance angle values ​​are calculated, and then processing is terminated.

[0066] According to the second embodiment, as explained above, the time per combustion cycle is short when the rotational speed NE of the internal combustion machine 20 is high, that is, when NE ≥ NX; therefore, the phase angle required to complete fuel injection in the required quantity is increased. By preferably reducing the fuel wetting quantity through split injection at the time of intake valve closing, as shown in step S204, a sufficient injection duration can be ensured to complete fuel injection in the required quantity.

[0067] If the rotational speed NE of the internal combustion machine 20 is low, that is, if NE < NX, the time per combustion cycle is long; therefore, the phase angle required to complete fuel injection in the required quantity becomes relatively small. For this reason, a process that effectively creates a counterflow or a process that extends the counterflow generation time is carried out, as shown in steps S206 to S208, preferably to reduce the fuel wetting quantity. According to the second embodiment, a more suitable process for reducing the fuel wetting quantity can be selected and preferably carried out according to an operating condition of the internal combustion machine 20.

[0068] Instead of determining the outcome by the rotational speed NE of the internal combustion machine 20, as shown in step S203, a determination can be made by the combustion state of the internal combustion machine 20. More precisely, the present invention can be configured such that: processing proceeds to the confirmatory assessment page if an operating state of the internal combustion machine 20 is unstable at step S203, and processing proceeds to the negative assessment page if an operating state of the internal combustion machine 20 is stable at step S203.For example, if an operating load on the internal combustion machine 20, calculated by the load calculation unit 54, is lower than a predetermined load, or if an injection delay angle magnitude is large during ignition of the igniter 28, it is determined that a combustion state of the internal combustion machine 20 is unstable and that a fuel wetting quantity reduction can preferably be achieved by split injection at the time of intake valve closing.

[0069] If a process is carried out in which a counterflow is effectively formed, or a process in which the counterflow generation time is extended, as shown in steps S206 to S208, an internal EGR ratio in the internal combustion machine 20 can be increased. Therefore, in cases where there is concern that a combustion state is so unstable that an internal EGR ratio is increased and exceeds an EGR ratio in which the fuel is unstable, as shown in step S204, a fuel wetting quantity reduction is preferably achieved by split injection at the time of intake valve closing.By preferably reducing the amount of fuel wetting by means of split injection at the time of intake valve closing to prevent an increase with respect to an internal EGR ratio, a combustion state of the machine 20 with internal combustion can be kept stable in order to reduce a fuel wetting amount.

[0070] According to each of the embodiments described above, the following effects are achieved:

[0071] The ECU 50 functions as a drive control device for the internal combustion machine 20. The internal combustion machine 20 includes: a fuel injector 21 that injects fuel; the intake timing variation mechanism 22, which controls the opening / closing of an intake valve provided at an intake port; and the exhaust timing variation mechanism 24, which controls the opening / closing of an exhaust valve provided at an exhaust port.

[0072] The ECU 50 includes the VT control unit 56, which controls at least either the intake timing variation mechanism 22 or the exhaust timing variation mechanism 24. When a request is made to reduce the amount of fuel wetting at the time of start-up of the internal combustion engine 20, which is the amount of fuel adhering to a wall surface of the internal combustion engine 20 facing an injection field where fuel is injected, the VT control unit 56 performs a wetting reduction control. During the wetting reduction control, at least either the intake timing variation mechanism 22 or the exhaust timing variation mechanism 24 is controlled to reduce the amount of fuel wetting by means of a counterflow that is blown back to an intake port.According to the wetting reduction control, the effects of increased temperature at the injection field and the like can be achieved by utilizing a counterflow that is blown back towards the intake port, thereby reducing the amount of fuel wetted. As a result, fuel wetting in the internal combustion engine 20 can be reduced to improve emissions.

[0073] The VT control unit 56 can be configured to perform a wetting reduction control, advancing the valve opening timing of an intake valve before the top dead center of the exhaust of the internal combustion engine 20 during the second and subsequent cycles after the engine 20 starts. According to this control, the counterflow generation time can be extended to reduce the amount of fuel wetting.

[0074] The VT control unit 56 can be configured to perform a wetting reduction control, advancing the valve closing timing of an exhaust valve before top dead center of the exhaust of the internal combustion engine 20 during the first stroke after the engine 20 starts. According to this control, air can be compressed in a combustion chamber of the internal combustion engine 20, and a counterflow can be effectively formed during the subsequent intake valve closing operations to reduce the amount of fuel wetting.

[0075] The VT control unit 56 can be configured to perform a control operation as a wetting reduction control to advance the valve closing timing of an exhaust valve to before top dead center of the exhaust of the internal combustion engine 20 during the first stroke after the engine 20 has been started. Furthermore, it can be configured to perform a control operation to advance the valve opening timing of an intake valve to before top dead center of the exhaust of the engine 20 during the second and subsequent strokes after the engine 20 has been started. According to this control operation, a counterflow generation duration can be extended to reduce the amount of fuel wetting between the first stroke immediately after the engine 20 has been started and a predetermined stroke at which the engine 20 has been started after the second stroke.

[0076] The VT control unit 56 can be configured to perform a control operation as a wetting reduction control to advance the valve closing timing of an exhaust valve to a point before the top dead center of the exhaust stroke of the internal combustion engine 20 on the second or a subsequent stroke after the start of the internal combustion engine 20, and furthermore to perform a control operation to advance the valve opening timing of an intake valve to a point before the top dead center of the exhaust stroke of the internal combustion engine 20. If a combustion condition becomes unstable as a result of advancing the intake valve opening timing, advancing the exhaust valve closing timing prevents the internal EGR ratio in the internal combustion engine 20 from becoming so large that it exceeds an EGR ratio at which fuel becomes unstable.For this reason, the amount of fuel wetting can be reduced while maintaining a stable combustion state of machine 20 with internal combustion.

[0077] The ECU 50 can further include the injection control unit 55, which controls the injection of fuel into the internal combustion engine 20. The injection control unit 55 can be configured to perform split injection when a counterflow generation time is reached, which is the duration during which a counterflow is generated in an injection field in the internal combustion engine 20, and the total amount of fuel to be injected into the internal combustion engine 20 in one cycle cannot be injected during the counterflow generation time. In split injection, a fuel injector is controlled such that it splits a closed intake valve injection, in which fuel is injected at the time of intake valve closure, into several injections.Since the penetration force at the time of fuel injection can be reduced by using split injection, the amount of fuel wetting can be reduced.

[0078] If the rotational speed NE of the machine 20 with internal combustion is greater than or equal to a rotational speed threshold NX, the ECU 50 can be configured to give higher priority to wetting reduction control by the VT control unit 56 than to split injection control by the injection control unit 55. If the time per combustion cycle is short and a phase angle required to complete fuel injection in a required quantity is increased, sufficient injection duration to complete fuel injection in a required quantity can be ensured by giving higher priority to the aforementioned wetting reduction control than to split injection control by the injection control unit 55.

[0079] If the combustion state of the internal combustion engine 20 is not a predetermined stable state, the ECU 50 prioritizes split injection control by the injection control unit 55 over wetting reduction control by the VT control unit 56. If the combustion state of the internal combustion engine 20 is unstable, a fuel wetting quantity reduction is preferably implemented by split injection at the time of intake valve closing to prevent an increase in the internal EGR ratio. As a result, the combustion state of the internal combustion engine 20 can be kept stable to reduce the fuel wetting quantity.

[0080] The ECU 50 can also include the wetting calculation unit 53, which determines a fuel wetting quantity based on at least one of the required injection quantity of fuel, temperature information of the internal combustion machine 20, and a number of revolutions of the internal combustion machine 20.

[0081] A control unit described in the present disclosure and a technique for its implementation can be realized by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, a control unit described in the present disclosure and a technique for its implementation can be realized by a dedicated computer provided by configuring a processor with one or more dedicated logic hardware circuits.Alternatively, a control unit described in the present disclosure, as well as the technology therefor, can be implemented by one or more dedicated computers configured with a combination of a processor and memory programmed to perform one or more functions, and a processor configured from one or more logical hardware circuits. A computer program can be stored as instructions to be executed by a computer on a computer-readable, non-volatile physical recording medium.

[0082] The present disclosure has been described in accordance with embodiments, but this is not to be interpreted as limiting the present disclosure to the embodiments or structures set forth above. The present disclosure also includes various modifications and modifications within an equivalent range. In addition, various combinations and modes, as well as other combinations and modes achieved by adding only a single element or more or fewer elements to the combinations and modes, are also included within the category and technical scope of the present disclosure.

Claims

[1] Drive control device (50) for an internal combustion machine (20), the internal combustion machine comprising a fuel injector (21) configured to inject fuel, an intake timing variation mechanism (22) configured to control the opening / closing of an intake valve provided at an intake port, and an exhaust timing variation mechanism (24) configured to control the opening / closing of an exhaust valve provided at an exhaust port, wherein the drive control device comprises: a valve timing control unit (56) configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is a quantity of fuel adhering to a wall surface of the internal combustion machine facing an injection field in which the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce the fuel wetting quantity during a start of the internal combustion machine, wherein the valve timing control unit is configured to to execute no control other than the wetting reduction control in order to avoid advancing the intake valve opening timing before top dead center of the internal combustion engine's exhaust point during the first stroke after the internal combustion engine's start-up, and to implement the control as the wetting reduction control in order to advance the valve opening timing of the intake valve before the top dead center of the exhaust of the internal combustion engine during a second and later stroke after the start of the internal combustion engine. [2] Drive control device (50) for an internal combustion machine (20), the internal combustion machine comprising a fuel injector (21) configured to inject fuel, an intake timing variation mechanism (22) configured to control the opening / closing of an intake valve provided at an intake port, and an exhaust timing variation mechanism (24) configured to control the opening / closing of an exhaust valve provided at an exhaust port, wherein the drive control device comprises: a valve timing control unit (56) configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is a quantity of fuel adhering to a wall surface of the internal combustion machine facing an injection field in which the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce the fuel wetting quantity during a start of the internal combustion machine, wherein The valve timing control unit is configured to perform a control as the wetting reduction control to advance the valve closing timing of the exhaust valve before top dead center of the exhaust of the internal combustion machine on a first stroke after the start of the internal combustion machine. [3] Drive control device (50) for an internal combustion machine (20), the internal combustion machine comprising a fuel injector (21) configured to inject fuel, an intake timing variation mechanism (22) configured to control the opening / closing of an intake valve provided at an intake port, and an exhaust timing variation mechanism (24) configured to control the opening / closing of an exhaust valve provided at an exhaust port, wherein the drive control device comprises: a valve timing control unit (56) configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is a quantity of fuel adhering to a wall surface of the internal combustion machine facing an injection field in which the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce the fuel wetting quantity during a start of the internal combustion machine, wherein The valve timing control unit is configured to perform the following as the wetting reduction control: a control to advance the valve closing timing of the exhaust valve to a top dead center of the exhaust of the internal combustion engine during a first stroke after the start of the internal combustion engine, and a control to advance the valve opening timing of the intake valve before the top dead center of the exhaust point of the internal combustion engine during a second and subsequent stroke after the start of the internal combustion engine. [4] Drive control device according to claim 1 or 3, wherein the valve timing control unit is configured to perform a control as the wetting reduction control to advance a valve closing timing of the ejection valve prior to the top dead center of the ejection of the internal combustion machine during the second and subsequent stroke after the start of the internal combustion machine. [5] Drive control device according to one of claims 1 to 4, further comprising: an injection control unit (55) configured to to obtain a counterflow generation duration, which is a duration in which the counterflow is generated in the injection field, and to implement a split injection control to control the fuel injector in such a way that it splits a closed intake valve injection, which is a fuel injection that is carried out when the intake valve is closed, into several injections if a fuel cannot be injected with a total injection quantity during the counterflow generation period with which fuel is injected into the internal combustion machine in one stroke. [6] Drive control device (50) for an internal combustion machine (20), the internal combustion machine comprising a fuel injector (21) configured to inject fuel, an intake timing variation mechanism (22) configured to control the opening / closing of an intake valve provided at an intake port, and an exhaust timing variation mechanism (24) configured to control the opening / closing of an exhaust valve provided at an exhaust port, wherein the drive control device comprises: a valve timing control unit (56) configured to perform a wetting reduction control to control at least one of the intake timing variation mechanism and the exhaust timing variation mechanism to reduce a fuel wetting quantity, which is an amount of fuel adhering to a wall surface of the internal combustion engine facing an injection field where the fuel is to be injected, by means of a counterflow blown back to the intake port when a request is made to reduce the fuel wetting quantity during a start of the internal combustion engine; and an injection control unit (55) configured to to obtain a counterflow generation duration, which is a duration in which the counterflow is generated in the injection field, and to implement a split injection control to control the fuel injector in such a way that it splits a closed intake valve injection, which is a fuel injection that is carried out when the intake valve is closed, into several injections if a fuel cannot be injected with a total injection quantity during the counterflow generation period with which fuel is injected into the internal combustion machine in one stroke. [7] Drive control device according to claim 6, wherein the valve timing control unit is configured to perform a control as the wetting reduction control to advance a valve opening timing of the intake valve prior to a top dead center of the exhaust of the internal combustion machine on a second and subsequent stroke after the start of the internal combustion machine. [8] Drive control device according to one of claims 5 to 7, wherein the split injection control by the injection control unit has a higher priority than the wetting reduction control by the valve timing control unit when a rotational speed of the internal combustion machine is greater than or equal to a predetermined rotational speed threshold. [9] Drive control device according to one of claims 5 to 8, wherein the split injection control by the injection control unit has a higher priority than the wetting reduction control by the valve timing control unit when a combustion state of the internal combustion machine is not a predetermined stable state. [10] Drive control device according to any one of claims 1 to 9, further comprising: a wetting calculation unit (53) configured to calculate the fuel wetting quantity based on at least one of the required fuel injection quantity, internal combustion machine temperature information, and number of internal combustion machine revolutions.

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