Internal combustion engine control device

Abstract

To provide an internal combustion engine control device capable of suppressing reduction in pressure of engine oil supplied to a hydraulic device when reducing a rotational speed of an internal combustion engine.SOLUTION: An internal combustion engine control device 10 controls an internal combustion engine 20 applied to a vehicle 100, the internal combustion engine comprising a dry sump type engine oil supply device 40 that supplies engine oil to a hydraulic device. When reducing a rotational speed of the internal combustion engine, the internal combustion engine control device increases an amount of gas suctioned into a cylinder 30 of the internal combustion engine.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine control device. [Background technology]

[0002] BACKGROUND ART Internal combustion engines equipped with dry sump type engine oil supply devices are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-113820 Summary of the Invention

[0004] In an internal combustion engine equipped with a dry sump-type engine oil supply system, the pressure inside the engine, including the crankcase, becomes very low, which tends to lower the pressure (oil pressure) of the engine oil supplied to hydraulic equipment such as a variable valve timing mechanism (VVT mechanism) installed in the engine. Furthermore, if the oil pump supplying the engine oil is a mechanical oil pump powered by the engine when the oil pressure is low, a decrease in the engine speed reduces the oil pump's discharge pressure, further lowering the oil pressure. This low oil pressure can cause problems with the operation of hydraulic equipment.

[0005] An object of the present invention is to provide an internal combustion engine control device that can suppress a decrease in the pressure of engine oil supplied to hydraulic devices when the rotation speed of the internal combustion engine decreases.

[0006] The internal combustion engine control device according to the present invention controls an internal combustion engine applied to a vehicle, the internal combustion engine having a dry sump type engine oil supply device that supplies engine oil to hydraulic equipment. The internal combustion engine control device according to the present invention is configured to increase the amount of gas drawn into cylinders of the internal combustion engine when the rotation speed of the internal combustion engine decreases.

[0007] According to the present invention, the amount of gas drawn into the cylinders of the internal combustion engine is increased when the rotation speed of the internal combustion engine decreases. This increases the amount of gas flowing out from the cylinders into the crankcase of the internal combustion engine (so-called blow-by gas). This suppresses a decrease in pressure inside the crankcase of the internal combustion engine, and as a result, suppresses a decrease in the pressure of engine oil supplied to hydraulic devices of the internal combustion engine.

[0008] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, features, and attendant advantages of the present invention will be easily understood from the description of the embodiments of the present invention. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an internal combustion engine control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing a routine executed by the internal combustion engine control device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] An internal combustion engine control device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an internal combustion engine control device 10 according to an embodiment of the present invention. As shown in FIG. 1, the internal combustion engine control device 10 (hereinafter simply referred to as "control device 10") is applied to an internal combustion engine 20 and controls the operation of the internal combustion engine 20. The internal combustion engine 20 is mounted on a vehicle 100. Hereinafter, the vehicle 100 may be a vehicle that is directly driven by an operator on board the vehicle 100 (i.e., a driver of the vehicle 100), or may be a vehicle that is remotely driven by an operator at a remote location who is not on board the vehicle 100 (i.e., a remote operator of the vehicle 100). Furthermore, the vehicle 100 may be a vehicle that is driven only by manual driving operation, a vehicle that is driven only by automatic driving control, or a vehicle that is driven by both manual driving operation and automatic driving control.

[0011] As shown in FIG. 1, the control device 10 includes an ECU (electronic control unit) 90 as a control device. The ECU 90 includes a microcomputer as a main component. The microcomputer includes a CPU, storage media such as ROM, RAM, and non-volatile memory, as well as an interface. The CPU executes instructions, programs, or routines stored in the storage media to realize various functions. In particular, in this example, the control device 10 stores programs in the storage media that realize the various controls executed by the control device 10.

[0012] In this example, the control device 10 has only one ECU 90, but it may also be configured to have multiple ECUs, with each ECU sharing the functions of the control device 10 described below.

[0013] Furthermore, the control device 10 may be configured to be able to update the program stored in the storage medium through wireless communication with an external device (for example, internet communication).

[0014] The main body (engine main body 21) of the internal combustion engine 20 is made up of a cylinder head 22 and a cylinder block 23. The internal combustion engine 20 also includes an intake valve 24, an exhaust valve 25, a spark plug 26, a fuel injection valve 27, and a piston 28. The engine main body 21 also has a plurality of cylinders 30 (four in this example).

[0015] An intake passage 31 and an exhaust passage 32 are connected to the engine body 21. A surge tank 33 is formed in the intake passage 31. A throttle valve 34 is arranged in the intake passage 31 upstream of the surge tank 33. Furthermore, a compressor 35 of a supercharger is arranged in the intake passage 31 upstream of the throttle valve 34.

[0016] The internal combustion engine 20 is equipped with a dry sump type engine oil supply device 40. The engine oil supply device 40 includes a scavenge pump 41, an oil pump 42, and an oil tank 43. The scavenge pump 41 sucks engine oil from the crank chamber 29 of the internal combustion engine 20 and sends the sucked engine oil to an oil tank 43 via an oil discharge passage 47. The interior of the oil tank 43 is partitioned by a separator 44. The engine oil sent to the oil tank 43 contains so-called blow-by gas, and the blow-by gas is separated from the engine oil by the separator 44.

[0017] The oil tank 43 is connected to the intake passage 31 upstream of the compressor 35 via an upstream blow-by gas passage 45a. The oil tank 43 is also connected to the surge tank 33 via a downstream blow-by gas passage 45b. An upstream flow rate control valve 46a is disposed in the upstream blow-by gas passage 45a, and a downstream flow rate control valve 46b is disposed in the downstream blow-by gas passage 45b. The upstream flow rate control valve 46a opens when the pressure in the intake passage 31 upstream of the compressor 35 becomes lower than the pressure in the oil tank 43, allowing blow-by gas to be introduced into the intake passage 31 via the upstream blow-by gas passage 45a. The downstream flow rate control valve 46b opens when the pressure in the surge tank 33 becomes lower than the pressure in the oil tank 43, allowing blow-by gas to be introduced into the intake passage 31 via the downstream blow-by gas passage 45b.

[0018] The oil pump 42 supplies engine oil stored in the oil tank 43 to the moving parts of the engine body 21 and to the hydraulic equipment of the internal combustion engine 20 via an oil supply passage 48. The engine oil supplied to the moving parts of the engine body 21 is used to lubricate the moving parts. In addition, the engine oil supplied to the hydraulic equipment of the internal combustion engine 20 is used as working oil for operating the hydraulic equipment.

[0019] In this example, the intake passage 31 upstream of the connection between the upstream blow-by gas passage 45a and the intake passage 31 is connected to the inside of the engine body 21 by a fresh air passage 49. As a result, when the pressure inside the engine body 21 becomes lower than the pressure in the intake passage 31, fresh air is introduced into the inside of the engine body 21 from the intake passage 31 via the fresh air passage 49.

[0020] The scavenge pump 41 and the oil pump 42 are operated by the power of the internal combustion engine 20 .

[0021] Furthermore, a rotation speed sensor 50 (or a crank angle sensor) is electrically connected to the ECU 90. The control device 10 is configured to detect the rotation speed of the internal combustion engine 20 by the rotation speed sensor 50.

[0022] <Control device operation> Next, the operation of the control device 10 will be described.

[0023] As described above, the scavenge pump 41 sucks engine oil from the engine body 21, so the pressure inside the engine body 21 is relatively low. Meanwhile, engine oil is supplied to moving parts of the engine body 21, etc. As a result, the oil pressure inside the oil supply passage 48 drops due to the influence of the low pressure inside the engine body 21. Furthermore, when the rotation speed of the internal combustion engine 20 drops, the discharge pressure of the oil pump 42 drops, so the oil pressure inside the oil supply passage 48 drops further. Because the oil supply passage 48 is also used to supply engine oil to hydraulic equipment of the internal combustion engine 20, a drop in oil pressure inside the oil supply passage 48 affects the operation of the hydraulic equipment.

[0024] Therefore, the control device 10 executes the routine shown in FIG. 2 at predetermined time intervals to suppress a drop in oil pressure in the oil supply passage 48 when the rotation speed of the internal combustion engine 20 drops.

[0025] That is, at a predetermined timing, the control device 10 starts the process from step S200 of the routine shown in Fig. 2, and proceeds to step S210 to determine whether or not the increase condition C1 is satisfied. The increase condition C1 is a condition that the rotation speed of the internal combustion engine 20 has decreased. The rotation speed of the internal combustion engine 20 decreases when the vehicle 100 starts to decelerate or immediately after the internal combustion engine 20 finishes racing.

[0026] If the control device 10 determines "No" in step S210, it proceeds directly to step S295 and temporarily ends the processing of this routine. On the other hand, if the control device 10 determines "Yes" in step S210, it proceeds to step S220 and executes intake gas increase control, and then proceeds to step S295 and temporarily ends the processing of this routine.

[0027] The intake gas increase control is a control for increasing the amount of gas taken into the cylinder 30 of the internal combustion engine 20. In this example, the intake gas increase control is a control for increasing the opening of the throttle valve .

[0028] In this way, when the increase condition C1 is met, that is, when the rotation speed of the internal combustion engine 20 decreases, the intake gas increase control is executed to increase the amount of gas taken into the cylinder 30, thereby increasing the amount of gas (blow-by gas) that flows out from the cylinder 30 through between the piston 28 and the cylinder inner wall 30s and into the crank chamber 29. This makes it possible to suppress a decrease in pressure inside the engine body 21, and as a result, to suppress a decrease in the pressure of engine oil supplied to hydraulic devices.

[0029] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0030] 10...control device, 20...internal combustion engine, 29...crankcase, 30...cylinder, 34...throttle valve, 41...scavenge pump, 42...oil pump, 43...oil tank, 50...rotational speed sensor, 90...ECU, 100...vehicle

Claims

[Claim 1] An internal combustion engine control device for controlling an internal combustion engine applied to a vehicle, the internal combustion engine having a dry sump type engine oil supply device that supplies engine oil to hydraulic equipment, An internal combustion engine control device configured to increase the amount of gas drawn into a cylinder of the internal combustion engine when the rotation speed of the internal combustion engine decreases.

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