JP2011127571A - Method of controlling early warm-up of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, when hydraulic pressure becomes equal to or higher than a predetermined value by a relief valve in a lubrication system for circulating lubrication oil, the relief valve is opened and returns the lubrication oil to an oil pan, however, when newly forming a relief oil passage for shortening warm-up operation, there occurs restriction on the design of a cooling system, and cost for development design is increased, thus causing an increase of manufacturing, and when the start and warm-up of an internal combustion engine are delayed, and when an oil temperature of a low load is low, the viscosity of the lubrication oil becomes high, a load of an oil pump becomes large and fuel economy is deteriorated. <P>SOLUTION: The internal combustion engine has an piston reciprocating in a cylinder and is equipped with a lubrication oil supply system supplying the lubrication oil for at least the reciprocation of the piston and including an oil jet control valve discharging the lubrication oil to the inside of the piston for cooling the piston. In the internal combustion engine, a temperature of the internal combustion engine is detected and when the detected temperature of the internal combustion engine is lower than a predetermined value, the oil jet control valve is controlled so that a discharge amount of the lubrication oil from the oil jet control valve becomes large. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an early warm-up control method for an internal combustion engine in an internal combustion engine including an oil jet that cools a piston with lubricating oil.

  Conventionally, it is known to use lubricating oil of an internal combustion engine in order to shorten the time for warm-up operation. For example, in the one described in Patent Document 1, the lubricating oil is supplied to each lubricating portion by an oil pump through a lubricating oil passage communicating with an oil pan, and a relief valve is provided in the lubricating oil passage, and the relief oil communicates with the relief valve. The path is formed from the cylinder head to the cylinder block, and the lubricating oil is returned from the relief valve via the relief oil path at the cold start, thereby warming the cylinder block and shortening the warm-up operation time. .

JP-A-6-317133

  By the way, in a normal internal combustion engine, the relief valve is provided so as to open when the hydraulic pressure of the lubricating oil becomes higher than a predetermined level, and to return the lubricating oil directly to the oil pan. Therefore, in the case of the normal internal combustion engine, it is necessary to newly provide a relief oil passage in the configuration described in Patent Document 1. For this reason, when such a relief oil passage is provided, there is a problem in that the cost for development design increases due to restrictions on the design of the cooling water handling, and the manufacturing cost increases. Furthermore, from the start of the internal combustion engine to the completion of warm-up, and when the low load lubricating oil temperature is low, the viscosity of the lubricating oil is high and the load on the internal combustion engine of the oil pump increases, so that the actual fuel consumption decreases. A defect also occurred.

  Therefore, the present invention aims to eliminate such problems.

  That is, the early warm-up control method for an internal combustion engine according to the present invention includes a piston that reciprocates in a cylinder, and supplies at least lubricating oil to the reciprocating operation of the piston and cools the piston inside the piston. In an internal combustion engine having a lubricating oil supply system including an oil jet control valve that discharges lubricating oil, the temperature of the internal combustion engine is detected, and when the detected temperature of the internal combustion engine is lower than a predetermined value, the oil jet control valve The oil jet control valve is controlled so as to increase the discharge amount of the lubricating oil.

  With such a configuration, the amount of lubricating oil discharged from the oil jet control valve is increased by controlling the oil jet control valve at a low temperature when the temperature of the internal combustion engine has not risen above the predetermined value. The discharged lubricating oil contacts the inside of the piston and cools the piston. As a result, the lubricating oil receives heat from the piston, the discharge amount is increased, and the entire lubricating oil is warmed by the received lubricating oil, thereby shortening the time required for the warm-up operation of the internal combustion engine.

  In order to increase the amount of lubricating oil discharged from the oil jet control valve with high accuracy, the engine speed of the internal combustion engine is detected, and the hydraulic pressure of the lubricating oil is adjusted based on the detected temperature of the internal combustion engine and the engine speed. It is preferable to estimate the oil amount and control the oil jet control valve in accordance with the estimated oil pressure adjusting oil amount.

  The present invention is configured as described above, and when the temperature of the internal combustion engine is a low temperature lower than a predetermined value, the oil jet control valve is controlled to increase the discharge amount of the lubricating oil, and the discharged and received heat from the piston Since the oil warms the entire lubricating oil, the time required for the warm-up operation of the internal combustion engine can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows schematic structure of embodiment of this invention. The flowchart which shows the outline of the control procedure of the embodiment. The flowchart which shows the outline of the control procedure of other embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  A multi-cylinder engine 100 schematically showing the configuration of one cylinder in FIG. 1 is, for example, a spark ignition gasoline engine mounted on an automobile. The engine 100 includes an intake system 1, a cylinder 2, and an exhaust system 3. The intake system 1 is provided with a throttle valve 4 that opens and closes in response to an accelerator pedal (not shown), and an intake manifold 6 that integrally has a surge tank 5 is attached downstream of the throttle valve 4. A spark plug 8 is attached to the ceiling of the combustion chamber 7 formed in the upper part of the cylinder 2. A fuel injection valve 9 is attached to an intake port side end of the intake manifold 6. The fuel injection valve 9 is controlled by an electronic control device 10 described later.

  The engine 100 is provided with a lubrication system that circulates lubricating oil to each lubrication portion such as a cam journal and a crank journal. Specifically, the lubricating oil stored in the oil pan is sucked up by an oil pump through an oil strainer, and sent to the main gallery, intake and exhaust camshafts, and the oil jet control valve 11 through an oil filter. A relief valve is provided between the oil pump and the oil filter. When the oil pressure of the lubricating oil rises above a certain level, the lubricating oil is returned to the oil pan via the relief valve to The hydraulic pressure is adjusted.

  The oil jet control valve 11 communicates with the main gallery. The oil jet control valve 11 projects from the inner wall surface of the cylinder block and communicates with a discharge nozzle 13 whose tip faces the inner surface of the piston 12. The opening degree of the oil jet control valve 11 is controlled by an early warm-up program, which will be described later, during the warm-up operation. In an operation state after the warm-up, a substantially constant amount of lubricating oil is directed toward the piston 12. It is opened to be discharged. That is, the oil jet control valve 11 is a type that can control the opening degree to a desired opening degree, and can control the discharge amount of the lubricating oil from the discharge nozzle 13 by changing the opening degree. Is. The amount of lubricating oil controlled by the oil jet control valve 11 is reciprocated in the cylinder 2 until the piston 12 starts to fall from the top dead center until the bottom dead center is reached. In particular, it continuously reaches the back surface of the top surface of the piston 12.

  The electronic control device 10 includes a microcomputer 10a, a memory 10b, an input interface 10c, and an output interface 10d. The microcomputer 10a controls the operation of the engine 100 by executing various programs described below stored in the memory 10b. Information necessary for operation control of the engine 100 is input to the microcomputer 10a via the input interface 10c. The microcomputer 10a sends control signals to the fuel control valve 9, the oil jet control valve 11, and the like. Output via the output interface 10d.

Specifically, the input interface 10c outputs the intake pressure signal a output from the intake pressure sensor 14 for detecting the pressure in the surge tank 5 and the rotation speed sensor 15 for detecting the engine speed. The rotation speed signal b, the vehicle speed signal c output from the vehicle speed sensor 16 for detecting the vehicle speed, the LL signal d from the idle switch 17 for detecting the open / closed state of the throttle valve 4, and the coolant temperature of the engine 100. A water temperature signal f output from the water temperature sensor 18 for detection, a voltage signal h output from the O ₂ sensor 19 and the like are input. On the other hand, the output interface 10d outputs an ignition signal m to the spark plug 8, a fuel injection signal n to the fuel control valve 9, an open / close signal o to the oil jet control valve 11, and the like.

  In such a configuration, the electronic control unit 10 sets the intake pressure signal a output from the intake pressure sensor 14 and the rotation speed signal b output from the rotation speed sensor 15 as main information according to the driving state. The fuel injection amount is calculated using a coefficient to determine the fuel injection time corresponding to the fuel injection amount, that is, the energization time for the fuel injection valve 9, and the fuel injection valve 9 is controlled by the determined energization time, Fuel is injected into the intake system 1. Such fuel injection control itself may apply what is known in this field.

  Further, the electronic control device 10 detects the coolant temperature as the temperature of the engine 100, and when the detected coolant temperature is less than a predetermined value, the amount of lubricant discharged from the oil jet control valve 11 is large. An early warm-up control program for controlling the oil jet control valve 11 is stored. An outline procedure of an early warm-up control program for promoting warm-up using this lubricating oil will be described with reference to FIG. This early warm-up control program is repeatedly executed at predetermined intervals during the warm-up operation.

  In FIG. 2, first, in step S <b> 1, the coolant temperature is detected based on the water temperature signal f output from the water temperature sensor 18. In step S2, it is determined whether or not the detected coolant temperature is less than a predetermined value. The cooling water temperature is for estimating the viscosity of the lubricating oil. The predetermined value is set based on the cooling water temperature when the relief valve is closed because the viscosity of the lubricating oil is high when the temperature of the lubricating oil is low and, as a result, the oil pressure of the lubricating oil is high and the relief valve is opened. For example, when it is determined that the cooling water temperature has not risen and is less than a predetermined value, such as during a cold start, step S3 is executed, and the cooling water temperature rises, for example, during a restart. If it is greater than or equal to the predetermined value, step S4 is executed.

  In step S3, the oil jet control valve 11 is opened with a large opening so that the operation amount is increased so that the discharge amount of the lubricating oil is increased. That is, by discharging the lubricating oil from the oil jet control valve 11, the relief valve is not opened, in other words, the oil jet control valve 11 is opened to replace the function of the relief valve and circulate the lubricating oil. is there. Therefore, the amount of operation of the oil jet control valve 11 to be increased is at least an amount that does not open the relief valve. Thereby, even if it is the oil pressure of the lubricating oil which opens a relief valve, a relief valve is not opened but lubricating oil is discharged from the oil jet control valve 11. FIG. In this case, since the discharge pressure for the lubricating oil to reach the back surface of the top surface of the piston 12 is required from when the piston 12 starts to fall from the top dead center to the bottom dead center, the cooling water temperature is low. In this case, the opening degree of the oil jet control valve 11 can be increased, but the opening degree of the oil jet control valve 11 is decreased as the cooling water temperature rises, and the discharge of the lubricating oil reaching the piston 12 is performed. The pressure is maintained.

  In step S4, the oil jet control valve 11 is opened at a predetermined opening. Thereby, in the operation state after warm-up, a substantially constant amount of lubricating oil is discharged from the oil jet control valve 11 toward the inside of the piston. Note that the opening degree or discharge amount of the oil jet control valve 11 is set to an upper limit opening degree or an upper limit amount so that the supply of lubricating oil to the other lubricating portions of the engine 100 does not become insufficient.

  Thus, for example, in the cold start, when the cooling water temperature is less than the predetermined value, that is, in the operating state where the temperature has not increased to the predetermined value (“Yes” in step S2), the viscosity of the lubricating oil is high and the relief valve is turned on. The oil jet control valve 11 is largely opened (step S3), and the lubricating oil is discharged from the discharge nozzle toward the inside of the piston 12 by the oil pressure of the lubricating oil at that time. Thereby, the lubricating oil comes into contact with the back surface of the top surface of the piston 12 and receives heat from the top surface. Since the top surface is a portion where the temperature of the piston 12 is high, the piston 12 is effectively cooled and the lubricating oil is efficiently warmed. And since the lubricating oil heated in this way is mixed with the lubricating oil which exists in an oil pan, the temperature of the whole lubricating oil rises rapidly.

  Therefore, the completion of the warm-up operation can be promoted, and the time until the warm-up is completed can be shortened. As a result, the actual fuel consumption can be improved by shortening the warm-up time.

  Next, an early warm-up control program for controlling the operation amount of the oil jet control valve with higher accuracy will be described with reference to FIG.

  First, similarly to the above-described embodiment, the cooling water temperature is detected in step S11, and subsequently, in step S12, it is determined whether or not the detected cooling water temperature is less than a predetermined value. If it is determined that the coolant temperature is less than the predetermined value, the engine speed of the engine 100 is detected based on the speed signal b output from the speed sensor 15 in step S13.

  In step S14, based on the detected coolant temperature and engine speed, the amount of lubricating oil that is recirculated from the relief valve when the oil jet control valve 11 is not controlled for early warm-up, that is, the amount of oil for hydraulic adjustment is estimated. To do. The amount of oil for oil pressure adjustment is determined based on the viscosity of the lubricating oil and the rotational speed of the oil pump at that time, that is, the engine rotational speed. Therefore, the viscosity of the lubricating oil is estimated from the cooling water temperature, The amount of oil for oil pressure adjustment is estimated by estimating the number of rotations of the oil pump from the number of rotations.

  In step S15, the opening degree of the oil jet control valve 11 is set according to the estimated oil amount for oil pressure adjustment, and the opening is made so that the discharge amount of the lubricating oil is increased. That is, the opening degree of the oil jet control valve 11 sufficient to discharge an amount of lubricating oil corresponding to the hydraulic pressure adjusting oil amount is set.

  If it is determined in step S12 that the cooling water temperature is equal to or higher than the predetermined value, in step S16, the oil jet control valve 11 is opened while maintaining a predetermined opening degree. A substantially constant amount of lubricating oil is discharged from the control valve 11 toward the inside of the piston 12. This step S16 corresponds to step S4 in the above-described embodiment.

  Thus, since the opening degree of the oil jet control valve 11 and thus the amount of lubricating oil discharged from the oil jet control valve 11 through the discharge nozzle is set based on the oil amount for oil pressure adjustment, the operating state of the engine 100 at that time is set. Therefore, it is possible to accurately control the optimal discharge amount of lubricating oil corresponding to the above.

  Note that the temperature of the lubricating oil or the temperature of the cylinder block itself may be applied as the engine temperature.

  Moreover, in the above-mentioned embodiment, although the thing in a gasoline engine was demonstrated, you may apply to another engine which has a piston which reciprocates the inside of a cylinder, for example, a diesel engine.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  As an application example of the present invention, the present invention can be applied to an internal combustion engine that includes an oil pan and includes a lubrication system that supplies lubricating oil to each lubricating portion.

DESCRIPTION OF SYMBOLS 2 ... Cylinder 10 ... Electronic control unit 10a ... Microcomputer 10b ... Memory 10c ... Input interface 10d ... Output interface 11 ... Oil jet control valve 12 ... Piston

Claims (2)

Lubricating oil supply system including an oil jet control valve that has a piston that reciprocates in a cylinder, supplies lubricating oil to at least the reciprocating operation of the piston, and discharges the lubricating oil to the inside of the piston to cool the piston Detecting the temperature of the internal combustion engine,
An early warm-up control method for an internal combustion engine that controls an oil jet control valve so that a discharge amount of lubricating oil from the oil jet control valve is increased when a detected temperature of the internal combustion engine is lower than a predetermined value. Detects the engine speed of the internal combustion engine,
Based on the detected temperature of the internal combustion engine and the engine speed, the amount of oil for adjusting hydraulic pressure of the lubricating oil is estimated,
2. An early warm-up control method for an internal combustion engine according to claim 1, wherein the oil jet control valve is controlled in accordance with the estimated oil amount for oil pressure adjustment.