JP2009127454A - Hydraulic control device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce emission at a cold time by a hydraulic control device of an engine having a so-called two-stage hydraulic system. <P>SOLUTION: This hydraulic control device 100 of the engine controls the hydraulic pressure of oil delivered by an oil pump 2 of the engine in low hydraulic pressure or high hydraulic pressure, and has an additional relief valve 150 for setting the low hydraulic pressure to third hydraulic pressure higher in the hydraulic pressure than the low hydraulic pressure according to the oil temperature of the engine. The additional relief valve 150 sets the low hydraulic pressure to the third hydraulic pressure when the oil temperature reaches a predetermined value T1 or lower. The additional relief valve 150 sets the hydraulic pressure to the low hydraulic pressure by performing the relief of oil delivered by the oil pump 2 when the oil temperature is higher than the predetermined value T1, and also sets the hydraulic pressure to the third hydraulic pressure by stopping the relief of the oil delivered by the oil pump 2 when the oil temperature reaches the predetermined value T1 or lower. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine hydraulic control device.

  Conventionally, a device for controlling the oil pressure in an engine of oil fed by an oil pump has been proposed. In such a device, the oil pressure in the oil passage is controlled by opening and closing the oil passage using a solenoid valve. For example, the relief valve may be opened at a low hydraulic pressure using an oil control valve, or may be opened at a high hydraulic pressure (normal hydraulic pressure). Such a system is sometimes referred to as a two-stage hydraulic system. In such a two-stage hydraulic system, the oil is relieved in a low hydraulic pressure state to reduce the load on the oil pump when the oil viscosity is high, or to stop the oil injection from the piston oil jet when cold. Can be. Thereby, the effect of the fuel consumption improvement by engine load fall or early warm-up completion can be acquired.

  For example, Patent Literatures 1 to 3 disclose hydraulic control devices that control the hydraulic pressure in the engine.

JP 2007-107485 A JP 2006-249940 A JP-A-8-177492

  By the way, in the two-stage hydraulic system as described above, by controlling the hydraulic pressure to a low hydraulic pressure in the cold state, the fuel consumption can be improved by reducing the fuel injection amount accompanying the engine load reduction, while the calorific value generated by the combustion. Will fall. In this respect, a decrease in the heat generation amount leads to a decrease in the combustion chamber temperature. When the oil pressure is controlled to a low oil pressure, the piston temperature decrease can be suppressed by stopping the oil injection to the piston. Even in this case, the combustion chamber temperature can be improved, and early warm-up can be achieved.

  However, the lower the oil temperature, the higher the oil viscosity. Therefore, even when the oil temperature is the same, the lower the oil temperature, the lower the engine load when the oil pressure is controlled to a lower oil pressure. It will be big. In this case, since the amount of heat generation is greatly reduced, it has been found that even if the oil injection to the piston is stopped, the temperature of the combustion chamber is lowered, and the emission of unburned HC and the like is thereby deteriorated.

  Therefore, an object of the present invention is to make it possible to reduce the emission of a hydraulic control apparatus for an engine provided with a so-called two-stage hydraulic system when it is cold.

  An engine hydraulic control apparatus according to the present invention that solves such a problem is an engine hydraulic control that controls the hydraulic pressure of oil discharged from an engine oil pump to a first hydraulic pressure or a second hydraulic pressure that is higher than the first hydraulic pressure. The apparatus further comprises hydraulic pressure changing means for changing the first hydraulic pressure to a third hydraulic pressure higher than the first hydraulic pressure in accordance with the oil temperature of the engine. By adopting such a configuration, when the oil pressure is controlled to the first oil pressure in the cold state, fuel injection accompanying an increase in engine load is achieved by changing the first oil pressure to the third oil pressure at an oil temperature at which emissions deteriorate. The amount can be increased, thereby improving the combustion chamber temperature. For this reason, by adopting such a configuration, it is possible to reduce emissions when cold. Note that if the first hydraulic pressure is further set to a low hydraulic pressure that is at least necessary when cold, the engine load can be suitably reduced when the first hydraulic pressure is controlled.

  Further, in order to switch the hydraulic pressure from the first hydraulic pressure to the third hydraulic pressure at the oil temperature at which the emission deteriorates, the engine hydraulic control device of such an engine, specifically, when the oil temperature is equal to or lower than a predetermined value, The changing means may be configured to change the first hydraulic pressure to the third hydraulic pressure (claim 2).

  In addition, such an oil pressure control device for an engine performs relief of oil discharged from the oil pump when the oil temperature is higher than the predetermined value, while the oil pressure changing unit performs the relief of the oil discharged from the oil pump. A relief valve that stops relief of oil discharged from the oil pump in the following cases can be used. With such a configuration, the hydraulic pressure is changed to the first hydraulic pressure while the relief valve constituting the hydraulic pressure changing means performs the oil relief, and the hydraulic pressure is changed to the third hydraulic pressure while the relief valve stops the oil relief. Can be controlled. Therefore, by adopting such a configuration, the first hydraulic pressure can be changed to the third hydraulic pressure easily and at a low cost according to the oil temperature, and this makes it possible to easily reduce the emission when cold and at a low cost. Can be achieved.

  The hydraulic control apparatus for an engine according to the present invention can reduce emissions when cold by changing the first hydraulic pressure to the third hydraulic pressure according to the oil temperature.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIGS. 1 to 4 are configuration diagrams showing a schematic configuration of an engine hydraulic control apparatus (hereinafter simply referred to as “hydraulic control apparatus”) 100 according to an embodiment of the present invention. The hydraulic control device 100 includes an oil relief device 5 in which the oil relief pressure is variable and an oil control valve (hereinafter referred to as OCV) 10. The hydraulic control device 100 can change the relief pressure of the oil relief device 5 according to the state of the OCV 10 that operates according to a command from an ECU (Electronic control unit) 20. 1 and 2 show a state in which the oil relief device 5 is relieved at a low oil pressure (corresponding to the first oil pressure described in the claims). 3 and 4 show a state in which the oil relief device 5 is relieved at a high hydraulic pressure (corresponding to the second hydraulic pressure in the claims). In this way, the hydraulic control apparatus 100 can switch the relief pressure to two stages.

  An oil pump 2 is disposed in an oil passage 1 that supplies oil in the oil pan 11 to various parts of the engine. The oil passage 1 branches to the first bypass passage 3 on the downstream side of the oil pump 2 and also branches to the second bypass passage 4. An oil relief device 5 is incorporated in the first bypass passage 3. The oil relief device 5 is connected to a first relief path 121 that relieves oil discharged from the oil pump 2 to the upstream side of the oil pump 2. The oil passage 1 supplies the oil discharged by the oil pump 2 to the main gallery. An oil temperature sensor that constitutes a part of the sensor / switches 30 is disposed in the oil pan 11. The hydraulic control device 100 includes a piston jet (not shown) that injects oil toward the piston for cooling the piston, and the hydraulic control device 100 is configured to stop oil injection from the piston jet at a low hydraulic pressure. Has been.

  As shown in an enlarged view in FIG. 5, the oil relief device 5 is configured by arranging a relief valve 52, a retainer 53, and a spring 54 sandwiched between the relief valve 52 and the retainer 53 in a case 51. The case 51 includes a small-diameter portion 511 having a small cross-sectional diameter and a large-diameter portion 512 having a large cross-sectional diameter. The stepped portion that transitions from the small diameter portion 511 to the large diameter portion 521 constitutes the stopper 17 that regulates the moving distance of the retainer 53 to the relief valve 52 side.

  The front end side of the small diameter portion 511 of the case 51 forms the main chamber 7. The main chamber 7 is provided with a first relief port 6 to which oil on the downstream side of the oil pump 2 is introduced and to which the first relief passage 121 is connected. A relief valve 52 is provided in the main chamber 7. The relief valve 52 receives the hydraulic pressure in the main chamber 7 at the pressure receiving surface 521. The case 51 is connected to a second relief passage 122 for discharging oil that has entered between the relief valve 52 and the retainer 53 to the upstream side of the oil pump 2.

  The distal end side of the large diameter portion 512 of the case 51 forms a sub chamber 8 into which oil on the downstream side of the oil pump 2 is introduced via the OCV 10. A retainer 53 is provided in the sub chamber 8. The area of the pressure receiving surface 531 of the retainer 53 that receives the hydraulic pressure in the sub chamber 8 is larger than the area of the pressure receiving surface 521 of the relief valve 52. For this reason, when the OCV 10 is switched to the high hydraulic pressure state and a hydraulic pressure equivalent to the hydraulic pressure applied to the pressure receiving surface 521 of the relief valve 52 acts on the pressure receiving surface 531 of the retainer 53, a larger force than the relief valve 52 acts on the retainer 53. Will be. In such a state, the retainer 53 compresses the spring 54. As a result, the relief pressure of the relief valve 52 increases. When the retainer 53 comes into contact with the stopper 17, it does not compress the spring 54 further.

  The oil relief device 5 is configured as described above. The case 51 is also used as a gear case in which a gear for transmitting the rotation of the crankshaft of the engine to the oil pump 2 is housed, and can be incorporated in this gear case.

Next, the OCV 10 will be described. The OCV 10 is a three-way valve that introduces oil supplied from the oil pump 2 through the second bypass passage 4 into the sub chamber 8 of the oil relief device 5 or discharges it to the oil pan 11.
A specific configuration will be described with reference to FIG. The OCV 10 includes a needle 102 in a case 101 having a first chamber 1011, a communication portion 1012, and a second chamber 1013. A ball valve 1021 is formed on the needle 102 and the distal end side, and a proximal end side is a drive unit 1022 that slides by energization of the coil unit 103. The needle 102 is disposed so that the ball valve 1021 is located in the first chamber 1011 and the drive unit 1022 is located in the second chamber 1012. A first spring 104 that contacts the ball valve 1021 is mounted in the first chamber 1011, and a second spring 105 that contacts the drive unit 1022 is mounted in the second chamber 1013. A boundary portion between the first chamber 1011 and the communication portion 1012 constitutes a first seal portion 106 where the ball valve 1021 is seated, and a boundary portion between the communication portion 1012 and the second chamber 1013 is a first portion where the drive portion 1022 is seated. The two seal part 107 is comprised. A first opening 108 is formed in the communication portion 1012, and a second opening 109 for discharging oil to the oil pan 11 is formed in the second chamber 1013.

  A second bypass passage 4 is connected to the first chamber 1011, and oil supplied from the oil pump 2 flows into the first chamber 1011. FIG. 6A shows a state where the coil unit 103 is not energized. In this state, the needle 102 biased by the second spring 105 is pushed upward, and the drive unit 1022 is seated on the second seal portion 107. At this time, since the first seal portion 106 is open, the oil flows into the communication portion 1012 and flows out from the first opening 108. On the other hand, FIG. 6B shows a state in which the coil unit 103 is energized. In this state, the drive unit 1022 is pulled downward against the spring force of the second spring 105. At this time, the ball valve 1021 is seated on the first seal portion 106. Thereby, the oil supplied from the second bypass passage 4 is not discharged from either the first opening 108 or the second opening 109. One end of the communication pipe 13 is connected to the first opening 108 of the OCV 10. The other end of the communication pipe 13 is connected to the sub chamber 8. That is, the OCV 10 and the sub chamber 8 are connected by the communication pipe 13.

  The ECU 20 is electrically connected to the OCV 10 (specifically, the coil unit 103) as a control target. The ECU 20 also includes a water temperature sensor for detecting the engine coolant temperature THW, a crank angle sensor for detecting the engine speed NE, and an accelerator opening ACCP (or load) in order to detect the engine operating state. Various sensors including an accelerator opening sensor for detection and the switches 30 are electrically connected. The ECU 20 controls the hydraulic pressure discharged from the oil pump 2 to a low hydraulic pressure or a high hydraulic pressure based on a program stored in a built-in ROM.

  At this time, specifically, the ECU 20 performs control for performing or stopping energization of the OCV 10 according to the engine operating state based on various sensors, outputs of the switches 30 and the like, so that the oil pump 2 discharges. Control the oil pressure to low or high. For example, the ECU 20 controls the oil pressure to a low oil pressure during cold by performing control for energizing the OCV 10 during cold based on the output of the water temperature sensor. At this time, the oil relief device 5 is in a state of relieving oil at a low hydraulic pressure. When the hydraulic pressure is controlled to a low hydraulic pressure, for example, the driving work of the oil pump 2 can be reduced. In this respect, since the low hydraulic pressure is set to a minimum required hydraulic pressure when cold, the engine load when the hydraulic pressure is controlled to be low can be suitably achieved. Further, when the oil pressure is controlled to a low oil pressure, oil injection from the piston jet can be stopped, so that the warm-up performance of the engine can be improved.

  Such a hydraulic control device 100 is characterized in that it further includes an additional relief valve (corresponding to a hydraulic pressure switching means and a relief valve described in claims) 150 shown below. The first passage 1 is further branched to the third bypass passage 140 on the downstream side of the oil pump 2, and an additional relief valve 150 is provided in the third bypass passage 140. The additional relief valve 150 will be described in detail with reference to FIG.

  The additional relief valve 150 includes a body 151, a retainer 152, and a spring 153. A cylinder 151a having a circular cross section is formed inside the body 151, and a cylindrical retainer 152 and a spring 153 having a bottom are disposed in the cylinder 151a. The retainer 152 slides in the cylinder 151 a and divides the cylinder 151 a into a main chamber 154 and a sub chamber 155. The body 151 has an oil introduction port 151 b communicating with the main chamber 154. An oil discharge port 151c communicating with the sub chamber 155 is formed at the end of the body 151 on the sub chamber 155 side. A communication hole 152 a that connects the main chamber 154 and the sub chamber 155 is formed at the bottom of the retainer 152. The position of the communication hole 152a and the position of the oil discharge port 151c are set so as not to overlap each other. The spring 153 is disposed in the main chamber 154 and has a free length in the state shown in FIG.

The oil discharged from the oil pump 2 is guided to the oil introduction port 151b through the third bypass passage 140. Since the oil pressure is controlled to a low oil pressure during cold weather, the oil relief device 5 is in a state of relieving oil at a low oil pressure. In this state, when the oil temperature is higher than the predetermined value T1 (corresponding to the predetermined value described in the claims), the additional relief valve 150 has the retainer 152 at the end on the sub chamber 155 side as shown in FIG. It will be in the state which is not located in a part. That is, when the oil relief device 5 is relieving oil at a low oil pressure and the oil temperature is higher than the predetermined value T1, the spring force of the spring 153 is set so as to be in the state shown in FIG. Has been. This predetermined value T1 is the oil temperature during cold, and when the oil pressure is controlled to a low oil pressure, the heat generation amount decreases as the engine load decreases, and the combustion chamber temperature remains even if the oil injection to the piston is stopped. It is set to an oil temperature that results in a decrease.
In this state, the oil that flows into the main chamber 154 from the oil introduction port 151b flows into the sub chamber 155 through the communication hole 152a. The oil flowing into the sub chamber 155 is discharged from the oil discharge port 151c to the upstream side of the oil pump 2 through the third bypass passage 140. In this way, the additional relief valve 150 performs relief of the oil discharged from the oil pump 2 in the state shown in FIG. At this time, the oil pressure discharged from the oil pump 2 is low.

  On the other hand, when the oil temperature is lowered, the viscosity of the oil is increased. At this time, while the engine friction increases, the fuel injection amount is increased so that misfire does not occur in the engine. For this reason, for example, when the oil temperature is lowered while the oil pressure is low, the drive of the oil pump 2 increases, and as a result, the oil pressure increases.

In the cold state, the oil relief device 5 is in a state of relieving oil at a low oil pressure. In this state, when the oil temperature is equal to or lower than the predetermined value T1, the oil temperature is higher than the predetermined value T1. The hydraulic pressure is increased as described above. At this time, the oil flowing into the main chamber 154 pushes the retainer 152 toward the sub chamber 155 against the spring force of the spring 153. As a result, as shown in FIG. 7B, the retainer 152 moves to the end on the sub chamber 154 side, and the communication hole 152a is closed. That is, in a state where the oil relief device 5 is relieving oil at a low oil pressure and the oil temperature is equal to or lower than the predetermined value T1, the spring force of the spring 153 is set so as to be in the state shown in FIG. Is set.
The additional relief valve 150 whose communication hole 152a is closed in the state shown in FIG. 7B stops the relief of the oil discharged from the oil pump 2. At this time, the oil relief amount decreases. For this reason, the hydraulic pressure of the oil discharged from the oil pump 2 is a third hydraulic pressure that is higher than the low hydraulic pressure.

  FIG. 8 shows a graph of the oil pressure that changes in accordance with the oil temperature in the low oil pressure state, together with the state of the additional relief valve 150 corresponding to this. As shown in FIG. 8, the oil pressure changes according to the oil temperature, and increases exponentially as the oil temperature decreases. For such characteristics, the predetermined value T1 is set as shown in the figure. When the oil temperature is higher than the predetermined value T1, the additional relief valve 150 performs oil relief, and as a result, the hydraulic pressure is low. It becomes hydraulic. When the oil temperature is equal to or lower than the predetermined value T1, the additional relief valve 150 stops the oil relief, and as a result, the hydraulic pressure becomes a third hydraulic pressure that is higher than the low hydraulic pressure.

  FIG. 9 is a graph showing the relationship between the lubricating oil pressure and the engine friction torque. In FIG. 9, when the engine speed is 1,400 rpm, the engine friction torque and the lubricating oil pressure are obtained when oil is injected into the piston (if present) and not (if not). The relationship is shown respectively. As shown in FIG. 9, in any case, when the hydraulic pressure increases, the engine friction torque tends to increase. For this reason, when the hydraulic pressure changes from the low hydraulic pressure to the third hydraulic pressure, the friction torque increases, and as a result, the fuel injection amount is increased to prevent the occurrence of misfire. As a result, the combustion chamber temperature rises, so that unburned HC can be reduced. That is, if the hydraulic pressure is changed from the low hydraulic pressure to the third hydraulic pressure, unburned HC can be reduced.

  FIG. 10 is a graph schematically showing the relationship between the oil temperature and the oil pressure in the hydraulic control device 100. In this graph, when the oil temperature is equal to or lower than the predetermined value T2, it is cold, and when the oil temperature is higher than the predetermined value T2, the oil pressure is controlled to a high oil pressure to ensure engine reliability. Is done. On the other hand, when the oil temperature is equal to or lower than the predetermined value T2, the oil pressure is controlled to a low oil pressure in order to improve fuel consumption. At this time, when the oil temperature is equal to or lower than the predetermined value T1, the hydraulic pressure is set to the third hydraulic pressure in order to reduce emissions. The third hydraulic pressure is set to be higher than the high hydraulic pressure by setting the oil relief amount from the oil relief device 5.

  Therefore, when the hydraulic pressure is changed to the third hydraulic pressure, the engine load is greatly increased and the fuel injection amount is greatly increased. As a result, the heat generation amount due to combustion can be significantly increased. As a result, the temperature of the combustion chamber can be greatly improved, so that unburned HC can be reduced as an emission. Further, NOx can be reduced as an emission by increasing the amount of EGR.

Note that when the hydraulic pressure becomes the third hydraulic pressure, oil injection to the piston is performed. At this time, the friction torque further increases significantly as shown in FIG. The temperature can be raised. However, from the viewpoint of increasing the combustion chamber temperature, it is considered that it is more preferable not to inject oil to the piston, and it is also considered that the combustion chamber temperature may eventually decrease. In such a case, for example, when the hydraulic pressure becomes the third hydraulic pressure, oil supply stopping means that can be realized by a valve or the like that stops oil supply to the piston jet is further provided, so that oil injection to the piston is performed. You may stop.
As described above, the hydraulic control device 100 includes the additional relief valve 150, so that the low hydraulic pressure can be changed to the third hydraulic pressure according to the oil temperature easily and at low cost. Can be achieved.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

  For example, in the engine hydraulic control apparatus according to the claims, the third hydraulic pressure may be lower than the second hydraulic pressure (or hydraulic pressure for stopping oil injection to the piston). In this case, the combustion chamber temperature can be improved by stopping the oil injection to the piston as the amount of heat generation increases. Further, for example, in the engine hydraulic control device according to the claims, it can be realized by an electromagnetic valve or the like that switches between the case of performing relief and the case of stopping the oil discharged from the oil pump when the hydraulic pressure is controlled to the first hydraulic pressure. An oil pressure changing means for changing the first oil pressure to the third oil pressure can be configured by a simple switching means and an electronic control means for controlling the switching means according to the oil temperature.

It is the block diagram which showed schematic structure of the hydraulic control apparatus of an Example, and is a figure which shows the state which the relief valve closed in the state which made OCV the low hydraulic pressure side. It is a figure which shows the state which the relief valve opened from the state shown in FIG. It is the block diagram which showed schematic structure of the hydraulic control apparatus of an Example, and is a figure which shows the state which the relief valve closed in the state which made OCV the high hydraulic pressure side. It is a figure which shows the state which the relief valve opened from the state shown in FIG. It is the block diagram which expanded and showed the oil relief apparatus. It is a figure which shows the structure of OCV, (a) is a figure which shows the state at the normal time which implement | achieves a high hydraulic pressure state, (b) is a figure which shows the electricity supply state which implement | achieves a low hydraulic pressure state. It is a block diagram which showed schematic structure of the additional relief valve, (a) is a figure which shows the state which performs oil relief, (b) is a figure which shows the state which stops the relief of oil. It is a figure which shows the graph of the oil pressure which changes according to oil temperature in a low oil pressure state with the state of the additional relief valve corresponding to this. It is a figure which shows the relationship between lubricating oil pressure and the friction torque of an engine with a graph. It is a figure which shows typically the relationship between the oil temperature and oil_pressure | hydraulic in a hydraulic control apparatus with a graph.

Explanation of symbols

1 Oil passage 2 Oil pump 3 First bypass passage 4 Second bypass passage 5 Oil relief device 51 Case 52 Relief valve 53 Retainer 54 Spring 10 OCV
20 ECU
140 Third bypass passage 150 Additional relief valve

Claims (3)

In the engine hydraulic control device for controlling the hydraulic pressure of the oil discharged from the engine oil pump to the first hydraulic pressure or the second hydraulic pressure higher than the first hydraulic pressure,
An engine hydraulic control apparatus comprising: a hydraulic pressure changing unit that changes the first hydraulic pressure to a third hydraulic pressure that is higher than the first hydraulic pressure in accordance with an oil temperature of the engine. The engine hydraulic control device according to claim 1,
The engine hydraulic control apparatus according to claim 1, wherein when the oil temperature is equal to or lower than a predetermined value, the hydraulic pressure changing means changes the first hydraulic pressure to the third hydraulic pressure. The engine hydraulic control device according to claim 1 or 2,
The oil pressure changing means performs relief of oil discharged from the oil pump when the oil temperature is higher than the predetermined value, while the oil pump discharges when the oil temperature is equal to or lower than the predetermined value. An engine hydraulic control device characterized by a relief valve for stopping oil relief.

Images