JP2015086768A - Internal combustion engine with oil jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the excessive injection of oil jetting without lowering a lubricating function of a lubricating portion.SOLUTION: Oil is supplied to an oil jet device 21 from an oil jetting oil passage 18, and basically, when the engine speed of an engine becomes a predetermined value and oil pressure increases to a reference value, oil is jetted. A relief passage 29 is provided on the oil jetting oil passage 18, and the relief passage 29 is provided with a relief valve 34 actuated according to intake negative pressure or cooling water temperature. When the intake negative pressure becomes large during deceleration or traveling on a down hill, (and) or when the cooling water temperature does not rise to the reference value, the relief valve 34 is opened to prevent or suppress the jetting of the oil even if the discharge pressure of an oil pump becomes high.

Description

  The present invention relates to an internal combustion engine provided with an oil jet device for cooling a piston, and is particularly suitable for a vehicle internal combustion engine.

  In an internal combustion engine for a vehicle, an oil jet device is provided on the lower surface of the upper end portion of the crank chamber to cool the piston. Inside the oil jet device, there is a pressure valve consisting of a valve body that closes the oil inlet and a spring that presses the oil inlet. If the engine speed increases and the oil passage pressure exceeds the reference value, Pushes the valve body and flows into the oil chamber.

  Oil is discharged from the oil pump, and the discharge pressure of the oil pump increases in proportion to the engine speed. Therefore, the operation of the oil jet device is also linked to the engine speed. However, if the engine speed is high, oil injection by the oil jet device is not always necessary, and cooling of the piston may not be necessary even if the engine speed is increased to a predetermined value.

  In this regard, Patent Document 1 focuses on the fact that the piston is not required to be cooled because the fuel is cut when the engine is decelerated, and a variable displacement type oil pump is used, and the oil pump discharges when the vehicle decelerates. It is described that the discharge pressure is controlled so that the pressure does not rise to a reference value.

JP 2013-68098 A

  Now, since the fuel injection is cut when the engine is decelerated, the need to cool the piston with oil is low, but there are other situations where the piston does not need to be cooled even if the engine speed is high to some extent. Yes. For example, in a state where the vehicle is warmed up while running, such as when the vehicle is started immediately after starting, the piston is not heated even if the engine speed is high. Can not be rejected.

  Also, when operating in a low temperature environment such as driving in a cold region, the engine temperature may not become so high even if it is operated continuously for a long time, and in this case also, the jet of oil jet continues to stop Is beneficial in terms of fuel economy.

  However, since Patent Document 1 can stop the jet of oil jet only when decelerating, it cannot respond to a request to stop jetting of oil jet during warm-up operation or operation in a low temperature environment. Oil is intended primarily for lubrication of crankshafts and camshafts, etc. When the engine speed increases, the oil discharge pressure must be increased to ensure a lubrication function. Although the principle does not change even during deceleration, etc., in Patent Document 1, since the discharge pressure of the oil pump is reduced during deceleration, there is a possibility that lubrication of each lubrication part may be incomplete.

  The present invention aims to improve such a current situation.

  The present invention relates to an internal combustion engine having a structure in which an oil jet device for cooling a piston is connected to a branch passage branched from an oil passage, and when the oil pressure in the oil passage exceeds a reference value, the oil jets from the oil jet device. The oil passage is connected to a relief passage that allows oil to escape, and the relief passage includes the relief passage when the intake negative pressure is higher than a preset reference value and / or when the piston does not need to be cooled. A relief valve is provided for releasing oil when the oil pressure in the oil passage rises to a reference value.

  In this case, the relationship between the relief valve opening and the oil jet ejection amount is that the oil jet ejection stops completely due to the relief valve opening, and the oil jet ejection amount decreases due to the relief valve opening. Includes both. In the case of suppressing the ejection amount, it is possible to stop completely until a reference value set in advance according to the number of revolutions of the engine, and to eject it when the reference value is exceeded.

  Now, when the vehicle decelerates or runs downhill, the engine is in the same state as the vacuum pump, so the negative pressure in the intake system rises greatly to the vacuum side. Therefore, by opening the relief valve in accordance with the increase in intake negative pressure, it is possible to stop or suppress the ejection of the oil jet to the piston without changing the discharge pressure of the oil pump. Similarly, even when the engine temperature has not risen to a predetermined value and piston cooling is not required, for example, by opening the relief valve using the cooling water temperature or oil temperature, the discharge pressure of the oil pump does not change. The jet of oil jet to the piston can be stopped or suppressed.

  As a result, while ensuring proper lubrication of each lubrication part, fuel consumption deterioration due to piston overcooling, increased consumption due to oil mist generation, or generation of burnout due to oil being sucked into the combustion chamber and burning are prevented. Or it can suppress remarkably. There is also an advantage that air bubbles mixed in the oil can be discharged from the relief passage. Further, the present invention allows oil to escape from the oil passage, and it is not necessary to provide a relief valve in each oil jet device, so that only one relief valve needs to be provided. Therefore, it is advantageous in terms of cost.

(A) is a schematic plan cross-sectional view of the embodiment, and (B) is a cross-sectional view taken along the line BB of (A) with a control system added. (A) is a principal part expanded sectional view in a non-relief state, (B) is a cross-sectional head in a relief state.

  Next, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to a three-cylinder internal combustion engine for a vehicle. Therefore, three cylinder bores 2 are formed in the cylinder block 1 side by side in the axial direction of the crankshaft. A piston 3 is slidably fitted in each cylinder bore 2. The piston 3 is connected to a crankpin (not shown) via a connecting rod 4.

  A cylinder head 5 is fixed to the upper surface of the cylinder block 1, and an intake port 7 that is opened and closed by an intake valve 6 and an exhaust port 9 that is opened and closed by an exhaust valve 8 are formed in the cylinder head 5. The spark plug 10 is desired on the upper bottom surface of the combustion chamber. An intake manifold 11 communicating with each intake port 7 is fixed to one longitudinal side surface of the cylinder head 5.

  An intake passage 12 is connected to the intake manifold 11, and a throttle valve 13 and a surge tank 14 are connected to the intake passage 12. In practice, a surge tank 14 is fixed to the intake manifold 11 and a throttle valve 13 is often attached to the surge tank 14. The surge tank 14 is provided with an intake pressure sensor 15.

  As shown in FIG. 1A, a main oil gallery 17 extending in the vertical direction is formed in the cylinder block 1 at a location near the corner portion at the outer end of the cylinder bores 2. An oil jet oil passage 18 extending parallel to the crankshaft O and located outside the row of the cylinder bores 2 is located at a height on one side of the crankshaft 18 as viewed and close to the lower end of the cylinder bore 2. It is formed in a state branched from the oil gallery 17. Needless to say, the lower end of the main oil gallery 17 is connected to the discharge port of the oil pump.

  An oil jet branch passage 19 located outside the cylinder bore 2 branches downward from the oil jet oil passage 18. An upper end portion of the oil jet branch passage 19 is a small-diameter orifice portion 19 a communicating with the oil jet oil passage 18. The oil jet branch passage 19 is open to a flat surface 20 provided at the lower end of the cylinder bore 2 in the lower surface of the cylinder block 1. An oil jet device 21 is attached to the flat surface 20. It is also possible to branch the branch passage from the main oil gallery 17.

  The oil jet device 21 has a cylindrical main body portion 22 whose upper portion is fitted in the oil jet branch passage 19 and a nozzle 23 branched from an exposed portion of the main body portion 22. The jet is ejected toward the lower surface of the piston 3. The main body 22 is provided with a flange 24, and the flange 24 is fixed to the cylinder block 1 with a screw 25.

  The upper end of the main body 22 in the oil jet device 21 is a small-diameter hole (oil inlet) 22a. The small-diameter hole 22a is closed from below by a ball-shaped valve body 27, and the valve body 27 is supported from below by a spring 28. ing. The spring 28 is supported by a plug-like bottom plate 26. When the pressure in the oil jet oil passage 18 rises to a predetermined value, the valve element 27 descends against the spring 28, whereby oil flows from the oil jet oil passage 18 into the main body portion 22 and is discharged from the nozzle 23. Erupts.

  A portion of the cylinder block 1 outside the oil jet oil passage 18 and close to the main oil gallery 17 (that is, a portion near the root of the oil jet oil passage 18) is outside the oil jet oil passage 18. A relief passage 29 branched in the direction is formed. The relief passage 29 has a horizontal portion 29a and a vertically long portion 29b extending downward from the end thereof, and the lower end is opened to a crank chamber or an oil pan.

  Then, the relief passage 29 is formed with a vertically long valve chamber 30 concentric with the vertically long portion 29b. The spring 32 is energized. The valve chamber 30 of the relief passage 29 is formed by drilling, and a spring 32 is supported from above by a plug 33 that closes the drill hole.

  The horizontal portion 29 of the relief passage 29 opens toward the valve chamber 30, and the valve element 31 closes the horizontal portion 29 a of the relief passage 29 in the lowered state and rises up against the spring 32. The horizontal portion 29a of the relief passage 29 and the vertically long oil pump 29b communicate with each other. Therefore, in the present embodiment, the relief valve 34 described in the claims is constituted by the valve chamber 30, the valve body 31, and the spring 32.

  A suction port 35 communicates with the upper end of the valve chamber 30, and a vacuum pump 36 is connected to the suction port 35. The vacuum pump 36 is driven by a command from an ECU (Engine Control Unit) 37, and the ECU 37 is connected to the intake pressure sensor 15 and the coolant temperature sensor 38 described above. The cooling water temperature sensor 37 is an example of an engine temperature detection unit, and an oil temperature sensor can be used as the engine temperature detection unit. Alternatively, since the radiator is turned ON / OFF depending on the temperature of the cooling water, the driving of the vacuum pump 36 may be related to the driving of the radiator.

  In the above configuration, when the engine speed reaches a preset reference speed, the discharge pressure of the oil pump exceeds the set value, and oil is ejected from the oil jet device 21 toward the piston 3. This is a basic mode, but when the intake negative pressure becomes higher than a predetermined value (for example, −75 KPa) during deceleration of the vehicle or traveling downhill, the vacuum pump 36 is driven by a signal from the intake pressure sensor 15. Then, the valve body 31 of the relief valve 34 rises (the relief valve 34 opens), and the oil leaks from the oil jet oil passage 18 to the crankcase and the oil pan. For this reason, the ejection of oil from the oil jet device is stopped or suppressed.

  Further, even in a state where the engine temperature has not risen to a preset reference temperature during a warm-up operation or an operation in a low temperature environment, a vacuum pump is provided by a command from the ECU 37 based on a signal from the coolant temperature sensor 38 When 36 is driven and the relief valve 34 is opened, the ejection of oil from the oil jet device 21 is stopped or suppressed. As a result, proper lubrication of the respective lubrication parts such as the crankshaft and the camshaft is ensured, while the fuel consumption deteriorates due to the supercooling of the piston 3, the oil consumption increases due to the oil mist, or the oil is sucked into the combustion chamber and burned. It is possible to prevent or remarkably suppress problems such as the generation of deposits. It is also possible to open the relief valve 34 when the two conditions of intake negative pressure and engine temperature overlap.

  In this case, since the relief valve 34 is provided in the vicinity of the base portion of the oil passage 18 for the oil jet, the three oil jet devices 21 can be accurately controlled while being controlled by one relief valve 34 (oil jet The pressure of the oil passage 18 can be reduced as a whole.)

  Various types of relief valves 34 can be used. For example, you may employ | adopt a ball | bowl and a hinge type rotation valve as a valve body. Moreover, when driving a valve body with an actuator, not only a vacuum pump like embodiment but an electromagnetic solenoid, a motor, etc. can be used.

  Further, the valve body can be directly driven by the intake negative pressure. Alternatively, an accumulator for accumulating the intake negative pressure is provided, and a thermo valve that opens and closes depending on the cooling water temperature or the oil temperature is provided in the suction passage that connects the accumulator and the suction port 35. If the value is less than the value, the suction passage may be kept open.

  It is also possible to stop the jet of oil jet during the intake stroke using the intake negative pressure, and if fine control is performed while fuel is being injected in this way, the oil is sucked into the combustion chamber Therefore, there is an advantage that deposits due to oil combustion can be prevented.

  The present invention can be actually embodied in an internal combustion engine for a vehicle. Therefore, it can be used industrially.

1 Cylinder block 2 Cylinder bore 3 Piston 5 Cylinder head 7 Intake port 11 Intake manifold 14 Surge tank 15 Intake pressure sensor 17 Main oil gallery 18 Oil jet oil passage 19 Oil jet branch passage 21 Oil jet device 29 Relief passage 30 Relief valve Constituting valve chamber 31 Relief valve disc 32 Relief valve spring 34 Relief valve 35 Suction port 36 Vacuum pump as an example of relief valve operating actuator 37 ECU
38 Cooling water temperature sensor

Claims (1)

An oil jet device for cooling the piston is connected to the branch passage branched from the oil passage, and the oil jets from the oil jet device when the oil pressure in the oil passage exceeds a reference value,
A relief passage for releasing oil is connected to the oil passage, and the oil is supplied to the relief passage when intake negative pressure is higher than a preset reference value and / or when cooling of the piston is not necessary. A relief valve is provided to release oil when the oil pressure in the passage rises to the reference value.
An internal combustion engine with an oil jet device.

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