JP2013044306A - Turbocharger oil supply structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbocharger oil supply structure for eliminating such drawbacks that oil supplied to a bearing of a turbocharger has high viscosity at the time of cold starting and is insufficient on quick acceleration and that methods for mounting a heater to heat oil or increasing an oil supply amount are expensive and increase a load on an oil pump.SOLUTION: An oil supply structure to a turbocharger of an engine includes: an oil pump 22 pumping lubricating oil from an oil pan 20 to deliver; an oil feed pipe 25 communicating with an exit of the oil pump 22 via an oil filter 23; a first oil path 26 connected to the oil feed pipe 25 to deliver the lubricating oil to a turbocharger 10; a second oil path 28 branched from the oil feed pipe 25 and communicating with the first oil path 26 via a flow control valve 27; an oil return path 29 returning the lubricating oil from the turbocharger 10 to the oil pan 20; a temperature sensor 42 measuring or estimating the temperature of the engine; and a control device 40 controlling opening and closing of the flow control valve 27 on the basis of the temperature sensor 42.

Description

  The present invention relates to an oil supply structure that supplies lubricating oil to a turbocharger mounted on some engines.

  A turbocharger is a technology that forcibly stuffs intake air into a cylinder, and can generate horsepower even with a small amount of fuel. Therefore, there is a possibility of developing a low-fuel-consumption and high-power engine, which is attracting attention. As is well known, a turbocharger has a turbine and a compressor formed at both ends of the same rotating shaft, and drives an intake compressor by rotating the turbine with exhaust gas.

  Here, since the shaft of the turbine (and the compressor) rotates at a very high speed, it is necessary to use a special bearing or a full float bearing for high-speed rotation for the bearing and always lubricate with oil. However, there is a possibility that sufficient lubricating oil cannot be supplied to the turbine shaft while the oil viscosity at the cold start is high.

  With respect to this problem, Patent Document 1 discloses a technique in which a heater with a time switch is provided in an oil passage from an oil pump to a turbocharger. That is, at the time of cold start, the lubricating oil supplied to the turbocharger is supplied with warmed and lowered viscosity.

  Patent Document 2 focuses on the point that the oil that has passed through the turbine bearing rapidly becomes hot and returns to the oil pan. In the cold state, the oil returned from the turbocharger returns to the vicinity of the oil pan strainer entrance. A technique for ensuring the above is disclosed.

Japanese Utility Model Publication No.59-084224 Japanese Utility Model Publication No. 58-158126

  Patent Document 1 is a direct solution, but an oil heater must be mounted. In the first place, the temperature of the oil itself sucked from the oil pan is cold, and the oil does not flow smoothly until it reaches the oil heater. That is, oil shortage occurs for an operation such as rapid acceleration immediately after cold start.

  Patent Document 2 is to deliver the return oil from the turbocharger to the entire engine in order to accelerate the warm-up of the entire engine. For operation such as sudden acceleration immediately after cold start, Oil supply is not in time.

  Regarding the shortage of oil in the turbocharger at the cold start, for example, a means of increasing the amount of oil supply can be considered. This method may supply sufficient oil to the turbocharger even immediately after cold start. However, increasing the amount of oil supplied increases the burden on the oil pump and eventually increases the engine load, leading to deterioration in fuel consumption.

  The present invention has been conceived in view of the above-described problems, and is a turbocharger oil supply structure that increases the amount of oil supplied to the turbocharger during cold start and reduces the amount of oil supplied when warm-up is completed. I will provide a.

More specifically, the turbocharger fueling structure of the present invention is
An oil supply structure for an engine turbocharger,
An oil pump that pumps and feeds lubricating oil from an oil pan;
An oil feeding pipe communicated with an outlet of the oil pump through an oil filter;
A first oil passage connected to the oil feeding pipe and sending the lubricating oil to the turbocharger;
A second oil passage that branches off from the oil feeding pipe and communicates with the first oil passage via a flow rate adjustment valve;
An oil return path for returning the lubricating oil from the turbocharger to the oil pan;
A temperature acquisition means sensor for measuring or estimating the temperature of the engine;
A control device for controlling opening and closing of the flow rate adjustment valve based on the temperature acquisition means sensor;
It is characterized by having.

  Since the turbocharger oil supply structure of the present invention is provided with the second oil passage capable of adjusting the flow rate, a large amount of oil can be supplied to the turbocharger during cold start. Therefore, even before the warm-up is completed, the turbocharger is supplied with sufficient lubricating oil. Therefore, it is possible to avoid a shortage of oil in the turbocharger even in the case of rapid acceleration immediately after the cold start.

  In addition, since a large amount of oil passes through the turbocharger during warm-up, the oil temperature of the engine oil can be rapidly increased. This reduces engine friction and mechanical loss, leading to improved fuel efficiency.

  In addition, after the warm-up is completed, the oil supply amount is reduced, so there is no excessive burden on the oil pump. From this point, low fuel consumption can be expected.

  Further, by providing hysteresis or a finite movable speed to the operation of the flow rate adjusting valve, the oil path can be switched smoothly, and the burden on the oil pump can be reduced.

  Further, by arranging the oil passage provided with the flow rate adjusting valve in the vicinity of the exhaust manifold, it is possible to raise the temperature of the supplied oil without providing a heater or the like, and to reduce the cost.

It is a figure which shows the structure of the turbocharger oil supply structure of this invention. It is a figure which shows the relationship between the opening degree of a flow regulating valve, and oil temperature.

  The turbocharger oil supply structure of the present invention will be described below with reference to the drawings. The following description exemplifies an embodiment of the present invention, and changes within the scope of the present invention are included in the technical scope of the present invention without departing from the spirit of the present invention. Needless to say.

  FIG. 1 is a configuration diagram schematically showing a turbocharger oil supply structure 1 of the present invention. The turbocharger 10 is represented by a compressor wheel 11 that sends intake air to the engine, a turbine wheel 12 that rotates by receiving exhaust gas, and a rotary shaft 13 that connects the wheels. In addition, the bearing part 14 of the rotating shaft 13 was represented with the square of the dashed-two dotted line. Lubricating oil is supplied here.

  On the other hand, the oil system includes an oil pan 20, a strainer 21, an oil pump 22 and an oil filter 23. In addition, an inlet pipe 25 connected from the oil filter 23 to the turbocharger 10, a first oil passage 26 for supplying oil to the bearing portion 14 of the turbocharger 10, and a first oil passage 26 are juxtaposed with the first oil passage 26 to adjust the flow rate. A second oil passage 28 for supplying oil to the bearing portion 14 of the turbocharger 10 through the valve 27 and an oil return passage 29 for returning the oil from the bearing portion 14 of the turbocharger 10 to the oil pan 20 are included.

  The turbocharger 10 needs to be connected to an exhaust manifold (not shown) connected to an exhaust port (not shown) and an intake manifold (not shown) connected to an intake port (not shown). Generally, it is provided outside the engine. On the other hand, since the oil pump 22 is provided in the engine, a pipe for feeding oil from the outer wall 30 of the engine to the turbocharger 10 is required. In FIG. 1, reference numeral 11 a represents intake air that is compressed by the compressor wheel 11 and sent to the intake port, and reference numeral 12 a represents exhaust gas that is discharged from the exhaust port and drives the turbine wheel 12.

  A union bolt is a bolt having a through hole in the bolt. The union bolt is attached to a through hole formed in the engine outer wall 30 and feeds lubricating oil out of the engine through the through hole. An inlet pipe 25 is connected to the union bolt and disposed up to the turbocharger 10. Similarly, on the turbocharger 10 side, lubricating oil is taken from the inlet pipe 25 through a union bolt. In the oil supply structure of the present invention, two union bolts on the turbocharger 10 side are also provided in order to prepare two oil passages.

  A union bolt constituting the first oil passage 26 is referred to as a first union bolt 31, and a union bolt constituting the second oil passage 28 is referred to as a second union bolt 32. The union bolt immediately after the oil filter 23 is a feed-side union bolt 33. The feed-side union bolt 33 is attached to the through hole of the engine outer wall 30. Moreover, the inlet pipe 25 that connects the feed-side union bolt 33, the first union bolt 31, and the second union bolt 32 is also referred to as an oil feed pipe.

  The inlet pipe 25 is preferably disposed adjacent to an exhaust manifold (not shown). This is because the exhaust manifold quickly becomes hot even immediately after the cold start, and if the oil supply system of the turbocharger 10 is disposed in the vicinity thereof, a quick increase in the oil temperature can be expected. In FIG. 1, the exhaust manifold itself is not shown, but the flow of exhaust gas that has passed through the turbine wheel 12 of the turbocharger 10 is indicated by reference numeral 17.

  That is, the code | symbol 25a of the inlet pipe 25 shows the part arrange | positioned in the vicinity of an exhaust manifold. In addition, the “near” here means a range in which heat can be easily received from the exhaust manifold, and more specifically, a space within a range of about several tens of millimeters, including a case where a part is in contact. It means that it is arranged.

  The feed-side union bolt 33 is configured to be supplied with oil immediately after the oil filter 23. The turbocharger 10 is assembled with a high accuracy in the clearance between the rotating shaft 13 that rotates at a high speed and the bearing portion 14 that receives it in a liquid-tight manner, so even if it is a small amount of dust remaining in the lubricating oil, This is because the rotation of the rotating shaft 13 may be hindered.

  In the turbocharger 10, two systems of oil passages 26 and 28 from the union bolts 31 and 32 are supplied to the bearing portion 14 of the rotating shaft 13. Here, in the second oil passage 28, a flow rate adjustment valve 27 is provided up to the bearing portion 14. The flow rate adjusting valve 27 is an electromagnetic valve whose opening and closing can be controlled by an electromagnetic actuator, for example. Although it is sufficient to control only opening and closing, the degree of opening may be controlled in stages. The flow rate adjustment valve 27 is electrically connected to the control device 40 and changes the opening of the valve based on an instruction signal from the control device 40.

  The diameters of the through holes provided in the union bolts 31 to 33 are defined. The turbocharger oil supply structure 1 of the present invention supplies a large amount of lubricating oil to the bearing portion 14 of the rotary shaft 13 using the first and second oil passages 26 and 28 at a predetermined time. Therefore, it is desirable that the diameter of the through hole of the feed-side union bolt 33 is larger than the sum of at least the diameter of the through hole of the first union bolt 31 and the diameter of the through hole of the second union bolt 32. This is because a sufficient amount of oil flows through the first and second oil passages 26 and 28.

  The diameters of the through holes of the first and second union bolts 31 and 32 can be appropriately determined depending on the design. Usually, the diameter of the through hole of the second union bolt 32 is set to be the same as or slightly smaller than the diameter of the first union bolt 31.

  The control device 40 is provided outside the engine, and is usually configured by an MPU (Micro Processor Unit) and a memory. The control device 40 is electrically connected to the flow rate adjusting valve 27, and can transmit opening / closing instruction signals Cc and Co to the flow rate adjusting valve 27 through a connecting line. Further, not only opening and closing but also instructions on how to open and close may be given. Here, how to open and close is how long it takes to move from open to closed, or from closed to open, and the acceleration of the movement of the valve body during the transition.

  The control device 40 is also connected to a temperature sensor 42 that measures the temperature inside the engine. The temperature sensor 42 may measure the temperature of the lubricating oil in the oil pan 20 or may measure the temperature of an engine (for example, a cylinder head). Further, it may be the temperature of the exhaust manifold. Furthermore, the temperature in the engine may be calculated or estimated based on these temperatures, other detected values such as the engine speed and the coolant temperature. Specifically, the temperature of the lubricating oil in the oil pan 20 is measured, and the controller 40 estimates the temperature of the lubricating oil supplied to the bearing unit 14.

  Including the case where the temperature of any part of the engine is directly used as a criterion for determination and the case where the temperature in the engine estimated by the control device 40 based on the temperature is used as a criterion for determination, this is called temperature acquisition means. Here, the description will be continued assuming that the temperature of the lubricating oil in the oil pan 20 is monitored and that value is used as a criterion for determination. That is, in the following description, the temperature sensor 42 is a temperature acquisition unit.

  The control device 40 controls the opening and closing of the flow rate adjustment valve 27 based on the temperature from the temperature acquisition means (temperature sensor 42). In the control, the control device 40 has a plurality of threshold values of a first threshold value T1 that is at least a predetermined temperature and a second threshold value T2 that is lower in temperature than the first threshold value.

  Next, operation | movement of the turbocharger oil supply structure 1 of this invention is demonstrated. At the cold start, the oil in the oil pan 20 is cooled and its viscosity is relatively high. The control device 40 detects that the temperature of the oil pan 20 is low by the temperature acquisition means (temperature sensor 42). Then, the control device 40 sends an instruction Co for opening the flow rate adjustment valve 27. As a result, the second oil passage 28 is opened, and the oil exiting the oil filter 23 passes through the inlet pipe 25 and is supplied to the bearing portion 14 through the first oil passage 26 and the second oil passage 28. The At this time, the temperature of the oil is still low, but since the amount supplied is large, there is no shortage of oil. The lubricating oil that has been heated through the bearing portion 14 returns to the oil pan 20 through the oil return passage 29.

  The oil temperature of the lubricating oil in the oil pan 20 increases as the warm-up operation proceeds. And if oil temperature exceeds 1st threshold value T1, the control apparatus 40 will transmit the signal Cc which closes to the flow regulating valve 27. FIG. At this time, the flow rate adjustment valve 27 closes slowly. When the second oil passage 28 is momentarily closed, a turbulent flow is generated in the oil flow flowing in the bearing portion 14, a partial oil deficiency occurs, and an instantaneous oil shortage occurs. This is because the rotation may be hindered. Therefore, the term “slowly close” as used herein refers to a time period in which turbulent flow or bubbles do not occur in the oil flow in the bearing portion 14, and is approximately 1 second to several seconds.

  When the second oil passage 28 is closed, the oil is supplied to the bearing portion 14 only from the first oil passage 26, and no extra load is applied to the oil pump 22. In addition, at this time, since the oil temperature is high, the viscosity of the oil is sufficiently low, and the lubrication between the rotating shaft 13 and the bearing portion 14 can be performed even if the supply amount is small.

  Further, once the temperature of the lubricating oil exceeds the first threshold value T1, the flow rate adjustment valve 27 remains closed (does not open) until it falls below a second threshold value T2 lower than the first threshold value. The first threshold value T1 is set to a temperature at which the oil in the oil pan 20 becomes sufficiently high, but the oil temperature may slightly rise or fall from the first threshold value T1 depending on the cooling of the oil or the operating state. is there. This is because it is not preferable to perform a so-called chattering operation in which the flow rate adjusting valve 27 opens and closes with the change.

  On the other hand, when the temperature of the lubricating oil falls below the second threshold value T2 due to a change in the operating state such as a decrease in the outside air temperature or a temporary stop, the control device 40 sends the instruction signal Co to the flow rate adjustment valve 27 again, and the second oil Open path 28. At this time, even if the oil temperature changes up and down across the second threshold T2, the flow rate adjustment valve 27 remains open. Similarly to the above, even if the oil temperature rises or falls across the second threshold value T2, chattering does not occur in the operation of the flow rate adjustment valve 27.

  FIG. 2A shows a graph of the relationship between the temperature by the above control and the opening degree of the flow rate adjustment valve 27. The horizontal axis represents the temperature of the temperature acquisition means (temperature sensor 42). The vertical axis indicates the opening degree of the flow rate adjustment valve 27. Further, the first threshold is indicated by a symbol T1, and the second threshold is indicated by a symbol T2. The state at the time of cold start is the state of 50. At this time, the flow rate adjustment valve 27 is fully open. Even if the engine is started and the oil temperature rises and reaches the second threshold value T2 (reference numeral 51), the flow rate adjustment valve 27 remains fully open.

  When the temperature further rises and reaches the first threshold value T1 (reference numeral 52), the flow regulating valve 27 is fully closed (reference numeral 53). When the flow rate adjustment valve 27 is fully closed, even if the temperature becomes equal to or lower than the first threshold T1 (reference numeral 54), the flow rate adjustment valve 27 maintains the fully closed state. That is, chattering of the flow rate adjusting valve 27 does not occur.

  Thereafter, when the oil temperature falls and reaches the second threshold value T2 (reference numeral 55), the flow regulating valve 27 is fully opened again (reference numeral 56). When the flow rate adjustment valve 27 is fully opened, the flow rate adjustment valve 27 maintains the fully open state even if the temperature becomes equal to or higher than the second threshold value T2 (reference numeral 57). That is, chattering of the flow rate adjusting valve 27 does not occur.

  This means that the flow rate adjusting valve 27 that opens and closes depending on the temperature in the engine has two threshold values, and its operation has a hysteresis characteristic. Such an operation of the flow regulating valve 27 may be controlled by the control device 40 or may be realized by a logic circuit using a Schmitt trigger element or a flip-flop.

  Further, when the flow rate adjustment valve 27 is closed, it is desirable that the second oil passage 28 is not completely closed, the oil passage is slightly opened, and the lubricating oil flows even in small increments. If the flow rate adjustment valve 27 of the second oil passage 28 is completely closed and the lubricating oil does not flow into the second oil passage 28, the oil upstream of the flow rate adjustment valve 27 stops and stays. Then, the temperature of the oil of that part falls. Then, the oil temperature decreases due to the operating condition, and when the second oil passage 28 is opened again, the cooled lubricating oil is supplied to the bearing portion 14. Furthermore, since the oil also returns to the oil pan 20, the temperature of the lubricating oil in the oil pan 20 is also lowered.

  On the other hand, even when the flow rate adjusting valve 27 is closed, if the lubricating oil slightly flows, the lubricating oil will not stay. Therefore, always keep the warm lubricating oil of the oil pan 20 upstream of the flow rate adjusting valve 27. I can keep it.

  FIG. 2B shows the relationship between the opening degree of the flow rate adjustment valve 27 and the oil temperature when such control is performed. Even when the flow control valve 27 is controlled to be closed, the gap 60 is slightly provided.

  Here, although the case where there are two threshold values of the flow rate adjusting valve 27 is shown, the opening degree of the flow rate adjusting valve 27 can be controlled in a plurality of stages, and the comparison is made at the time of cold start and after the warm-up is completed. A plurality of thresholds after completion of warm-up may be prepared as in the case of a low temperature and a higher temperature. In the present embodiment, the case where there are two oil passages has been described, but there may be three or more oil passages.

  Moreover, when using the temperature which the temperature acquisition means estimated based on the temperature obtained by the sensor, the horizontal axis in FIG. 2 is the estimated temperature.

  The turbocharger oil supply structure of the present invention can be suitably used for an engine equipped with a turbocharger.

DESCRIPTION OF SYMBOLS 1 Turbocharger oil supply structure 10 Turbocharger 11 Compressor wheel 11a Intake 12 Turbine wheel 12a Exhaust gas 13 Rotating shaft 14 Bearing part 17 Exhaust flow 20 Oil pan 21 Strainer 22 Oil pump 23 Oil filter 25 Inlet pipe (oil supply pipe)
25a In the vicinity of the exhaust manifold 26 First oil passage 27 Flow rate adjustment valve 28 Second oil passage 29 Oil return passage 30 Engine outer wall 31 First union bolt 32 Second union bolt 33 Feeding union bolt 40 Controller 42 Temperature Sensor

More specifically, the turbocharger fueling structure of the present invention is
An oil supply structure for an engine turbocharger,
An oil pump that pumps and feeds lubricating oil from an oil pan;
An oil feeding pipe communicated with an outlet of the oil pump through an oil filter;
A first oil passage connected to the oil feeding pipe and sending the lubricating oil to the turbocharger;
A second oil passage that branches off from the oil feeding pipe and communicates with the first oil passage via a flow rate adjustment valve;
An oil return path for returning the lubricating oil from the turbocharger to the oil pan;
A temperature acquisition means to measure or estimate the temperature of the engine,
A control device for controlling the opening and closing of the flow regulating valve based on the temperature acquired hand stage,
It is characterized by having.

Claims (1)

An oil supply structure for an engine turbocharger,
An oil pump that pumps and feeds lubricating oil from an oil pan;
An oil feeding pipe communicated with an outlet of the oil pump through an oil filter;
A first oil passage connected to the oil feeding pipe and sending the lubricating oil to the turbocharger;
A second oil passage that branches off from the oil feeding pipe and communicates with the first oil passage via a flow rate adjustment valve;
An oil return path for returning the lubricating oil from the turbocharger to the oil pan;
A temperature acquisition means sensor for measuring or estimating the temperature of the engine;
A control device for controlling opening and closing of the flow rate adjustment valve based on the temperature acquisition means sensor;
Turbocharger refueling structure.