JPH0540274Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a lubricating device for a supercharged engine.

(Prior Art) Generally, in an engine lubricating system, an oil pump is directly driven by the engine. Therefore, the oil pressure of the oil supplied to the lubricating section increases as the engine speed increases.

However, the lubrication requirement does not correspond to the engine speed, but rather to the engine load. Therefore, even if the engine is in a high rotation range, the level of lubrication requirement is low at low load, and therefore, at low load, the loss of engine output is large due to unnecessary oil pressure increase, leading to a decrease in engine fuel efficiency. There is a possibility that

For this reason, for example, Japanese Utility Model Publication No. 53-5924 proposes a method to suppress unnecessary work of the oil pump by increasing the oil pressure (i.e., the amount of oil supplied) as the engine load increases. Engines designed to improve fuel efficiency are known.

However, in the case of engines equipped with a supercharger, especially those equipped with a turbo supercharger, the bearings of the supercharger are also lubricated with oil supplied from the oil pump, so the bearings simply respond to the engine load. If the oil pressure is controlled by the above-mentioned method, as described below, there is a risk that the bearing portion of the supercharger will run out of oil when the engine is under low load, leading to a decrease in lubrication performance and a decrease in its reliability. That is, in a turbocharged engine, for example, during steady running or deceleration at medium speeds and low loads, the throttle valve is closed but the turbocharger's rotational speed is high and the turbocharger is still in the supercharged state ( In other words, a phenomenon in which the lubrication requirement is high may occur.
In this case, if the oil pressure in the oil passage decreases in response to the engine load (ie, the throttle valve opening), there is a risk that oil shortage will occur in the bearing portion of the turbocharger.

(Purpose of the invention) The present invention is an attempt to solve the problems pointed out in the above-mentioned section of the prior art. This was done with the aim of both improving fuel efficiency and improving the reliability of the supercharger.

(Means for achieving the objective) In the present invention, as a means for achieving the above objective, oil from an oil pump driven by the engine is supplied to the bearing of the supercharger through an oil passage. The lubrication system for a supercharged engine includes an operating state detecting means for detecting the operating state of the engine, and a hydraulic pressure in the oil passage is forced in a low load region of the engine in response to an output of the operating state detecting means. and a means for reducing the oil pressure when the intake pressure in the intake passage between the throttle valve of the engine and the supercharger is equal to or higher than a predetermined pressure even in a low engine load region. and an operation prohibiting means for prohibiting the operation.

(Function) In the present invention, with the above-mentioned means, in the low engine load region where the lubrication requirement is low, the oil pressure in the oil passage is reduced by the oil pressure reducing means, and the loss of engine output due to driving the oil pump is suppressed. When it is necessary to ensure the amount of oil supplied to the supercharger bearing, even in the low engine load range,
That is, when the intake pressure in the intake passage between the throttle valve and the supercharger is equal to or higher than a predetermined pressure, the operation of the oil pressure lowering means is prohibited.

(Effect of the invention) Therefore, according to the lubrication system for a supercharged engine of the present invention, in a low load region of the engine where the lubrication requirement is low, the oil pressure in the oil passage is reduced and the engine oil pressure is reduced due to the drive of the oil pump. The fuel efficiency of the engine is improved by suppressing the loss of output, and when the lubrication requirement of the supercharger bearing is high even in the low load range, maintaining the oil pressure at a high pressure reduces the amount of oil to the bearing. Since the supply amount is secured, the lubricity of the bearing is good and the reliability of the supercharger is improved, which has practical effects such as improving engine fuel efficiency and improving the reliability of the supercharger. .

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows a system diagram of an automotive supercharged rotary piston engine 1 equipped with a lubricating device according to an embodiment of the present invention. It is a turbo supercharger that is connected by 10. The turbine 8 of the turbocharger 2 is connected to the exhaust passage 4 of the rotary piston engine 1, and the blower 9 is connected to the intake passage 3. An injector 6 and an oil jet 7 are located downstream of the throttle valve 5 in the intake passage 3 of the rotary piston engine 1.
However, pressure sensors 14 are provided between the throttle valve 5 and the blower 9, respectively. In addition, the oil jet 7, the oil jacket 11 provided on the bearing part of the rotating shaft 10 of the turbo supercharger 2, and the oil jet (not shown) provided in the metal part of the eccentric shaft 15 of the rotary piston engine 1, Oil is supplied from an oil supply system Q, which will be described later. Furthermore, a pressure sensor 16 is provided in a negative pressure introduction pipe 45 that connects the intake passage 3 downstream of the throttle valve and a three-way switching valve 35 to be described later.

The oil supply system Q includes an oil pump 21 driven by the rotary piston engine 1. This oil pump 21 includes an oil tank 2
2 (that is, the oil pan of the rotary piston engine 1) is supplied to the oil gear rally 40 via the main oil passage 41. Furthermore, the oil supplied to this oil gear rally 40 is
From the oil gear rally 40, the first oil passage 4
Oil jet 7 provided in the intake passage via 2
Then, it is distributed and supplied to the oil jacket 11 of the turbo supercharger 2 through the second oil passage 43, and from the third oil passage 44 to the oil jet provided on the eccentric shaft side through the metering oil pump 19. be done. Further, a pressure regulator 25, which will be described later, is provided in the middle of the main oil passage 41 for controlling the hydraulic pressure of the oil in the main oil passage 41.

The pressure regulator 25 is constructed by connecting a piston 26 biased by a first spring 28 and a diaphragm 30 biased by a second spring 29 via a rod 27. The piston 26 moves forward and backward in accordance with the air pressure (specifically atmospheric pressure or intake pressure) introduced into the negative pressure chamber 31.
6 to open and close the oil escape port 32, thereby controlling the oil pressure in the main oil passage 41. Specifically, a three-way switching valve 35 is provided in the negative pressure chamber 31, and by switching the three-way switching valve 35, the negative pressure chamber 31 is switched between the atmospheric side and the downstream side of the throttle valve 5 in the intake passage 3 of the rotary piston engine 1. I am trying to connect it selectively to both sides.

The three-way switching valve 35 is controlled by a control signal _A1 from the control unit 20, which will be described later, and in this embodiment, the operating conditions of the three-way switching valve 35 are set as follows. are doing. That is, as shown in FIG. 3, in this embodiment, the three-way switching valve 35 has three operating regions, namely, the throttle valve downstream pressure is the pressure Po ₁
Area A corresponds to the above high load area, Area C corresponds to the low speed/low load area where the throttle valve downstream pressure is pressure Po ₂ or less and the engine speed is N ₁ or less, and areas other than these two areas. It is divided into three regions, region B corresponding to the medium load region. In areas A and C, the three-way switching valve 35 is connected to the intake passage 3 side of the rotary piston engine 1, and in area B, the three-way switching valve 35 is basically connected to the atmosphere. Therefore, area B
, atmospheric pressure, the first spring 28 and the second spring 28
Due to the balance between the resultant force of the three springs 29 and the hydraulic pressure acting on the piston 26, the main oil passage 4
The oil pressure within 1 is set. When the oil pressure in region B is used as a reference, the oil pressure in region A is set higher than the reference oil pressure because the pressure introduced into the negative pressure chamber 31 is equal to or higher than atmospheric pressure. On the other hand, the oil pressure in area C is
Negative pressure is introduced into the piston 26 and the rod 27.
This is set based on the balance between the spring force of the first spring 28 and the oil pressure acting on the piston 26, and is lower than the reference oil pressure. That is, the oil pressure in the main oil passage 41 can basically be set in three stages depending on the engine load.

Furthermore, in this embodiment, by applying the present invention, even if the engine load is in region C (i.e., the region in which the oil pressure is lower than the reference oil pressure), under certain conditions, cancels this and maintains the oil pressure at the standard oil pressure. That is, when the turbocharger 2 is still rotating at a high speed even in a low engine load region, it is necessary to ensure sufficient lubricity of the bearing of the turbocharger 2. In this case, the oil pressure is maintained at the standard oil pressure without being lowered to ensure the amount of oil supplied to the bearing. The state is determined based on the intake pressure in the intake passage 3 between the throttle valve 5 and the turbocharger 2. Specifically, when the intake pressure is equal to or higher than a specified value Po ₃ (for example, 100 mmHg), the hydraulic pressure control (lowering operation) is canceled.

The control unit 20 has an engine speed signal _B1 , a water temperature signal _B2 , a deceleration signal _B3 , and an intake pressure signal _B4 (corresponding to the intake pressure between the downstream side of the throttle valve and the turbocharger 2). (detected by pressure sensor 14) and an intake pressure signal B ₅ (detected by pressure sensor 16) corresponding to the intake pressure downstream of the throttle valve. A control signal _A1 for the switching valve 35 is output.

In addition, in FIG. 1, the reference numeral 23 indicates an oil cooler;
24 is an oil filter.

Hydraulic control by this control unit 20 will be explained below with reference to the flowchart shown in FIG.

First, after starting the control, it is determined whether or not it is time to start the engine (step _S1 ). If it is at startup,
Hydraulic control is stopped until oil is sufficiently distributed to each lubricating part (steps _S13 to _S15 ). That is,
In this case, the three-way switching valve 35 is set to the atmosphere side for a predetermined period of time to maintain the oil pressure at the reference oil pressure, regardless of other conditions.

On the other hand, in cases other than when starting or when a predetermined period of time has passed after starting, information for performing hydraulic control, that is, water temperature Tw, throttle valve downstream pressure P ₁ , throttle valve upstream and turbo supercharger. The pressure between P ₂ and the rotor oil temperature T _R ,
The engine rotation speed Ne and the presence or absence of a deceleration signal are input (step S ₂ ).

Next, in step _S3 , the current throttle valve downstream pressure P ₁ is compared with the throttle valve downstream pressure Po ₁ (shown in Fig. 3 and stored as a map value) which serves as a control reference. . If P ₁ > Po ₁ , that is, in region A, from the perspective of ensuring the reliability of the rotary piston engine 1 and turbocharger 2, hydraulic control is performed to adjust the oil pressure of the lubricating oil to the above standard. Set it higher than the oil pressure (Step S ₁₆ ). Therefore, in this case, the three-way switching valve 35 is connected to the intake passage 3.
connected to the side. In this case, after the hydraulic pressure up operation, it is determined whether the rotor oil temperature T _R is abnormal or not, and if it is abnormal, further cooling is impossible and there is a risk of damaging engine reliability. The system determines that there is a problem and saves engine output to ensure engine reliability (step
S ₁₉ , Step S ₂₀ ).

On the other hand, as a result of the determination in step _S3 , if it is determined that P ₁ < Po ₁ , the water temperature Tw is equal to the specified water temperature.
whether the throttle valve downstream pressure P ₁ is less than or equal to the throttle valve downstream pressure _{Po 2 (} see Figure 3), which is the control reference (step S ₅ ), and whether the engine rotation It is determined whether the number Ne is less than or equal to the control reference rotation speed N ₁ (see FIG. 3) (step S ₆ ). Then, when Tw<To, the hydraulic control is stopped from the perspective of promoting engine warm-up, and when Po ₂ and Ne>N ₁ , the hydraulic control is stopped from the perspective of prioritizing maintaining lubricity over improving fuel efficiency.
Maintain the oil pressure at the reference oil pressure (step _S17 ).

On the other hand, Tw > To and P ₁ < Po ₂ and Ne < N ₁
(i.e., region C in Figure 3), the hydraulic pressure is determined by the magnitude relationship between the pressure P ₂ between the throttle valve upstream and the turbocharger and the specified value Po ₃ (for example, 100 mmHg). It is determined whether or not to perform control (step _S7 ). In other words, if P ₂ > Po ₃ , it is determined that the rotation of the turbocharger 2 has not yet decreased sufficiently, and therefore it is necessary to supply sufficient oil to its bearing. Then, the oil pressure control (oil pressure lowering operation) is stopped and the oil pressure is maintained at the standard oil pressure (step _S17 ). On the other hand, if P ₂ > Po ₃ , then the rotor oil temperature _TR is compared with the specified value To (step S ₈ ),
If T _R > To, the oil pressure control (hydraulic pressure reduction operation) is stopped and the standard oil pressure is maintained in order to secure the oil supply amount, improve cooling performance, and ensure engine reliability. (Step S ₁₈ ). Furthermore, it is determined whether the rotor oil temperature _TR is abnormal (step _S19 ). If the rotor oil temperature does not drop even though the standard oil pressure is maintained, engine output is saved from the perspective of ensuring engine reliability (step
_S20 ).

On the other hand, as a result of the determination in step _S8 , if T _R >To, it is determined whether or not the deceleration is occurring (step _S9 ), and if it is not the deceleration, the area C
It is determined that the control may be performed immediately, and the hydraulic control (hydraulic pressure lowering operation) is activated (step _S12 ). On the other hand, in the case of a deceleration state, the rotation of the turbo supercharger 2 is not sufficiently reduced at the initial stage, and therefore, from the viewpoint that it is necessary to ensure a sufficient amount of oil supply, Activate the hydraulic control after a predetermined time (step
_S10 , _S11 ).

In this way, in this example, even if the oil pressure is originally lowered from the perspective of improving fuel efficiency, oil pressure control is prohibited under conditions deemed necessary to protect the engine or turbocharger. In this way, it is possible to improve fuel efficiency and ensure the reliability of the turbocharger.

[Brief explanation of drawings]

Fig. 1 is a lubrication system diagram of a supercharged engine equipped with a lubrication system according to an embodiment of the present invention, Fig. 2 is a control flowchart of the lubrication system shown in Fig. 1, and Fig. 3 is a hydraulic control diagram. FIG. 1... Rotary piston engine, 2... Turbo supercharger, 3... Intake passage, 4... Exhaust passage, 5
...Throttle valve, 6...Injector,
7...Oil jet, 8...Turbine, 9...
Blower, 10... Rotating shaft, 14, 16... Pressure sensor, 19... Metering oil pump, 20...
...control unit, 25...pressure regulator.

Claims (1)

[Scope of utility model registration request] A lubricating device for a supercharged engine that supplies oil from an oil pump driven by the engine to the bearing of a supercharger through an oil passage, and is operated to detect the operating state of the engine. a state detection means, and an oil pressure lowering means for forcibly reducing the oil pressure in the oil passage in a low load region of the engine in response to an output of the operating state detection means;
an operation inhibiting means for prohibiting the operation of the oil pressure lowering means when the intake pressure in the intake passage between the throttle valve of the engine and the supercharger is equal to or higher than a predetermined pressure even in a low engine load region; A lubricating device for a supercharged engine, characterized by the following: