JPH108976A - Hybrid supercharged engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the bearing part of an exhaust turbine supercharger and prevent troubles by providing an oil pressure sensor in a lubricant supply system for the exhaust turbine supercharger to supply high pressure and high temperature intake air produced by a mechanical supercharger during starting an engine, and sending the air while bypassing a compressor of the exhaust turbine supercharger. SOLUTION: In an engine intake system, a mechanical supercharger 2 driven by an engine E and an exhaust turbine supercharger 9 are provided. An intake passage 12 via which both supercharges 2, 9 are connected together is connected to an intake manifold 8 via a bypass passage 5 to form a three-forked passage 13. A valve 3 is provided in a pipe passage forming the three-forked passage 13 for switching between the intake passage 12 and the bypass passage 5. During starting an engine, if oil pressure detected by an oil pressure sensor 4 provided in a lubricant supply system for the exhaust turbine supercharger 9 is below a preset value, the valve 3 is switched to the opening side of the bypass passage 5 to supply high pressure and high temperature intake air while bypassing a compressor 9b in the exhaust turbine supercharger 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharger for an engine, in which a mechanical supercharger and an exhaust turbine supercharger are combined, and in particular, a positive displacement mechanical supercharger is provided upstream of a compressor of the exhaust turbine supercharger. The present invention relates to a hybrid supercharged engine provided with a charger.

[0002]

2. Description of the Related Art In engines such as automobiles, it has been practical to provide a turbocharger in an intake system in order to increase output per exhaust capacity, reduce weight per horsepower, and reduce external dimensions. Feeder (turbocharger)
And mechanical superchargers (superchargers) are used.

In the case of an exhaust turbine supercharger, a turbine is driven by exhaust gas from an engine, and air is compressed and supplied by a compressor coaxial with the turbine.
It is small and light and has a great effect on improving the output of the engine.
There is an advantage that the mounting position is relatively free. However, the acceleration of the turbine rotor is likely to be delayed at the time of rapid acceleration, and the turbine cannot be instantaneously increased in speed to a required number of revolutions, and a time delay (turbo lag) occurs at the start of engine rotation. In the rotation range, there is a disadvantage that it is difficult to increase the output because the exhaust energy is small.

In the case of a positive displacement mechanical supercharger,
Driven from the engine crankshaft via gears and belts, air can be supplied to the engine at a flow rate proportional to the number of revolutions of the engine. It has excellent responsiveness, and has the advantage that it can be supercharged with no time delay, especially when the engine is started. However, in a high rotational speed range, the drive loss of the mechanical supercharger increases with an increase in the intake air flow rate due to an increase in the rotational speed, so that a large drive horsepower is required, and the fuel efficiency of the engine deteriorates.

[0005] Therefore, as a supercharging device that makes use of the respective advantages and compensates for the disadvantages, a hybrid (composite) in which an exhaust turbine supercharger is provided downstream of a positive displacement mechanical supercharger as shown in FIG. Patent No. 54-109508
No. pp. 139 to 163. In an engine using such a hybrid supercharger, the mechanical supercharger is turned on via a magnetic clutch or the like on the crankshaft.
It is connected so that it can be turned off, and its drive is controlled according to the operating state of the engine.

That is, at the time of starting an engine in which the performance of the exhaust turbine supercharger is not sufficiently exhibited, or in a low / medium rotation range, the mechanical supercharger is driven to perform supercharging without time delay, and In the high rotation range where the exhaust turbine turbocharger is sufficiently effective, the drive of the mechanical turbocharger is stopped, By operating the turbocharger independently matched to the high-speed characteristics of the above, it is possible to prevent the fuel consumption from deteriorating and to improve the performance of the engine in a high rotation range. Also, when the engine speed is constant, a substantially constant boost pressure can be obtained regardless of the load fluctuation.

[0007]

However, in such a hybrid type supercharging device, the engine is cranked by the starter, and at the same time, the mechanical supercharger changes the supercharging pressure corresponding to the rotation speed of the engine. It occurs without delay and supplies a large flow of high-pressure intake air to the compressor of the exhaust turbine supercharger. For this reason, the exhaust turbine supercharger is forcibly rotated tens of thousands of revolutions per minute immediately after starting the engine, that is, several hundred revolutions per second. Will be able to rotate at high speed.

On the other hand, oil is supplied into the bearing housing of the exhaust turbine supercharger by an oil pump directly connected to a crankshaft or driven by another drive shaft. Starting, the oil discharge amount is increased in proportion to the engine speed to increase the oil supply amount into the bearing housing of the exhaust turbine supercharger. for that reason,
Immediately after the start of the engine, the amount of oil supply into the bearing housing of the exhaust turbine supercharger is still insufficient, and the metal parts and the like are not well-lubricated.

Therefore, when lubrication is insufficient immediately after the start of the engine, the exhaust turbine turbocharger is forced to rotate at a high speed of several hundred revolutions per second, so that the bearing portion of the exhaust turbine turbocharger is abnormally worn, This causes seizure, and causes a problem that the exhaust turbine supercharger breaks down. In particular, when starting the engine, the inlet side of the compressor has a higher pressure than the outlet side of the compressor due to the high-pressure intake air discharged by the mechanical supercharger, and the thrust load is lower than that of a normal exhaust turbine supercharger. Since the direction is opposite to that in the middle, the thrust bearing designed to receive the thrust load in one direction is most likely to be worn because it receives the force in the other direction.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to supply high-pressure and high-temperature intake air generated by a mechanical supercharger at the start of an engine to an exhaust turbine supercharger. By avoiding forced high-speed rotation of the exhaust turbine turbocharger when oil lubrication is inadequate without bypassing the compressor and driving the compressor, the bearings of the exhaust turbine turbocharger are protected and failures are prevented. Another object of the present invention is to provide a hybrid supercharged engine in which the startup performance of the engine is further improved by directly supplying high-pressure and high-temperature intake air generated by the mechanical supercharger to the intake manifold.

[0011]

In order to achieve the above object, an exhaust turbine supercharger is connected downstream of a mechanical supercharger driven by the power of an engine, and the mechanical supercharger is connected to an exhaust turbine supercharger. An intake passage connecting the turbine and the exhaust turbine supercharger is connected to an intake manifold by a bypass passage to form a three-way junction, and at least one valve is provided in a pipe forming the three-way junction, and the exhaust turbine supercharger is provided. A hydraulic pressure sensor is provided in the lubricating oil supply system of the feeder, and when the hydraulic pressure sensor detects that the hydraulic pressure in the lubricating oil supply system is equal to or less than a set value, the mechanical supercharger is moved to the bypass passage side. A hybrid supercharged engine configured to operate the valve so as to close the bypass passage when detecting that the hydraulic pressure has become greater than a set value. Subjected to.

An exhaust turbine supercharger is connected downstream of a mechanical supercharger driven by the power of the engine,
An intake passage connecting the mechanical supercharger and the exhaust turbine supercharger is connected to an intake manifold by a bypass passage to form a three-way junction, and at least one valve is provided in a pipe forming the three-way junction. A timer that detects the start of the engine and measures the time from the start of the engine,
When the engine is started, the mechanical supercharger is connected to the bypass passage side, and when it is detected that a predetermined time has elapsed from the start of the operation, the valve is operated so as to close the bypass passage side. To provide a hybrid supercharged engine.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
An embodiment will be described. In the intake system of the engine E, a positive displacement mechanical supercharger (supercharger) 2 connected to the crankshaft of the engine E via an electromagnetic clutch downstream of the air cleaner 1 and driven by the power of the engine E is provided. Further, an exhaust turbine supercharger (turbocharger) 9 driven by a coaxial turbine 9 a provided in an exhaust system of the engine E is provided downstream of the mechanical supercharger 2. The compressor 9b of the turbocharger 9 is connected to the intercooler 6
Is connected to the intake manifold 8 of the engine E.

An intake passage 12 connecting the mechanical supercharger 2 and the exhaust turbine supercharger 9 and an intake manifold 8 are connected by a bypass passage 5 to form a three-way 13.
A valve 3 for switching a pipe line between the intake passage 12 and the bypass passage 5 is provided in a pipe line forming the mechanical supercharger 2 by the switching of the valve 3 to the exhaust turbine supercharger 9 or the bypass passage 5. The connection is made so that the intake air passes through either the main passage 11 or the bypass passage 5 passing through the compressor 9 b of the exhaust turbine supercharger 9.

Further, a hydraulic pressure sensor 4 is provided in a lubricating oil supply system of the exhaust turbine supercharger 9, for example, in a bearing housing or a lubricating oil supply port.
Switching of the valve 3 is controlled by the controller 10 which receives the detection signal of the oil pressure sensor 4 while accurately grasping the lubricating oil supply state of the lubricating oil supply system and comparing the lubricating oil supply state with a predetermined set value. Configure to control.

That is, when the oil pressure sensor 4 detects that the oil pressure of the lubricating oil supply system is equal to or less than the set value, that is, that the lubricating oil supply is insufficient, the mechanical supercharger 2 is bypassed. When the valve 3 is switched so as to communicate with the passage 5 side, and when it is detected that the oil pressure of the lubricating oil supply system has become larger than the set value, that is, that the lubricating oil supply is sufficient, the mechanical type The valve 3 is switched so that the supercharger 2 communicates with the exhaust turbine supercharger 9 side.

With the above configuration, by directly detecting the oil pressure in the bearing housing of the lubricating oil supply system of the exhaust turbine supercharger 9 or the lubricating oil supply port,
The lubricating oil supply state of the lubricating oil supply system can be accurately grasped, and the switching control of the valve 3 according to the lubricating state can be performed. That is, when the engine E is started, the oil pressure of the lubricating oil supply system of the exhaust turbine supercharger 9 is low and the lubrication is insufficient, so that the oil pressure is detected by the oil pressure sensor 4 and the intake air is passed through the bypass passage 5. , And forced high rotation of the compressor 9b can be avoided, so that abrasion and seizure of the bearing portion of the exhaust turbine supercharger 9 can be prevented.

After a certain period of time (for example, about 10 seconds to 15 seconds depending on the type of the engine) has elapsed after the start of the engine E, the oil pump started to operate when the engine E was started is proportional to the engine speed. The amount of lubricating oil is supplied, the lubricating oil in the lubricating oil supply system of the exhaust turbine supercharger 9 becomes sufficient, and the hydraulic pressure increases. The controller 10 controls the valve 3 so that the intake air discharged from the mechanical supercharger 2 passes through the compressor 9 b of the exhaust turbine supercharger 9 and the intercooler 6.
Is switched, it is possible to perform ordinary hybrid supercharging.

In addition, as described above, immediately after the start of the start of the engine E, the intake air discharged from the mechanical supercharger 2 is supplied directly to the intake manifold 8 via the bypass passage 5, so that the exhaust turbine Since a pressure drop and a temperature drop caused by passing through the feeder 9 and the intercooler 6 can be avoided, and high-pressure and high-temperature intake air can be supplied to the intake manifold 8, an effect of improving engine performance at the time of starting can be obtained.

Next, as a second embodiment, the valve 3
A hybrid supercharged engine in which a timer is used to control the switching of the engine will be described. In this hybrid supercharged engine, an exhaust turbine supercharger 9 is connected downstream of the mechanical supercharger 2 driven by the power of the engine E, and this mechanical supercharger 2 and the exhaust turbine supercharger are connected. An intake passage 12 connecting the intake passage 9 and the intake manifold 8 is connected by a bypass passage 5 to form a three-way junction 13, and a valve for switching the intake passage 12 and the bypass passage 5 in the pipeline forming the three-way intersection 13. The provision of 3 is the same as in the first embodiment.

However, in the second embodiment, instead of the oil pressure sensor 4, a timer for detecting the start of the engine E and measuring the time from the start is provided, and a timer is provided from the start to the predetermined time. Switches the valve 3 so that the intake air discharged from the mechanical supercharger 2 passes through the bypass passage 5, and when a predetermined time has elapsed from the start of the start, the intake air is supplied to the exhaust turbine supercharger 9. The valve 3 is configured to be switched so as to pass through the compressor 9b.

The fixed time, that is, the set time of the timer, is usually 10 seconds to 15 seconds until the lubricating oil in the exhaust turbine supercharger 9 is sufficiently filled. Since the time from the start of the start to the time when the lubricating oil is sufficiently supplied slightly changes depending on the determination criteria for the start of the start, an optimum value is determined in advance by measurement in accordance with the type of the engine and the criteria for the start of the start. It is better to find the time and use that value.

With the above configuration, the switching of the valve 3 is controlled by a simple and inexpensive device such as a timer, and the mechanical supercharger 2 is generated from the start of the engine E until a predetermined time. The high-pressure and high-temperature intake air bypasses the compressor 9b of the exhaust turbine supercharger 9 and is supplied directly to the intake manifold 8, so that the forced high-speed rotation of the exhaust turbine supercharger 9 at a time when the oil lubrication is insufficient is performed. By avoiding this, it is possible to protect the bearing portion of the exhaust turbine supercharger 9 and further improve the start-up performance of the engine E.

In addition, since the valve 3 is operated so that the intake air passes through the compressor 9b side of the exhaust turbine supercharger 9 when a predetermined time has elapsed from the start of the start, ordinary hybrid supercharging can be performed. it can. In addition, the adoption of a timer eliminates the need for installing a new sensor such as the oil pressure sensor 4 and simplifies the control method, so that the apparatus and the control method can be prevented from becoming complicated and costly, and the reliability with less trouble A highly efficient switching system can be created.

The start of the engine E is detected, for example, by referring to the engine speed. After the starter is turned on, the engine speed is reduced to a predetermined idle speed (500 to 700 rpm). The engine E operates normally when the engine E starts normally, such as when the engine start is judged to have started, or when a certain time (for example, several seconds) has elapsed after the starter ON signal is generated. Check the indicator that indicates that you are driving
If it is K, there is a method of determining that the start is started.

The mechanical supercharger 2 communicates with the bypass passage 5 and the exhaust turbine supercharger 9 as follows.
As shown in FIG. 1 described above, a valve 3 for switching a pipe line may be provided in a three-way 13 between the bypass passage 5 and the intake passage 12, but as shown in FIG.
And valves 3a and 3b
May be provided to open and close the intake passage 12 and the bypass passage 5 by switching the valves 3a and 3b to switch the intake passage.

As shown in FIG. 3, no valve is provided in the intake passage 12 forming the three-way 13 and the valve 3 is provided only in the pipe of the other bypass passage 5, and the hydraulic pressure of the lubricating oil supply system is reduced. The valve 3 is set so that the intake air discharged from the mechanical supercharger 2 passes through the bypass passage 5 only while detecting that the pressure is equal to or less than the set value or only during a predetermined time from the start of the start. May be opened and closed.

[0028]

As described above, according to the first aspect of the present invention, when starting the engine, the high-pressure and high-temperature intake air generated by the mechanical supercharger is supplied to the compressor of the exhaust turbine supercharger. By bypassing, avoid the forced high-speed rotation of the exhaust turbine turbocharger when lubricating oil supply system has low oil pressure, especially when lubrication is insufficient, protect the bearings of the exhaust turbine turbocharger and prevent failure. In addition, the high-pressure and high-temperature intake air generated by the mechanical supercharger can be directly supplied to the intake manifold, so that the start-up performance of the engine can be further improved.

Further, a lubricating oil supply system of the exhaust turbine supercharger, for example, a hydraulic pressure sensor capable of detecting a hydraulic pressure state in a bearing housing or a lubricating oil supply port is provided, and a valve is controlled by inputting this detection signal. It is possible to accurately switch the intake passage in accordance with the hydraulic pressure of the oil. According to the second aspect of the present invention, the use of a timer further eliminates the need for installation of a new sensor such as a hydraulic sensor, and simplifies the control method. The cost can be prevented from increasing, and a highly reliable switching system with few failures can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hybrid supercharged engine showing an embodiment of the present invention.

FIG. 2 is a partial configuration diagram showing another embodiment of a three-way valve according to the present invention.

FIG. 3 is a partial configuration diagram showing another embodiment of a three-way valve according to the present invention.

FIG. 4 is a configuration diagram of a hybrid supercharged engine according to the related art.

[Explanation of symbols]

E ... engine 1 ... air cleaner 2 ... mechanical supercharger (supercharger) 3, 3a, 3b ... valve 4 ... oil pressure sensor 5 ... bypass passage 6 ... intercooler 7 ... exhaust manifold 8 ... intake manifold 9 ... exhaust turbine supercharging (Turbocharger) 9a Turbine 9b Compressor 10 Controller 11 Main passage 12 Intake passage 13 Three-way junction

Claims (2)

[Claims] An exhaust turbine supercharger (9) is connected downstream of a mechanical supercharger (2) driven by the power of an engine (E), and the mechanical supercharger (2) is connected to the mechanical supercharger (2). An intake passage (12) connecting the exhaust turbine supercharger (9) and an intake manifold (8) are connected by a bypass passage (5) to form a three-way (13), and a pipe forming the three-way (13) At least one valve (3) is provided in the road, and a hydraulic pressure sensor (4) is provided in a lubricating oil supply system of the exhaust turbine supercharger (9). The lubricating oil supply system is provided by the hydraulic pressure sensor (4). When it is detected that the hydraulic pressure in the engine is below the set value, the mechanical supercharger (2) is connected to the bypass passage (5).
And the valve (3) is configured to operate the valve (3) so as to close the bypass passage (5) when it is detected that the hydraulic pressure has become larger than a set value. Expression engine. 2. An exhaust turbine supercharger (9) is connected downstream of a mechanical supercharger (2) driven by the power of an engine (E), and the mechanical supercharger (2) is connected to the exhaust gas turbine supercharger (9). An intake passage (12) connecting the exhaust turbine supercharger (9) and an intake manifold (8) are connected by a bypass passage (5) to form a three-way (13), and a pipe forming the three-way (13) At least one valve (3) is provided in the road, and a timer is provided for detecting the start of the engine (E) and measuring the time from the start of the engine. The feeder (2) is connected to the bypass passage (5) side, and when it is detected that a predetermined time has elapsed from the start of the start, the bypass passage (5) side is closed.
A hybrid supercharged engine configured to operate the valve (3).