JPH01315616A - Supercharger asisting device for engine - Google Patents

Abstract

PURPOSE:To improve the acceleration characteristics by mounting a pressure air turbine which is supplied with pressure air from a pressure air source, on a shaft on which both the exhaust turbine of a supercharger and a compressor turbine are commonly mounted and operating the pressure air turbine during the early supercharging period. CONSTITUTION:Both a compressor turbine 116 and a pressure air turbine 119 are mounted coaxially with the shaft 117 of an exhaust turbine 131 which is driven by exhaust gas discharged from an engine 111. The pressure air from a pressure air tank 141 is sent via a valve 143 to the pressure air turbine 119 and the compressor turbine 116 is driven by both the power generated by said turbine 119 and the power of the exhaust turbine 131. The air having been reduced in pressure via the pressure air turbine 119 is mixed with the supercharged air fed from the compressor turbine 116 and an engine 111 is supercharged with the mixed air. The valve 143 is controlled by a controller 153 to be opened at the suitable time, such as the early time of supercharging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a supercharging device for an engine, particularly an automobile engine. By supplying air supplied from a compressor driven by a turbine and exhaust air that has finished its work in a pressurized air turbine and has been reduced to near the intake pressure, it is possible to sufficiently supercharge the engine during acceleration. This is a device with improved acceleration performance.

[Prior Art] In the past, air was often supplied from a compressor driven by the engine's exhaust turbine, and sufficient supercharging could not be achieved unless the engine rotated at high speed.

[Problems to be Solved by the Invention] This invention provides a supercharger using a conventional exhaust turbine.
By providing a supercharging auxiliary device driven by pressurized air, the engine speed and torque increase immediately when acceleration is required, without causing so-called turbo lag, and even when the engine speed is low. The purpose is to enable rapid acceleration.

Furthermore, since sufficient air for supercharging can be supplied, it is possible to prevent black smoke from being emitted from the engine exhaust due to incomplete combustion during acceleration, which often occurs particularly in diesel engines.

Furthermore, even when auxiliary supercharging using pressurized air is performed over a long period of time, such as during climbing, the purpose is to increase the ratio of supercharging by the exhaust turbine as well as increasing the engine output.

This also has the effect of increasing the energy efficiency of the compressed air turbine and reducing the consumption of pressurized air by expanding the compressed air while supplying thermal energy even when the temperature of the compressed air turbine increases. This is one of the problems that invention should solve.

[Means for Solving the Problems] The auxiliary device of the present invention applies high-pressure compressed air supplied from a pressurized air tank or a pressurized pump during acceleration, in addition to a supercharging intake system driven by an exhaust turbine. In addition to the compressed air turbine, the rotation speed is suddenly increased, and the power generated by the adiabatic expansion energy is used to drive the compressor, thereby supplying additional supercharging air to the intake system, which is then used to drive the compressor. By supplying the exhaust gas of the pressurized air turbine, whose pressure has been reduced to near the intake pressure due to expansion, to the intake system, the purpose is achieved by supercharging the necessary and sufficient air when the engine accelerates.

[Function] In a conventional turbocharger using an exhaust turbine, even when you step on the accelerator to accelerate, the engine speed increases and the displacement increases until it can sufficiently drive the exhaust turbine. , required some time. This point is particularly noticeable when the engine speed is low.

In this invention, the sensor detects when the accelerator is pressed, opens the pressurized air supply valve, and supplies high-pressure air from the high-pressure air tank to the pressurized air turbine, causing the turbine to rapidly increase its rotational speed. rises and drives the compressor turbine. Therefore, the supercharging air is also supplied sufficiently and quickly.

In this way, the rotation speed of the pressurized air turbine increases rapidly, but due to the inertia of the impeller, the rise time does not reach zero. However, the high-pressure air introduced during this time has not done enough work, so it passes through the turbine with high pressure and rushes into the engine's intake pipe from the exhaust pipe, resulting in the pressurized air turbine not working properly. Responsible for supplying supercharged air until startup. During this time, the pressurized air contributes only a small amount to the generation of power, but
Since the supply is instantaneous, the drop in efficiency can be ignored.
The effect of rapid air supply is great.

The pressurized air tank is replenished with air by a pressurizing pump, but if the energy recovered during braking is used for driving the tank, the actual power consumption required to operate the supercharging auxiliary device of the present invention can be reduced. It becomes relatively smaller and efficiency is further improved.

When you step on the accelerator, the supply of fuel also increases, but according to conventional technology, the supply of air required for this combustion cannot keep up, so especially in diesel engines, black smoke is emitted during acceleration due to incomplete combustion. It was inevitable.

The supercharging device of this invention operates as described above,
Since sufficient air can be supplied, complete combustion is possible.
It can prevent the emission of black exhaust gas.

Embodiment FIG. 1 is a diagram schematically showing the configuration of a supercharging auxiliary device called a parallel coaxial type according to a first embodiment of the present invention.

In FIG. 1, the driving operations of the driver 151 (accelerator,
The state of the brakes, clutches, gear shifts, etc.) is detected by a sensor 152 and transmitted as a control signal to a controller 153.

On the other hand, parameters indicating the operating status of the engine (boost pressure, engine speed, fuel injection amount, engine temperature, etc.)
is also applied to the controller and used to control the engine.

Exhaust gas discharged from the engine 111 is guided to an exhaust turbine 131 through an exhaust pipe 121, and power is generated depending on the exhaust pressure. The exhaust gas that has completed its work in the exhaust turbine is sent to the exhaust system via the exhaust pipe 122.

The exhaust turbine is coupled to shaft 117 and transmits the generated power thereto. This shaft 117 is common and coaxially connected to the shafts of the compressor turbine 116 and the compressed air turbine 119.

When pressurized air is supplied from the pressurized air tank 141 to the pressurized air turbine 119 via the valve 143, the generated power is transmitted to the shaft 117. This power is transmitted to the compressor turbine 116 in cooperation with the power of the exhaust turbine.
compresses the air supplied from the air filter 161 via the pipe 162, and supplies supercharging air to the engine 111 via the pipe 163.

The air that has completed its work in the pressurized air turbine and whose pressure has been reduced to near the intake pressure is also merged into the pipe 163 and utilized as part of the supercharging air.

FIG. 2 is a sectional view showing the specific structure of the main parts of the supercharging auxiliary device according to the first embodiment of the present invention.

The compressor turbine 216 is connected to the turbine shaft 21
7 to an exhaust turbine 218.

A pressurized air turbine 219 is also coaxially mounted to turbine shaft 217.

Compressor turbine 216 is driven by exhaust flow and/or pressurized air flow through respective turbines, 218, 219.

The exhaust gas of the engine is guided to the exhaust turbine scroll 221, which gives energy to the exhaust turbine 218 to decelerate and
After being expanded, it is discharged into the exhaust pipe 228.

The pressurized air supplied from the pressurized air tank 141 via the pressurized air control valve 143 is guided to the pressurized air scroll 222, gives energy to the pressurized air turbine 219, and
After deceleration and expansion, the pressurized air turbine exhaust outlet pipe 224
is discharged.

The intake air taken in through the intake pipe 227 is compressed by the compressor turbine 216, and the compressor scroll 2
20 to a scroll outlet pipe 223.

Here, the intake air flowing from both sides of the swing valve 225 and the exhaust air of the pressurized air turbine 219 meet, but depending on the air pressure on both sides of the swing valve, the swing valve is placed at a position intermediate between the two illustrated positions. Take. Further, the swing valve may be omitted depending on the case.

The compressor frame 229 is a support frame that has functions such as bearings, lubrication, and cooling.

Whether the nozzle ring 230 is necessary or not is determined depending on the method of expanding the pressurized air, and is employed in this embodiment.

FIG. 3 is a diagram schematically showing a supercharging auxiliary device called a parallel independent type according to a second embodiment of the present invention.

In FIG. 3, exhaust gas discharged from the engine 111 is guided to an exhaust turbine 131 via an exhaust pipe 121.
After generating power in the turbine 131, the exhaust pipe 1
22 and is sent to the exhaust system. The generated power drives compressor turbine 301 through shaft 311 . As a result, the air taken in through the air filter 161 passes through a pipe 162, is compressed by the turbine 301, and is supplied to the engine 111 through a pipe 163.

An auxiliary compressor turbine 302 is connected in parallel with the compressor turbine 301 and is connected to a pressurized air turbine 331 by a shaft 312 .

Pressurized air is supplied from the pressurized air tank 141 via the valve 143 to the pressurized air turbine 331 to generate power. This power drives the auxiliary compressor turbine 302 through the shaft 312 to compress the air from the tube 162 and supply it to the engine 111 along with the exhaust of the turbine 331 as part of the supercharged intake air.

Therefore, when the driver 151 steps on the accelerator, the sensor 152 detects this, sends a signal to the controller 153, opens the valve 143 via the signal line 154, and pressurized air drives the pressurized air turbine 331. do. The power generated thereby drives the auxiliary compressor turbine 302 to take in air through the pipe 162 and supply air to the intake pipe 163 of the engine.

This air supply is performed by controlling the supply of pressurized air independently of the supercharged intake air by the compressor turbine 301, so if the engine speed is low and the exhaust turbine is insufficiently supplied with air. Even if there is, the engine can be rotated rapidly.

FIG. 4 is a cross-sectional view of the structure of the main parts of a supercharging auxiliary device according to a second embodiment of the present invention.

The compressor turbine 401 has a turbine shaft 40
Although not shown, it is connected to the output shaft of a normal exhaust turbine via 2. compressor scroll 40
3 is connected to the intake pipe of the engine. The compressor turbine's power is also connected to the intake pipe 404. Auxiliary compressor 406 is coupled to compressed air turbine 408 via an auxiliary compressor turbine shaft 407 . When pressurized air introduced from the pressurized air tank is injected into the pressurized turbine scroll 410, the pressurized air turbine 408 generates torque and the auxiliary turbine shaft 4
07 to rotate the auxiliary compressor turbine 406.

As a result, the turbine auxiliary compressor intake pipe 405
Air is sucked in through the auxiliary compressor scroll 409 and after being pressurized, the air is pushed out to the auxiliary compressor scroll 409 and output to the auxiliary compressor outlet pipe 411.

The pressurized air that rotates the pressurized air turbine 408 and completes its work passes through the pressurized air exhaust pipe 412 and is sent to the balance blade 413.
At the end of the auxiliary compressor outlet pipe 411, it joins the intake air through the auxiliary compressor outlet pipe 411.

The balance blade 413 is provided for the purpose of reducing the vortex loss of the combined air by swinging so that there is no large difference in the air velocity on both sides of the blade, but when the loss can be ignored. can be omitted.

The combined air pushes open the swing valve 414, reaches the compressor outlet joint pipe 415, and is sent to the intake port of the engine (not shown). compressor turbine 4
01 is not operating, the swing valve 414 is pneumatically displaced to the position 414b to prevent intake air from flowing back toward the compressor scroll 403.

The swing valve 414 is located at an intermediate position between 414a and 414b depending on the ratio of the respective discharge air flow rates of the compressor turbine 401 and the auxiliary compressor turbine 406. Depending on the shape of the merging portion, the swing valve 414 may be omitted.

FIG. 5 is a graph for explaining the effects of the engine supercharging device of the present invention. The horizontal axis shows engine speed, and the vertical axis shows engine torque and intake pressure. Curve 501 is the torque of the engine without supercharging.

Curve 502 is the intake pressure when a normal exhaust turbocharger is used, and curve 503 is the intake pressure when equal-pressure supercharging is performed using pressurized air. Ideally, the pressure should be constant regardless of the engine speed. It is maintained.

A curve 504 shows a state in which supercharging is performed in a range where the engine speed is low, such that the lower the engine speed is, the higher the intake pressure is.

Curves 512, 513, and 514 respectively represent the intake (
These are curves showing the engine torque corresponding to 502, 503, and 504. As can be seen from this graph, when the intake boost pressure is increased, the torque also increases almost proportionally.

When using a large vehicle with a manual transmission, it is necessary to engage the clutch at low engine speeds to prevent clutch wear.

However, when starting or accelerating, even if the vehicle speed is low,
The torque must be large enough.

However, with the torque characteristic as shown in curve 512, where the required torque can be obtained, the rotational speed is high and the clutch is inevitably required to slip, which has the disadvantage of shortening the life of the clutch. In a low rotational speed range, the required torque may not be reached, so the vehicle may not be able to start or accelerate.

According to this invention, the supercharging air pressure is increased as shown by curve 503 or 504 even when the engine is rotating at low speed,
Because the air supply can be controlled to the necessary and sufficient amount,
A torque characteristic shown by curve 513 or 514 is obtained. Therefore, the load on the clutch at the time of starting is small, and the life of the vehicle is not adversely affected.

The pressure of the pressurized air tank is usually 10 to 50 kg.
/cI! 1, while the pressure for supercharging is 2,
About 5 kg/cnf is sufficient. Therefore, by using this pressure difference to rotate the pressurized air turbine and using the expansion energy to drive the compressor turbine, the energy efficiency for supercharging is improved.

Figure 6 shows what happens when a car using a manual transmission starts and is running at a low speed and then tries to accelerate.
It is a graph showing the performance of a normal exhaust turbocharger and a supercharging device of the present invention.

A curve 601 shows the increase characteristic of the intake pressure of only the exhaust turbocharger, and the intake pressure gradually increases as the engine speed increases. As a result, the engine torque does not increase rapidly.

On the other hand, according to the supercharging device of the present invention, air is supplied from the pressurized air tank as shown by curve 600 immediately after stepping on the accelerator, and air is rapidly supplied by the operation of the pressurized air turbine. As fuel is injected, engine torque also increases rapidly. As the exhaust energy rapidly increases, the exhaust turbo system becomes responsible for supplying supercharging air. The supply of pressurized air is therefore curve 600
As shown in the figure, it decreases rapidly after the peak. Then, the engine torque increases rapidly, and the vehicle speed can be accelerated in a shorter time than when only the exhaust turbocharger is used, as shown by curve 612.

[Effects of the Invention] In the first embodiment of the present invention, exhaust energy and expansion energy of pressurized air are added on the turbine shaft to drive the compressor turbine, so supercharging is performed by one compressor turbine. Since air can be supplied to the intake pipe, the dynamic performance of the turbocharger is improved, and since only one shaft and bearing assembly is required, costs can be reduced.

In the second embodiment of the present invention, the compressor turbine 501, which is the main turbine, is driven only by the exhaust turbine, so there is a slight disadvantage in supplying supercharged intake air during acceleration, but compared to the auxiliary compressor. The supercharging effect can be enhanced by supplying high-pressure air from the compressed air tank and forcing the necessary amount of air equivalent to the boost pressure into the intake pipe at the beginning of acceleration. Additionally, an auxiliary compressor can be added to the conventional exhaust turbocharger without any modification, which is advantageous for modification.

In both of the above two embodiments, the pressurized air turbine is driven by high pressure air from the pressurized air source, regardless of the operation of the exhaust turbine during acceleration, that is, regardless of the engine speed and exhaust energy. Because the compressor turbine can be rapidly driven from
Supercharged air can be supplied to the engine in an extremely short time after stepping on the accelerator.

Furthermore, regarding the time lag caused by the inertia of the compressor turbine impeller, high-pressure air that has not completed its work passes through the turbine and rushes into the intake pipe, making it impossible to instantly supply a large amount of air. , Sufficient supercharging during acceleration can be performed.

With conventional technology, even if a large amount of fuel is supplied immediately after stepping on the accelerator during acceleration, the supply of air to compensate for this is delayed, and this state may continue, resulting in black exhaust gas due to incomplete combustion of fuel. emissions were unavoidable.

This phenomenon is particularly noticeable in diesel engines, but according to the charging device of the present invention, sufficient air is supplied during acceleration, making it possible to prevent black smoke from being emitted due to incomplete combustion. .

When auxiliary supercharging with pressurized air is performed for a long time, such as when pitching, and it is necessary to replenish the pressurized air,
A portion of the engine's output can be used to drive a pressure pump to create pressurized air.

When auxiliary supercharging is performed using pressurized air, the engine output increases and at the same time the exhaust energy also increases, increasing the proportion of supercharging by the exhaust turbine and significantly reducing the consumption of pressurized air.

Therefore, the amount of increase in engine output is much larger than the energy consumed for replenishing pressurized air, and the effect of increasing engine output due to auxiliary supercharging is large. In particular, when a pressurized air turbine is installed coaxially with the exhaust turbine, the temperature of the pressurized air turbine system and its surroundings will be higher than that of the pressurized air, and the expansion of the pressurized air will be affected by the supply of heat energy rather than adiabatically. The energy efficiency of the pressurized air turbine increases, and the amount of pressurized air consumed can be expected to decrease accordingly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of an engine supercharging assist device of the present invention, FIG. 2 is a sectional view showing the structure of the main part of the device of the first embodiment, and FIG. The second part of this invention
FIG. 4 is a block diagram showing the embodiment, FIG. 4 is a sectional view showing the structure of the main part of the device of the second embodiment, and FIG. 5 is a graph for explaining the effects of the engine supercharging auxiliary device of the present invention. , FIG. 6 is a graph showing the performance of a conventional exhaust turbocharger and the supercharging device of the present invention when attempting to accelerate from a low speed running state. 111: Engine 116: Compressor turbine 117: Shaft 119: Pressurized air turbine 121.122: Exhaust pipe 131: Exhaust turbine 141: Pressurized air tank 142: Pressurizing pump 143: Valve 151: Driver 152: Sensor 153: Controller 161: Air filter 162, 163 Two pipes 216: Compressor turbine 217: Shaft 218: Exhaust turbine 219: Pressurized air turbine 220: Compressor scroll 221: Exhaust turbine scroll 222: Pressurized air scroll 223 Varnish scroll outlet pipe 225: Swing Valve train 227: Intake pipe 229: Compressor frame 230: Nozzle ring 301: Compressor turbine 302: Auxiliary compressor turbine 311: Shaft 312: Shaft 331: Pressurized air turbine 401: Compressor turbine 402 Nishaft 403: Compressor scroll 404 Second intake pipe 405 : Auxiliary compressor intake pipe 406: Auxiliary compressor 407: Shaft 408: Pressurized air turbine 409: Auxiliary compressor scroll 410: Pressurized turbine scroll 411: Auxiliary compressor outlet pipe 412: Pressurized air exhaust pipe 413: Balance blade 414: Rocking Valve 501: Engine torque without supercharging 502: Boost pressure by exhaust turbocharger 503
: Isobaric supercharging with pressurized air Intake pressure 504: Boost pressure increased at low speed 512: Exhaust turbo only torque 513: Engine torque during isobaric supercharging

Claims (3)

[Claims] (1) In a device having a turbocharger driven by engine exhaust gas, a pressurized air turbine is driven by expansion energy of pressurized air supplied from a pressurized air source to rotate a compressor turbine, and a pressurized air turbine is used to rotate a compressor turbine. and means for supplying supercharging air to the intake system of the engine by merging the exhaust air of the air turbine with the output pipe of the compressor turbine, during a period when the rotational speed of the pressurized air turbine and the exhaust turbine is low at the beginning of supercharging. , an engine supercharging auxiliary device characterized by supplying high-pressure air whose expansion energy has not been sufficiently consumed to an intake pipe. (2) A pressurized air turbine and a compressor turbine are provided coaxially with the shaft of the exhaust turbine driven by engine exhaust gas, and a device is provided to add pressurized air with high pressure to the compressed air turbine during supercharging. An engine supercharging auxiliary device that connects the turbine output pipe and pressure turbine exhaust pipe to the engine intake pipe. (3) A compressor turbine is provided coaxially with the shaft of an exhaust turbine driven by engine exhaust gas, and the output pipe of this compressor turbine is connected to the engine intake pipe, and pressurization is supplied from a pressurized air source during supercharging. A supercharging device for an engine, wherein an auxiliary compressor turbine is provided coaxially with the shaft of a compressed air turbine driven by air, and an output pipe of the auxiliary compressor turbine and an exhaust output pipe of the compressed air turbine are respectively connected to the intake pipe.