JP2001342839A - Turbo supercharging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a series two-stage supercharge type turbo supercharging system capable of cooling air supplied from a low-pressure stage compressor and avoiding a failure caused by temperature rising of a high-pressure stage compressor by driving a cooling fan with excess energy of exhaust gas. SOLUTION: This series two-stage supercharge type turbo supercharging system has a first turbine 31 of a first supercharger 30 and a second turbine 41 of a second supercharger 40 in an exhaust passage 22 of an internal combustion engine 10, and a second compressor 42 of the second supercharger 40, an intermediate supplied-air cooler 50, and a first compressor 32 of the first supercharger 30 sequentially from the upstream of an intake passage 12. The downstream side than the first turbine 31 and the second turbine 41 is provided with a fan driving turbine 51 for driving the cooling fan 53 for the intermediate supplied-air cooler 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-line two-stage turbocharging system in an internal combustion engine such as a diesel engine or a gasoline engine, in which compressors are arranged in two stages in series.

[0002]

2. Description of the Related Art In a supercharged engine, an intercooler or a charger is provided downstream of a compressor in an intake passage for cooling supply air heated by a compressor in order to sufficiently supply and charge intake air to a cylinder. A supercharged cooler called a cooler is provided to cool the compressed and heated supply air.

In order to cool the supercooler, which exchanges heat with the air supply, running air is blown, or air is blown by a fan directly driven by an engine or an electric fan. In the above-described means other than the cooling by the traveling wind, a driving loss occurs, and fuel efficiency is deteriorated.

In a large engine, a large-capacity turbine is driven when the load or the number of revolutions is large, and the turbine is switched to a small-capacity turbine when the load or the number of revolutions is small, and the turbine is driven and supercharged. There is a switching type two-stage supercharging system.

On the other hand, since the exhaust gas discharged from the first-stage exhaust gas turbine still has sufficient exhaust energy available, the second-stage exhaust gas turbine is provided to provide the second-stage exhaust gas turbine.
There has been proposed an in-line two-stage supercharging system in which a stage compressor is driven, the air supply is further compressed, and the air is supplied to the engine at high supercharging to improve the charging efficiency.

A configuration in which the superchargers are arranged in two stages in series is conventionally known.
There is a two-stage supercharged engine for a vehicle disclosed in JP-A-118933.

When the compressors are arranged in two stages in series as in this example, the supply air is compressed by the compressor at the low pressure stage on the upstream side to increase the temperature, and the temperature is further increased by the compressor at the high pressure stage on the downstream side. Therefore, especially when no cooling device is provided, a maximum of 20 at the outlet of the compressor in the high pressure stage
At 0 degrees or more, the heat resistance and durability of the high-pressure stage compressor become problematic, and when the supply air temperature increases, the efficiency of filling the cylinder with air also deteriorates, so that the supply air needs to be cooled.

[0008] For this reason, Japanese Utility Model Application Laid-Open No.
In the two-stage supercharging engine for a vehicle disclosed in Japanese Patent Application Publication No. H06-32, a low-pressure stage supercharger and a high-pressure stage supercharger are provided in order from the upstream side of the intake passage,
A first intake air cooling device (intermediate intake air cooling device) for cooling the intake air coming out of the low-pressure stage supercharger and a second air supply cooling device (the intermediate air intake cooling device) for cooling the intake air coming out of the high-pressure stage supercharger ( An intercooler is provided so that the two air supply cooling devices are traversed through the flow path of the cooling air and the second air supply cooling device is located on the upstream side.
It proposes a configuration in which it is arranged in a stack.

However, in this configuration, even if the second most downstream air supply cooling device (intercooler) can be arranged, the first air cooling device provided between the two compressors can be arranged.
Is also configured in the same manner as the second air supply cooling device, so that it is arranged in a two-tiered configuration in terms of engine layout, space, and cooling performance. Is difficult in practice.

[0010] Therefore, after simplifying and reducing the size of the air supply cooling device, the first and second air supply cooling devices are mounted in different parts, and a separate cooling fan or the like is provided to ensure cooling performance. A practical solution is to arrange and cool to the force generated wind.

In particular, in the case of in-line two-stage supercharging, there is not always a region that always requires cooling when considered at the outlet of the low-pressure stage compressor. It is not necessary that the arranged intermediate air supply cooling device always operate at full capacity.

The point is that it is only necessary to cool the high-pressure stage compressor below the heat-resistant temperature. Therefore, the intermediate air supply cooler disposed in the intake passage is simplified as much as possible, and the intermediate air supply cooler is cooled when necessary. It is preferable to use a cooling fan to cool the intermediate air supply cooler, since this configuration can be used, and the configuration of the intake pipe itself can be significantly simplified.

[0013]

However, in a one-stage supercharging system, a system for cooling an air supply cooler by a cooling fan as described below has been proposed, but each system has a problem. There is no configuration that can be adopted as it is in the stage supercharging system.

For example, in Japanese Patent Laid-Open Publication No. 51-53115, in a single-stage supercharging system, a cooling fan driven by a fan driving turbine provided on the upstream side of an exhaust passage of a turbocharger supplies air. There has been proposed an air supply cooling device that cools an air supply cooler provided in a passage.

However, in this configuration, since the fan driving turbine for the cooling fan is provided in the exhaust bypass passage branched from the upstream side of the exhaust turbine driving the compressor, the exhaust gas energy is supplied to the exhaust turbine of the supercharger. Since the exhaust gas and the exhaust gas energy are branched into the exhaust passage of the fan driving turbine before being supplied, there is a problem that the thermal efficiency of the engine is reduced.

In order to prevent this, when the load is low and the exhaust gas energy is small, the exhaust gas energy is prevented from being wasted on the exhaust bypass passage side.
Since it is necessary to provide an exhaust bypass valve at the branch inlet and perform opening / closing control using at least one detected value such as an air supply pressure, an exhaust pressure, an engine speed, etc., there is a problem that an exhaust system becomes complicated. is there.

Particularly, when such a configuration in which the exhaust bypass passage is provided upstream of the supercharger is used in a two-stage supercharging system, the supercharging of the low-pressure stage and the supercharging of the high-pressure stage are performed. Since the ratio is controlled by the valve opening of the adjustment valve provided in the exhaust bypass passage that bypasses the exhaust gas turbine, if the exhaust gas is diverted upstream, it is affected by the amount of branching. The control value for supercharging changes. Therefore, control that anticipates this change is required, but this control is complicated, and there is a problem that actual implementation becomes difficult.

In Japanese Utility Model Laid-Open Publication No. 60-114233, a bypass passage is provided in a ventilation passage downstream of a compressor of a supercharger, and a turbine for driving a cooling fan for an intercooler is provided in the bypass passage. Japanese Patent Application Laid-Open No. 5-30428 discloses a configuration in which a turbine for driving a cooling fan for an intercooler is provided in a ventilation passage downstream of a compressor of a supercharger.

In each of these air supply turbines,
Since the energy of the supply air compressed by the compressor driven by the exhaust turbine is used, there is a problem that the thermal efficiency of the engine is reduced. Also, since the fan drive turbine is driven according to the supply air amount,
In the case of a branch passage, it is necessary to control a branch valve to control the rotation of the cooling fan.

Further, for a high-output, low-fuel-consumption engine, the size of the supercooler tends to be large, and it is necessary to provide the supercooler in a place other than where the traveling wind is applied. There is a demand for a method of cooling a supercharger that does not select an installation location and does not sacrifice fuel efficiency.

The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide an in-line two-stage supercharger capable of efficiently converting exhaust energy into turbocharger energy to enable high supercharging. By driving the cooling fan with the excess energy of the exhaust gas in the turbocharged system of supply,
An object of the present invention is to provide a turbocharging system that can cool a supply air from a low-pressure stage compressor and avoid a failure due to a rise in temperature of a high-pressure stage compressor.

[0022]

SUMMARY OF THE INVENTION In order to achieve the above object, a turbocharger system includes a first turbine and a first turbine of a first supercharger driven by exhaust gas in an exhaust passage of an internal combustion engine. A turbocharger having a second turbocharger and a second compressor driven by the second turbine and a first compressor driven by the first turbine arranged in two stages in series from the upstream side of an intake passage. In the supercharging system, an intermediate air supply cooler is provided between the first compressor and the second compressor to cool the air supply compressed and heated by the second compressor, and the first turbine and the second turbine are provided. A fan drive turbine is provided downstream of the turbine, and the cooling fan driven by the fan drive turbine cools the intermediate air supply cooler. It is.

That is, the high pressure stage (first) and the low pressure stage (second)
An air supply cooler cooled by a cooling fan is provided between the two compressors, and the cooling fan is driven by using exhaust energy after both superchargers have been used. The fan driving turbine of the cooling fan is provided downstream of both the first turbine of the first supercharger at the high pressure stage and the second turbine of the second supercharger at the low pressure stage.

With the above configuration, it is possible to provide a very simple configuration in which only the intermediate supercooler is disposed in the intake passage between the two compressors of the high pressure stage and the low pressure stage. Further, since the cooling fan is driven to rotate using the exhaust gas energy after leaving the second turbine of the second supercharger of the low pressure stage, which was normally discarded without recovering the energy as it is, the fuel consumption and efficiency are reduced. It does not cause deterioration.

In particular, the condition in which the first compressor in the high pressure stage is exposed to the danger of temperature is when the second compressor in the low pressure stage is generating a high compression ratio. When the exhaust gas energy for driving the exhaust gas is large, the energy of the exhaust gas after passing through the second supercharger on the downstream side is also large, and the cooling fan driven by the exhaust turbine using this energy works more effectively. Works as follows.

On the other hand, when the compression ratio is low and the cooling of the supply air is not necessary, the energy of the exhaust gas to the second turbine in the low pressure stage may not be supplied much.
The rotation of the cooling fan driven by the exhaust turbine is reduced, and the cooling function does not work much.

In other words, if the performance of the fan drive turbine is first adjusted and set well, the turbine rotates quickly when the supply air needs to be cooled, without special control, and the supply air is cooled. When cooling is not required, the turbine rotates slowly and adjusts automatically, so that no special control system is required.

In a configuration that drives a cooling fan turbine upstream of a turbocharger turbine, which is different from the above configuration, the energy of the exhaust gas is extracted by the cooling fan turbine. Therefore, the operation of the two-stage turbocharger on the downstream side is affected, and the supercharging pressure control is complicated.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a turbocharging system according to the present invention will be described with reference to the drawings.

The turbocharger system 1 includes an engine 1
Exhaust passage 22 connected to exhaust manifold 21
In the order from the upstream side, the first supercharger 30 of the high pressure stage
The turbine 31, the second turbine 41 of the second supercharger 40 in the low-pressure stage, the fan drive turbine 51 that drives the cooling fan 53 for the intermediate supercooler 50 through the speed reducer 52, and the muffler (silencer) 23 Is provided.

In addition, an air cleaner 13, an air cleaner 13, is sequentially provided from an upstream side to an air supply passage 12 connected to the air supply manifold 11.
First of the second supercharger (turbocharger) 40 of the low pressure stage
The compressor 42, the intermediate supercooler 50, the first high pressure stage
The first compressor 32 and the supercooler (intercooler: charge cooler) 15 of the supercharger 30 are provided.

That is, the second supercharger 40 of the low pressure stage
On the downstream side of the turbine 41, a fan driving turbine 51 for recovering the exhaust energy of the exhaust gas G is provided, a reduction gear 52 is mounted on a shaft, a cooling fan 53 is connected, and an intermediate supercooler 50 is provided immediately near the turbine. And the second supercharger 4 of the low pressure stage
0 air supply A that has been compressed by the second compressor 42
Is cooled.

The cooling of the supercharger 15 downstream of the first compressor 32 of the first supercharger 30 is performed by a cooling fan driven directly by the engine, a running wind or the like, similarly to the known technique. The configuration is as follows.

An exhaust bypass passage 24 bypassing the first turbine 31 of the first supercharger 30 in the high-pressure stage is provided, and a regulating valve 2 is provided at the inlet of the exhaust bypass passage 24.
5 is provided.

By controlling the opening and closing of the regulating valve 25 based on the engine speed and the like, the first turbine 31 of the first supercharger 30 and the second turbine of the second supercharger 40 are controlled.
The drive amount of the turbine 41 is adjusted, and by this adjustment, the ratio of the compression ratio of the supply air by the first compressor 32 in the high-pressure stage and the second compressor 42 in the low-pressure stage is adjusted.

According to this configuration, the exhaust gas G discharged from the exhaust manifold 21 of the engine 10 is sent to the first supercharger 30 at the high pressure stage to drive the first turbine 31,
The first compressor 32 on the same axis is rotated to supercharge the intake air, and the gas that has passed through the first turbine 31 is
Further, it is sent to the second supercharger 40 of the low pressure stage to drive the second turbine 41.

The exhaust gas G is usually supplied to the muffler 2
In the supercharging system according to the present invention, the fan driving turbine 51 for extracting exhaust energy from the exhaust gas G is driven, and then the muffler 23 is released.
It is released to the atmosphere through.

On the other hand, after passing through the air cleaner 13, the supply air A is supplied to the second compressor 42 of the second supercharger 40 at the low pressure stage.
And then cooled by an intermediate supercooler 50 cooled by a cooling fan 53, and then cooled by a first compressor 32 of a first supercharger 30 at a high pressure stage.
Then, the pressure is further increased and the temperature is increased. After being cooled by the supercooler 15, the air is supplied to the intake manifold 11.

According to the turbocharger system having the above-described structure, the turbine 41 of the second supercharger 40, which is normally discarded,
Exhaust energy after driving the cooling fan 5
3 to protect the first compressor 31 by cooling the intermediate supercooler 50, so that the energy loss is reduced as compared with the electric or engine direct drive fan,
It is possible to improve fuel efficiency and increase the output of the engine.

Further, since the cooling fan 53 is not driven directly from the crank shaft of the engine 10, the range of installation locations can be widened and the degree of freedom in layout can be increased.

Incidentally, as an example, the second low-pressure stage
When the outlet temperature of the air supply A of the compressor 42 is about 100 ° C., the temperature and pressure of the air supply are about 90 ° at the inlet of the first compressor 32 when the cooling fan 53 is not driven.
℃, about 170kPa, about 200 ℃ at the outlet, about 290kP
a, when the intermediate supercooler 50 is cooled by driving the cooling fan 53, the first compressor 32
About 60 ° C, about 170 kPa at the entrance of the
° C and about 300 kPa, which shows that the cooling effect is remarkable.

[0042]

As described above, according to the turbocharger system of the present invention, the following effects can be obtained.

Since only the intermediate supercooler is arranged in the intake passage between the two compressors of the low pressure stage and the high pressure stage, the turbocharger system can have a very simple configuration.

Then, the cooling fan for cooling the intermediate supercooler is driven by utilizing the exhaust gas energy after leaving the turbine of the low-pressure stage supercharger, which was normally discarded without recovering the energy as it is. Therefore, fuel efficiency and efficiency do not deteriorate, and energy can be used efficiently. Therefore, fuel efficiency is improved and engine output is also increased.

Further, if the performance of the drive turbine is adjusted in advance, the cooling amount is automatically adjusted to an appropriate value, so that no special control system is required.

That is, when the compressor of the low pressure stage requiring the cooling of the air supply generates a high compression ratio, the exhaust energy is large, so that the fan driving turbine rotates quickly, and the compression ratio which does not require the cooling of the air supply is required. Is low, the exhaust energy is small, and the rotation of the turbine for driving the fan is slow.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a turbocharging system according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbocharger system 12 Intake passage 22 Exhaust passage 30 First supercharger 31 First turbine 32 Second compressor 40 Second supercharger 41 Second turbine 42 Second compressor 50 Intermediate supercooler 51 Fan drive Turbine 53 cooling fan

Claims (1)

[Claims] An exhaust passage of an internal combustion engine includes a first turbine of a first supercharger driven by exhaust gas and a second turbine of a second supercharger, and is driven by the second turbine. In a turbocharger system in which a second compressor and a first compressor driven by the first turbine are arranged in two stages in series from the upstream side of an intake passage, a turbocharger is provided between the first compressor and the second compressor.
An intermediate air supply cooler for cooling the air supply that has been heated by being compressed by the second compressor, and a fan drive turbine provided downstream of the first turbine and the second turbine; A cooling fan driven by the turbocharger to cool the intermediate supply cooler.