JPS6126596Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to improvement of a supercharged internal combustion engine.

A supercharger, which performs supercharging by recovering exhaust energy that would otherwise be discarded to the outside as driving force for the intake compressor, does not impair the engine's driving force during operation, so it is an effective way to improve engine efficiency. It is seen as a promising method.

An internal combustion engine equipped with such a supercharger has conventionally been systemized as shown in FIG.

To explain this, in the figure, 1 is the engine body, 2 is an intake passage, 3 is an exhaust passage, and 4 is a supercharger.

The supercharger 4 includes a turbine 4a located in the middle of the exhaust passage 3 and rotated by exhaust pressure, and a compressor 4c directly connected to the turbine 4a via a rotating shaft 4b.
By driving c, the intake air from the air cleaner 5 is pressurized and the engine main body 1 is supercharged. The exhaust gas whose pressure has decreased after passing through the turbine 4a is muffled through a muffler (not shown) and is discharged to the outside.

This kind of supercharging effect becomes more noticeable at high loads with large exhaust energy, but the supercharger 4
As a result, the supercharging pressure tends to increase too much when the engine speed increases to a certain extent under high load because the engine is matched with those that effectively exert a supercharging effect even in the low engine speed range.

In order to deal with this, an exhaust bypass passage 7 is formed bypassing the turbine 4a, and an exhaust bypass valve device 8 (usually a waste valve) is configured to respond to the boost pressure in the intake passage 2 via a pressure signal passage 9. A valve port 8a called a gate valve, a swing valve 8b that opens and closes this valve port 8a, and this swing valve 8
and a swing valve controller 8c as an actuator. ), when the boost pressure exceeds a predetermined value, the exhaust bypass passage 7
is opened to allow part of the exhaust gas to be diverted.

By controlling the amount of exhaust gas supplied to the turbine 4a in this way, the supercharging pressure is controlled, and while a sufficient supercharging effect is obtained from the low engine speed range, the durability of the supercharger 4 and the engine body 1 is improved. This is to ensure that the system is not damaged.

In addition, in the event that the exhaust bypass valve device 8 described above malfunctions, the intake passage (intake manifold) 2 is provided with a relief valve 10, and when the pressure inside the intake passage 2 (supercharging pressure) exceeds a set value, the relief valve 10 closes.
Excessive intake air is released to the atmosphere through the

By the way, in such a supercharged internal combustion engine, in order to cool the above-mentioned supercharged intake air to prevent knocking as much as possible and to ensure high output, air cooling is installed in the intake passage 2 downstream of the compressor 4c. Some intercoolers (not shown) are installed.

In this case, the intercooler is usually provided between the compressor 4c and the intake throttle valve 11, and particularly located upstream of the relief valve 10.

Therefore, since the intercooler has ventilation resistance, if the exhaust bypass valve device 8 malfunctions, even if the supercharging pressure reaches the opening set pressure of the relief valve 10 or higher upstream of the intercooler, the In this case, the pressure may become lower than the valve opening set pressure and the relief valve 10 may not operate.

As a result, due to excessive intake pressure upstream of the intercooler, the intake passage (duct) 2 may fall off at the intercooler connection, or the intercooler core may become deformed, resulting in poor operation or a decrease in output. The dot was hot.

In addition, the exhaust bypass valve device is not limited to the relief valve 10, but also when the pressure signal passage 9 that applies boost pressure to the swing valve controller 8c of the exhaust bypass valve device 8 is connected to the intake passage 2 downstream of the intercooler. 8 does not operate properly, a situation similar to that described above may occur.

Therefore, in a supercharged internal combustion engine in which an intercooler is interposed in the intake passage downstream of the compressor, this invention aims to connect the boost pressure outlet of the pressure signal passage of the exhaust bypass valve device to the intake passage downstream of the compressor and upstream of the intercooler. A relief valve which is connected to the intake passage and is connected to the intake passage downstream of the compressor and upstream of the intercooler, opens when the exhaust bypass valve device fails and the boost pressure exceeds the set boost pressure, and regulates the maximum boost pressure; It is an object of the present invention to solve the above problem by providing a pressure sensor that detects the boost pressure so as to cut off fuel supply to the engine when the boost pressure exceeds a set boost pressure.

Hereinafter, embodiments of this invention will be described based on the drawings.

As shown in FIG. 2, an air-cooled intercooler 12, which will be described later, is interposed in the intake passage 2 downstream of the compressor 4c of the supercharger 4 and upstream of the intake throttle valve 11.

Similarly, a pressure signal passage 9 that applies supercharging pressure to the swing valve controller 8c of the exhaust bypass valve device 8 described above is applied to the intake passage 2A downstream of the compressor 4c and upstream of the intercooler 12.
The supercharging pressure outlet 9A is connected in communication.

Furthermore, in the intake passage 2A, there is a relief valve as a boost pressure control device that regulates the maximum boost pressure by releasing excessive intake air to the atmosphere when the exhaust bypass valve device 8 malfunctions. 10 is interposed.

In this embodiment, when the boost pressure exceeds a predetermined value set higher than the valve opening setting of the exhaust bypass valve device 8, the valve body 10a opens against the force of the valve spring 10b, and the excessive intake air is passed through the hose 10c. The air is discharged into the intake passage 2 upstream of the compressor 4c.

The intercooler 12 is located in front of the engine body 1 as shown in FIG.
The car cooler radiator (condenser) 15 and the engine cooling radiator 16, which are fixedly supported by the engine body 1 or the engine body 1 and are fixedly supported on the cross member 14, are mounted at their mounting positions so as to provide as little resistance to the running wind as possible. and the shape is selected.

In addition, the total opening cross-sectional area of the core 12a of the intercooler 12 is set to be approximately 2 to 4 times larger than the minimum opening cross-sectional area of the passage inlet of the compressor 4c, thereby reducing the flow velocity of the intercooler 12 and reducing ventilation resistance and cooling. Efficiency is being improved.

Furthermore, as shown in FIG. 4, the inlet portion 12b and outlet portion 12c of the intercooler 12 are formed into a substantially oval shape similar to the ducts of the intake passages 2 and 2A. Therefore, the joining is easy and there is no leakage, and it is possible to uniformly distribute intake air to each core 12a, thereby further reducing ventilation resistance.

In FIG. 3, 17 is a cooling fan, 18 is a hood, 19 is an undercover, 20 is a protection plate, and 21 in FIG. 4 is an intercooler mounting bracket.

The rest of the configuration is the same as that in FIG. 1, so the same members as in FIG. 1 are given the same reference numerals and explanations will be omitted.

With this configuration, the air taken in from the air cleaner 5 is pressurized by the compressor 4c, which operates in conjunction with the turbine 4a driven by exhaust gas pressure, and is supercharged to the engine body 1.

At this time, the supercharged intake air is cooled by the running wind by the intercooler 12 installed in the intake passage 2, so the intake air temperature decreases and the occurrence of knocking is suppressed, and the air density increases, so that the engine A high output is ensured.

As the load on the engine increases, the supercharging pressure also increases, and when this supercharging pressure reaches the valve opening setting pressure of the exhaust bypass valve device 8, the swing valve 8b opens and a part of the exhaust gas bypasses the turbine 4a. As a result, the rotation of the turbine 4a and the compressor 4c interlocked with the turbine 4a is reduced, and an increase in supercharging pressure is suppressed.

If this exhaust bypass valve device 8 malfunctions and the boost pressure increases further, the relief valve 10 will operate when the boost pressure reaches a certain set value and the maximum boost will be achieved as described above. Regulate pressure.

By the way, in this embodiment, the intercooler 12
Since the upstream intake passage 2A serves as a signal extraction passage for the supercharging pressure of the exhaust bypass valve device 8 and the relief valve 10 described above, the intercooler 1 due to the provision of the intercooler 12 in the intake passage 2
Even if the boost pressure upstream of the intercooler 12 becomes slightly higher than the boost pressure downstream of the intercooler 12 due to the ventilation resistance of 2, this boost pressure serves as a signal to activate the exhaust bypass valve device 8 or the relief valve 1 described above.
0 is activated to prevent supercharging pressure from becoming excessive.

As a result, the maximum value of the boost pressure upstream of the intercooler 12 is always regulated to an appropriate value, and as in the conventional example, the relief valve 10 and the like are provided in the intake passage 2 downstream of the intercooler 12, and the above-mentioned intercooler The relief valve 10 etc. do not operate due to fluctuations in the boost pressure upstream and downstream of the intercooler 12, and the boost pressure upstream of the intercooler 12 becomes excessive, causing the intake passage (duct) 2A, etc. to fall off, and the core 12a of the intercooler 12. Deformation of the engine, resulting in poor engine operation and a decrease in output, can be avoided.

Further, since an excessive increase in supercharging pressure is prevented in this way, wear of the bearings due to over-rotation of the turbine 4a and compressor 4c of the supercharger 4 can be further prevented.

Furthermore, in this embodiment, the shape of the core 12a of the intercooler 12, etc. described above reduces ventilation resistance as much as possible and reduces fluctuations in the supercharging pressure above and downstream of the intercooler 12, so that the supercharging effect is reduced. It has little impact on

Next, FIG. 5 shows another embodiment of this invention.

This includes a pressure sensor 22, which is a supercharging pressure detection device, instead of the relief valve 10 in the previous embodiment.
Based on the signal from the pressure sensor 22, a fuel cutoff signal is applied to the fuel injection valve 24 provided in the intake passage (intake manifold) 2 downstream of the throttle valve 11 via the fuel control circuit 23 to supply fuel. This is an example in which this invention is applied to a system in which the displacement of the engine main body 1 is reduced by shutting off the pump, and the boost pressure is controlled, and the maximum boost pressure is regulated.

In other words, in this case as well, by providing the pressure sensor 22, which is a supercharging pressure detection device, in the intake passage 2A upstream of the intercooler 12, the supercharging pressure upstream of the intercooler 12 can be adjusted as in the previous embodiment. It is obvious that excessive increases can be prevented.

Furthermore, in this embodiment, instead of cutting off the fuel supply based on the signal from the pressure sensor 22, even if the fuel amount is increased, the output of the engine body 1 can be reduced, and an excessive increase in supercharging pressure can be prevented. At the same time, it goes without saying that deterioration of the three-way catalyst (not shown) installed in the exhaust passage 3 can be prevented by bringing it to the reducing atmosphere temperature.

In the figure, 25 is an ignition switch, 26 is a throttle valve opening switch, and 27 is an air flow meter.

As explained above, according to this invention, in a supercharged internal combustion engine in which an intercooler is interposed in the intake passage downstream of the compressor, the turbocharger operates the exhaust bypass valve device provided in the exhaust passage that bypasses the turbine. A relief valve that opens when the boost pressure exceeds the set boost pressure and regulates the maximum boost pressure when the exhaust bypass valve device malfunctions, or shuts off fuel supply to the engine when the boost pressure exceeds the set boost pressure. The passage for taking out the boost pressure signal of the pressure sensor that detects the boost pressure is installed in the intake passage downstream of the compressor and upstream of the intercooler, so that the intercooler core will not be damaged due to an excessive increase in the boost pressure upstream of the intercooler. Deformation and falling of the intake passage (duct) can be avoided, resulting in improved engine operability and output performance.

Further, since an excessive increase in supercharging pressure upstream of the intercooler is prevented, wear of the bearing due to excessive rotation of the turbine or compressor of the supercharger can be further prevented.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the conventional example, Fig. 2 is a schematic diagram showing the first embodiment of the invention, Figs. 3 and 4 are sectional views of the main parts thereof, and Fig. 5 is the invention. FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention. 4a...Turbine, 4c...Compressor, 4
...Supercharger, 2...Intake passage, 12...Intercooler, 7...Exhaust bypass passage, 8...Exhaust bypass valve device, 9...Pressure signal passage, 9A...Supercharging pressure outlet, 10 ... Relief valve, 22 ... Pressure sensor, 2A ... Intake passage downstream of compressor and upstream of intercooler, 23 ... Fuel control circuit, 2
4...Fuel injection valve.

Claims (1)

[Scope of utility model registration request] A supercharger equipped with a compressor that is integrated with a turbine driven by engine exhaust pressure to supercharge intake air, and an intercooler that is installed in the intake passage downstream of the compressor and cools the supercharged intake air. In an internal combustion engine, a boost pressure outlet for operating an exhaust bypass valve device provided in an exhaust passage that bypasses the turbine, and a valve that opens when the boost pressure exceeds a set boost pressure when the exhaust bypass valve device malfunctions;
A relief valve that regulates the maximum boost pressure, or a pressure sensor that detects the boost pressure so as to cut off fuel supply to the engine when the boost pressure exceeds the set boost pressure, is connected to the boost pressure signal output passage downstream of the compressor. An internal combustion engine with a supercharger, characterized in that the supercharger is provided in each intake passage upstream of the intercooler.