JPS5912128A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To improve responsiveness of an internal combustion engine with an exhaust turbosupercharger, by providing a recirculation valve for recirculating a part of a fresh air to the low-pressure side of the supercharger at the initial stage of the compression stroke, and utilizing the energy possessed by exhaust gas as effective output of the engine. CONSTITUTION:Air-fuel mixture produced by a carburetor 8 is pressurized by a compressor 1 disposed coaxially with an exhaust gas turbine 2 driven by exhaust gas and then supplied to a combustion chamber when an intake valve 4 is opened. In such an internal combustion engine, a recirculation valve 5 is provided in the cylinder head in addition to the intake valve 4 and an exhaust valve 3, so as to recirculate a part of fresh air to the low-pressure side of the compressor 1 via a recirculation pipe 6 having a recirculation control valve 7 at the time when the recirculation valve 5 is opened. That is, the recirculation valve 5 is controlled to open and close at the first half of the compression stroke, while the recirculation control valve 7 is controlled to close at the time of high-load operation and to open at the time of low- or no-load operation of the engine.

Description

[Detailed description of the invention] The present invention is an internal combustion engine with an exhaust gas drive supercharger.

That is, it relates to a turbocharged internal combustion engine.

Turbocharging has become extremely popular in internal combustion engines in recent years, and has been adopted in many small internal combustion engines for automobiles. Turbocharged internal combustion engines perform supercharging using recovered exhaust energy, which has a significant effect on increasing maximum output and downsizing the engine.9 However, if the recovered energy exceeds the energy required for supercharging.

It cannot be said that the recovered energy is used effectively.

In order to utilize such exhaust energy, conventionally the exhaust gas was divided into two stages: one for supercharging and one for output.

The output shaft was connected to the engine's output shaft via a reduction gear train and a shock absorber. Therefore, the structure becomes complicated and there is a drawback that noise is generated.

Furthermore, conventional turbocharged internal combustion engines also have the disadvantage of low responsiveness.

An object of the present invention is to use relatively simple means to extract a portion of the exhaust gas recovered by the exhaust turbine as effective shaft output in excess of that required for supercharging, and at the same time improve the responsiveness of the engine. It's about improving.

The structure of the present invention includes an exhaust gas drive supercharger.

In addition, an internal combustion engine is provided with a return valve in addition to a normal intake valve and exhaust valve, so that a part of fresh air can be returned to the low pressure side of the supercharger through the return valve at the beginning of a compression stroke.

By adopting this configuration, fresh air compressed to more than the boost pressure expands in the cylinder in the latter half of the intake stroke, and at the beginning of the compression stroke, a part of the expanded fresh air returns and lowers the cylinder pressure. In order to keep it low, power is generated through the r-stiff and is taken out as an effective shaft output.

That is, the exhaust energy f recovered by the exhaust turbine is divided and distributed to supercharging and effective shaft output at appropriate ratios depending on the operating conditions of the engine. By controlling the recirculation of fresh air, the output can be rapidly increased or decreased, so responsiveness is greatly improved.

The figure is an explanatory diagram of an example in which the present invention is implemented in a gasoline engine with a carburetor. A compressor 1 is driven by an exhaust turbine 2 to compress intake air. There is an exhaust valve at the head of the cylinder 3. A return air valve 5 is provided in addition to the intake valve 4, and a portion of the fresh air is supplied from the return air valve 5]
A reflux pipe 6 is provided on the low pressure side of the compressor 1 for refluxing.

Therefore, the intake valve 4 closes before the end of the intake stroke.

The return air valve 5 is opened and closed during the first half of the compression stroke.

An example of the opening/closing timing is as follows: Intake valve closing timing Before bottom dead center 80 degrees Return valve opening timing Before bottom dead center 5 degrees Return valve closing timing Before top dead center 70 degrees 7 This is a return air control valve that adjusts the amount of return air.It opens when the load is light and closes as the load becomes heavier.

Note that 8 is a carburetor and 9 is a spark plug.

For example, in an engine with a high supercharging pressure of 1.7 kg/cm, the air is at about 8 pm before the bottom dead center of the intake valve 4.
After closing at 0 degrees, it expands in the latter half of the intake stroke, pushing down the first stone and generating power. That is, a part of the exhaust gas is used as effective shaft output.

During heavy loads, the return air control valve 7 is closed, so even if the return air valve 5 opens in the first half of the compression stroke, the fresh air that is taken in does not flow back through the return pipe 6, and all of the fresh air is compressed inside the cylinder. In other words, fresh air sucked in at a supercharging pressure of 1.7 kg/cm passes through the intake valve 4, which closes at 80 degrees before the bottom dead center, then expands and generates power, and when the cylinder reaches the bottom dead center, the The supercharging pressure becomes 0.3 kg/cm2, and from then on it operates exactly the same as a normal supercharging engine with a supercharging pressure of 0.3 kg/cm2.

When the load is light or no load, the return air control valve 7 opens, and the fresh air is not compressed in the first half of the compression stroke and flows into the Koni/Pure 9.
For example, fresh air that is recirculated to the low pressure side of dimension 1 has a boost pressure of 1.2
kg 70m (when the load is light, the outlet pressure of J1 is lower than that when the load is heavy), and after the intake valve 4 closes at 80 degrees before bottom dead center, it expands and generates power. When the gas is generated and the gas reaches 5 degrees before the bottom dead center, the pressure becomes equal to atmospheric pressure, and when the return valve 5 opens, the gas flows back through the return pipe 6. Thereafter, the cylinder pressure becomes equal to the inlet pressure of Sigillelli 1 until the return valve 5 closes 70 degrees before the top dead center of the cylinder. However, at this point, the cylinder volume is -3/3 of the cylinder volume when the cylinder is at bottom dead center, so the amount of air-fuel mixture that remains in the cylinder and is combusted next is reduced by the throttle valve in a conventional engine. The engine output is also equal to the case where the intake pipe pressure is -3/3 of the atmospheric pressure.In other words, in this engine, the output is controlled by the return air control valve 7, so the carburetor The throttle valve No. 8 performs only an auxiliary operation for adjusting the eye ring, and as a result, the engine's throttle loss or displacement loss is greatly reduced, and at the same time, the new throttle valve sucked into the cylinder is used for acceleration and deceleration. Since it is only necessary to control the air return WL, the response becomes extremely good.

Furthermore, during partial load, the air-fuel mixture that has been once drawn into the cylinder and heated in the air 1δ1 is recirculated, so the fuel vaporization is complete, and the fluctuations in the air-fuel ratio from one air point to the next and every η cycle are extremely small. Become. Therefore, stable operation can be achieved even with a lean mixture, and the fuel efficiency can be further improved.

In addition, in this engine, fresh air highly compressed by the Conlaret η1 expands in the latter half of the intake stroke in the cylinder, so fresh air is supplied from the outlet of the Conlaret 1 at a relatively high pressure and high temperature when the intake valve 4 is opened. . Accordingly, according to [1] of Nzirelli 1, if an intake air cooling device is provided between the intake valves 4, a large temperature difference can be obtained and the intake air can be effectively cooled. In other words, it is effective in lowering the turbine input temperature) and has a positive effect on increasing output.

In short, the present invention uses an extremely simple mechanism to recover and use exhaust energy f not only for supercharging but also for effective shaft output, and improves the responsiveness of the engine, thereby reducing the size and weight of a single engine and improving fuel efficiency. This has a great effect on improving responsiveness.

[Brief explanation of the drawing]

The figures are for detailed explanation of the present invention. 0 Figure 5 is a Conrare. 2 is an exhaust gas, 7.3 is an exhaust valve, 4 is an intake valve, 5 is a return valve, 6 is a return pipe, 7 is a return air control valve, 8 is a carburetor, and 9 is a spark plug. Applicant Isao Matsui [phase] 159-

Claims (1)

[Claims] An exhaust turbine drive supercharger is installed, and a return valve is provided in addition to the normal intake valve and exhaust valve, and at the beginning of the compression stroke, part of the fresh air is released from the return valve to the low pressure of the supercharger. Internal combustion engine 6 designed to allow air to flow back to the side