ES2405283B1 - LOAD RENEWAL SYSTEM IN INTERNAL COMBUSTION ENGINES OF 4 TIMES WITH COMMON VALVE AND FLOW CONTROLLED BY SHEETS. - Google Patents

Abstract

The present invention aims to improve the renewal of the load in the 4-stroke alternative internal combustion thermal engines by using common valves for the renewal of the load. This means that all cylinder valves are used for both intake and exhaust (improving the exchange area). In order for the engine to work in these conditions it is necessary to regulate the flow out of the cylinder. The solution adopted in this invention are reed valves similar to those used in time thermal engines. One of them will be placed on the intake branch and another on the exhaust branch just before communicating with each other in a common duct or volume. This volume will be connected to the cylinder and will circulate both the fresh mixture (or air only) and the exhaust gases.

Description

SYSTEM OF RENEWAL OF THE LOAD IN INTERNAL COMBUSTION ENGINES OF 4 TIMES WITH COMMON VALVE AND FLOW CONTROLLED BY SHEETS

Technical sector

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The invention is part of the technological sector of alternative internal combustion engines. Specifically, it is part of technical modifications that improve the process of renewal of the load (air intake) in four-stroke engines.

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State of the art

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The behavior of Alternative Internal Combustion Engines {MCIA} is largely determined by their capacity to renew the load. That is, the ability of the engine to evacuate the exhaust gases (residual products of combustion) and replace them with air or fresh air-fuel mixture and in adequate conditions to be combusted and continue the cycle.

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The process of renewal of the load (breathing) has a direct relationship with the performance of the engine. The greater the mass flow of fresh air admitted, the greater the amount of fuel is susceptible to being burned, and therefore, greater torque or effective power generated. To measure the efficiency of this process, a parameter known as volumetric efficiency is usually used. This relates the degree of filling achieved with gas ut with respect to the maximum theoretical possible.

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For the reasons mentioned, much of the development and optimization of MCIA since its inception has focused on the improvement of volumetric performance. This depends on a large number of variables, but since it is related to the flow of gas through the motor ducts, the most important are the pressure losses in the circuit and the time available to perform the renewal. Under this perspective, of all the elements that flow through the fresh flow (air filter, manifolds, ducts ...) the greatest restriction is in the inlet valves to the cylinder. The classic intake system by seat valves offers a very small passage surface, which accelerates the flow, often reaching shock situations (sonic blocking), reducing filling capacity. This phenomenon is more pronounced the higher the engine's rotation regime, since the flow rate increases (and with it the dynamic friction losses) and the time available to admit and expel gases is less.

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Simplifying the case study, the problem fundamentally lies in the fact that the passage area of the valves is limited by the size of the cylinder and the elements that must be housed in it (spark plugs, injectors ...). Therefore, the solutions provided to date to improve volumetric performance are quite complex mechanically. The ones of greater application at present are the systems of variable distribution, where the elevation of valve is modified (valve lift) or the moment and duration of opening of the same (valve timing) according to the speed of rotation of the engine.

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Therefore, it is convenient for the increase of engine performance, to develop specific mechanisms or solutions aimed at increasing the capacity of renewal of engine load. This patent proposes 2 novel ideas that combined can be viable and profitable. At present there is no commercial engine with similar solutions.

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The use of a common valve for intake and exhaust has already been addressed in previous patents, but without success. Partly because of the complexity of the system and lack of flow regulation on the actual solution adopted. The proposed control mechanism, with reed valves, has never been employed as suggested. Neither commercially nor in any other invention. It is true that these mechanisms are widely spread in the market for 2-stroke engines, but as far as is known, their use as flow regulator systems in a 4-stroke internal combustion engine of common valves has not been considered.

Detailed description of the invention

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The present invention proposes a special system of renewal of the load in 4-stroke engines. A common valve system for intake and exhaust is suggested whose flow is governed by reed valves (they work by pressure difference). The objective is to improve the flow of fresh gas to the cylinder (high volumetric efficiency) in a simpler and cheaper way than with the variable distribution systems existing to date. Ideas and mechanical elements already known are combined for this, but whose operation as a whole represents a great novelty.

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   It should be clarified that the presented invention is valid for any alternative 4-stroke internal combustion engine. This means that it applies to both atmospheric and supercharged engines, compression ignition (diesel) or ignition (gasoline), direct or indirect injection. Its operation is independent of any of these variables, since the process of renewal of the load is similar in all of them. However, the main advantage of this proposal over existing ones (variable distribution systems) is, as

mechanics have increased. For this situation to occur with the regime more

high possible, the size of the valves is increased as much as possible

number or its opening length (raised), looking for the maximum passage area for the

gas. However, these parameters are directly limited by geometry and

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cylinder dimensions. The intake and exhaust valves are different and

independent, and its dimensions are limited by the caliber of the cylinder and the

adjacent elements (spark plugs, injectors ...). On the other hand, the elevation is limited by

the possibility of collision of the valves with the piston and also by a suitable

low speed engine operation that requires valve openings

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little.

As a measure to alleviate these problems, the main solution provided by the system

It is proposed to use all cylinder valves for the same processes. This is,

the same valves by which the admission of fresh mixture (or only air in the

case of a diesel or direct injection engine) will serve to evacuate the gases from

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exhaust combustion product. In this way, the area would almost double

useful for the passage of gases to or from the cylinder. Even in the case of an engine

extremely simple 4-stroke, it would not be necessary to have at least 2

valves (one for intake and one for exhaust). In this case you could have a

single valve This system is called here, known as a single valve

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(monovalve), common valve or dual use valve (dual duty

valve).

This conception of the engine, although it is new, since there are not too many

engines running like this in the world (none commercial), it is not entirely innovative.

There is evidence of some old patents that dealt with this type of

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engine. The main problem with this type of mechanism is to maintain

4-cycle engine cycle (its processes) in operation using only valves

common.

For a common valve system to work in practice it is necessary to separate the

Inlet flow of the exhaust out of the cylinder. But, upon fair admission

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after the escape, there is a risk of introducing a mixture back into the cylinder

of burnt gases instead of a fresh mixture. It is in the solution of this point

where it is believed that previous attempts were unsuccessful, by providing solutions

extremely complex mechanics or solutions based on the dynamic fluid of the

gas that were practically not applicable. The solution proposed in this

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invention is the regulation of intake and exhaust flows by means of simple

reed valve systems that work by pressure differences.

The general scheme of the proposed system can be seen in the accompanying figure 1

   This technical memory. The elements that flow through the flow of fresh air in its first

part of the route to the engine are the usual ones in any engine of

alternative internal combustion (MCIA). Starting from the atmosphere (1) it passes through the

air filter (2), intake ducts (3), or any other item that is

deem necessary. Just at the end of this group of elements, before the duct

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divide each of the different cylinders (assuming the engine is not

single cylinder) a reed valve (4) similar to those used would be installed

for admission to crankcase in 2-stroke engines. A generic image of it

it can be seen in figure 2. Its correct position would be the one indicated in figure 1, with

the vertex of the sheets in the direction of advance of the incoming air.

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This valve flows into a volume of small dimensions (5) that has been

called common duct already communicates with the branch of gases of

escape. This volume can be a small section of duct or have a

geometry everything complex that interests, but in general, it will be interesting

as small as possible to avoid gas storage between cycles.

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The exhaust leaf valve (8) is similar to the intake valve but is located in

reverse direction. That is, with the vertex of the sheets towards the direction of exit of the

exhaust gases. Downstream of the exhaust blades, all the

typical and necessary elements that a MCIA can have. Exhaust ducts (9),

smoke treatment systems, catalysts, silencers, etc. (10), until evacuating

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the gases to the atmosphere (1).

The common duct (S), through which both fresh and exhaust gases circulate

It communicates immediately with the cylinder valve (s) (6). During the phase of

4-stroke engine exhaust, burned gases will leave the cylinder (7) for these

ducts, while in the rear (intake phase) clean air will flow into the

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inside of it. Mixing of both is avoided by regulating the flow with the valves of

sheets, as explained below based on the scheme in Figure 1.

During the exhaust phase, the cylinder valves are open and the product gases

of combustion that have higher atmospheric pressure (3-4 [bar]) and high

temperature flood the inlet ducts to the cylinder and the common duct. How

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the pressure is high in that area, the exhaust blades open, letting the gas flow

towards the escape branch. As the piston rises from the neutral

lower (PMI) towards the upper dead center (PMS) this gas is evacuated, and the

Common duct pressure is approaching atmospheric.

Upon reaching the PMS and starting the descent (admission phase), a depression is generated in the

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common area, so that the exhaust plates are closed and when mounted in

in the opposite direction, the admission ones are opened, leaving fresh air free passage through the

   admission branch. In this way, the flow outside the cylinder is regulated allowing the

Engine work with double flow valves without problem of mixing the intake and exhaust flows.

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As added advantages to this idea, by working the cylinder valves with intermittent flows (hot / cold), better engine cooling occurs. The possible problems of high temperature exhaust gases are also minimized, and especially the problems of cooling and mechanical resistance of the exhaust valves are reduced, which is often a problem in engines of this type.

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Therefore, the present invention does not involve the creation of an innovative common valve engine, since it was recorded in previous patents. Nor are reed valves themselves a novel idea. The innovation of the present idea comes from the combination of both solutions. The possibility of making an old idea viable as was the single-valve motor thanks to its combination with a well-known and very simple system such as reed valves.

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The blades simply allow a motor design to be practically feasible, which in itself can obtain a volumetric performance superior to the usual commercial engines. The advantage of this proposal with respect to the current systems of variable distribution with which large volumetric yields are achieved is the simplicity and economy of this new model. Cylinder seat valves are less thermally requested, which could reduce their manufacturing cost. There is a single camshaft for intake and exhaust that can be fixed. All mechanisms to vary the valve elevation or the valve opening and closing time of a variable system are eliminated. As a counterpart, it is necessary to include new elements that are reed valves. However, its cost is much lower than any of the aforementioned.

Description of the drawings

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Figure 1 shows the general scheme of the charging system in a 4-stroke alternative internal combustion engine with common valve and flow control by valves. The combustion air is admitted directly from the atmosphere

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   (1) through the filter (2) and circulates through the different intake ducts (3). At the end of this branch you find the intake reed valve (4) that communicates with the volume or common duct (5} From this volume the flow can travel to the exhaust through the exhaust leaf valve (8}, through the exhaust ducts (9} and the various gas treatment systems (10} to finally be evacuated to the atmosphere (1}.

The other path the flow can take from the common volume (S)

is to him

inside the cylinder (7), to which you will have access through the seat valves (6).

In

the figure 2 be sample a scheme from a valve from sheets since two

different perspectives The valve body (1) has holes or windows

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(3) through which the flow can circulate. For this it is necessary that the sheets

metal (4) that cover (close) them in their normal resting position

deformed as shown in figure 2. In

that situation is says the valve is

open and flow circulation is possible. To avoid excessive opening of the

sheets,

these present a stop, top, maximum as a noun, top as an adverb from opening (4) that is metal and rigid (no

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   deformable).

Claims (2)

1. Load renewal system in alternative internal combustion engines

4-stroke characterized by understanding:

to.

One or several common valves that serve both for the admission of air (or

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air / fuel mixture) into the cylinder and also to

evacuate exhaust gases from combustion.

b.

An independent intake and exhaust duct in its initial part

that communicates them

with the atmosphere, but releases in a volume

very small common found after control valves

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(sheets) if the direction of flow into the cylinder is followed.

C.

A reed valve in the intake duct located in such position

which will open when the pressure in the intake duct exceeds that of the

common volume

d.

A reed valve in the exhaust duct located in such a position that

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it will open when the pressure in the common volume exceeds the pressure in the

exhaust duct This means that it is located in an inverse position to the

of admission.

2. Load renewal system in alternative internal combustion engines

4-stroke according to claim 1, wherein the flow into the cylinder

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It is controlled by the opening and closing of the common seat type valve

while the reed valves exert control over the flow entering or leaving

in the common volume.