Simplified Supercharged Internal Combustion Engine With Emissions Control

Abstract

Internal supercharging of non-radial, reciprocating internal combustion engines is achieved by means of a unique form of crankcase compression. The engine includes a sealed crankcase and a first one-way valve in fluid communication with the crankcase and disposed so that external air is induced into the crankcase upon movement of the piston in one direction. An air reservoir is provided in fluid communication with the crankcase and a second one-way valve is disposed between the crankcase and the air reservoir so that air in the crankcase is forced into the reservoir upon movement of the piston in the reverse direction, the net effect being a positive displacement supercharger. Passageways are provided for introducing the resulting pressurized air into the cylinder and separately into the exhaust for afterburning purposes, a pressure regulator proportioning the airflows thereto. The pressurized air also pressurizes the fuel tank and thus the fuel supply to the engine. In a particular embodiment a lubricating oil reservoir is provided adjacent the air reservoir with air-oil separator means therebetween.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a simplified, supercharged reciprocating internal combustion engine with emissions control. More specifically, it relates to a reciprocating internal combustion engine wherein the crankcase is incorporated into the induction system by means of an air reservoir and multiple valve means whereby pressurized air for supercharging, fuel system pressurization and emission control is efficiently generated by crankcase compression.

While the present invention will be described with particular reference to two- and four-stroke cycle gasoline-fueled internal combustion engines, it should be understood that the invention is not limited thereto. The supercharging, pressurization and emission-control concepts disclosed herein can also be adapted for use with other internal combustion engines burning various engine fuels, including diesel fuel, liquefied petroleum gases and other fuels not yet in widespread use, as those skilled in the art will recognize in the light of the present disclosure.

2. Description of the Prior Art

The history of the internal combustion engine to its present stage of high development reflects continued and protracted efforts by the automotive and aircraft industry to increase the efficiency thereof, particularly in terms of power output per unit of fuel and power output per unit of weight. Thus, for example, there has been progressive increase in compression ratios and power output over the years and corresponding increase in the octane number of the gasoline fuels to accommodate the same. Supercharging is becoming more prevalent.

More recently, ecological consideration have resulted in greater emphasis being placed upon the pollution problems associated with the internal combustion engine. The private automobile, for example, has been blamed for more than half the pollutants in the atmosphere adjacent large population centers in the United States, the pollutants including crankcase and fuel supply emissions as well as the more obvious exhaust emissions. These interrelated and sometimes conflicting efforts to increase engine output and yet control emissions are reflected in the prior art.

Connolly et al. U.S. Pat. No. 1,283,399, for example, discloses a two-cycle engine in which pressurized air from the crankcase is routed to ejector nozzles in the exhaust and fuel inlet passages to induce the more rapid flow of the exhaust gases and air fuel mixture respectively. The object is to more effectively exhaust and scavenge the cylinder of the engine than in two-cycle engines of conventional design, thereby increasing engine output. Such two-cycle engines, however, burn a mixture of gasoline and lubricating oil, making effective emission control non-feasible.

Another approach is reflected in Spencer U.S. Pat. No. 1,812,566, which discloses a four-cycle engine having a separate centrifugal-type supercharger driven by the engine crankshaft. At least a portion of the air-flow to the supercharger passes through the crankcase whereby the latter is ventilated and cooled simultaneously. The addition of a separate supercharger and the attendant complexity increases the weight, initial cost and operating expenses of the engine and aggravates the maintenance problems.

Still another approach is reflected in Kylen U.S. Pat. No. 2,067,715, which discloses a four-cycle engine having a rotary valve and special ductwork whereby pressurized gases from the crankcase can be introduced directly into the cylinder when the piston reaches the bottom of its stroke. In addition to added complexity, the supercharging gases pulsate in pressure unduly because no reservoir space having valved separation from the crankcase is provided. Also, the introduction of the supercharged gas at the bottom of the cylinder could interfere with the introduction of the fuel supply via the conventional valve inlet at the top of the cylinder. Additional complexity results from the fact that the lubrication system is independent of the crankcase.

Another approach, which is directed specifically to supplying air to the exhaust system for afterburning and exhaust emission control, is disclosed in Schrag U.S. Pat. No. 3,491,533. An air blower drawing air from the air filter is driven by belt drive from the crankshaft. The output of the air blower is then introduced into the exhaust system. This approach does not provide engine supercharging and involves a separate blower system. It results in a lower loss in exchange for limited exhaust emission control.

Still other efforts are disclosed, for example, in the article entitled "GM's New Supercharger" in the April 1970 edition of "Science & Mechanics". It involves separate dual compressors with intercoolers and aftercoolers, 3,000 psi trunk compartment tanks, a third valve for each cylinder, and associated hardware and controls. While only useful when accelerating for passing and emergency situations, it illustrates the extreme complexities to which designers will go to obtain problem free supercharging. Yet it doesn't control emissions continuously or effectively.

OBJECTS OF THE INVENTION

It is therefore a general object of the present invention to provide a combined supercharging and emission control system for internal combustion engines which has the advantages of prior art approaches without certain of the disadvantages thereof. It is another general object to provide simplified supercharging for reciprocating, non-radial internal combustion engines along with a completely closed induction system and total emissions control.

It is another general object to cope with the problems of prior art efforts to achieve supercharging and emissions control in a more efficient and less costly manner. It is still another general object to provide a system of supercharging and emissions control for internal combustion engines which can be applied thereto without radical engine redesign or the requisite addition of auxiliary blowers or the like.

It is a specific object to provide a low cost supercharging system relying upon crankcase compression wherein the supercharging pressures do not fluctuate to the same extent as on similar prior art engines. It is another object to provide a supercharged internal combustion engine of simplified design wherein excess supercharging air is employed for exhaust emission control. It is still another specific object to provide a supercharged internal combustion engine relying upon positive-displacement crankcase compression wherein the pressurized air is employed for supercharging, emissions control and pressurization of the fuel system.

These and other objects of the present invention will become apparent as the detailed description thereof proceeds.

SUMMARY OF THE INVENTION

These objects are achieved in a particular embodiment by a reciprocating internal combustion engine primarily comprising conventional elements and, in addition, new or modified elements which make possible the many advantages of the present invention without major additional cost or complexity. The engine comprises a cylinder with inlet and exhaust passages, a piston reciprocally disposed within the cylinder, the piston having a conventional piston rod secured thereto, the latter driving a crank assembly for translating reciprocating movement of the piston into rotary movement.

The crankcase of the engine is sealed relative to said cylinder in the sense that displacement of the piston will increase or decrease the pressure within said crankcase depending upon the direction of movement. The crankcase has a one-way inlet valve disposed so that external air from the engine air intake, which is preferably filtered, is drawn into the crankcase upon a compression or exhaust strokes of the piston (in the four-cycle embodiment). The sealed crankcase is in fluid communication with an air reservoir and separated therefrom by means of a second one-way valve whereby air in the crankcase is forced into said reservoir upon a power or induction stroke of the piston. The pressurized air in the reservoir becomes the source of air for supercharging, for exhaust emissions control and for pressurizing the fuel system.

In a particular embodiment, there is a lubricating oil reservoir in fluid communication with the crankcase and the air reservoir. To avoid any undesired entrainment of oil in the supercharging air, an air-oil separator such as, for example, louvered baffle, wire mesh screen, loose packed metal shavings or the like, or combinations thereof, is employed. The separator should not unduly restrict airflow but should trap entrained oil.

To control pressure in the system, a pressure regulator is provided whereby air pressure is maintained at a preset or predetermined maximum value, e.g., 10-20 psig, as the case may be. This is readily accomplished by a simple waste gate or dump valve which proportions the pressurized air going to the engine and to the exhaust system. Whenever the pressure incipiently increases above the predetermined value, additional air is vented via the exhaust system where it aids in exhaust emissions control. Thus, for example, the dumped air would provide oxygen for combustion of unburned hydrocarbons, that is, afterburning, and would dilute the exhaust gases and thereby drop the temperature thereof or at least offset the temperature rise resulting from afterburning.

In addition to supercharging and emissions control, the pressurized air from the positive displacement crankcase supercharger may be employed for pressurizing the fuel system, resulting in a completely enclosed induction system. As will become apparent from the drawings, the pressurized fuel system eliminates the escape of fuel vapors into the atmosphere, a significant contributing cause to pollution. At the same time it eliminates the pressure differential between the carburetor inlet and fuel tank.

Another benefit is, of course, the cooling of the crankcase which inherently takes place and the diversion of crankcase emissions, including those resulting from piston blow-by, back into the combustion chamber or, in part, to the exhaust where the supercharger bypass air completes the combustion thereof. Accordingly, the supercharging of the engine is accomplished by a completely enclosed induction system and total emissions control.

The one-way valves employed in the practice of the present invention may comprise conventional valve means, including poppet valves, rotary valves, reed-type check valves, and equivalents. The reed-type check valves are preferred. They are inexpensive, long lasting and fully adequate for the purpose intended.

The present invention is adaptable for use in connection with either single cylinder or multi-cylinder installations. It is particularly advantageously employed with opposed cylinder engines such as encountered with the well-known Volkswagon and Corvair engines. It may also be used in connection with inline engines and, less advantageously, in connection with V-type engines. Radial engines do not, of course, lend themselves to supercharging by the present invention, as those skilled in the art will recognize.

Manifestly, in multi-cylinder engines crankcase sealing between adjacent cylinders is required and, in many cases, such sealing does not require a major engine redesign. A typical embodiment may have a crankcase compression ratio of about 3 to 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more clearly understood from the following detailed description of specific embodiments, read in conjunction with accompanying drawings, wherein:

FIG. 1 is a diagrammatic elevation view in section showing the present invention as applied to a four-cycle engine; and

FIG. 2 is a similar diagrammatic view in section showing the present invention as applied to a two-cycle engine.

It should be understood that these drawings are diagrammatic and graphic symbols are employed therein and that the drawings are not necessarily to scale. While much mechanical detail has thus been omitted, the simplified presentation is believed to be more readable and readily understandable by those skilled in the art. It should also be understood, of course, that the invention is not limited to the particular embodiment illustrated.

DETAILED DESCRIPTION OF THE DRAWINGS, INCLUDING PREFERRED EMBODIMENTS

Referring to FIG. 1, the four-cycle internally supercharged gasoline-fueled engine comprises cylinder 10 with spark plug (not shown), fuel inlet valve 12 and exhaust outlet valve 14 with corresponding fuel inlet passage 16 and exhaust outlet passage 18, respectively. As piston 20 reciprocates, piston rod 22 rotates crank 23, crank counterweight 24 and crankshaft 25 within crankcase 26.

As piston 20 travels upward on either the compression stroke or exhaust stroke, air from air cleaner 28 is induced via air intake 30 and one-way truncated pyramid-shaped reed valve 32 into the crankcase and lower portion of the cylinder. As piston 20 travels downward on the power stroke or fuel induction stroke, the air in the crankcase is compressed and forced via reed-type valve 34 and air-oil separator screen 36 into air reservoir 38. It should be recognized that air reservoir may be larger or smaller or configured differently to suit particular situations and various design parameters.

Lubricating oil reservoir 40 is separated from the pressurized air reservoir 38 by means of air-oil separator screens 42. The air-oil separators 36 and 42, which may of any efficient conventional design, as aforementioned, are required to separate the lubricating oil from the induction system.

Pressurized air from reservoir 38 communicates via duct or pipe 44 with carburetor inlet passage 46 and bypass passage 48 which in turn communicates with exhaust passage 18 via reed-type check valve 50. The proportion of pressurized air diverted to carburetor inlet passage 46 and by pass passage 48 is determined by the position of waste gate or dump valve 52. Gate 52 is pivotally mounted at axis 54 and is moved by lever arm 56 which is in turn positioned by arm 58 of pressure regulator 60, which senses the pressure at the inlet to carburetor 62 by means of probe 64.

Fuel tank 66 is pressurized by pressurized air which communicates therewith via passageway 68. Fuel tank 66 is pressure-sealed by means of reed-type valve 70. Fuel from the fuel tank enters carburetor 62 via line 72.

To relieve all trapped pressure when the engine is not operating, pressure regulator 60 is overridden by a solenoid (not separately shown) at engine shutdown. This allows the pressurized air to enter exhaust manifold 18 via bypass passage 48.

Referring to FIG. 2, the two-cycle supercharged engine of the present invention comprises cylinder 100 having spark plug 102 and intake port 104 and exhaust port 106. Piston 108 having deflectors 110 and 112 reciprocates within cylinder 100 whereby connecting rod 114 rotates crank 116 and thus crankshaft counterweight 118 and crankshaft 120. Crankshaft 122 is sealed to cylinder 100 whereby, as in the four-cycle engine of FIG. 1, air from engine intake 124 is induced into crankcase 122 via one-way reed-type valve 126 upon the compression stroke of piston 108. Thus, when piston 108 descends during a power stroke, the entrapped air is compressed and forced into air reservoir 128 via reed-type valve 130 and air-oil separator screen 132.

Air reservoir 128 is separated from lubricating oil reservoir 134 by louvered baffle 136. Still further air-oil separation is achieved by means of loosely packed metal shavings 138 which are held in place by screens 140 and 142.

Pressurized air from supercharging and emissions control passes from reservoir 128 via passageway 144. The proportions which pass into carburetor inlet passageway 146 and bypass passageway 148 are determined by the position of pressure control means 150, which in this exemplar may be a diaphragm-actuated pressure control valve with pressure sensing at the carburetor inlet (not shown).

A pressurized fuel system may be employed as in FIG. 1 wherein pressurized fuel is introduced to pressurized carburetor 152 and thence to inlet port 104. Bypassed air enters exhaust manifold 154 via bypass 148 for purposes of afterburning.

Lubricating oil is circulated from oil reservoir 134 to the engine air intake 124 by means of engine-driven oil pump 156 and oil line 158. If an external supercharger were mounted on the engine air intake, the engine-driven oil pump 156 could be eliminated, the oil being adequately circulated by the resulting pressure differentials.

From the above description it is apparent that the objects of the present invention have been achieved. While only certain embodiments have been set forth, alternative embodiments and various modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of the present invention.

Claims

Having described the invention, what is claimed is:

1. A supercharged internal combustion engine comprising in combination:

a. a cylinder with inlet and exhaust passages;

b. a piston reciprocally disposed within said cylinder, said piston having a piston rod secured thereto;

c. a crank assembly secured to said piston rod for translating reciprocating movement of the piston into rotary movement, said crank assembly being housed within a crankcase sealed pressurewise relative to said cylinder;

d. a first one-way valve means in fluid communication with said crankcase and disposed so that external air is induced into said crankcase upon movement of said piston in one direction;

e. an air reservoir in fluid communication with said crankcase;

f. a second one-way valve means disposed between said crankcase and said air reservoir so that air in said crankcase is forced into said reservoir upon movement of said piston in the reverse direction; and

g. a passageway for pressurized air between said air reservoir and said inlet and exhaust passages.

2. The engine of claim 1 including a vessel for a fuel supply in fluid communication with said inlet passage and passageway between said air reservoir and said vessel whereby pressurized air pressurizes the fuel supply therein.

3. The engine of claim 1 including an oil reservoir adjacent said air reservoir and an air-oil separator means therebetween.

4. The engine of claim 1 wherein said valve means comprises reed-type check valves.

5. The engine of claim 1 including pressure regulating means controlling the pressure in said air reservoir.

6. The engine of claim 5 wherein said pressure regulating means bypasses pressurized air from said air reservoir to said exhaust passage when the air pressure in said air reservoir incipiently increases above a predetermined value.

7. The engine of claim 1 including override means on said air pressure regulator to drop the pressure to ambient conditions upon shutdown of said engine.

8. The engine of claim 7 wherein said override means comprises a solenoid-controlled dump valve.

9. The engine of claim 2 including one-way pressure relief valves in said exhaust passage and in said fuel supply vessel.

10. A supercharged internal combustion engine comprising in combination:

a. a cylinder with inlet and exhaust passages;

b. a fuel supply vessel in fluid communication with said inlet passage;

c. a piston reciprocally disposed within said cylinder, said piston having a piston rod secured thereto;

d. a crank assembly secured to said piston rod for translating reciprocating movement of the piston into rotary movement, said crank assembly being housed within a crankcase sealed pressurewise relative to said cylinder;

e. a first one-way valve means in fluid communication with said crankcase and disposed so that external air is induced into said crankcase upon movement of said piston in one direction;

f. air and oil reservoirs in fluid communication with said crankcase, the air and oil reservoirs being separated by air-oil separator means;

g. a second one-way valve means disposed between said crankcase and said air reservoir so that air in said crankcase is forced into said air reservoir upon movement of said piston in the reverse direction;

h. passageways for pressurized air between said air reservoir and said inlet and exhaust passages and said fuel supply vessel; and

i. pressure regulating means controlling the pressure of the pressurized air.