HK1020764A - Method for pollution abating engine and installation on a city bus and other vehicles - Google Patents

Description

Method for reducing engine pollution and its installation on city bus and other vehicles

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The present invention relates to a method for reducing engine pollution with a separate expansion chamber and its installation on city buses and other vehicles.

In french patent application, national registration number 95/02838, the authors have described a method for a pollution-reducing engine with a separate external expansion chamber, in this method, an air-fuel mixture is drawn into a separate intake and compression chamber and compressed therein, and then (still under pressure) to a separate combustion chamber, to be ignited therein or with a spark in the case of an engine with a homogeneous mixture, or in the case of diesel engines with heterogeneous mixtures, with natural ignition, in order to increase the temperature and pressure of the above-mentioned mixture, the mixture will expand in the latter chamber after the transfer means of the aforementioned independent combustion chamber and expansion and exhaust chamber (which is also independent) are opened, in order to perform work therein, and then be exhausted to the atmosphere through the exhaust pipe; in this method, when operating in town (or with low power), the fuel injector is no longer operated, and in this case a small amount of supplementary compressed air from an external air reservoir, in which compressed air is stored at very high pressure, is fed into the combustion chamber, slightly after the fuel-free compressed air from the inlet cum compression chamber has entered the combustion chamber. This small amount of compressed air will be heated and expanded upon contact with the mass of hot air contained in the combustion chamber so as to increase the pressure in the combustion chamber, thereby producing work upon expansion. Thus, such engines employ dual mode or dual energy operation.

In urban and suburban areas, public transportation is often provided by urban buses driven by conventional engines, which are often diesel engines with heterogeneous mixtures, which are particularly polluting.

Attempts have been made to drive these vehicles on fuels which are said to be less polluting (diesters, liquefied petroleum gas, etc.), but the results are particularly weak in terms of pollution.

The method of reducing engine pollution and its installation on urban buses makes it possible not only to eliminate the discharge of all the polluting gases, but also to allow the pollutants to be removed locally and in large quantities from the air in cities and towns.

Characterized by the fact that the measures used, in particular in order to facilitate the removal of the above-mentioned fuel route of the engine for single-mode operation with injection of only supplementary compressed air, consist in installing one or more activated carbon filters or any other filtering and purifying means such as molecular sieves, chemical means and the like upstream of the air inlet into the intake and compression chamber of the engine, not only to intercept dust and other scum, but also to purify the air entering the engine while removing the pollutants therefrom.

When installed on an urban bus, the pollution-reducing operation of the engine according to the invention and the ecological advantages it represents over conventional engines can be understood. The supplementary compressed air stored at very high pressure in the vehicle's air reservoir is filtered and purified by means of an activated carbon filter or the like before being compressed, the ambient air (contaminated by other vehicles) drawn into the inlet cum compression chamber by the engine is filtered and purified by means of an activated carbon filter (or any other means enabling its purification); it is thus clear that the air after expansion and exiting through the exhaust port is still filtered and purified. Furthermore, since the mode of operating the engine on conventional fuel has been eliminated, there is no longer any particulate or other residue from the previous combustion left in the combustion chamber (which thus becomes the expansion chamber).

The engine method according to the invention can be used for all vehicles, but it requires a large amount of additional compressed air and a relatively large storage container on board the vehicle. It is particularly attractive when installed on urban buses, on the one hand, in view of the large amount of air drawn into the engine, thus enabling pollutants to be removed from a considerable volume, and on the other hand, in view of the possibility of installing a large-volume reservoir of make-up compressed air on the bus, and, incidentally, also because, when the bus is heavily parked, the reservoir of make-up compressed air on board the vehicle can be constantly filled by installing an air-filling station at the bus stop or at the parking lot.

The method is equally applicable to service vehicles (garbage and other service vehicles and taxis or small vans operating in urban environments).

Other objects, advantages and features of the present invention will become apparent upon reading of the non-limiting description of an embodiment of the invention, given with reference to the accompanying drawings, in which:

the only figure shows, in a diagrammatic and sectional view, an embodiment according to the invention in which the inlet and compression chambers and the expansion and exhaust chambers are each controlled by a system consisting of a connecting rod, a crank and a piston sliding in a cylinder, in which the inlet and compression chamber 1, the volumetric expansion chamber 2 and the expansion and exhaust chamber 4 can be seen, in which an injector 22 for the supplementary compressed air is housed, which is supplied with compressed air stored in an air reservoir 23 at very high pressure. The intake/compression chamber 1 is connected to the expansion chamber 2 through a port 5, and the opening and closing of the port 5 is controlled by a shutter 6 sealed. The expansion chamber 2 is connected to the expansion and exhaust chamber by means of a port 5 or a transfer device 7, and its opening and closing is controlled by a sealed shutter 8. The inlet cum compression chamber 1 operates like a reciprocating compressor set in which a piston 9 sliding in a cylinder 10 is controlled by a connecting rod 11 and a crankshaft 12. The expansion and exhaust chamber 4 controls a conventional piston engine block having a piston 15 sliding in a cylinder 16, which rotates a crankshaft 18 via a connecting rod 17. The expanded air is discharged through an exhaust port 19, the opening of which is controlled by a valve 20. The rotation of the crankshaft 12 of the intake/compression chamber 1 is generated by the motive power crankshaft 18 of the expansion/exhaust chamber 4 through a mechanical rod 21. The engine is shown in a situation where the air that has been purified and decontaminated from it by the activated carbon filter 24 has been sucked into the expansion chamber 2 and compressed therein in a suction-compression cycle performed by the piston/connecting rod/crank set (9, 10, 11), while the port 5 has been closed by the sealed shutter 6. The air purified and compressed in the expansion chamber 2, from which the pollutants have been removed, is therefore at a high temperature (several hundred degrees, depending on the compression ratio chosen), after which the ejector 22, supplementing the compressed air, operates to let in a small amount of compressed air at ambient temperature, which expands to a pressure slightly higher than that in the expansion chamber 2 to enable it to enter the chamber; this small quantity of compressed air, when in contact with the mass of air at high temperature contained in the expansion chamber, will be heated and expand and increase the pressure so that it does work when it expands, which expansion will occur when the piston 15 of the expansion chamber reaches top dead centre and opens the delivery duct 7 controlled by the sealed shutter 8. This expansion with hot air is carried out until the expansion piston 15 driving the engine powered crankshaft 18 reaches bottom dead center, after which the expanded, contaminant-free and cleaned air is discharged to the atmosphere via the exhaust pipe 19, while the valve 20 is opened, while the piston 15 of the expansion and exhaust chamber 4 is on its upward stroke.

The method is used for filtering the air (carbon filters, molecular sieves, chemical means and the like) flowing into the engine according to the invention, the number of filters used being variable and not changing the principle of the invention in any way, just like a unit made up of an intake and compression chamber, a combustion chamber and an expansion and exhaust chamber, representing an operative element, being reproduced according to the example of a traditional multi-cylinder engine.

Claims (4)

1. A method of operating an engine capable of reducing pollution, wherein an air-fuel mixture is sucked into and compressed in a separate inlet and compression chamber (1), then, while still under pressure, is sent to a separate and constant volume combustion chamber (2) where it is ignited in order to increase the temperature and pressure of the above mixture, the mixture, after opening the transfer means (7) connecting the combustion or expansion chamber (2) with the expansion and exhaust chamber (4), is expanded in the latter chamber in order to perform work therein, and is then discharged to the atmosphere via the exhaust port (19), in this method, when operating at low power, the fuel injector is no longer operated and, in this case, slightly after the fuel-free compressed air from the inlet and compression chamber (1) enters the combustion chamber, a small amount of additional compressed air from an external air reservoir (23) is fed into the combustion chamber. Air is stored in the air reservoir at very high pressure and ambient temperature, and a small quantity of compressed air at ambient temperature, when brought into contact with the high-temperature air mass contained in the combustion or expansion chamber, is heated and expanded and increases the pressure in the chamber (1) so that work is produced during expansion, thereby achieving dual-mode or dual-energy operation, characterized in that all the components for operating the engine with conventional fuel are omitted, the engine is operated in a single mode with only supplementary compressed air injected into the combustion chamber, and the combustion chamber thus becomes the expansion chamber.

2. A method of operating a pollution-reduced engine according to claim 1, wherein the air taken in by the engine is filtered and cleaned by means of an activated carbon filter (24) or some other mechanical or chemical means, molecular sieves or the like, so that clean and pollution-free air is discharged to the atmosphere.

3. Installation of an engine for implementing the method according to claim 1 or 2, characterized in that the installation is used in urban buses with the aim of removing pollutants from the mass of air in urban and suburban environments. A tank for filling the supplementary compressed air at a very high pressure may be installed at a parking lot or at a bus stop.

4. Installation of an engine for implementing the method according to claim 1 or 2, characterized in that the installation is used in urban service vehicles with the aim of removing pollutants from the mass of air in urban and suburban environments.