Patent Application
20120067032
The present invention relates to internal combustion engines, and, more particularly, to systems for facilitating the regeneration of particulate filters used with such internal combustion engines.
For a number of years, the evermore stringent EPA limitations on products of combustion from internal combustion engines have given rise to the need for particulate filters filtering particles from an internal combustion engine's exhaust system. Although diesel power systems have employed particulate filters, known as diesel particulate filters (DPF) for a number of years, direct fuel injection for other types of internal combustion engines have also indicated the need for a particulate filter. Such particulate filters have filtration media for collecting particles on the filter media to prevent the particles from being discharged to the atmosphere. As with any filter, there is a finite capacity to the particles trapped by the filter and there exists a need for regeneration of the filter or burning off the particles.
Generally, such regeneration requires an elevated temperature in the exhaust, either by the addition of hydrocarbon fuels or by other forms of temperature increase. Regardless of the specific mechanism to regenerate the filter, there have been a number of systems proposed for increasing the load on engines and, therefore, increasing the exhaust temperature upstream of the particulate filter. Such systems may involve manipulation of exhaust gasses by increased restriction or manipulation of flow through complex variable intake valve systems or variable turbine geometry systems. While these provide the increase in exhaust temperatures necessary, they do so at an increased cost and complexity in the engine system.
What is needed, therefore, in the art is a simplified system for increasing exhaust gas temperatures for regeneration purposes.
The present invention includes, in one form, a power system with an air breathing, fuel consuming internal combustion engine having a plurality of cylinders and producing a rotary output and products of combustion. An intake manifold receives combustion air from a common inlet and it distributes the air to the cylinders for combustion. A fuel system delivers fuel at controlled rates to at least a group of cylinders less than the total number of cylinders for such engine. A particulate filter receives products of combustion from the engine with the particulate filter requiring periodic regeneration. A valve is positioned in the intake manifold to at least restrict combustion air flow to the group of cylinders, the fuel system at least reducing fuel flow substantially simultaneously with the reduction of airflow to the group of cylinders.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner.
Referring now to the drawings, and more particularly to
The cylinders of engine 12 receive fuel, as will be described later, and produce combustion, which is delivered past exhaust valves (not shown) and exhaust manifold 26 and from there to the inlet 28 of the turbine 30 for a turbocharger 32. The exhaust gasses thus passing from turbine 30 pass through turbine outlet 34 to an exhaust aftertreatment device 36, which may be an oxidization catalyst or particulate filter or a combination of both and, from there, through an exhaust line 38 to the ambient. The exhaust aftertreatment device 36 does collect particles harmful to the environment and must be periodically regenerated or cleaned of the particles.
The air for combustion enters the power system via intake line 40 through appropriate filtration devices and is delivered to the intake of compressor 42 connected to and driven by the turbine 30 by shaft 44. Pressurized air from compressor 42 extends via line 46 to the inlet of an after cooler or intercooler 48 for reducing the temperature of the pressurized gas and, thus, the density of air and oxygen consumed by engine 12. The after cooler or intercooler may be any one of a variety of coolers including air-to-air coolers relying on ambient air for cooling or an air-to-liquid cooler relying on engine coolant for particular applications. The air thus cooled enters intake line 24 leading to intake manifold 18.
The power system of
Engine 12 has a fuel system indicated schematically by reference character 58, which receives control inputs from engine parameter sensors and a primary input via line 60 or a plurality of lines from an electronic control unit 62 or ECU. The ECU 62 preferably provides control of EGR valve through line 64 to control flow of exhaust gasses from the products of combustion of engine 12 to the intake manifold 18.
In accordance with the invention, a valve 66 is provided within intake manifold 18 and is controlled by ECU 62 via line 68. Valve 66 is established in flow relation between the intake runners 20 and 22 within intake manifold 18 to selectively at least restrict and also to block intake air flow to cylinders 16 fed by runners 22. Substantially simultaneously with the blockage or restriction of flow to the cylinder group fed by runners 22, the fuel flow to that group of cylinders by fuel system 58 is reduced or terminated. This, in effect, eliminates the group of cylinders fed by runners 22 to take away their power generating capacity and increase the load on the remaining cylinders both from overall engine parasitic loads and from the additional parasitic loads produced by the inactive group of cylinders.
The valve 62 may take several forms, some of which are illustrated in
Using both forms of valves, and others as apparent to those skilled in the art, the flow to the second set of cylinders fed by runners 22 is varied to the point where combustion air flow may be substantially blocked along with a substantially simultaneous termination of fuel flow to the cylinders 16. This effectively imposes an increased load on the engine, especially during part throttle conditions in which there is insufficient natural load on the engine 12 to raise exhaust temperatures to the point of facilitating regeneration of particulate filter 36. In addition, the valves provide a simplified way of increasing exhaust temperatures during light load conditions by partially blocking flow, thus improving operation of various exhaust aftertreatment devices.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
