Patent Application
20140124060
The present disclosure relates generally to hysteresis-based controls, and more particularly, to closed loop systems and methods of compensating hysteresis-based current control in switched reluctance (SR) machines.
Internal combustion engines generate mechanical energy by burning a mixture of fuel and a source of oxygen, the oxygen generally obtained by the intake of ambient air. In a diesel engine, the combustion process involves burning a mixture of diesel fuel and air, which results in the generation of exhaust, which includes exhaust gases and particulate matter. The particulate matter is often referred to as soot. The exhaust, including the particulate matter, is exhausted from the diesel engine through an exhaust system. A diesel particulate filter (DPF) is often employed as part of the exhaust system in order to filter all or most of the soot from the exhaust before the exhaust is released from the exhaust system.
Over time, particulate matter trapped by the filter can accumulate in the filter and reduce the operating efficiency of the associated engine. Specifically, a substantially clogged filter can increase the back pressure to the engine and hinder the ability of the engine to discharge waste exhaust gases. As a result, the engine must consume more fuel and work harder to produce the same amount of power as compared to when the filter is free of accumulated particulates. Accordingly, exhaust regeneration systems are often employed to periodically clean the filter. Such regeneration systems generally free the filter of particulates by heating the particulates to temperatures sufficient to combust or vaporize the particulates.
Exhaust regeneration systems may use any one of a variety of different ways to determine if such cleaning of the filter is necessary. One method involves monitoring the pressure differential across the filter to determine if the back pressure indicates excessive soot loading. More specifically, the pressure differential is typically measured using pressure sensors that are coupled to each of the upstream and downstream conduits, located before and after the particulate filter, through relatively narrow tubes which place the pressure sensors in direct fluid communication with exhaust gases entering and exiting the filter. If the back pressure, or the pressure of gases detected within the conduit located upstream of the filter, is significantly greater as compared to that of the downstream conduit, the pressure sensor may produce an electrical signal to an electronic control unit (ECU), or the like, to suggest filter regeneration.
Currently existing systems place the pressure sensors substantially in direct line with the exhaust gases passing through the particulate filter. Although fairly accurate, such exposure allows soot, water, ice, and the like, to build up within and clog the tubes or lines leading to the sensors over time. Excessive build up and clogging of the pressure sensor lines can cause significant errors in pressure readings if not complete mechanical and/or electrical failure of the sensors. Such setbacks can prevent prompt alert for the need to clean or regenerate the filter, which can further result in inefficient engine performance and excess fuel consumption. Similarly, repairs for unclogging the pressure sensor lines or for replacing the pressure sensor assembly can cause additional downtime and costs.
The present disclosure is directed to overcoming one or more of the problems associated with the prior art exhaust regeneration systems identified above.
In one aspect of the present disclosure, a pressure management system for an exhaust regeneration system is provided. The pressure management system may include a first tube capable of retaining a first fluid and extending between a proximal end and a distal end, a first fitting coupled between the distal end of the first tube and an exhaust conduit for receiving an exhaust fluid, and a pressure sensor manifold. The first fitting may include a first diaphragm configured to provide a sealed interface between the first fluid of the first tube and the exhaust fluid of the exhaust conduit, and communicate a pressure of the exhaust fluid through a pressure of the first fluid. The pressure sensor manifold may include at least a first inlet coupled to the proximal end of the first tube and a pressure sensor configured to determine the pressure of the exhaust fluid based at least partially on the pressure of the first fluid at the first inlet.
In another aspect of the present disclosure, an exhaust regeneration system is provided. The exhaust regeneration system may include a particulate filter disposed between an upstream exhaust conduit and a downstream exhaust conduit, and a pressure sensor manifold. The pressure sensor manifold may include an upstream inlet, a downstream inlet and a pressure sensor configured to detect a pressure at each of the upstream and downstream inlets. The upstream inlet may be coupled to the upstream exhaust conduit via a first fitting, and the downstream inlet may be coupled to the downstream exhaust conduit via a second fitting. Each of the first and second fittings may include a diaphragm configured to provide a sealed interface between one of the exhaust conduits and the corresponding one of the inlets, and communicate a pressure therebetween.
In yet another aspect of the present disclosure, a method for monitoring pressure across a particulate filter is provided. The method may include the steps of providing a first diaphragm that is sealably disposed between an upstream exhaust conduit and a first volume and configured to communicate a pressure of an upstream exhaust fluid within the upstream exhaust conduit through a first fluid within the first volume; providing a second diaphragm sealably disposed between a downstream exhaust conduit and a second volume and configured to communicate a pressure of a downstream exhaust fluid within the downstream exhaust conduit through a second fluid within the second volume; monitoring pressures of the first and second fluids within the corresponding first and second volumes; and determining a pressure differential across the upstream and downstream exhaust conduits based on a comparison of the pressures in the first and second volumes.
Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Generally, corresponding reference numbers will be used throughout the drawings to refer to the same or corresponding parts.
Similarly, the embodiment of
As shown by the arrows indicated in
Turning to
Furthermore, the pressure management system 104 may provide one or more inlet lines or tubes, such as a first tube 120 and a second tube 122, which may be respectively coupled to the first and second inlets 114, 116 of the pressure sensor manifold 112. Each of the first and second inlet tubes 120, 122 may extend between a proximal end 124, which is coupled to one of the inlets 114, 116 of the pressure sensor manifold 112, and a distal end 126, which is coupled to one of the upstream and downstream conduits 106, 108 of the associated particulate filter 102. For example, the proximal end 124 of the first tube 120 may be coupled to the first inlet 114, while the distal end 126 of the first tube 120 may be coupled to the upstream conduit 106 of the particulate filter 102 of
Similarly, the closed loop pressure management system 204 of the exhaust regeneration system 200 of
The pressure management system 204 may optionally or additionally include first and second inlet lines or tubes 220, 222, which may be respectively coupled to the first and second inlets 214, 216 of the pressure sensor manifold 212. Each of the first and second inlet tubes 220, 222 may extend between a proximal end 224 that is coupled to one of the inlets 214, 216 of the pressure sensor manifold 212, and a distal end 226 that is coupled to one of the upstream and downstream conduits 206, 208 of the particulate filter 202 associated therewith. In the embodiments shown in
Each of the distal ends 126, 226 of the inlet tubes 120, 122, 220, 222 may be coupled to the corresponding conduit 106, 108, 206, 208 though a fitting 300, as shown for example in
The fitting 300, as shown in
The diaphragm 310 may be formed of a material that is sufficiently rigid and capable of maintaining a seal under extreme temperatures and pressures, but also sufficiently flexible so as to allow pressure from within an attached conduit 106, 108, 206, 208 to interface or communicate with pressure enclosed within inlet tubes 120, 122, 220, 222. Specifically, the diaphragm 310 may be made to be at least partially movable, for instance expandable and contractible, within the aperture 308 of the fitting 300 in response to changes in pressure within the conduits 106, 108, 206, 208. Moreover, the diaphragm 310 may enable a change in the pressure of exhaust fluids flowing through a connected conduit 106, 108, 206, 208 to effect a change in volume within the conduit 106, 108, 206, 208, which further effects a corresponding change in volume and pressure within the aperture 308 of the fitting 300. For example, an increase in exhaust pressure within a conduit 106, 108, 206, 208 coupled to the second end 304 of the fitting 300 in
Turning now to
In step 400-3, the pressure within the first volume, for example, corresponding to the pressure within the upstream conduit 106, 206, may be detected by the pressure sensor 110, 210. Similarly, the pressure within the second volume, for example, corresponding to the pressure within the downstream conduit 108, 208, may be detected by the pressure sensor 110, 210 in step 400-4. In step 400-5, a pressure differential between the first and second volumes, and thus representative of a pressure differential between the upstream and downstream conduits 106, 108, 206, 208, may be determined based on the pressures detected in steps 400-3 and 400-4. A single pressure sensor 110, 210 may be employed to detect the individual pressure in each of the inlets 114, 116, 214, 216, as well as determine a pressure differential therebetween. In other modifications, more than one pressure sensor may be employed to independently detect the pressure in each of the first and second inlets 114, 116, 214, 216. In such configurations, a controller, processor, or the like, may be used to calculate the pressure differential based on the individually detected pressures.
Additionally, in step 400-6, information corresponding to the pressure differential determined in step 400-5 may be communicated through electronic signals to a controller, processor, or the like. Such signals may be communicated via the communication port 118, 218 of
In general, the foregoing disclosure finds utility in any suitable exhaust system having a particulate filter. The foregoing disclosure more particularly finds utility in various industrial applications, such as the farming, construction and mining industries in providing smoother and more efficient control of machines typically used in association with work vehicles and/or machines, such as tractors, backhoe loaders, compactors, feller bunchers, forest machines, industrial loaders, skid steer loaders, wheel loaders, and the like.
Moreover, the present disclosure finds utility in any application for monitoring the condition of particulate filter and is not limited to exhaust systems with filter regeneration capabilities. Specifically, the disclosed systems and methods provide the ability to monitor pressures across a particulate filter for the purposes of determining the condition of the filter, without directly exposing the pressure sensors to the exhaust fluids or gases. By providing a fitting with a diaphragm directly in between the pressure sensors and the exhaust conduits, the pressure sensors are sealed and protected from exhaust gases, particulates, soot, water, ice, and the like.
From the foregoing, it will be appreciated that while only certain embodiments have been set forth for the purposes of illustration, alternatives and 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 this disclosure and the appended claims.
