US20120036833A1

US20120036833A1 - Scavenging Vacuum Pressure Provisioning with Exhaust Treatment

Info

Publication number: US20120036833A1
Application number: US13/206,799
Authority: US
Inventors: Rex Schertz; John D. Anderson
Original assignee: AGCO Corp
Current assignee: AGCO Corp
Priority date: 2010-08-11
Filing date: 2011-08-10
Publication date: 2012-02-16
Also published as: WO2012021651A1; US20120036843A1

Abstract

In one embodiment, a method that includes collecting particles from an intake flow of air for a diesel engine; removing the particles collected using scavenging vacuum pressure and without adding exhaust restriction; and treating combustion products of the diesel engine.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to copending U.S. provisional application entitled, “Air Filter Aspiration and Exhaust Treatment and Aspiration Fan Drive,” having Ser. No. 61/372,780, filed Aug. 11, 2010, which is entirely incorporated herein by reference.

TECHNICAL FIELD

The present disclosure is generally related to diesel engines and, more particularly, is related to a system and method for aspirating an air filter assembly of a diesel engine, which uses exhaust treatment.

BACKGROUND

Utility vehicles, such as agricultural tractors, and plant machinery are often required to work in dusty environments. In order to avoid dust entering the air intake of an internal combustion engine of such a vehicle or machine, it is known to filter intake air upstream of the engine.
A typical air intake system includes, in airflow order, a pre-filter and a main filter. The pre-filter removes larger dust particles from the intake air, and then the main filter removes smaller particles. Without the pre-filter, the main filter tends to clog in an unacceptably short time.
The particles collected by the pre-filter are typically removed by scavenging vacuum pressure that is created from engine exhaust. However, reliance on an engine exhaust system to provide such vacuum pressure can be problematic due to various factors, such as structural complexity and back pressure being too high to accommodate additional requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic diagram of an example embodiment of a tractor with a diesel engine assembly.

FIG. 2 is a schematic diagram of an example embodiment of an exhaust treatment system.

FIG. 3 is a perspective view of an example embodiment of an intake treatment system.

FIG. 4 is a flow chart depicting an example embodiment of a method for operating a diesel engine.

FIG. 5 is a perspective view of another example embodiment of a diesel engine assembly.

FIG. 6 is a perspective view showing detail of an example embodiment of an aspiration fan drive.

FIG. 7 is a perspective view of selected components of an example embodiment of an aspiration fan drive.

FIG. 8 is an assembly view of an example embodiment of an aspiration fan drive.

FIG. 9 is a flow chart depicting another example embodiment of a method for operating a diesel engine.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Overview

Detailed Description

As will be described in more detail below, scavenging vacuum pressure can be provided for aspirating an air filter of a diesel engine that implements exhaust treatment (e.g., Selective Catalytic Reduction (SCR)). In various embodiments, this is accomplished by an idler pulley that engages a drive belt of the engine, and which imparts rotational speed to a fan that produces the scavenging vacuum pressure. Notably, rotational speeds of the fan in excess of 8,000 RPM can be achieved.
The use of various exhaust treatment technologies limit the ability to use exhaust pressure to provide various functions, such as scavenging vacuum pressure. In contrast to the prior art, the use of an engine driven idler pulley to produce scavenging vacuum pressure enables the use of exhaust treatment with an aspirated air filter since the idler pulley does not draw from or rely on exhaust pressure to function. Though certain embodiments described herein achieve these and/or other benefits, it should be understood in the context of the present disclosure that all of these benefits may not necessarily be provided through a single embodiment or realized in all embodiments described herein.
As shown in FIG. 1, a tractor 100 includes an engine compartment 102, a cab 104 and wheels, of which wheels 106 and 108 are depicted. A diesel engine assembly 110 is housed within engine compartment 102, and includes intake treatment system 112, engine 114 and exhaust treatment system 116.
Intake treatment system 112 is positioned along the flow path of intake 118, which provides a flow of air to engine 114. Exhaust treatment system 116 is positioned along the flow path of exhaust 120, which directs combustion products from engine 114.
In operation, intake treatment system 112 removes particles (e.g., dust) from a flow of air that is provided to engine 114 via intake 118 to facilitate combustion. Thereafter, combustion products are directed to exhaust treatment system 116, which performs a catalytic reaction with the combustion products to reduce undesirable emissions.
In FIG. 2, exhaust treatment system 116 is shown to incorporate a catalyst 122, a controller 124 and a supply 126 of additives. Specifically, catalyst 122 includes an SCR catalyst positioned within exhaust 120 along the flow path of the combustion products. The combustion products are represented by arrow A. Notably, exhaust treatment system 116 functions as means for performing SCR on combustion products of a diesel engine.
An injector 128 is fluidicly coupled to supply 126. Injector 128 selectively dispenses additives (e.g., DEF) into exhaust 120, with the dispensed additives being represented by arrow B. Notably, the additives are dispensed within exhaust 120 and upstream of catalyst 122 to stimulate a reaction that is known to reduce various emissions such as NOx. Dispensing of the additives is performed responsive to signals from controller 124, which monitors various system parameters. By way of example, controller 124 can monitor exhaust temperature via sensor 130. Remaining products, represented by arrow C, are directed to atmosphere with exhaust 120.
It should be noted that use of exhaust treatment system 116 increases the backpressure on diesel engine assembly 110 to such an extent that exploitation of the flow of combustion products to produce vacuum pressure may not be practicable. Notably, such vacuum pressure can be used for scavenging particles from an air filter assembly that, if not removed, could reduce the ability of the assembly to provide an appropriate volume of clean air for combustion. In this regard, FIG. 3 depicts intake treatment system 112 (in greater detail), which does not rely on engine exhaust for producing scavenging vacuum pressure.
As shown in FIG. 3, intake treatment system 112 communicates with intake 118. Specifically, intake treatment system 112 includes an air filter assembly 132 that removes particles from an intake flow of air represented by arrow D. Air filter assembly 132 then provides a flow of filtered air (represented by arrow E) to engine 114 via intake 118. As such, air filter assembly 132 functions as means for collecting particles from an intake flow of air for the diesel engine.
An aspiration fan assembly 134 also is depicted in FIG. 3. Aspiration fan assembly 134 incorporates a fan 136 that is mechanically driven by engine 114 (not shown in FIG. 3) to produce scavenging vacuum pressure. The scavenging vacuum pressure is applied to air filter assembly 132 by aspiration conduit 138 to remove particles collected in air filter assembly 132 from the intake flow of air. That is, the particles are drawn away from air filter assembly 132, through aspiration conduit 138, and toward fan 136. Thus, aspiration fan assembly 134 functions as means for removing the particles collected using scavenging vacuum pressure and without adding exhaust restriction to the system.
An example embodiment of a method for operating a diesel engine is depicted in FIG. 4 that includes collecting particles from an intake flow of air (block 140). In block 142, the particles that were collected are removed using scavenging vacuum pressure and without adding exhaust restriction. Then, as shown in block 144, combustion products of the diesel engine are treated. By way of example, SCR can be used.
FIG. 5 is a perspective view of another example embodiment of a diesel engine assembly 110 that includes an intake treatment system 112, an engine 114 and an exhaust treatment system 116. Intake treatment system 112 is positioned along the flow path of an intake 118. Exhaust treatment system 116 is positioned along the flow path of exhaust 120 and includes an SCR catalyst 122 for reacting with combustion products.
Intake treatment system 112 of FIG. 5 incorporates an air filter assembly 132 that removes particles from an intake flow of air. Specifically, air filter assembly 132 includes a pre-filter 146 positioned upstream of a main filter 148. Pre-filter 146 removes particles that are drawn into air filter assembly 132. Pre-filter 146 collects these particles until scavenged as will be described later. As such, pre-filter 146 functions as means for pre-filtering the flow of air.
Main filter 148 receives pre-filtered air from pre-filter 146 and removes smaller particles from the air flow. Air filter assembly 132 then provides a flow of filtered air to engine 114 via intake 118. Thus, main filter 148 functions as means for filtering the flow of air.
Aspiration fan assembly 134 incorporates a fan (not shown in FIG. 5) that is mechanically driven by engine 114 to produce scavenging vacuum pressure. The scavenging vacuum pressure is applied to air filter assembly 132 by aspiration conduit 138 to remove particles collected in air filter assembly 132. In particular, aspiration conduit 138 applies the scavenging vacuum pressure to pre-filter 146 to draw particles collected by the pre-filter into the aspiration conduit such that efficiency of air filter assembly 132 is maintained.
A more detailed view of diesel engine assembly 110 is provided by FIG. 6. As shown in FIG. 6, engine 114 includes various accessories, such as an alternator 150 that is driven by an engine drive belt 152. Notably, engine drive belt 152 engages about and extends between a first pulley 154, which is coupled to alternator 150, and a second pulley 156, which is a drive pulley. Aspiration fan assembly 134 includes a compound idler pulley 158, an outer surface of which engages an outer surface of engine drive belt 152 to rotate compound idler pulley 158.
As shown in FIGS. 6-8, compound idler pulley 158 includes a first pulley stage 160 and a second pulley stage 162, with the first pulley stage being positioned to engage engine drive belt 152. Second pulley stage 162 drives a fan 164 (FIG. 7) of aspiration fan assembly 134 responsive to rotation of first pulley stage 160.
As shown most clearly in FIG. 7, first pulley stage 160 and second pulley stage 162 are coaxial and form an integral component. So configured, rotation of first pulley stage 160 results in rotation of second pulley stage 162. Additionally, second pulley stage 162 exhibits a longer radius (R₂) than the radius (R₁) of first pulley stage 160 such that R₂>R₁. Thus, compound idler pulley 160 functions as a means for converting rotational motion to higher speed rotational motion.
Also depicted in FIG. 7 are fan pulley 166 and aspiration drive belt 168. Aspiration drive belt 168 engages about and extends between fan pulley 166 and second pulley stage 162. Notably, second pulley stage 162 exhibits a longer radius (R₂) than the radius (R₃) of fan pulley 166 such that R₂>R₃. In some embodiments, second pulley stage 162 exhibits a longer radius (R₂) than the radius (R₁) of first pulley stage 160, which also exhibits a longer radius than the radius (R₃) of fan pulley 166 (i.e., R₂>R₁>R₃). So configured, aspiration fan assembly 134 is capable of driving fan 164 at speeds in excess of 8,000 RPM. Thus, fan pulley 166 is also capable of functioning as a means for converting rotational motion to higher speed rotational motion.
The assembly view of FIG. 8 depicts several components in greater detail. In this regard, compound idler pulley 158 is secured to an engine mount 170 by a bolt 172 that passes, in sequence, through spacer 174, compound idler pulley 158, bearing 176, retaining ring 178 and spacer 180. Also depicted is fan support 182 that mounts stator 184, which supports axle 186 (FIG. 7) of fan 164. Stator 184 also secures fan 164 to housing 188, which surrounds fan 164 and serves as a connector for aspiration conduit 138. An evacuation port 190 is located at base of aspiration conduit 138 adjacent to housing 188 for expelling particles scavenged from pre-filter 146.
FIG. 9 is a flow chart depicting another example embodiment of a method for operating a diesel engine that includes pre-filtering intake air to remove larger particles (block 190), and then filtering the air to remove smaller particles (block 192). In block 194, mechanically drive a fan to produce the scavenging vacuum pressure, which is then applied to remove particles that were collected during pre-filtering (block 196). Notably, the fan is mechanically driven in a manner that does not add exhaust restriction. Then, as shown in block 198, SCR is performed on combustion products of the diesel engine.
It should be emphasized that the above-described embodiments, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding. Many variations and modifications may be made to the above-described embodiments without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

Therefore, at least the following is claimed:

1. A method comprising:

collecting particles from an intake flow of air for a diesel engine;

removing the particles collected using scavenging vacuum pressure and without adding exhaust restriction; and

treating combustion products of the diesel engine.

2. The method of claim 1, wherein removing the particles collected using scavenging vacuum pressure further comprises mechanically driving a fan to produce the scavenging vacuum pressure.

3. The method of claim 1, wherein removing the particles collected using scavenging vacuum pressure further comprises converting rotational motion used for driving engine accessories to higher speed rotational motion to produce the scavenging vacuum pressure.

4. The method of claim 3, wherein converting rotational motion further comprises:

driving a component at a first speed of rotational motion; and

using the component to generate the higher speed rotational motion.

5. The method of claim 4, wherein the component is a belt-driven component.

6. The method of claim 3, wherein the converting rotational motion further comprises:

driving a component at the first speed of rotational motion at a first location of the component, the first location exhibiting a first radius; and

generating the higher speed rotational motion at a second location of the component exhibiting a second radius, the second radius being longer than the first radius.

7. The method of claim 1, wherein collecting particles from an intake flow of air further comprises pre-filtering the air to remove larger particles, and then filtering the air to remove smaller particles.

8. The method of claim 7, wherein, in removing the particles collected using scavenging vacuum pressure, the scavenging vacuum pressure is directed to particles removed by the pre-filtering.

9. The method of claim 1, wherein treating combustion products further comprises performing Selective Catalytic Reduction (SCR).