Patent Application
20090308346
The invention relates to a work machine and more specifically a work machine operating under highly contaminated conditions and to the removal of excess debris and particles from the air used to cool the work machine prime mover engine and to supply combustion air.
The class of work machines utilized for agricultural, industrial and other uses termed as work machines typically operates in a highly contaminated environment, thus making the function of cleaning air used by an air breathing internal combustion engine especially important. Nowhere is this as important as in the agricultural field where the work machine is in a field harvesting crops which generates significant contaminants in the form of debris and particles. It is necessary for such machines to have a pre-cleaner since the ambient level of particles is so significant. An air filter alone would quickly become clogged. In the present environment, pre-cleaners are employed upstream of the primary filter for the air intake system of the engine. Such pre-cleaners may take various forms but, as used commercially, usually are systems imparting a centrifugal motion to the air leading to the primary air filter inlet. Such centrifugal motion causes the denser particles to be thrown to the outer periphery of the pre-cleaner, leaving the less contaminated air to exit to the primary filter through a central inlet. Such air pre-cleaners have an outlet for the accumulated particles and some units have that outlet connected to an aspirator positioned in a muffler in the engine exhaust system. Problems can occur with an arrangement of this type since the connection to the exhaust system has the potential of increasing back pressure and thereby decreasing the efficiency of the engine. In addition, the performance of the flow through the engine exhaust system depends significantly on engine load thereby generating a variable removal of particles from the pre-cleaner.
Other approaches seek to remove excess particles from a pre-cleaner by utilizing the pressure drop created by the engine cooling fan since this fan is solely dependent on engine rpm and not engine load. However this too has limitations on its effectiveness.
What is needed in the art therefore is a system in which excess particles from an engine pre-cleaner are removed consistently and with a minimum of parasitic losses.
In one form, the invention includes a working vehicle having a vehicle body and an air breathing, fuel consuming, internal combustion engine carried by the vehicle body. An air intake system for the engine includes a primary air filter and a pre-cleaner for collecting larger particles, the pre-cleaner having a conduit to carry away the particles. A cooling system is connected to the engine and has a heat exchanger through which air flows to remove heat from the engine. A device for removing debris from the air flowing through and upstream of the heat exchanger has a conduit for carrying away debris. A device is provided for pulling air through the debris conduit and a venturi device is interposed in the debris conduit and has a throat connecting to the particle conduit for removing particles from the pre-cleaner.
In another form, the invention is an internal combustion engine system having an air breathing, fuel consuming, internal combustion engine and an air intake system for the engine including a primary air filter and a pre-cleaner for collecting larger particles, the pre-cleaner having a conduit to carry away the particles. A cooling system is connected to the engine and has a heat exchanger through which air flows to remove heat from the engine. A device is provided for removing debris from the air flowing through and upstream of the heat exchanger, the device having a conduit for carrying away debris. A device is provided for pulling air through the debris conduit and a venturi device is interposed in the debris conduit. The venturi device has a throat connecting to the particle conduit for removing particles from the pre-cleaner.
Referring to
Work machine 10 includes a transmission 12 providing motive power for the work machine as well as powering agricultural crop harvesting and processing components and various hydraulic accessory devices. Transmission 12 is powered by an air breathing fuel consuming internal combustion engine, generally shown at 14.
Internal combustion engine 14 may be one of a number of types of internal combustion engine including turbocharged or non-turbocharged but in any case the engine requires a source of combustion air delivered to an intake manifold of engine 14 by an inlet conduit 16. Inlet conduit 16 extends from a primary air filtration unit 18. Primary air filtration device is constructed to provide removal of fine particles from the air consumed by engine 14. Since the work machine 10 operates in an extremely debris laden environment in air pre-cleaner 20 is connected to an up stream of primary air filtration device 18.
Throughout this application, the term “particles” is used to denote unwanted material in the combustion air stream for engine 14. As mentioned later, the term “debris” is used to denote unwanted material in the engine cooling air stream. These terms are used for convenience to designate separate materials that need to be removed from use by the work machine engine 14. It should be apparent to those skilled in the art that other terms may be used to designate these materials.
Air pre-cleaner 20 has a lower facing air inlet 22 which receives the primary air for combustion by engine 14. Air pre-cleaner 20 may take any one of a number of forms but as practice commercially it is a form of centrifugal flow where inlet air is forced into a swirl pattern so that the heavier particles pass to the outside by virtue of centrifugal action and the finer particles including air pass through a central outlet (not shown) to primary air filtration device 18. In order to carry away the particles thus collected by pre-cleaner 20, an outlet 24 connects to a particle conduit 26.
Engine 14, as usually employed in work machines, is a liquid cooled engine in which a liquid coolant is circulated through internal passages in engine 14 and to a heat exchange device generally indicated by reference character 28. Heat exchange device 28, in usual form, is a radiator in which coolant is supplied from an engine via coolant conduit 30 to a lower portion of the radiator and returned to the engine by an upper coolant conduit 32. Details of the coolant flow passages, as well as the pumping means for circulating the coolant, are not shown to facilitate an understanding of the present invention.
The coolant device or radiator 28 is an air to liquid heat exchanger in which air flow is passed through device 28 by a fan only the hub 34 of which is shown. Fan hub 34 may be driven from an engine accessory pulley 36 by a mechanical connection 38. This connection may be continuous or interrupted as needed for coolant flow. Furthermore, the fan hub 34 may be driven by other devices such as hydraulic and electrical.
The engine cooling air flow is from the right to the left of
Device 40 may be in other forms such as reciprocating ducts on rectangular or square screens. Still other forms are available to those skilled in the art. Whatever form of device 40 is used, it will have a conduit through which debris is carried away to the device 52.
As shown particularly in
The device 52 generates a consistent flow of air from radial inlet 46 through downward facing outlet 54. The primary air flow through radiator 28 keeps the debris on rotating screen 42, but at the point where the debris passes across inlet 46, the pressure across the screen is interrupted sufficiently so that debris on the screen 42 is removed through inlet 46 and passes to downward facing outlet 54. This operation is a continuous one since the vehicle can be operating in a highly debris laden environment at any time. Consequently there is continuous air flow passing from the inlet 46 to the outlet 54.
In accordance with the invention, the venturi device 50, shown in detail in
An alternative form of venturi is shown in
For both devices the needed function of disposing of the particles from the air inlet pre-cleaner is continuously and effectively accomplished with a minimum of parasitic losses. This is because the function of the cleaning of engine air cooling flow remains constant and is unaffected by power output and demands on engine 12. Since the device is a simple venturi and aspiration device there are no moving parts to add complication and a potential for unreliability to the system.
Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
