Abstract:
An apparatus and method for diagnosing mechanical problems in turbocharged engines. In its preferred embodiment, the apparatus consists of a boot that is coupled to a turbocharge system—preferably at the air inlet thereof. The apparatus further includes a source of air pressure that may be delivered to the turbocharge system, a first pressure gauge to measure the pressure of the air that is being delivered, and a second pressure gauge to measure the pressure of the air within the turbocharge system. Under pressure, and with the engine off, the turbocharge system can be inspected for leaks. In addition, under pressure, the operation of turbocharge system components—such as the wastegate valve/diaphragm and the boost sensor—can also be inspected.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    This invention relates generally to engine diagnosis and, more specifically, to an apparatus and method for diagnosing pressure-related and other problems in turbocharge systems.  
           [0003]    2. Background of the Invention  
           [0004]    Turbocharge systems are used, particularly on diesel engines, to increase engine power by compressing the air that enters the engine&#39;s combustion chambers. They operate by utilizing the hot exhaust gases exiting the cylinders to spin a compressor wheel (also known as an impeller), pressurizing air drawn into the system and routing that pressurized air, into the engine.  
           [0005]    A typical turbocharge system generally includes a number of additional components. Too much impeller speed can cause impeller shaft or bearing failure. To address this, the turbocharger uses a waste gate valve, which allows exhaust gas to bypass the turbine once the ideal pressure level or boost is exceeded. This has the effect of reducing impeller speed, and thus helps prevent shaft and bearing failures.  
           [0006]    Additionally, if the turbocharged air is too hot when it enters the engine, engine knocking and reduced output can be caused. To address this, the turbocharger typically includes an intercooler (or charge air cooler), which cools the turbocharged air before it enters the cylinders.  
           [0007]    A turbocharge system&#39;s efficiency can be diminished by leaks at any point in the turbocharge system. Such leaks can occur in a number of places, including in the boots and clamps utilized in the system, in seams, in gaskets or O-rings, in the intercooler, and at the point where the turbocharge system couples to the intake manifold. Currently, such leaks are tested for by starting the engine and listening to the sounds the turbo system makes—in an effort to detect higher pitched sounds that would indicate the presence of a leak. This can be difficult, however, because the engine noise can interfere with a mechanic&#39;s ability to hear such higher pitched sounds. Moreover, other problems, such as improper functioning of the wastegate or of the boost sensor, can also resist ready diagnosis.  
           [0008]    A need therefore existed for an apparatus and method that simulates running pressure conditions in a turbocharge system when the engine is off, to permit the more effective diagnosis of pressure-related and other mechanical problems in a turbocharge system. The present invention satisfies these needs and provides other, related, advantages.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention to provide an apparatus and method that simulates running pressure conditions in a turbocharge system with the engine off, so as to permit the more effective diagnosis of pressure-related mechanical problems in a turbocharge system.  
           [0010]    It is a further object of the present invention to provide an apparatus and method that simulates running pressure conditions in a turbocharge system with the engine off, so as to permit the more effective diagnosis of problems with the wastegate and boost sensor in a turbocharge system.  
         BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS  
         [0011]    In accordance with one embodiment of the present invention, an apparatus for diagnosing potential mechanical problems in turbocharge systems is disclosed. The apparatus comprises, in combination: a source of pressurized air; and means for delivering said pressurized air to any portion of a turbocharge system for a vehicle engine in a substantially air-tight manner when said vehicle engine is in an off condition.  
           [0012]    In accordance with another embodiment of the present invention, an apparatus for diagnosing potential problems in turbocharge systems is disclosed. The apparatus comprises, in combination: a source of pressurized air; means for delivering said pressurized air to any portion of a turbocharge system for a vehicle engine in a substantially air-tight manner when said vehicle engine is in an off condition; wherein said means for delivering said pressurized air comprises a boot adapted to be positioned over an exposed end of a turbo inlet following removal of an air filter from said turbo inlet; a first display gauge in communication with said source of pressurized air and adapted to display the pressure of said pressurized air as it is provided to said any portion of a turbocharge system; and a second display gauge adapted to display the pressure within said any portion of a turbocharge system.  
           [0013]    In accordance with still another embodiment of the present invention, a method for diagnosing potential mechanical problems in turbocharge systems is disclosed. The method comprises: providing a source of pressurized air; providing means for delivering said pressurized air to any portion of a turbocharge system for a vehicle engine in a substantially air-tight manner when said vehicle engine is in an off condition; coupling said delivering means to said turbocharge system; delivering said pressurized air to said turbocharge system; inspecting said turbocharge system for mechanical problems.  
           [0014]    The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a perspective view of the diagnosis apparatus of the present invention coupled to a turbocharger inlet.  
         [0016]    [0016]FIG. 2 is a cross-sectional view of the apparatus shown in FIG. 1, taken along line  2 - 2 .  
         [0017]    [0017]FIG. 3 is a plan view of a turbocharge system, with the diagnosis apparatus of the present invention coupled thereto.  
         [0018]    [0018]FIG. 4 is a perspective view of a turbocharge system, including the charge air cooler.  
         [0019]    [0019]FIG. 5 is a perspective view of a turbocharger with a wastegate.  
         [0020]    [0020]FIG. 6 is a perspective view of a turbocharger without a wastegate. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    Referring first to FIGS. 3 and 4, a typical turbocharge system  10  is described. The turbocharge system  10  is coupled to an engine  12 , at the exhaust manifold  14 . (Air is also permitted to pass into the turbo housing  18  at a second end through a turbo inlet  19 , at an end of which is located an air filter (not shown).) An exhaust pipe  16  carries exhaust gases from the exhaust manifold  14  to the turbo housing  18 . Inside the turbo housing  18  (not shown), exhaust gases exiting the engine will spin a turbine, then exit the engine through the exhaust pipe at the back of the turbo housing  18 . A shaft connecting the turbine wheel to the compressor wheel will spin the compressor wheel. Air drawn into the turbo housing  18  through the turbo inlet  19  (which air will pass through an air filter (not shown)) is then compressed by the compressor wheel.  
         [0022]    A wastegate valve or diaphragm  20  (“wastegate  20 ”) is coupled to the turbo housing  18 . The wastegate  20  allows an amount of gas to bypass the turbine when ideal boost is exceeded. This has the effect of reducing compressor wheel speed, so as to reduce shaft and bearing failures.  
         [0023]    After compression, the turbocharged air passes through a first length of tubing  22  to an intercooler (or charge air cooler)  26 . The intercooler  26  cools the turbocharged air before it reaches the combustion chamber in the engine  12 . The cooling of the compressed air raises its oxygen content, allowing it to burn fuel more cleanly. As can be seen in FIGS. 3 and 4, the first length of tubing  22  consists of sections of straight and angled tubes, joined by a series of clamps  24  over rubber boots  25 . Gaskets, O-rings and seals (not shown) are also commonly used in the joining together of the straight and angled sections of the first length of tubing  22  and the coupling of the first length of tubing  22  to the turbo housing  18  and the intercooler  26 .  
         [0024]    From the intercooler  26 , the turbocharged air next passes through a second length of tubing  28 . Like the first length of tubing  22 , the second length of tubing  28  consists of sections straight and angled tubes, joined by a series of clamps  24  over rubber boots  25 . Gaskets, O-rings and seals (not shown) are also commonly used in the joining together of the straight and angled sections of the second length of tubing  28  and the coupling of the second length of tubing  28  to the intercooler  26  and the intake manifold  30  of the engine  12 .  
         [0025]    Where the turbocharge system  10  is part of an engine  12  fed by an electronic fuel system, it will typically also be coupled to a boost sensor  32 , which measures changes in the intake manifold pressure. Where the turbocharge system  10  is part of an engine  12  fed by a mechanical fuel system, it will typically also be coupled to an air fuel control  34 .  
         [0026]    Turning now to FIGS.  1 - 3 , the diagnosis apparatus  100  (“apparatus  100 ”) of the present invention is shown and described. The apparatus  100  consists of a boot  102 . The boot  102  preferably consists of a tube  101 , preferably formed of material of the kind typically used in automotive hoses, such as silicone, which tube  101  is fitted at one end in an air-tight manner to a plate  103 . The tube  101  is dimensioned to be fitted over the turbo inlet  19 , after the removal therefrom of the air filter (not shown). So as to secure the tube  101  in a substantially air-tight manner to the turbo inlet  19 , at least one and preferably two adjustable clamps  104  are positioned around the tube  101 . Attaching the diagnosis apparatus  100  to the turbocharge system  10  by fitting the tube  101  over the turbo inlet  19  is only one method of so attaching the apparatus  100 —and any boot configuration (and any material) permitting such coupling to the turbo inlet  19  or to any other portion of the turbocharge system  10  so as to permit the delivery thereto of pressurized air would be encompassed within the meaning of the term “boot.” 
         [0027]    Located in the plate  103  and passing therethrough are a first opening  106  and a second opening  108 . The first opening  106  is dimensioned to receive a first air pressure gauge  110 . The second opening  108  is dimensioned to receive a hose  112 , which hose  112  is in turn coupled to a first opening in a valve  114 . The valve  114  is coupled at a second opening thereof to an air adjustment valve  116 , which air adjustment valve  116  is coupled to a hose  118  leading to a pressurized air source (not shown). Coupled either to a third opening in the valve  114  or to a valve  120  coupled to the air adjustment valve  116  is a second air pressure gauge  122 .  
       Statement of Operation  
       [0028]    The first step when using the apparatus  100  to diagnose mechanical problems with a turbocharge system  10  is to couple the apparatus  100  thereto. Preferably, this is accomplished by removing the air filter (not shown) and positioning the boot  102  over the turbo inlet  19 . (As discussed below, for certain tests, it will be preferable to position the boot  102  at a different part of the turbocharge system  10 .) Once in position, the boot  102  should be secured in a substantially air-tight manner by tightening the clamps  104  therearound. Throughout the diagnosis process, the engine  12  is preferably not running.  
         [0029]    Once the boot  102  is in position, the air intake system is pressurized by opening the air adjustment valve  116 , permitting air from the pressurized air source (not shown) to pass therethrough, through the rear of the boot  102 , and into the turbocharge system  10 . The air pressure of the air coming from the pressurized air source is determined by examination of the second air pressure gauge  122 . Air pressure within the turbocharge system  10  is determined by examination of the first air pressure gauge  110 . Of course, the intake system should not be pressurized beyond the specifications for the particular engine  12  at rated load.  
         [0030]    With the system pressurized, the user may now inspect the turbocharge system  10  for any leaks. The user will want to pay attention to the first air pressure gauge  110 , to determine if the turbocharge system  10  is holding pressure, and will want to pay particular attention to such leak-prone areas as the rubber boots  25 , clamps  24 , seams, O-rings, diaphragms, intercooler  26 , and the intake manifold  30 .  
         [0031]    With the system pressurized, the air fuel control  34  can be tested by removing its top plug (not shown), and visually inspecting the operation of the diaphragm therein to determine if it is functioning correctly—and performing any necessary adjustment where improper functioning is detected. Operation of the wastegate  20  is tested by observing actuation of the valve in response to pressure, and performing necessary adjustments as appropriate. When testing the wastegate  20 , depending on the particular turbocharge system  10 , it may be necessary to couple the boot  102  in a more direct manner (such as to the air inlet tube at the air fuel control connection (not shown)), since some turbocharge systems  10  will not permit the pressurized air to pass sufficiently quickly from the turbo inlet  19  to the wastegate  20  to permit testing. It may also be necessary, when testing the wastegate  20 , to use additional attachment hardware so as to permit suitable attachment.  
         [0032]    The boost sensor (not shown) on engines with electronic fuel systems can be tested for accuracy in the following manner. With the engine off and the ignition key on, diagnostic equipment is coupled to the boost sensor. The apparatus  100  is then pressurized, and the user compares the pressure shown on the first air pressure gauge  110  with that shown on the diagnostic equipment to determine if the boost sensor is accurately measuring pressure.  
         [0033]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.