Abstract:
A fuel injection flush tool adapted to be connected to a conventional fuel injection flush canister in which a supply of combustible liquid fuel injection cleaner is stored. Liquid cleaner is delivered from the flush canister to a gasoline or diesel-driven engine being serviced by which to burn off carbon deposits from the fuel injectors and related parts during a tune-up or service. During one embodiment, air is applied to the flush canister so that the liquid cleaner is delivered from the canister at a pressure which corresponds to the operating pressure of the engine running at idle. In this case, the fuel injectors can advantageously be cleaned (i.e., decarbonized) in a relatively short time and at reduced cost without having to turn off the engine, disable the fuel pump, or remove seats, fuses, relays, etc.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a fuel injection flush tool adapted to be detachably connected to a conventional fuel injection flush canister from which a supply of combustible liquid fuel injection cleaner can be delivered for efficiently cleaning the fuel injectors of the engines of both gasoline and diesel-driven motor vehicles at relatively low cost, in a relatively short time and without having to disable the fuel pump. 
     2. Background Art 
     Motor vehicles need to be serviced from time-to-time, for example, to eliminate the buildup of carbon deposits which can cause the engine of the vehicle to run poorly and inefficiently. It is known to use a combustible liquid chemical cleaner to decarbonize the engine. That is to say, a liquid cleaner is supplied under pressure from a flush canister to remove carbon from the cylinders, fuel rails, pistons, intake valves, etc. of the engine. In many cases, tuning up the engines of most modern vehicles consists primarily of the aforementioned decarbonization process. 
     To initiate such a process, the engine of the vehicle being serviced must be running at operating temperature. The technician has to either refer to the vehicle&#39;s technical operating manual or guess the fuel pump pressure at which the liquid cleaner will be delivered to the engine to remove the carbon deposits therefrom. What is more, the fuel lines must first be disconnected and the electric fuel pump turned off. Similarly, the fuel pump fuse or relay should be disconnected from the fuel pump circuit. In some cases, it may be necessary for the technician to drop the fuel tank or remove the seats. These preliminary actions and disconnections required prior to starting the decarbonization process are frequently difficult and time consuming to accurately and fully achieve. Consequently, the cost to complete an engine tune-up may be correspondingly increased. 
     Therefore, what is needed is an efficient, low cost and easy-to-use tool by which a cleaning fluid can be delivered, under OEM fuel specification pressure, from a flush canister to the fuel injectors of a motor vehicle engine to remove carbon deposits therefrom. 
     SUMMARY OF THE INVENTION 
     In general terms, fuel injection flush tools are disclosed which are detachably connected to a conventional fuel injection flush canister so that a supply of combustible liquid fuel injection cleaner can be delivered, under pressure, to clean the fuel injectors of a gasoline or diesel-driven motor vehicle. By virtue of the fuel injection flush tools herein disclosed, the fuel injectors can be cleaned in a short time and with reduced cost. To this end, the technician need not shut down the engine or turn off the vehicle&#39;s fuel pump during the cleaning process. Moreover, the mechanic need not look up or guess the fuel pump pressure at which the cleaner should be delivered to the fuel injectors. 
     According to one preferred embodiment, the flush tool is connected between the engine and the gas tank or the fuel pump of the vehicle being serviced. A cleaning fluid inlet line and a fuel injector supply line are connected in series from the flush canister to the fuel injectors to be cleaned. A cleaning fluid flow control valve is located in the cleaning fluid inlet line to control the flow of cleaning fluid from the flush canister to the fuel injectors. A fuel inlet line is connected from the fuel pump or the gas tank of the vehicle to the intersection of the series connected cleaning fluid inlet line and fuel injector supply line. A fuel flow control valve is located in the fuel inlet line to control the flow of fuel to the fuel injector supply line. A first pressure gauge monitors the pressure of (e.g., shop) air being supplied to the fuel injection flush canister to pressurize the liquid cleaner therein. A second pressure gauge is connected in the fuel inlet line to monitor the fuel pump pressure. 
     Prior to initiating the cleaning process, the engine of the vehicle being serviced is initially not running and each of the cleaning fluid and fuel flow control valves are closed in order to block the flow of cleaning fluid and fuel through the cleaning fluid inlet line and the fuel inlet line. With the engine turned on, the fuel flow control valve is opened to permit the flow of fuel from the fuel pump or the gas tank to the fuel injectors by way of the fuel inlet line and the fuel injector supply line ahead of the still-closed cleaning fluid flow control valve located in the cleaning solution inlet line. The second pressure gauge from the fuel inlet line indicates the operating pressure of the fuel pump with the engine at idle. The first pressure gauge indicates the pressure of the air supplied to the flush canister which is adjusted to match the operating pressure of the fuel pump. 
     The fuel injector cleaning (i.e., decarbonization) process is initiated by once again closing the fuel flow control valve to block the flow of fuel through the fuel inlet line. The cleaning fluid flow control valve in the cleaning fluid inlet line is now opened to establish a flow path for the liquid cleaner from the fuel injection flush canister to the fuel injectors via the series connected cleaning fluid inlet line and the fuel injector supply line. Thus, combustible fuel injection cleaner is delivered under pressure (corresponding to the operating pressure of the fuel pump originally measured by the second pressure gauge) to the fuel injectors, whereby carbon deposits will be burned away. 
     For servicing certain vehicles, an auxiliary fuel return line can be connected from the gas tank of the vehicle to the fuel inlet line behind the fuel flow control valve. The fuel return line is temporarily disconnected from a normally closed pressure regulator valve that commonly communicates with the fuel rail of such vehicles for connection to the fuel inlet line during the fuel injection cleaning process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a fuel injection flush tool according to a first preferred embodiment of this invention detachably connected to a conventional fuel injection flush canister prior to the process of cleaning (i.e., decarbonizing) the fuel injectors and related parts of a gasoline engine of a motor vehicle; 
         FIG. 2  shows the fuel injection flush tool of  FIG. 1  prior to the cleaning process with fuel flowing therethrough to the fuel injectors to be cleaned; 
         FIG. 3  shows the fuel injection flush tool of  FIG. 1  during the cleaning process with a liquid cleaner flowing therethrough between the flush canister and the fuel injectors; 
         FIG. 4  shows the fuel injection flush tool of  FIG. 1  during the fuel injector cleaning process including an auxiliary quick-connect fuel return line to return fuel to the fuel tank of the vehicle; 
         FIG. 5  shows a fuel injection flush tool according to another preferred embodiment of this invention to be detachably connected to the conventional fuel injection flush canister of  FIG. 1  for cleaning the fuel injectors of a gasoline engine; and 
         FIG. 6  shows a fuel injection flush tool according to yet another preferred embodiment connected to the conventional fuel injection flush canister of  FIG. 1  during the process of cleaning the fuel injectors and related parts of a diesel engine of a motor vehicle with a diesel injection pump or with a common rail system. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  of the drawings shows a fuel injection flush tool  1  according to a first preferred embodiment of this invention for cleaning the fuel injectors and related parts of a gasoline engine of a motor vehicle. The tool is shown connected to a conventional fuel injection flush canister  3  of the kind having a supply of combustible liquid fuel injection cleaner  5  to be delivered to the fuel injectors. A hook  7  extends from the top of the flush canister  3  to enable the canister to be hung at a work area. Shop air, under pressure, is supplied to the flush canister  3  via an air hose  9  to enable the cleaner  5  to be expulsed from the canister under pressure. An air pressure regulator  10  is selectively adjusted (i.e., rotated) to set the pressure of the air flowing through the air hose  9  to the flush canister  3  depending upon the operating pressure of the fuel pump of the motor vehicle being serviced. A pressure gauge  12  communicates with the air hose  9  to indicate the pressure of the air flowing therethrough to flush canister  3 . 
     The fuel injection flush tool  1  is installed by first disconnecting the fuel lines of the engine of the motor vehicle being serviced and then locating tool  1  between the engine and the gas tank or the fuel pump. The flush tool  1  is shown in  FIG. 1  connected to the fuel injection flush canister  3  when the engine is not running prior to the start of the cleaning process. A cleaning fluid inlet line  14  runs from the flush canister  3  to the fuel injectors to be cleaned (best shown in  FIG. 2 ) by way of a fuel injector supply line  15  that is connected in series with the cleaning fluid inlet line  14 . A check valve  16  is located in the cleaning fluid inlet line  14  to prevent the back flow of cleaning solution and fuel to the flush canister  3 . A cleaning fluid flow control (e.g., ball) valve  18  is also located in the cleaning fluid inlet line  14  to open and close the flush canister  3 . In the case of  FIG. 1 , prior to commencement of the fuel injector cleaning process when the engine is turned off, the cleaning fluid flow control valve  18  is moved (i.e., rotated) to a closed position to block the flow of cleaner  5  from the canister  3  to the engine. 
     A fuel inlet line  20  is connected to the intersection of the series connected cleaning fluid inlet line  14  and the fuel injector supply line  15  at a T-coupler  22  located ahead of the control valve  18 . The fuel inlet line  20  supplies fuel from the fuel pump or gas tank of the vehicle being serviced to the fuel injectors. A check valve  24  is located in the fuel inlet line  20  to prevent the back flow of cleaning solution and fuel to the fuel pump or gas tank. A fuel flow control (e.g., ball) valve  26  is also located in fuel inlet line  20  to control the flow of fuel to the fuel injectors. In the case of  FIG. 1 , prior to commencement of the fuel injector cleaning process when the engine is turned off, the fuel flow control valve  26  is moved (i.e., rotated) to a closed position to block the flow of fuel from the fuel pump or gas tank to the engine. 
     A pressure gauge  28  communicates with the fuel inlet line  20  to monitor the operating pressure of the fuel pump of the engine. Prior to commencement of the fuel injector cleaning process when the engine of the vehicle being serviced is turned off, the corresponding fuel pump operating pressure indicated by pressure gauge  28  will be 0. The air pressure indicated by the pressure gauge  12  that communicates with the air hose  9  is set by the technician to match the pressure indicated by the pressure gauge  28 . In this case, the air pressure regulator  10  is adjusted so that no air flows to the flush canister  3  by way of air hose  9 . 
     An auxiliary quick-connect fuel return line  30  is shown detachably connected to the fuel inlet line  20  at a 4-way block  32  located behind the fuel flow control valve  26 . Such a fuel return line  30 , by which to return fuel flowing through the fuel inlet line  20  to the fuel pump or gas tank, is typically not required in most newer vehicles. The fuel return line  30  is coupled to the 4-way block  32  at a normally closed pressure responsive valve  34 . The application of the fuel return line  30  will be explained in greater detail when referring to  FIG. 4 . 
       FIG. 2  of the drawings shows the fuel injection flush tool  1  still prior to commencement of the fuel injector cleaning process. However, in this case, the gasoline engine of the vehicle being serviced is now running and idling. The cleaning fluid flow control valve  18  located in the cleaning fluid inlet line  14  remains closed to continue blocking the flow of the liquid cleaner  5  from the flush canister  3  to the fuel injectors. So that the engine may be provided with the fuel needed to operate, the fuel flow control valve  26  located in the fuel inlet line  20  is now opened to complete a fuel path between the fuel pump or gas tank and the fuel rail  35  of the fuel injectors  36  by way of the fuel inlet line  20  and the fluid injector supply line  15  that is connected to the cleaning fluid inlet line  14  at the T-coupler  22 . In the example shown in  FIG. 2 , the fuel injectors  36  are those found in a 4-cylinder engine. 
     Once the engine of the vehicle being serviced is running, the pressure gauge  28  that communicates with the fuel inlet line  20  will indicate the operating pressure of the fuel pump. The flush canister  3  is pressurized by shop air being supplied thereto via the air hose  9 . The technician adjusts the air pressure regulator  10  until the air pressure indicated by the pressure gauge  12  which communicates with the air hose  9  matches the engine operating fuel pump pressure indicated by pressure gauge  28 . By virtue of the foregoing, the technician does not have to perform a table look-up or guess the pressure at which the air is supplied to the flush canister  3  to pressurize the fuel injection cleaner therein during the fuel injector cleaning process as will now be described. 
       FIG. 3  of the drawings shows the fuel injection flush tool  1  during the fuel injector cleaning (i.e., decarbonization) process. In this case, the fuel flow control valve  26  located in the fuel inlet line  20  is returned to its closed position to block the flow of fuel from the fuel pump or gas tank to the fuel injectors  36  of the gasoline engine being serviced. However, the cleaning fluid flow control valve  18  located in the cleaning fluid inlet line  14  is now moved (i.e., rotated) to the open position to establish a flow path for the liquid cleaner  5  from canister  3  to the fuel injectors  36  via the series connected cleaning fluid inlet line  14  and the fuel injector supply line  15 . That is, the fuel injector cleaner  5  is expulsed under pressure (corresponding to the operating pressure of the fuel pump) from the fuel injection flush canister  3  by the air being supplied to the canister via air hose  9 . The cleaning fluid flows through the cleaning fluid inlet line  14  and the fuel injector supply line  15  to the fuel rail  35  for distribution to the fuel injectors  36 , whereby carbon deposits will be burned away. 
     It may be appreciated that with the fuel control valve  26  closed, the engine of the vehicle will run off the cleaning solution being supplied by cleaning fluid inlet line  14  and the fuel injector supply line  15  rather than the fuel flowing through fuel inlet line  20  and the fuel injector supply line  15 . The engine operating pressure and the air pressure indicated by pressure gauges  28  and  12  remains unchanged from those shown in  FIG. 2  prior to the cleaning process. The engine will continue to run until all of the fuel injection cleaner (about 11.5 ounces) within the flush canister  3  has been consumed, at which time the engine will automatically stall and the fuel pump will shut off. 
     It may also be appreciated that the engine need not be turned off and the fuel pump need not be disabled during the cleaning process. With the fuel flow control valve  26  closed and the fuel inlet line  20  blocked, pressure will build up in the fuel pump, whereby the fuel pump will be internally bypassed such that fuel is automatically returned to the gas tank. 
     As was explained while referring to  FIG. 1 , an auxiliary fuel return line  30  may need to be connected to the fuel inlet line  20  of the fuel injection flush tool  1  when certain older motor vehicles are being serviced. Referring in this regard to  FIG. 4  of the drawings, such a fuel return line  30  is shown detachably connected from the pressure responsive valve (designated  34  in  FIG. 3 ) at the 4-way block  32  of the fuel inlet line  20  to the gas tank of the vehicle. As will be known to those skilled in the art, the fuel inlet line  20  of the older vehicles identified above is commonly connected to a normally closed fuel pressure regulator valve  40  that communicates with the fuel rail  35  and opens to release fuel back to the fuel tank in the event fuel pressure exceeds a maximum operating pressure. In the example of  FIG. 4 , the fuel return line  30  has been temporarily disconnected from the pressure regulator valve  40  and connected to the fuel inlet line  20  at the 4-way block  32  during the cleaning process. 
     In this case, the cleaning fluid flow control valve  18  is opened prior to starting the engine for cleaning. It has been found that when return line  30  is used, the air pressure applied to the flush canister  12  may have to be reduced by about 10 psi to avoid leakage at regulator valve  40 . The fuel flow control valve  26  remains closed so that the fuel inlet line  20  is blocked as described while referring to  FIG. 3 , and a fuel return path is established from the gas tank, through the fuel inlet line  20  behind valve  26  and the fuel return line  30 , and back to the gas tank. Thus, neither the gasoline engine nor the fuel pump needs to be disabled during the cleaning process. That is, the engine will continue to run on the liquid cleaner  5  being supplied thereto via the cleaning fluid inlet line  14  and the fuel injector supply line  15 . Instead of bypassing itself as in the case of  FIG. 3 , fuel supplied to the fuel pump is recycled back to the gas tank by way of the aforementioned fuel return path including inlet and return lines  20  and  30 . At the conclusion of the cleaning process, the engine will stall and the fuel pump will shut off. The fuel return line  30  is disconnected from the 4-way block  32  of the fuel inlet line  20  and reconnected to the pressure regulator valve  40  at the fuel rail  35 . 
       FIG. 5  of the drawings shows a modified fuel injection flush tool  50  to be used with a fuel return line  52  (such as that designated  30  and previously described while referring to  FIG. 4 ) commonly associated with certain older motor vehicles. Like the fuel injection flush tool  1  of  FIGS. 1-4 , the flush tool  50  of  FIG. 5  is detachably connected to a conventional fuel injection flush canister  54  containing a supply of combustible liquid fuel injection cleaner to be delivered to the fuel injectors of the gasoline engine being serviced to remove carbon deposits therefrom. As in the case of the flush canister  3  previously described, the canister  54  includes an air hose  56  to supply shop air, under pressure, an air pressure regulator  58  to control the pressure of the air being supplied to canister  54  via air hose  56 , and a pressure gauge  60  that communicates with the air hose  56  to measure the pressure of the air supply. A cleaning fluid inlet line  62  carries fuel injector cleaner from the flush canister  54  to the fuel injection flush tool  50  for delivery to the fuel injectors when a cleaning fluid flow control (e.g., ball) valve  64  which is located in the cleaning fluid inlet line  62  is rotated from the closed position (as shown) to an open position. An optional pressure gauge  66  is connected in the inlet line  62  to measure the pressure of the cleaner flowing therethrough. 
     A fuel inlet line  70  is connected between the fuel pump or the gas tank of the vehicle being serviced and a 3-way block  72 . A normally closed fuel flow control (e.g., ball) valve  74  is located in the fuel inlet line  70  to control the flow of fuel therethrough. The cleaning fluid inlet line  62  is detachably connected to the 3-way block  72 . A fuel injector supply line  76  is connected from the 3-way block  72  to the fuel injectors to be cleaned. A pressure gauge  78  communicates with the fuel inlet line  70  at a 3-way block  80  by way of a T-coupler  82  so as to measure the operating pressure of the fuel pump of the engine during idling. In this regard, and as previously explained, the air pressure delivered to the fuel injection flush canister  54  through air hose  56  (measured by pressure gauge  60 ) is adjusted at pressure regulator  58  to match the engine operating fuel pump pressure measured by pressure gauge  78 . The fuel return line  52  is also connected to the 3-way block  80  by way of a normally closed pressure responsive valve  81  and the T-coupler  82 . 
     The use and operation of the fuel injection flush tool  50  of  FIG. 5  for servicing the aforementioned older cars is identical to the flush tool  1  shown in  FIG. 4 . Thus, prior to initiating the cleaning operation (with the cleaning fluid flow control valve  64  remaining closed and the fuel flow control valve  74  opened), a fuel path is established from the gas tank, through the fuel inlet line  70  and the fuel injector supply line  76 , and to the fuel injectors to be cleaned. During the cleaning process, the fuel flow control valve  74  is closed and the cleaning fluid flow control valve  64  is opened at the same time. Liquid cleaner now flows under pressure from the fuel injection flush canister  54  to the fuel injectors through the cleaning fluid inlet line  62  and the fuel injector supply line  76  so that the engine will run off the liquid cleaner. With the fuel flow control valve  74  closed and the fuel inlet line  70  blocked, the pressure responsive valve  81  will open, and fuel from the fuel pump or gas tank will be returned to the tank via the fuel return line  52  so that the engine need not be turned off and the fuel pump need not be disabled during cleaning. 
       FIGS. 1-5  of the drawings show fuel injection flush tools  1  and  50  having particular application for removing carbon deposits and cleaning the fuel injectors and related pats of an engine that runs on gasoline.  FIG. 6  of the drawings shows a fuel injection flush tool  90  to remove carbon deposits from a diesel engine. As with the previously described fuel injection flush tools  1  and  50 , the tool  90  shown in  FIG. 6  is connected to a conventional fuel injection flush canister  3  having a supply of combustible liquid fuel injection cleaner  5  to be delivered to the fuel injectors  120  of the diesel engine. Because the liquid cleaner  5  will be continuously recycled back to the high pressure diesel fuel injection pump  92  (as will soon be explained), the requirement to pressurize the cleaner by applying shop air to the flush canister  3  is eliminated. Therefore, in most cases, no air hose (designated  9  and  56  in  FIGS. 1-5 ) need be connected to canister  3 . In this case, when the cleaning process commences, the canister  3  is opened (at an air inlet valve  4  thereof) so that the liquid cleaner  3  will simply flow therefrom to the fuel injection flush tool  90  under the influence of gravity. However, for a common rail fuel system, an air hose (not shown) may be required to apply air pressure to the canister  3  to cause the cleaner to be expulsed therefrom. 
     The fuel injection flush tool  90  includes a cleaning fluid inlet line  94  that is connected in series with a diesel pump inlet line  96  at a T-coupler  98 . The series connected inlet lines  94  and  96  are connected between the flush canister  3  and the diesel fuel injection pump  92 . A cleaning fluid flow control (e.g., ball) valve  100  is located in the cleaning fluid inlet line  94 . Prior to commencing the cleaning operation, the flow control valve  100  is closed to block the flow of liquid cleaning from the flush canister  3  to the fuel injection pump  92 . Also prior to the cleaning operation, the series connected cleaning fluid and diesel pump inlet lines  94  and  96  are disconnected from the fuel injection pump  92 , and the pump is connected to the fuel tank (via a line  101 ) of the vehicle. 
     The fuel injection pump  92  is connected to the fuel rail  102  of the diesel engine being serviced by a diesel pump outlet line  104 . An excess fuel/liquid cleaner collector  106  at the outlet of the fuel rail  102  is connected by way of a fuel inlet line  108  to the T-coupler  98  at the intersection of the series connected cleaning fluid and diesel pump inlet lines  94  and  96 . Fuel injector lines  107  run from the fuel rail  102  to the fuel injectors  120  and from the fuel injectors to the fuel inlet line  108 . A fuel flow control (e.g., ball) valve  110  is located in the fuel inlet line  108 . Prior to connecting the fuel injection flush tool  90  between the flush canister  3  and the fuel pump  92  as shown, a fuel return line  114  is connected between the fuel rail  102  and the fuel tank of the vehicle. 
     The fuel injectors  120  to be cleaned (i.e., decarbonized) lie in fluid communication with the fuel rail  102  by way of the fuel injector lines  107  to receive either diesel fuel from the fuel pump  92  during normal vehicle operation when no cleaning is performed or cleaning fluid from the flush canister  3  via the pump  92  when the fuel injectors are being cleaned. In the example of  FIG. 6 , the fuel injectors  120  are found in a 4-cylinder diesel engine. 
     During the operation of cleaning the fuel injectors  120 , the cleaning fluid flow control valve  100  in the cleaning fluid inlet line  94  and the fuel flow control valve  110  in the fuel inlet line  108  are both moved to the open position. The air inlet valve  4  of the fuel injection flush canister  3  is opened so that liquid cleaner  5  from the flush canister will flow to the fuel injection flush tool  90 . Accordingly, the liquid cleaner  5  will now pass through a continuous flow path including the cleaning fluid inlet line  94 , the diesel pump inlet line  96 , the high pressure fuel injection pump  92 , and the diesel pump outlet line  104  to the fuel rail  102 . The liquid cleaner  5  is supplied to the fuel injectors  120  from the fuel rail  102  via the fuel injector lines  107  where it will combust and burn away carbon deposits. 
     Excess liquid cleaner  5  that is not combusted by the fuel injectors  120  is pumped along the aforementioned continuous flow path from the liquid cleaner collector  106  of fuel rail  102  and the fuel injector lines  107 , through the fuel inlet line  108 , and back to the diesel pump inlet line  96  at the T-coupler  98 . Thus, it may be appreciated that the liquid cleaner is continuously recycled through the fuel injection flush tool  90  with the fuel pump  92  continuing to operate while the fuel injectors  120  are being cleaned so as to avoid an early consumption of the cleaner and provide for a reliable cleaning of the fuel injectors of the diesel engine being serviced. 
     As an option, the diesel fuel injection pump  92  can be connected to the fuel inlet line  108  by means of connecting the pump return line  116  to a pressure responsive valve  118  that communicates with inlet line  108 .