Abstract:
A fuel drain structure in a fuel line comprising a bypass channel for connecting a fuel influx side and a fuel efflux side of a regulator, and a rotary valve for opening and closing the bypass channel, contributing to a prevention of fuel remaining in the fuel line from entering the engine when the engine stops running, and minimization of pollution occurring when the engine is re-started.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of Korean Application No. 10-2003-0019344, filed on Mar. 28, 2003. 
   FIELD OF THE INVENTION 
   The present invention relates to a fuel drain structure in a fuel line, and more particularly to a drain structure for draining fuel from the line when the engine stops running. 
   BACKGROUND OF THE INVENTION 
   In general, when an engine stops running and fuel provided from a fuel pump remains in a fuel line, the fuel tends to flow into the engine via an injector due to pressure increased by high temperature around the engine, which contributes to air pollution by excessive incomplete combustion when the engine gets re-started. 
   SUMMARY OF THE INVENTION 
   Embodiments of the present invention provide a fuel drain structure in a fuel line for effectively draining the fuel leftover in the fuel line when the engine ceases moving, thereby preventing the fuel from leaking into a combustion chamber via an injector and thus reducing incomplete combustion of the fuel when the engine is re-started. 
   In one embodiment of the present invention, a fuel drain structure in a fuel line comprises a regulator adjusting pressure of fuel pumped out from a fuel pump to a fuel line, wherein the regulator includes a housing forming a chamber by coupling with a valve seat. A fuel inlet is at one side of the chamber while a fuel outlet is formed at the valve seat. A valve is resiliently supported via a spring at an upper side of the valve seat. A bypass channel connects a fuel influx passage and a fuel efflux passage of the regulator, such that the fuel leftover inside the fuel line is forced to flow into the fuel tank through the bypass channel while the engine stops running. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the nature and objects of the present invention, reference should be made to the following detailed description with the accompanying drawings, in which: 
       FIG. 1  is a block diagram of a fuel supply system including a regulator according to an embodiment of the present invention; 
       FIG. 2  is a schematic view of a regulator according to an embodiment of the present invention; and 
       FIGS. 3 and 4  illustrate operational states of the regulator according to an embodiments of the present invention, wherein  FIG. 3  shows a state when an engine is running and  FIG. 4  illustrates a state when the engine stops running. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. 
   As shown in  FIG. 1 , fuel pumped out from a fuel tank  11  via a fuel pump  12  is filtered at a fuel filter and is injected into an intake manifold of an engine  10  through an injector  16 . A pressure sensor  17  and a regulator  30  are mounted at a return line  22  for adjusting the fuel pumped from the fuel pump  12  to be injected through the injector  16  to the engine at a constant pressure. A fuel-stopping solenoid valve  14  restricts the fuel from being provided to the injector  16  according to the on/off state of the ignition key, and a temperature sensor  15  measures fuel temperature. Both the fuel-stopping solenoid valve  14  and temperature sensor  15  are mounted at a feed line  21 . 
   With reference to  FIG. 2 , the regulator  30  comprises a housing  31  forming a chamber  32  by coupling with a valve seat  33 . A fuel inlet  34  is at one side of the chamber  32  for allowing the fuel to flow therein from the return line  22 . A fuel outlet  35  is formed at the valve seat  33  for guiding the fuel passed through a valve  36  to flow back to the return line  22 . 
   The valve  36  resiliently supported by a spring  37  is secured at an upper side of the valve seat  33 . When pressure of the fuel applied to the fuel inlet  34  is higher than the resilient force of the spring  37 , the valve  36  ascends, and the fuel starts to pass through the fuel outlet  35 . 
   A bypass channel  40  traverses the influx and efflux passages of the regulator  30 . The bypass channel  40  may be an independent pipe or integrally formed with the housing  31 . By way of reference, the bypass channel is preferably about b  0 . 3  mm in diameter. 
   The cross-sectional view of the inlet side of the bypass channel  40  is funnel-shaped, and the inlet of the bypass channel  40  has a larger diameter than the outlet. A rotary valve  50  having a sectoral-spool shape in its cross-sectional view is mounted at the inlet side of the bypass channel  40 . The rotary valve  50  operates in response to an actuator  62  activated by an electronic control unit (ECU)  60 . The ECU may comprise a processor and other associated hardware and software or firmware as may be selected and programmed by a person of ordinary skill in the art based on the teachings set forth herein. 
   The rotary valve  50  is activated by the actuator  62  in the embodiment of the present invention, however, the operational means may be an actuator, a rotational force of a motor or the like. The ECU  60  renders the rotary valve  50  to be closed when the engine is started, and be opened when the engine is stopped in motion. 
   The operation of the present invention will now be described. 
   Once the engine starts to move, the fuel pumped out from the fuel pump is delivered into the feed line  21  through the opened fuel-stopping solenoid valve  14 , and is injected via the injector  16  into the engine at a preset pressure. Fuel not injected through the injector returns to the fuel tank  11 . 
   When the engine stops its motion, some of the fuel still remains in the fuel line without being injected through the injector  16 . 
   The ECU  60 , therefore, detects whether the engine ceases running, and if so, stops the activation of the fuel pump  12 , and closes the fuel-stopping solenoid valve  14 . The ECU  60  further rotates the rotary valve  50  to an open side for leading the fuel rested between the fuel-stopping solenoid valve  14  and the regulator  30  of the fuel line to be discharged through the bypass channel  40 . 
   The fuel remaining in the fuel line returns to the fuel tank  11  through the bypass channel  40 , such that the fuel is not injected into the engine  10  via the injector  16  due to the temperature and pressure being increased by heat around the engine. 
   As apparent from the foregoing, there is an advantage in the fuel drain structure in a fuel line in that the fuel inlet side and fuel outlet side of the regulator is connected by the bypass channel being opened and closed via the rotary valve, resulting to prevent the fuel remaining in the fuel line from entering the engine through the injector when the engine stops its operation, thus reducing pollution in the course of re-starting the engine.