Fuel supplying apparatus and fuel injecting apparatus of internal combustion engine

Abstract

A fuel supplying apparatus of an internal combustion engine includes a first fuel supply system, a second fuel supply system, and a pulsation propagation suppressing unit. The first fuel supply system pressurizes a fuel by a low-pressure pump, and supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism. The second fuel supply system is branched from the first fuel supply system, further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism. The pulsation propagation suppressing unit is provided in at least one of the first fuel supply system and the second fuel supply system, and suppresses propagation of a pulsation generated in the high-pressure pump to the first fuel injection mechanism.

1 . A fuel supplying apparatus of an internal combustion engine, comprising: 
 a first fuel supply system that pressurizes a fuel by a low-pressure pump, and that supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism;    a second fuel supply system that is branched from the first fuel supply system, that further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and that supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism; and    a pulsation propagation suppressing unit that is provided in at least one of the first fuel supply system and the second fuel supply system, and that suppresses propagation of a pulsation generated in the high-pressure pump to the first fuel injection mechanism, wherein    the pulsation propagation suppressing unit is a throttle that is provided between a part of the first fuel supply system, at which the second fuel supply system is branched from the first fuel supply system, and the first fuel injection mechanism.    
   
   
       2 . The fuel supplying apparatus according to  claim 1 , wherein 
 the throttle is a variable throttle having a throttling amount which can be changed, and    the throttling amount of the throttle is changed according to the operating state of the internal combustion engine.    
   
   
       3 . The fuel supplying apparatus according to  claim 2 , wherein 
 the throttling amount of the variable throttle is increased in proportion to an increase in a flow rate of the fuel supplied to the first fuel supply system.    
   
   
       4 . The fuel supplying apparatus according to  claim 2 , wherein 
 the throttling amount of the variable throttle is increased as the number of revolutions of the internal combustion engine at which the pulsation propagated from the high-pressure pump to the first fuel injection mechanism is increased.    
   
   
       5 . A fuel supplying apparatus of an internal combustion engine, comprising: 
 a first fuel supply system that pressurizes a fuel by a low-pressure pump, and that supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism;    a second fuel supply system that is branched from the first fuel supply system, that further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and that supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism; and    a pulsation propagation suppressing unit that is provided in at least one of the first fuel supply system and the second fuel supply system, and that suppresses propagation of a pulsation generated in the high-pressure pump to the first fuel injection mechanism, wherein    the pulsation propagation suppressing unit is a check valve that is provided between a part of the first fuel supply system, at which the second fuel supply system is branched from the first fuel supply system, and the first fuel injection mechanism.    
   
   
       6 . The fuel supplying apparatus according to  claim 5 , wherein 
 driving of the low-pressure pump is stopped according to the operating state of the internal combustion engine.    
   
   
       7 . A fuel supplying apparatus of an internal combustion engine, comprising: 
 a first fuel supply system that pressurizes a fuel by a low-pressure pump, and that supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism; and    a second fuel supply system that is branched from the first fuel supply system, that further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and that supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism, wherein    a path length from the high-pressure pump to the first fuel injection mechanism is a length such that the number of revolutions of the internal combustion engine, at which a pulsation propagated from the high-pressure pump to the first fuel injection mechanism is increased, is out of a common range of the number of revolutions of the internal combustion engine.    
   
   
       8 . The fuel supplying apparatus according to  claim 7 , wherein 
 the path length from the high-pressure pump to the first fuel injection mechanism is a length such that the number of revolutions of the internal combustion engine, at which the pulsation propagated from the high-pressure pump to the first fuel injection mechanism is increased, is smaller than the number of revolutions during idling in the common range of the number of revolutions of the internal combustion engine.