Fuel pump for inter-cylinder direct fuel injection apparatus

Abstract

Disclosed herein is a fuel pump for an inter-cylinder direct fuel injection apparatus, in which occurrence of corrosion and attrition caused by cavitation or erosion can be suppressed, their resistance against the environment can be improved, and an excellent lifetime can be achieved in the case of the use of an aluminum material even if the temperature reaches as high as 100° C. or higher and the pressure reaches as high as 7 to 12 MPa. In the fuel pump for an inter-cylinder direct fuel injection apparatus, made of aluminum or an aluminum alloy, a coating film plated with Ni—P or a Ni—P based material is formed by electroless plating.

1 . A fuel pump for an inter-cylinder direct fuel injection apparatus comprising: 
 a pump body made of aluminum or an aluminum alloy; and    a fuel passage of the pump body in which gasoline added with or without alcohol flows;    wherein a coating film plated with Ni—P or a Ni—P based material is formed on the pump body and the fuel passage of the pump body.    
   
   
       2 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein the coating film plated with the Ni—P or the Ni—P based material is formed in a thickness of 10 μm or more.  
   
   
       3 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein the coating film plated with the Ni—P or the Ni—P based material is formed in a thickness of 10 μm or more and 50 μm or less.  
   
   
       4 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein the coating film plated with the Ni—P or the Ni—P based material is 500 HV or more.  
   
   
       5 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein an oxide coating film or a chromate coating film is formed between the aluminum or the aluminum alloy and the coating film plated with the Ni—P or the Ni—P based material.  
   
   
       6 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein an oxide coating film or a chromate coating film is further formed on the aluminum or the aluminum alloy and the coating film plated with the Ni—P or the Ni—P based material.  
   
   
       7 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein the fuel passage includes a pressurizing chamber and a low pressure chamber, the pressurizing chamber and the low pressure chamber being partitioned from each other via the aluminum or the aluminum alloy, and 
 wherein there is provided a portion at which the aluminum or the aluminum alloy is exposed at a part, on the side of the low pressure chamber, of the aluminum or the aluminum alloy for partitioning the pressurizing chamber and the low pressure chamber from each other.    
   
   
       8 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein the coating film plated with the Ni—P or the Ni—P based material is amorphous.  
   
   
       9 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , further comprising: 
 a pump body made of aluminum or an aluminum alloy;    a seal made of a coating film plated with Ni—P or a Ni—P based material, which is applied to the aluminum or the aluminum alloy; and    a press-fitting member.    
   
   
       10 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 9 , wherein the seal of the coating film plated with the Ni—P or the Ni—P based material is formed in a thickness of 10 μm or more.  
   
   
       11 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 9 , wherein the seal of the coating film plated with the Ni—P or the Ni—P based material is formed in a thickness of 10 μm or more and 50 μm or less.  
   
   
       12 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 9 , wherein the seal of the coating film plated with the Ni—P or the Ni—P based material is 500 HV or more.  
   
   
       13 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 9 , wherein an oxide coating film or a chromate coating film is formed between the pump body made of the aluminum or the aluminum alloy and the seal of the coating film plated with the Ni—P or the Ni—P based material.  
   
   
       14 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 9 , wherein an oxide coating film or a chromate coating film is further formed on the pump body made of the aluminum or the aluminum alloy and on the seal of the coating film plated with the Ni—P or the Ni—P based material.  
   
   
       15 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 14 , wherein the coating film plated with the Ni—P or the Ni—P based material is amorphous.  
   
   
       16 . A fuel pump for an inter-cylinder direct fuel injection apparatus having a pump body made of aluminum or an aluminum alloy, the apparatus comprising: 
 a fuel passage of the pump body provided with holes, gasoline added with or without alcohol flowing in the fuel passage,    wherein each of the holes is continuous to the other holes in the vicinity of a short portion; and    a coating film plated with Ni—P or a Ni-p based material is formed on the fuel passage.    
   
   
       17 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 16 , wherein the plated coating film is formed in a thickness of 10 μm or more.  
   
   
       18 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 16 , wherein the plated coating film is formed in a thickness of 10 μm or more and 50 μm or less.  
   
   
       19 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 16 , wherein the coating film plated with the Ni—P or the Ni—P based material is amorphous.  
   
   
       20 . A fuel pump for an inter-cylinder direct fuel injection apparatus as claimed in  claim 1 , wherein a screw of the pump body is plated with the Ni-p.