Patent Publication Number: US-2007102300-A1

Title: Method for ceramic electroplating a cylinder assembly of an internal combustion engine

Description:
FIELD OF THE INVENTION  
      The present invention relates to a method for ceramic electroplating a cylinder assembly of an internal combustion engine, and particularly to a method for electroplating ceramic material on the outer wall of a piston and on the surface of a cylinder inner-wall, which causes the engine cylinder assembly not only has a smooth and lubricative surface layer, resistance to oxidation at high temperature and increased kinetic energy (horse power), but also has more conformation with environmental protection, prolonged service life of cylinder and heat resistance (heat dissipation).  
     BACKGROUND OF THE INVENTION  
      In general, in order to solve a problem that has difficulty to provide cylinder inner-wall with a lubrication effect which can provide a piston for extended reciprocal movement as well as reduced friction coefficient and increased kinetics power by adding lubricant into fuel in a cylinder, those in the art may use a lubricating oil which causes the outer wall of a piston very close to the surface of a cylinder inner-wall when the piston reciprocally travel in the cylinder inner-wall, which has little lubricating effect for the reciprocal travel of the piston and also can not eliminate the increased the friction between the piston and the cylinder inner-wall during the reciprocal travel which causes decreased kinetic energy (horse power).  
      It is well-known that ceramic material can provide the outer wall of a piston reciprocally traveling along the cylinder inner-wall for a long time with excellent properties such as well-lubricating effect, resistance to oxidation at high temperature, high hardness, heat resistance and long-wearing, and mean while, the ceramic material can be electroplated on the surface of a work-piece to have a thickness thereof on the work-piece according to the requirement, which cause the work-piece also has smooth and lubricative surface with the ceramic properties such as resistance to oxidation at high temperature, high hardness, heat resistance and long-wearing; however, conventional electroplating methods are not suitable for surface treatment of an aluminum alloy based cylinder assembly of an internal combustion engine, since the reciprocating movement of the piston of a cylinder assembly of an internal combustion engine along the cylinder inner-wall has further lubricating effect; besides, for an automobile, an airplane and a vessel, etc., the intake, ignition, explosion and exhaust of the engine cylinder typically are functioned over the top of the piston to make the piston moving in the cylinder body for generating expansion and compression stroke reciprocally, so the lubricant between the piston and the cylinder inner-wall do not have appropriate reciprocal movement which causes the limited reciprocal movement of the cylinder assembly of an internal combustion engine without damage, but this also constraint the application of ceramic material in the electroplating process of a cylinder assembly of an internal combustion engine, because, since the hard nature and fragility of ceramic material, if ceramic material is electroplated on the engine cylinder assembly, the ceramic layer is apt to fall off because it cannot sustain the lubrication action generated by the unavoidable reciprocal movement of the engine cylinder assembly. Thus, this problem becomes an unbreakable technical bottleneck of the ceramic electroplating method for application of the surface treatment of a cylinder assembly of an internal combustion engine which requires reciprocating motion.  
     SUMMARY OF THE INVENTION  
      Accordingly, the object of the present invention is to provide a method for ceramic electroplating a cylinder assembly of an internal combustion engine which requires a reciprocating movement. By this design, a cylinder assembly of an internal combustion engine has properties of ceramic material, such as resistance to oxidation at high temperature, heat resistance and long-wearing to have softness with smooth and lubricative features and thus has reduced frictional resistance, accelerated kinetics power and prolonged service life of cylinder for increasing the kinetic energy (horse power).  
      To achieve the noted object of the present invention, the technical means utilized by the present invention is to provide a method for ceramic electroplating a cylinder assembly of an internal combustion engine, comprising the following steps: after an engine cylinder assembly&#39;s aluminum alloy based work-pieces having been inspected are chemically degreased and roughened, placed into a electroplating tank, containing a electroplating solution formulated from Nickel Sulfate, Nickel Chloride and Boric acid and an additive formulated from ceramic powder, metal alloy powder, Sodium citrate, and adding softening agent into the electroplating tank, and blowing air by an air tube installed therein for stirring the electroplating solution, which not only causes the electroplating solution and the additive become uniform but also increases the electroplating rate; and after the work-pieces in the electroplating tank are suspended on cathode hook-bars while nickel plates are disposed in the anode and the right middle of the cylinder inner-wall is also connected to a current auxiliary anode with a suitable voltage, thus causes metallic ions and ceramic material in the electroplating solution accumulate on the work-pieces and forms a electroplating layer alternatively stacked with one metal alloy layer by one ceramic layer, so that the ceramic is electroplated on the surface of the work-pieces, and then after the work-pieces are taken out and cleaned for grinding, thus completing the cylinder assembly of an internal combustion engine having smooth and lubricative surfaces, resistance to oxidation at high temperature, heat resistance (heat dissipation), long-wearing, gasoline saving, conforming with environmental protection and softness. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a flow chart according to an embodiment of the present invention;  
       FIG. 2  shows a 3-D appearance diagram of a piston according to an embodiment of the present invention;  
       FIG. 3  shows an assembling illustrative diagram of a cylinder assembly of an internal combustion engine according to an embodiment of the present invention;  
       FIG. 4  shows an upward-viewing illustrative diagram of an auxiliary anode of a cylinder inner wall of an internal combustion engine according to an embodiment of the present invention; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      First, referring to  FIG. 1 , the steps for performing the present invention are: 
      a. Inspection  1 : inspecting engine cylinders of internal combustion engines if the surface or appearance of aluminum alloy based work-pieces thereof have any defect or flaw, and eliminating the defects;     b. Arrangement  2 : arranging the inspected work-pieces in order;     c. Chemically degreasing  3 : placing the work-pieces into a chemically degreasing sink for a degreasing operation, wherein the chemically degreasing sink contains a weak alkaline solution with concentration 10-20%, and the time of the degreasing operation is about 5-30 minutes to allow the grease becoming soluble compounds for removing;     d. Cleaning  4 : placing the chemically degreased work-pieces into a tank for cleaning by purified water;     e. Suspension  5 : suspending the cleaned work-pieces;     f. Roughening  6 : transporting the suspended work-pieces into a sodium hydroxide (NaOH) solution tank for roughening to make the surfaces thereof have capillarity;     g. Cleaning  7 : placing the roughened work-pieces into a bath containing purified water for cleaning;     h. Activation  8 : placing the cleaned work-pieces into a solution tank added with nitric acid HNO 3  for removing aluminum oxide on the surfaces of the work-pieces and activating the surfaces at the same time;     i. Cleaning  9 : placing the activated work-pieces a bath containing purified water for cleaning;     j. Zincating  10 : using a chemical agent to form a film on the surface of the work-pieces for treating as a bridge for ceramic electroplating process;     k. Cleaning  11 : placing the zincated work-pieces into a bath containing purified water for cleaning;     l. Ceramic electroplating  12 : placing the zincated work-pieces into a electroplating tank and acting as a cathode as shown in  FIG. 4 , and hanging a nickel plate as anode in the electroplating tank, in which the electroplating solution formulated from Nickel Sulfate, Nickel Chloride and Boric acid, and an additive formulated from ceramic powder, metal alloy powder, Sodium citrate and softening agent, are added into the electroplating tank, wherein the metal alloy powder can selected based on the hardness, hue and the likes according with the requirements of the finished product, and the softening agent can be 2-ethyl hexyl Sulfate and wherein 1 liter of the electroplating solution and additive is formulated from 150 g-300 g Nickel Sulfate, 25 g-60 g Nickel Chloride, 15 g-45 g Boric acid, along with 50 g-200 g ceramic powder, 5 g-50 g Sodium citrate and 5 g-30 g other metal alloy powder, with PH between 3.5 and 5; and the working temperature of the electroplating tank is in the range of 50° C.-70° C., an air tube blows air into the electroplating tank for stirring the electroplating solution and the additive sufficiently, and after the electroplating tank applies a 3V-7V voltage and a 50A-500A current, which the amount of the current is determined by the number of the work-pieces, which causes metallic ions and ceramic material in the electroplating solution to accumulate on the work-pieces and forms a electroplating layer alternatively stacked with metal alloy layers and ceramic layers, thus electroplating ceramic on the surface of the work-pieces to form ceramic parts having required thickness according with the ceramic material of a piston  30  and a inner wall  21  of a cylinder  20  of a cylinder assembly of an internal combustion engine; and then connecting a right middle  210  of the inner wall  21  of the cylinder  20  to a current auxiliary anode which causes ceramic electroplating layer at the right middle  210  become uniform and has better electric conducting adhesion as shown in  FIG. 4 ;     m. Cleaning  13 : transporting the parts electroplated with ceramic into a bath for cleaning with running purified water;     n. Blow-drying  14 : after the cleaned parts blow-dried, taking off from suspension hooks;     o. Grinding  15 : surface treating the blow-dried ceramic parts via grinding (such as, polishing) which makes the ceramic parts having smooth and lubricative surfaces, whereby completing finished products  16 .    

      By the implementation flow of the above-mentioned method, the present invention can be applied to a reciprocal-moving cylinder assembly of an internal combustion engine. Since ceramic material has excellent properties such as high hardness, heat resistance, long-wearing, high lubrication and resistance to oxidation at high temperature. Therefore, the present invention electroplates ceramic material on the holes of the inner wall  21  and the outer wall surface  31  of a cylinder of an internal combustion engine as shown in  FIGS. 2 and 3 , which can cause the inner wall  21  of the cylinder  20  and the outer surface  31  of the piston  30  of an internal combustion engine have the properties of the ceramic material such as well-lubricating effect, heat resistance, long-wearing and resistance to oxidation at high temperature. After the present invention applies to a cylinder assembly of an internal combustion engine used by an automobile, an airplane and a vessel, etc., the smooth surface of the piston  30  and the inner wall  21  of the cylinder  20  has high lubrication in compression stroke, reduced friction coefficient and increased power efficiency; furthermore, since the surface has a ceramic electroplated cylinder assembly of an internal combustion engine, not only can reach the object of gasoline saving but also conforming with environmental protection due to no smoke emission and prolonged service life.