Rotory engine with rotor land

Abstract

A rotary internal combustion engine with a rotor body made at least in major part of a first material, with at least the contact surface of the rotor lands including a second material having a greater wear resistance than that of the first material with respect to frictional engagement with the portion of the inner surface of the internal cavity contacting the at least one land. For at least one of the end faces, the land(s) include(s) the first material and the contact surface is defined by a surface layer of the second material on the first material. A method of axially positioning a rotor of a rotary engine within an internal cavity of an outer body of the engine are also discussed.

1 . A rotary internal combustion engine comprising:
 an outer body enclosing an internal cavity, the outer body rotationally receiving a shaft extending through the internal cavity;   a rotor body received in the internal cavity and made at least in major part of a first material, the rotor body having two axially spaced apart end faces each extending in proximity of a respective inner surface of the internal cavity, and a peripheral face extending between the end faces, the rotor body being engaged to an eccentric member of the shaft to rotate within the cavity in sealed engagement with walls defining the cavity, the rotor body including at least one land protruding axially from each of the end faces and defining a contact surface extending at a fixed position with respect to the end faces, the contact surface frictionally engaging a portion of the inner surface of the internal cavity, at least the contact surface including a second material;   wherein for at least one of the end faces, the at least one land includes the first material and the contact surface is defined by a surface layer of the second material on the first material;   wherein the second material has a greater wear resistance than that of the first material with respect to frictional engagement with the portion of the inner surface of the internal cavity contacting the at least one land.   
     
     
         2 . The engine as defined in  claim 1 , wherein the first material has a lower mass per volume than the second material. 
     
     
         3 . The engine as defined in  claim 1 , wherein the first material includes titanium. 
     
     
         4 . The engine as defined in  claim 1 , each of the at least one land includes the first material and the contact surface of each of the at least one land is defined by a surface layer of the second material on the first material. 
     
     
         5 . The engine as defined in  claim 1 , wherein the second material includes one or more of titanium nitride, diamond-like carbon, cobalt chrome, nanocrystalline cobalt-phosphorus, nickel, thallium and boron. 
     
     
         6 . The engine as defined in  claim 1 , wherein the at least one land for each of the end faces includes a plurality of spaced apart lands located radially outwardly of oil seal grooves defined in the end face. 
     
     
         7 . The engine as defined in  claim 1 , wherein the outer body has two axially spaced apart end walls and a peripheral wall extending between the end walls, with inner surfaces of the end walls and of the peripheral wall enclosing the internal cavity, and the peripheral face of the rotor body defines three circumferentially spaced apex portions remaining adjacent the inner surface of the peripheral wall during rotation of the rotor, the contact surface of each land frictionally engaging a portion of the inner surface of a corresponding one of the end walls. 
     
     
         8 . The engine as defined in  claim 1 , wherein the second material has a greater hardness than that of the first material. 
     
     
         9 . The engine as defined in  claim 1 , wherein the second material is the same material as that of the portion of the inner surface of the internal cavity contacting the at least one land. 
     
     
         10 . A rotary internal combustion engine comprising:
 an outer body having two axially spaced apart end walls and a peripheral wall extending between the end walls, with inner surfaces of the end walls and of the peripheral wall enclosing an internal cavity, the outer body rotationally receiving a shaft extending through the internal cavity;   a rotor body received in the internal cavity, the rotor body having two axially spaced apart end faces each extending in proximity of the inner surface of a respective one of the end walls, and a peripheral face extending between the end faces and defining three circumferentially spaced apex portions, the rotor body being engaged to an eccentric member of the shaft to rotate within the cavity with each of the apex portions remaining adjacent the inner surface of the peripheral wall, the rotor body including at least one land protruding axially from each of the end faces and defining a contact surface extending at a fixed position with respect to the end faces, the contact surface frictionally engaging a portion of the inner surface of a corresponding one of the end walls of the internal cavity;   wherein at least the contact surface of the at least one land has a greater wear resistance than that of a first material forming at least a major part the rotor body with respect to frictional engagement with a material of the portion of the inner surface of the corresponding one of the end walls contacting the at least one land;   wherein for at least one of the end faces, the at least one land includes the first material, and the contact surface thereof is defined by a layer of a second material over the first material.   
     
     
         11 . The engine as defined in  claim 10 , wherein for each of the end faces, the at least one land includes the first material, and the contact surface thereof is defined by the layer of the second material. 
     
     
         12 . The engine as defined in  claim 10 , wherein the layer of the second material is obtained through a microstructure transformation of the first material. 
     
     
         13 . The engine as defined in  claim 10 , wherein the layer of the second material is defined by a coating of the second material applied on the first material. 
     
     
         14 . The engine as defined in  claim 10 , wherein the second material is the same as the material of the inner surface of the corresponding one of the end walls contacting the at least one land. 
     
     
         15 . A method of axially positioning a rotor of a rotary engine within an internal cavity of an outer body of the engine, the method comprising:
 forming at least a major part of a body of the rotor from a first material;   forming at least one land protruding axially and rigidly from each of the end faces with each land having a contact surface having a greater wear resistance than that of the first material with respect to frictional engagement with a same base material, including forming the at least one land protruding from at least one of the end faces from the first material and defining the contact surface with a second material having the greater wear resistance; and   engaging the rotor within the internal cavity with the contact surface of each of the at least one land contacting a portion of a corresponding wall of the internal cavity, the portion of the corresponding wall being made of the base material.   
     
     
         16 . The method as defined in  claim 15 , wherein the first material includes titanium. 
     
     
         17 . The method as defined in  claim 16 , wherein defining the contact surface with the second material includes performing a microstructure transformation on the contact surface to create a surface layer of the second material on the contact surface. 
     
     
         18 . The method as defined in  claim 16 , wherein defining the contact surface with the second material includes applying a coating of the second material on the at least one land to define the contact surface.