Abstract:
An apparatus for reducing fuel consumption in an internal combustion engine such as a diesel engine used in a truck compartment, comprising a thermal insulation cover that also includes reflective fabric over the exhaust manifold, around the intake plenum for intake air and intake air box, covering the turbocharger compressor with a heat insulating material that includes a reflective fabric layer and the turbocharger drive turbine housing except for the bearing area in order to greatly reduce heat build up in the truck engine compartment thereby reducing intake air temperature for increased engine efficiency.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for improving the fuel efficiency of an internal combustion engine, and specifically to a method and apparatus to minimize, reduce and lower the operational combustion engine compartment temperature to maintain relatively low intake air temperature in order to achieve improved combustion engine efficiency and reduced fuel consumption without reducing engine performance. 
     2. Description of Related Art 
     Internal combustion engines are used to power vehicles such as cars and trucks. Internal combustion engines utilize air and fuel to create a combustion charge which is burned to create rotary movement of a crank shaft. The rotation of the crank shaft is used to propel the vehicle and power other systems on the vehicle. 
     An internal combustion engine generally includes an engine block having at least one combustion chamber, an air intake port, an air intake manifold connected to the air intake port and an exhaust port connected to an exhaust manifold. Air is fed to the air intake manifold by an intake plenum. Air is mixed with fuel creating a charge within the intake manifold which is drawn into the engine block by the expansion of a combustion chamber. The charge is compressed and burned by the combustion chamber. The products of the burned charge are released from the engine block through the exhaust port and travel through the exhaust manifold which is normally connected to a muffler. 
     When used to power a car or truck, the combustion engine is normally located towards the front of the car or truck within an engine compartment formed by an engine bay which is covered by a hood. The combustion of fuel within an engine block (which is iron or aluminum) creates a large amount of heat which is conducted and radiated within the engine compartment. This heat productivity causes the intake manifold and intake plenum in the engine compartment to be continuously heated which increases the temperature of the intake air delivered to the engine, reducing engine gasoline and diesel fuel efficiency. 
     Some engines used to power cars or trucks utilize turbochargers. Turbochargers use the velocity of the exhaust gases expelled from the engine block to rotate a compressor which compresses the intake air delivered to the intake manifold above atmospheric pressure. The pressurized air allows the engine to operate more efficiently by providing a charge with increased density. Turbochargers by their nature create additional radiant heat energy within the engine compartment by providing an increased surface area for exhaust heat to emanate and increasing the time the exhaust gases spend within the engine compartment as they are forced to follow a longer path in order to turn a compressor. 
     It is known to attempt to reduce the temperature in the engine compartment to allow a person to work on an engine while the engine is running without subjecting the person to the dangers of being burned. Some areas of an engine compartment are covered by heat protectors to reduce the heat that radiates from the engine. 
     The present invention is especially useful in a large truck diesel engine to greatly improve fuel efficiency by significantly reducing the temperature of the ambient air within the engine compartment by insulating heat producing components as well as the intake plenum. 
     Prior art methods of decreasing the heat generated within the engine compartment include insulating wraps which are wrapped around exhaust headers such as those manufactured by Design Engineering, Inc. and Cool It Thermo Tec. These wraps are formed by high temperature fiber wraps which are used to insulate exhaust headers. These wraps are applied to an exhaust header by wrapping them around the tubes that comprise the header and securing it in such fashion with clamps. Additionally, those conventional wraps are designed to prevent radiant heat from escaping rather than preventing radiant heat from entering. 
     What is needed is a method and a system for thermally insulating both conductive and radiant heat generating engine parts including turbochargers and exhaust headers to reduce the heat radiated within the engine compartment. Also the intake air box and intake air plenums are covered with thermal insulation to reduce the heating of the intake air delivered to the engine so that the overall efficiency of the engine is increased. The present invention provides a system for reducing conductive and radiant heat generated within the engine compartment and to reduce the temperature of the intake air delivered to the engine via the intake air box and intake plenum. 
     BRIEF SUMMARY OF THE INVENTION 
     A method and system for increasing diesel combustion engine efficiency and reducing fuel consumption in a large truck diesel engine with a turbocharger that includes lowering intake air temperatures by reducing engine compartment heating. The exhaust manifold is covered with thermal insulation layers forming a thermal shield to reduce engine compartment heat. The turbocharger compressor and turbine are both covered with thermal insulation layers except for the bearing location to reduce engine compartment heat, the intake air box and intake plenum are covered with a light weight reflective insulation to prevent heating of the intake air. The engine compartment hood is also insulated to prevent heat build up that would cause increased compartment heating. By insulating many components that produce and radiate heat, the overall efficiency of an engine can be greatly increased by reducing the heating of the intake air. 
     Exhaust manifold multi-layered thermo shields are used to thermally insulate the exhaust manifold to reduce the heat radiated from the exhaust manifold into the engine compartment. The shield is wrapped around the exhaust manifold so that most of the manifold is insulated. The heat insulating and radiating materials used to cover the exhaust manifold include a thermal insulating layer of manning glass, a thermal insulating layer of heavy stevens cloth, a wire mesh layer adjacent the stevens cloth to prevent cloth wear, and a top layer of a heat reflecting fabric such as aluminum coated fibers known as GENETEX to reflect engine compartment heat. The layered insulating materials form a laminate insulating shield that is cut and shaped to effectively cover thermally the exhaust manifold to reduce engine compartment heat while being a relatively light weight shield that is resilient and flexible enough to be shaped about the top of the manifold headers and held firmly in place by wires or safety straps. 
     The turbocharger is insulated with a thermal insulation shield of the same materials as the exhaust manifold above also using individual layers of manning glass and stevens cloth. A wire mesh layer is also used to prevent wear on the insulation from vibration. The outer layer is also an aluminum fabric known as GENETEX that reflects heat. Since the turbocharger compressor is somewhat cylindrical, the insulating layered shield is cylindrical to fit substantially around and over the compressor secured by peripheral wires. The turbine housing of the turbocharger is likewise covered with the same thermal insulation materials as the exhaust manifold and secured by peripheral wires. However the external area of the turbine housing near the bearings is not covered to protect the bearings from overheating. The insulation shield is held in place by wire ties. Thus, two separate thermo shields are used on the turbocharger. 
     The hood is insulated with a layer of manning glass and a layer of planar aluminum foil that is fixed by adhesive to the hood surface. 
     The air intake passage and air intake plenum are thermally insulated with a layer of manning glass and an outside layer of aluminum foil which is affixed by an adhesive to the outside housing of the passages and plenum. 
     The fuel lines are insulated to reduce the heat that they absorb to prevent fuel vapor lock. 
     By greatly reducing the ambient and radiated heat built up within the engine compartment, the heating of the intake air is significantly reduced relative to the traditional temperatures present from engine compartment heat, greatly improving fuel efficiency and reducing fuel consumption. Reducing the temperature of the intake air increases engine efficiency. Reducing the radiant heat within the engine compartment and insulating fuel lines also eliminates the potential for vapor lock which is caused by the heating and subsequent boiling of fuel within the fuel lines. 
     Fifteen to twenty percent savings in fuel consumption has been achieved on Detroit Diesel Truck Series 60 engines using the method and system of the present invention. 
     In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective view, partially in phantom, of a combustion engine that includes a turbo charger and intake air plenum. 
     FIG. 2 shows a perspective view, partially cut away and exploded of the thermo-insulating shield used with the hood of a vehicle for insulation. 
     FIG. 3 shows a perspective view of representative insulation shield for intake air box in an exploded view. 
     FIG. 4 shows a perspective view of an intake plenum exploded with a thermal insulation shield that can be wrapped around the intake air plenum. 
     FIGS. 5 a  and  5   b  show the insulating shields in perspective, that are used (partially exploded) for the turbo charger broken into two segments for the turbine (FIG. 5 a ) and for the compressor (FIG. 5 b ). 
     FIG. 6 show an exploded view of the exhaust manifold and insulating shield used. 
     FIG. 7 is a perspective exploded view of a fuel line with a thermal panel illustrating how the thermal panel is wrapped around the fuel line and secured using hook and lock fasteners. 
     FIG. 8 shows a side elevational, cross sectional view of the laminate insulating shield showing the layered materials that form the shield which covers the exhaust manifold and the turbo charger. 
     FIG. 9 shows a side elevational, cross sectional view of the laminate used as a thermal insulating shield for the intake air plenum, intake air box and the hood. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1 a representative conventional diesel engine  100  is shown. The components include an intake air box  120 , intake air plenum  110 , turbocharger  130 , fuel lines  140  which is connected to the turbo charger compressor  130   b.  The turbocharger  130  includes a compressor  130   b  to compress intake air to raise the air pressure above ambient and a driving turbine  130   a  that utilizes exhaust gases to drive compressor  130   b.  The engine block is attached to an exhaust manifold seen in FIG.  6 . Other components of diesel engine  100  fuel lines and an intake manifold. The engine is mounted in the engine compartment and covered by a metal access hood. The example that was tested is a Detroit Diesel 60 Series engine which is a six cylinder engine built by DETROIT DIESEL having large horsepower. The engine components generate large amounts of heat which radiate into the engine compartment continuously. The present invention is a method that provides for installation of exhaust manifold and turbo charger component insulation wrap, insulation shields between radiant heat producing engine parts and intake parts, intake air insulation shielding, hood reflective thermal insulation and fuel line insulation. By insulating all components that radiate heat and those parts that absorb unwanted heat, the overall efficiency of the engine is greatly increased by reducing the heating and relative temperature of the intake air coming into the turbo charger  130  and subsequently burned. 
     Exhaust manifold insulation wrap  250  is used to insulate the exhaust manifold  150 . The exhaust gasses from the combustion of fuel and air exit the engine block passing through the exhaust manifold  150 . To reduce heat radiated by the exhaust manifold  150 , exhaust manifold insulation wrap is tied to the exhaust manifold using stainless steel wire ties  250   t  or other suitable heat impervious wire. The exhaust manifold insulation wrap  250  is shaped to properly conform to the surface of the exhaust manifold  150  for efficient reflection and insulation of heat radiated from exhaust manifold  150  as well as ease of attachment. Stainless steel wire ties  250   t  are passed through sleeves or holes within exhaust manifold insulation wrap  250  and passed around exhaust manifold  150 . Both ends of wire ties  250   t  are secured by twisting the two together so that exhaust manifold insulation wrap  250  is secured so that it substantially covers exhaust manifold  150 . 
     Exhaust manifold insulation wrap  250  is constructed from a laminated insulation blanket formed by four different material layers as seen in FIG. 8. A reflective aluminized heat impervious fabric know as GENETEX forms the first outside layer  200   a  which faces outward of the exhaust manifold. A heat impervious fiberglass insulation layer with high insulation properties known as MANNING GLASS forms the second layer  200   b.  The third layer  200   c  is formed by a fiberglass wrap known as STEVENS CLOTH. The fourth layer  200   d  is formed by heat impervious wire mesh which faces exhaust manifold  150 . These layers are arranged to reduce the heat radiated by the exhaust manifold  150  by first reflecting the radiated heat and reducing radiated heat which cannot be reflected. 
     Turbocharger  130  is insulated with the same laminate insulation as the exhaust manifold  150 . The turbocharger is comprised of drive turbine  130   a  connected by a drive shaft to a compressor  130   b.  The exhaust gases from the engine combustion of fuel and air exit the engine block passing through the exhaust manifold  150  and are used to drive compressor  130   b  by passing through the drive turbine  130   a.  Compressor  130   b  compresses the intake air so that a more dense combustion charge is produced at a higher pressure than ambient. To reduce heat radiated by turbocharger  130 , drive turbine insulation wrap  230   a  and compressor insulation wrap  230   b  are wrapped around the housing of turbine  130   a  and housing of compressor  130   b.  Drive turbine insulation wrap  230   a  and compressor insulation wrap  230   b  are attached using stainless steel wire  230   t  or other suitable heat impervious wire. Each turbo insulation wrap  230   a  and compressor wrap  230   b  are circular in shape so that they properly conform to the surface of the turbine  130   a  and compressor  130   b  for efficient reflection and insulation of radiant heat as well as ease of attachment. Stainless steel wire ties  230   t  are passed through sleeves which extend along opposite lengthwise edges of drive turbine insulation wrap  230   a  and compressor insulation wrap  230   b.  Drive turbine insulation wrap  230   a  is wrapped around turbine  130   a  and wire ties  230   t  are pulled tight so that drive turbine insulation wrap  230   a  becomes circular in shape and conforms in shape to turbine  130   a,  effectively covering turbine  130   a.  The opposite ends of the wire ties  230   t  which secure drive turbine insulation wrap  230   a  are secured together by twisting the two together. Compressor insulation wrap  230   b  is wrapped around the compressor  130  in the same fashion as drive turbine insulation wrap  230   a  and wire ties  230   t  are pulled tight so that compressor insulation wrap  230   b  becomes circular in shape and conforms to the shape of compressor  130   b,  effectively covering compressor  130   b.  The opposite ends of wire ties  230   t  which secure compressor insulation wrap  230   b  are secured together by twisting the two together. The shape of the compressor insulation wrap  230   b  is adapted so that the area adjacent to the bearings of compressor  230   b  are not covered to prevent overheating the bearings. Similarly, the shape of the drive turbine insulation wrap  230   a  is adapted so that the area adjacent to the bearings of drive turbine  230   a  are not covered to prevent overheating of the bearings. 
     Drive turbine insulation wrap  230   a  and compressor insulation wrap  230   b  are constructed from the same laminated insulation fabric which forms exhaust manifold insulation wrap  250  as seen in FIG. 8. A reflective aluminized heat impervious fabric known as GENETEX forms the first outside layer  200   a  which faces outward of the exhaust manifold. A heat impervious fiberglass insulation layer with high insulation properties known as MANNING GLASS forms the second layer  200   b.  The third layer  200   c  is formed by fiberglass wrap known as STEVENS CLOTH. A fourth layer,  200   d  is formed by heat impervious wire mesh which faces exhaust manifold  150 . These layers are arranged to reduce the heat radiated by the turbocharger drive turbine  130   a  and compressor  130   b  as well as reflecting any heat that may be absorbed by the turbocharger from the exhaust manifold  150  by first reflecting the radiated heat by the exhaust manifold  150  as well as insulating the turbine  130   a  and compressor  130   b.    
     The fuel lines  140  are insulated by fuel line insulation  240  which is wrapped around the fuel lines  140  and secured using hook and lock fasteners  240   a  and  240   b.  Fuel line insulation  240  is constructed from a two layer laminate. The fuel line insulation wrap  240  comprises an outside layer and an inside layer. The outside layer is formed by reflective aluminized fabric know as GENETEX and the inside layer is formed by insulation fabric know as STEVENS CLOTH. By using aluminized fabric and insulation fabric around fuel lines  140 , heat absorbed into fuel lines  140  is reduced. The outside layer reflects heat radiated within the engine compartment, while the inside layer insulates the fuel lines  140  from heat which cannot be reflected. By insulating the fuel lines  140  the potential for fuel vapor lock within the fuel lines  140  is reduced. 
     Hood  160  is insulated by hood insulation  260 . Hood insulation  260  is formed by a three layer laminate having a first layer  260  formed by reflective aluminum foil that reflects heat, a second layer  260   b  formed by insulation known as MANNING GLASS and a third layer  260   c  formed by an adhesive backing as seen in FIG.  9 . Hood insulation  260  is pliable so that it may easily conform to the shape of the hood  160 . Hood insulation  260  is secured to hood  160  by an adhesive backing  260   c  for easy installation. First layer  260   a  of hood insulation  260  is reflective and faces engine  100  so that the heat is reflected within the engine compartment. The second layer  260   b  of hood insulation  260  insulates so that heat generated by the heating of hood  160  by the sun does not radiate into the engine compartment. 
     Plenum insulation wrap  210  is used to insulate intake plenum  110  and air box insulation wrap  220  is used to insulate intake air box  120 . Intake plenum  110  carries intake air from intake air box  120  to turbocharger  130 . Intake air fed to turbocharger  130  is used to create the intake charge which is burned within engine  100 . Insulating intake plenum  110  and intake air box  120  reduces the heating of the intake air by the heat radiated by exhaust manifold  150  and turbocharger  130 . 
     Plenum insulation wrap  210  and air box insulation wrap  220  are constructed from the same laminate which forms hood insulation  260 . Plenum insulation wrap  210  and air box insulation wrap  220  are formed by a three layer laminate having a first layer  260   a  formed by reflective aluminum foil that reflects heat, a second layer  260   b  formed by insulation known as manning glass and a third layer  260   c  formed by an adhesive backing as seen in FIG.  9 . These layers are arranged to reduce the heat absorbed by intake plenum  110  and intake air box  120  and the subsequent heating of the intake air. The first layer  260   a  first reflects the radiant heat within the engine compartment, the second layer reduces the radiated heat which can not be reflected, and the third layer affixes the plenum insulation wrap  210  and air box insulation wrap  220  to the intake plenum  110  and intake air box  120 . 
     Plenum insulation wrap  210  is wrapped around intake plenum  110  and affixed by adhesive third layer  260   c  to intake plenum  110 . Similarly, air box insulation wrap  220  is wrapped around intake air box  120  and affixed by adhesive third layer  260   c.  One or more pieces of plenum insulation wrap  210  or air box insulation wrap  220  may be used to insulate intake plenum  110 . Plenum insulation wrap  210  and air box insulation wrap  220  are shaped to properly conform to the surface of intake plenum  110  and intake air box  220  so that the entire intake plenum  110  and intake air box  120  are covered and properly insulated. The shape of the plenum insulation wrap  210  and air box insulation wrap  220  assures efficient reflection of radiant heat as well as ease of attachment. 
     By greatly reducing the ambient and radiated heat built up within the engine compartment the heating of the intake air is reduced. The heating of the intake air is further reduced by the insulation of intake air box  120  and intake plenum  110 . Fifteen to twenty percent savings in fuel consumption has been achieved on Detroit Diesel Truck Series 60 engines using this method. Fuel savings on trucks used for several weeks in normal working environment achieved 10-15% improvement in fuel efficiency. 
     The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made there from within the scope of the invention and that obvious modifications will occur to a person skilled in the art.