Method and Device for Reducing Corrosion in Internal Combustion Engines

1. Field of the Invention

This invention relates to a method and device for preventing corrosion in the cylinders of an internal combustion engine.

2. Relevant Art and Information Disclosure

As shown in FIG. 5, the general construction of an internal combustion engine 24 that is used for trucks, buses etc. includes a plurality of engine cylinders 10 (combustion chambers) fitted into cavities formed in an engine block 12. The opening in the block through which each cylinder is inserted fits snuggly around the cylinder and a space is left between the surface of the cavity and the external wall of the cylinder. Water is pumped through this space in order to cool the cylinder wall.

There are many designs of engine blocks having various cooling passages intended to provide greater efficiency in cooling the cylinders.

For example:

U.S. Pat. No. 4,702,204 is for a water cooled engine having a passageway through the water cooling jacket through which the lubricating oil passes and is cooled thereby.

U.S. Pat. No. 4,759,316 is for an engine with a cooling system comprising head side and block side cooling jackets to provide a large cooling surface.

U.S. Pat. No. 4,889,079 to Takeda et al is for an engine having a cylinder head comprising a plurality of partitions and plugs between cylinder heads to provide a passageway for cooling liquids.

U.S. Pat. No. 4,930,470 to Kabat is for a composite engine block comprising a bipartite liner structure forming a fluid cooling jacket in combination with a skin structure composed of lightweight damping material.

The market has shown no preference for any of these constructions over a simple design shown in cross section in FIG. 1. which includes a row of engine cylinders 10 positioned in a cavity 14 of an engine block 12. This sectional view is taken looking parallel to the axis of the cylinders and looking at the bottom of the cylinders. The plane of the sectional view is close to the bottom of the cylinders so that entry ports 16 are shown where cooling water may enter and circulate in the space 18 between the outer cylinder wall and the wall of the cavity. The direction of the currents of cooling water is indicated by the arrows. The cooling water passes out through a pair of exit slots (not shown) positioned diametrically opposed to one another at the top of the engine block at locations indicated by "A".

The engines having this design are sold by the Cummings Corp and are popular because of its simplicity and economy of construction.

The term, "standard" engine will be used in this specification to designate any engine having a construction similar to that shown in FIG. 1 and having an engine block with cavities in which are located cylinders and a space for cooling water between the inner cavity wall and the outer cylinder wall and, further, which has at least a pair of entrances at the bottom end of the cavity and at least one exit at the top end of the cavity.

The life of internal combustion engines is limited by corrosion of the cylinders with use so that, periodically, the engine must be "overhauled", i.e., have its cylinders replaced. The cylinders are generally degraded by the corrosive action of the water on the exterior walls of the cylinders. Overhaul is a major undertaking involving removal of the engine from the vehicle, extraction of the degraded cylinders, valves, etc. and insertion of new cylinders.

It is an object of this invention to provide an engine block characterized by simple construction and a longer life between overhauls than is experienced with engine blocks of the prior art.

It is another object of this invention to provide a method and device for greatly extending the life of already existing engine blocks between overhauls.

It is another object to reduce the rate of corrosion of the cylinders in engine blocks.

These and other objects will become apparent to the reader after reading the description and studying the drawings.

This invention is directed toward a device inserted into the water cooling region between the interior cavity wall of an engine block and the outer cylinder wall which greatly reduces the rate of corrosion of the cylinder thereby extending the life of the engine between overhauls.

In one embodiment, the device is a metal strip, bent substantially to a U-shape, anchored to the edge of each entrance such that the ends of the U-strip extend into the cavity adjacent to the cylinder wall and in which the ends of the strip are configured to divert the stream of circulating water such as to prevent formation of velocity and pressure gradients in the stream that cause excessive corrosion of the cylinder.

FIG. 1 shows a sectional view looking down on the cylinders in the engine block of a standard engine (prior art).

FIG. 2 shows the pattern of corrosion that takes place on the outer surface of a cylinder taken from a standard engine.

FIG. 3A and 3B show the U shaped diverters which modify current flow according to the invention.

FIG. 4 shows the U shaped divertesr of FIG. 3A and 3B inserted, legs first into the entry to the cooling cavity of the standard engine block to modify water flow patterns.

FIG. 5 is a top view of an engine block (head removed showing the tops of the engine cylinders.

The following detailed description illustrates the invention by way of example and not by way of limitation of the priciples of the invention. This description will clearly enable one skilled in the art to make and use the invention and includes an embodiment which I believe is the best mode of carrying out the invention.

The invention is based on a study by the inventor during the course of many overhauls of standard engines and other engine designs. It was noted that areas of excessive corrosion formed a characteristic pattern on the exterior walls of each cylinder. This pattern was invariably located in a position related to the location of the water inlets and outlets and is illustrated in FIG. 2. (prior art). There is shown the pattern of corrosion 20 that has been formed in the exterior wall of the cylinder 10 which extends from the bottom edge to the top edge of the engine cylinder and extends annularly around a portion of the cylinder centered under the exit port at the top edge A which is located midway between the entrances but at the top end of the cavity.

Although I do not wish to be bound by theory, it is believed that, in the absence of the diverters of this invention which would otherwise divert the flow of water, water enters through each entrance 16 and divides into two streams, one going clockwise and the other going counter clockwise around the cylinder as shown by the arrows in FIG. 1. Corrosion occurs where the streams meet and thereafter flow to the exit port at the top of the cylinder. The condition is illustrated in FIG. 1 which shows arrows indicating the flow of water from each entrance 16 splitting and flowing circumferentially in opposite directions around the cylinder. The streams meet at two locations (A) midway between the entrances 16 and then flow vertically to the exit ports (not shown) at the top of the cylinder. This location of vertical flow is also the region where excessive corrosion of the cylinder wall takes place (under A in FIG. 1). It is believed that the excessive corrosion is due to increased concentration of air bubbles that accumulate because of pressure and velocity gradient conditions and that a difference in concentration of air bubbles between adjacent regions can produce differences in electrical potential resulting in corrosion by electrolysis.

Diverters, which are an embodiment of this invention, are inserted into the water passageway between the cylinder and cavity wall and prevent formation of these regions of excessive corrosion by disrupting the water flow pattern shown in FIG. 1. Two diverters, adapted to the "standard" engine design, are shown in the perspective views, FIG. 3 A and 3B. Each diverter, 22a or 22b, is seen to be substantially a strip bent into a substantially U-shaped configuration.

As shown in FIG. 4, the diverter 22a or b is partially inserted, legs first, into the entrance of the cooling region 18 by squeezing the legs together, then allowing the legs to spring back so that the edge of the slotted entrance 16 engages a detente 23, on the edge of the diverter. The diverter is thereby locked in the entrance 16 where it diverts the flow of cooling water around the engine cylinder so that the water current pattern is everywhere substantially continuously circumferential as shown by the arrows in FIG. 4. "Substantially continuously circumferential" is meant to mean that in all parts of the cooling area and particularly close to the cylinder wall, the water flows entirely in one direction, clockwise or counter clockwise depending on the orientation of the diverters.

In order to provide counter clockwise flow as shown in FIG. 4, the diverter 22 B (shown in FIG. 3B) is located on the right side of the cylinder 10. As shown in FIG. 3B. a flap 20 is located on one side of the "U" near one end. A detente 22 is also located on one side. Diverter 22A, located on the left side of the cylinders shown in FIG. 4, does not have flaps 20.

As indicated by the arrows in FIG. 4 with a diverter 22 located in each entrance 16 to the cavity 14, water entering the cavity through either entry is diverted by the ends of the respective diverter to flow in substantially one circumferential direction with the result that there are no substantial velocity or pressure gradients of flow where bubbles of air would accumulate to generate corrosive electrolysis. The presence of these diverters 22A and B in the entrances 16 has thereby resulted in a very substantial reduction in rate of corrosion and increased life between engine overhauls.

The material selected for making the diverter 22 a or b in the foregoing embodiment is low carbon steel. This selection is made on the basis of the matching the diverter with the cylinder wall to minimize any electrolysis that might occur if the materials of the diverter and cylinder are different. Furthermore, low carbon steel has a resiliency that meets the requirement for a springlike material in view of the method for attaching the diverter to the edge of the cavity. However it will be understood that other materials may be selected such as a nonmetal or a plated metal which may be better than lowcarbon steel depending on the application.

In the foregoing paragraphs, a device and method of using the device has been described which meets the objects of this invention, namely, to substantially reduce corrosion of the cylinders in internal combustion engines. The embodiment described is adapted to a "standard" engine in which the water cooling passage is a cavity in the block surrounding the cylinder through which water passes from two slotted entrances at the bottom end of the cavity to an exit at the top end. The invention is based on the principle of preventing excessive velocity and pressure gradients in the stream of water surrounding an engine cylinder by insertion of diverters. Application of this principle such as selection of an appropriate shape of the diverter obviously depends on a variety of factors such as shape of the cavity, location and shape of the entrances and exits, etc. Variations in the method and device of this invention such as modification of the shape or location of the diverter depemnding on the engine design may become apparent which are embodiments of this invention. For example, the diverter may be made of a material other than steel. Furthermore, an application of this principle need not be limited to the prevention of corrosion in engine cylinders but may be applied to other situations where corrosion results from electrolysis produced by velocity gradients. In view of the above, I wish my invention to be defined by the scope of the appended claims and in view of the specification if need be.