"All engines require a valve or port system to admit and exhaust the working gases from the cylinder and various valve arrangements are shown in Figure 1. Earlier engines had these valves at the side of the cylinder head and opening in an upward direction into a sideways extension of the cylinder head combustion chamber. The camshaft, which operated these valves, was therefore positioned at the side of the engine, adjacent to the crankcase, and therefore with the potential for splash lubrication from the crankshaft, as described in paragraphs 17 and 21. Modern engines have a more compact hemispherical combustion chamber to give greater efficiency, reduced emissions, and with the valves mounted on the top of the cylinder head and opening in a downwards direction. Such overhead valves can be operated by rods and rocker levers from a camshaft in the original position, but modern designs tend to use a simplified operating arrangement, with the camshaft mounted above the cylinder head to operate the overhead valves more directly."
"many lower rated engines, and certainly those in lawn mowers, do not require an oil pump supplying oil under pressure to provide satisfactory service lives, because the oil splash generated by the moving components, provides a sufficient oil feed rate for adequate lubrication of the working parts, including the crankshaft bearings and the cylinder head area. This oil splash is typically generated by arranging for some of the moving components to have limited contact with the oil in the sump. The contact has to be limited because otherwise various components such as the pistons and rings would be flooded with oil and be unable to prevent excessive amounts of the oil from reaching the combustion chamber."
"The engine may be running at 3,000 RPM, it will be firing 1500 times a minute, that is 25 times a second. You would therefore have a very rapid fluctuating high load being applied 25 times a second to the shaft. The way in which that is carried is not so much by this relatively simple mechanism but another one, which is known as a squeeze film which is that it takes a certain amount of time for the oil to be squeezed out under a high load. Therefore, for these very short periods of time such as occur on an engine crankshaft you can get a very high load capacity because of the effect of the time it takes to squeeze out the oil. But the important point is that, for that to be effective 25 times a second, it is essential before the load is applied the next time that that oil film is fully filled with oil. Now, that is the reason why we require a pressure supply on more highly rated engines: it is to fill that space to be ready to carry the high load that will occur each time the engine fires."
"This invention relates to lubrication systems for internal combustion engines. Such engines have been established for over 100 years, and there has been no fundamental change to their lubrication system over the years. Thus, it is traditional to provide an oil lubrication system in which a separate oil pump is provided for circulating the oil to the various moving parts thereof. An object of the invention is to provide a lubrication system in which oil is circulated without the need for a separate pump."
"According to the invention, in an internal combustion engine comprising a crankshaft and an associated oil sump, a camshaft in a cylinder head above the oil sump, and a timing belt connecting these shafts via respective pulleys, the timing belt is adapted at all times when the engine is in operation to entrain a sufficient quantity of oil from the oil sump to lift it to the cylinder head for lubricating purposes."
"Conveniently, oil is returned to the sump via an oil cooler, to enable the entrained oil to be used additionally for cooling purposes."
"As known per se, the camshaft and crankshaft pulleys have similarly formed tooth sets, but are of different diameters to effect the timing required, and the timing belt is of an impermeable material over its width and formed with a set of teeth around its inner face for meshing with said toothed pulleys."
"In accordance with a feature of the invention, an additional oil pulley is provided immersed in oil within the oil sump, and below the level of the crankshaft pulley, the oil pulley also being toothed and the timing belt having an additional set of teeth extending around its outer face for meshing with the teeth of the oil pulley, said outer teeth providing the means for entraining oil to the cylinder head. In one form, the additional set of teeth may be formed with scoops for entraining the oil. Preferably, said additional teeth are designed to run closely within a closed passage, whereby they act with the wall of said passage to entrap and entrain said oil. Preferably the engine lubrication system includes a toothed pulley, the teeth of which run over a part of the rotation within a restricted passage and a belt having matching teeth which also runs for part of its movement within a restricted passage, these runs being guided to a meshing point at which oil under pressure as a result of the meshing action is available."
"Consequently, the oil is then forced through the ports 22 by its own inertia and a squashing action of the toothed timing belt engaging with the oil pulley. Oil from the oil pulley pick-up ports 17 flows out of the transfer ports 18 effectively formed between the oil pulley teeth 8, before and after meshing with the teeth 9 of the timing belt. Consequently, the outside run of this belt is filled not only with oil from the ports 22, but also by centrifugal force acting on the oil as a result of the meshing action with the oil pulley. When oil has been transferred to the outside run of the belt, it is thus forcibly lifted through the closed passage 16 to the outlet 13 in the cylinder head 15. At this point, oil under pressure is then directed, as required, through the oil gallery 14 for the purpose of lubrication and, in the case where an oil cooler is included in the system, also for cooling. When the cooling and lubrication functions are complete, oil is returned to the sump 3 via the branches 14A, 14C and 14D."
"Referring to Figure 4, and also to Figure 1, the cylinder head 15 is provided with an oil gallery 14 which is fed from the outlet 13 of the casing 10. The gallery includes a branch 14A for feed to the crankshaft big end, branches 14B for the cylinders and return via the branch 14A to the big end, branch 14C for ancillary equipment such as the engine valves and associated tappets, and a branch 14D for overflow back to the oil sump 3."
"There is nothing in the claim requiring that the generated hypohalite ions should be materially or substantially responsible for the biocidal action of the composition. To introduce such a requirement, as the judge did, is impermissible. In effect it is introducing, by way of construction, a requirement that the claim must be fairly based on the patent specification which was a requirement under thePatents Act 1949 , but is not under thePatents Act 1977 ."
"Generally in an OHC engine, an oil pump or the like is used to lubricate a principal bearing portion, a sliding portion or the like. However, particularly in an OHC engine having a single cylinder, since installation of a forced lubrication apparatus such as an oil pump costs much and is not economical, a so-called scrape splash type lubrication system is conceived, in which an oil scraper is provided on a revolutionary portion such as a crankshaft, and lubrication oil in an oil pan is splashed, thus the lubrication oil is supplied to each bearing portion or each sliding portion. However, in this scrape-splash type lubrication system, since the lubrication oil is splashed with the oil scraper, there may be a case where the splash tends not to be even and the oil is not supplied sufficiently to a place on which the lubrication is necessary. Particularly, it is necessary to supply sufficiently the lubrication oil on a sprocket portion or a chain portion in an OHC engine with a chain drive." "… the object of the present device is to provide an OHC engine lubrication apparatus, which catches an oil mist scraped and splashed with an oil scraper to supply the oil mist to a sprocket portion or a chain portion and can improve a lubrication performance of the sprocket, the chain and the like with a simple structure without installing a forced lubrication apparatus such as an oil pump. In order to achieve the foregoing object, the OHC engine lubrication apparatus of the present device in an OHC engine with a chain drive, which has a structure in which an oil scraper is fitted onto a revolutionary portion within a crankcase to scrape and splash lubrication oil in an oil pan within the crankcase, is constituted such that a guide portion is provided, which is formed on an upper portion of a sprocket or a chain within the crankcase to catch an oil mist and to flow down or drop down the oil mist on the sprocket or the chain."
"…in the case of an OHC engine the structure is one in which the camshaft is in a head part of the engine main body which is separate from the crankcase, and so there is the problem that the valve drive cams and least a portion of the timing valve drive system are located in positions which are distant from an oil reservoir and there is insufficient lubrication of the timing valve drive system."