GB2371084A

GB2371084A - I.c. engine valve timing arrangement with annular cam discs

Info

Publication number: GB2371084A
Application number: GB0101107A
Authority: GB
Inventors: Gary John Knight
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-01-16
Filing date: 2001-01-16
Publication date: 2002-07-17
Anticipated expiration: 2021-01-16
Also published as: GB2371084B; GB0101107D0

Abstract

A valve timing arrangement for an internal combustion engine, including one or more discs (12) a means to drive the said discs (12). The discs (12) are similar in shape to that of a cross-section of a tube or pipe, and have an inner circle (32). On each inner circle (32) there is one or more raised sections (14) of predetermined profile for indirectly operating the engine cylinder valves (24). As the disc (12) rotates, the raised section (14) comes into contact with the end of the rocker arm (20) that is positioned in the discs inner circle (32), and moves it closer to the discs axis. Moving the other end of the rocker arm (22) that is positioned on top the of the valve (30), opening the valve (24). The disc (12) rotates at a speed that the raised sections (14) operates the valve (24) via rocker arm (22) with in the appropriate timing constraints of the engine cycle.

Description

IMPROVEMENTS TO INTERNAL COMBUSTION ENGINES This invention relates to internal combustion engines, and in particular valve timing arrangements including one or more discs for indirectly operating the valves of the engine cylinders.

The engine cylinder valves in a modem motor car, petrol or diesel, take a considerable amount of energy and fuel consumption to operate; clearly any reduction in the effort to operate the engine cylinder valves would result in a substantial saving in running costs, improved engine efficiency, and performance. Widely used valve timing gear includes a push-rod and tappet arrangement, an overhead cam (OHC), an overhead valve (OHV), with or without rocker arms coupling the cams of the camshaft to the tops of the valves. A camshaft to operate the valves via push-rods, camfollowers, rocker arms, or bucket tappets. Valve springs to return the valves to the closed position, and to keep the valves closed when the camshaft is not operating them, and the valves, normally two per cylinder one inlet valve and one exhaust valve. Each valve has an associated cam which operates the valve once every revolution of the camshaft. A main area of energy loss arises in the operation of each valve, Rotation of the camshaft brings the cam into contact with the valve top, via camfollower, bucket tappet or rocker arm with or without a push-rod and moves the valve into the combustion chamber a Required amount. This involves a considerable effort.

It is an object of the invention to provide an improved valve timing gear arrangement for an internal combustion engine. According to the present invention there is provided a valve timing arrangement for an internal combustion engine, the arrangement including one or more metallic or hard composition discs.

A timing belt drive coupled to a shaft by a timing belt pulley, the shaft being the means to drive the said discs. The discs are positioned in the cylinder head, or cylinder block of an internal combustion engine petrol or diesel, and can be different sizes for different engines.

They can also be different shapes for different engines, but generally they are similar in shape to that of a cross-section of a tube, pipe, or ring shaped. The discs rotate in a housing or bearing by means of the said shaft. The shaft is coupled to the discs by gear sections and there are gear sections on the shaft and on the discs. The gear sections can vary in size according to the speed that the discs are to be rotated. The rotational speed of the discs can also be changed by adjustment of the timing belt pulley arrangement which arrangement may include a timing chain rather than a timing belt or may include timing gears. Because the discs are similar in shape to that of a cross-section of a tube, pipe, or ring shaped, this means that they have an inner circle. On the inner circle there is one or more raised sections of predetermined profile, the peak of the raised sections go towards or go to the discs axis. (Axis being an imaginary line about which a given body or system rotates). The raised sections are for indirectly driving respective valves of engine cylinders, via rocker arms, push-rods or both.

One end of the rocker arm, or push-rod is positioned in the inner circle of the disc. The other end of the rocker arm is positioned on the top of the respective valve. The other end of a push-rod is coupled to a rocker arm. Each disc can operate one or more valves and the timing belt drive means being arranged to rotate the discs via the shaft at such a speed that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle. If there is more than one disc, the discs can be mounted on one or more shafts, or actually part of a shaft so that the shaft directly rotates the discs as part of itself. In this case the shaft is rotated by a timing belt drive coupled to the shaft by a timing belt pulley. The rotational speed of the shaft and therefor the discs can be changed by adjustment of the timing belt pulley arrangement, which arrangement may include a timing chain rather than a timing belt or may include timing gears. The timing belt drive means being arranged to rotate the shaft at such a speed that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which Figure 1 is a cross-sectional view of a shaft a side view of a disc coupled to the said shaft by gear sections on both the shaft and the disc. The disc shows two raised sections on its inner circle. A rocker arm with one end positioned in the discs inner circle, the other end positioned on the top of an engine cylinder valve, the said valve shown in the closed position and a valve spring ; Figure 2 is a view similar to that of figure 1 but showing one of the raised sections on the discs inner circle in contact with the end of the rocker arm that is positioned in the discs inner circle, and the valve in the open position; Figure 3 is an overhead view of a disc in its housing, two rocker arms one either side of the disc. One end of each rocker arm is positioned in the discs inner circle, the other end of each rocker arm is positioned on the top of the two valves, and two valve springs; Figure 4 is a cross-sectional view of a shaft a side view of a disc coupled to the said shaft by gear sections on both the shaft and the disc. The disc showing one raised section on its inner circle; Figure 5 is a view similar to that of figure 4 but showing a shaft with half as many gear teeth, and a disc showing two raised sections on its inner circle; Figure 6 is a cross-sectional view of a shaft a side view of a disc coupled to the said shaft by gear sections on both the shaft and the disc. The disc shows one raised section on its inner circle, a push-rod with one end positioned in the discs inner circle the other end coupled to a rocker arm, the other end of the rocker arm positioned on top of a valve and a valve spring.

Also shown a cross-sectional view of a bush to guide the push-rod; Figure 7 is a three dimensional view of two discs positioned on a shaft, the discs have no gear sections, and each disc shows one raised section on their respective inner circles.

Referring to figure 1 the valve (24) is in the closed position the rocker arm (22) is passive at this time, the shaft (l 0) coupled to the disc (12) by gear sections rotates the disc (12) by means of a timing belt (not shown). One of the raised section (14) On the discs inner circle (32) comes closer to the end of the rocker arm (20) positioned in the discs inner circle (32).

Further rotation of the disc will case the raised section (14) to come into contact with the end of the rocker arm (20) moving it towards the discs axis. Forcing the other end of the rocker arm (22) positioned on top of the valve (30) and start to open the valve (24). Further rotation of the disc (12) and the end of the rocker arm (20) will be at the peak of the raised section (14) and the valve (24) will be fully open as shown in figure 2. Continued rotation of the disc (12) will cause the raised section (14) to go out of contact with the end of the rocker arm (20). Allowing the valve spring (28) to return the valve (24) to the closed position, in turn returning the rocker arm (22) to its original position before contact with the raised section (14). Although only two raised section (14) are shown on the discs inner circle (32), there can be another two raised section on the other side of the disc (12) that can operate another valve via another rocker arm (not shown). This means one disc can operate two valves via two rocker arms (22) as shown in figure 3. The shaft (10) shown in figures 1 and 2 rotates at half engine speed by means of a timing belt (not shown) the said shaft (10) has half as many gear teeth (8) as gear teeth (16) on the disc (12). Meaning the disc (12) will rotate at quarter engine speed, to keep the valve timing correct. This is not always the case, If a disc has only one raised section per side the disc will then rotate at half engine speed instead of quarter engine speed this is shown in comparison in figures 4 and 5. In figure 4 the disc (12) shows one raised section (14) on its inner circle (32) in this case the disc (12) will rotate at half engine speed via the shaft (10) which has the same number of gear teeth as the disc. Figure 5 a disc (12) shows two raised sections (14) on its inner circle (32) in this case the disc (12) will rotate quarter engine speed via the shaft (10) which has half the number of gear teeth as the disc. In figure 3 the disc rotates in the housing (26) only the gear teeth (16) of the disc can be seen. Figure 6 shows the disc (12) operating a valve (24) via a rocker arm and a push-rod. As the shaft (10) rotates the disc (12) the raised section (14) on the discs inner circle (32) will come into contact with the end of the push-rod (20) that is positioned in the discs inner circle (32).

Further rotation will cause the raised section (14) to move the end of the push-rod (20) towards the discs axis. Therefore forcing the push-rod (34) guided by a bush (36) to push the end of a rocker arm (22) in turn forcing the other end of the rocker arm (22) positioned on the top of the valve (30) and open the valve (24) a required amount. Continued rotation will cause the raised section (14) to go out of contact with the end of the push-rod (20) allowing the valve spring (28) to return the valve (24) to the closed position. In turn returning the rocker arm (22) and push-rod (34) to their position when the valve was closed. Although one raised section (14) is shown on the discs inner circle (32), there can be another raised section (14) on the other side of the disc (12) that can operate another valve via another push-rod and rocker arm. This means one disc can operate two valves. The shaft (10) has the same number of teeth (8) as teeth (16) on the disc (12) therefor the disc will rotate at half engine speed. If the number of raised sections (14) is increased the rotational speed of the disc (12) will have to be changed to keep the valve timing correct. In figure 7 it is shown that when there is more than one disc the discs (12) can be linked together by a shaft (48), two discs (12) are shown in this case the discs (12) mounted on the shaft (48) are rotated by the said shaft (48). The shaft is rotated by a timing belt coupled to the shaft (48) by a timing belt pulley (timing belt and timing belt pulley not shown). The way the discs (12) operate the valves is the same as described in figures 1 and 2. Depending upon how many raised sections (14) are on the discs inner circle (32) will determine the rotational speed of the shaft (48). This speed can be changed by changing the timing belt drive arrangement which arrangement may include a timing chain rather than a timing belt, or may include timing gears. The shaft (48) shown in this figure has two discs (12) mounted on it, therefore this arrangement can operate a minimum of four valves, (valves not shown).

In all cases the means to drive the discs being arranged to rotate the discs at a speed that each raised section indirectly operates the respective valve within the appropriate timing constraints of the engine cycle.

It will be appreciated that the described system can be applied to any internal combustion engine having at least one piston and cylinder incorporating at least two valves, and the valves being indirectly operated by one or more discs, the discs having the preferred number of raised sections which is two per side, ie four per disc, and a means of driving the said discs at quarter crankshaft speed. In this case the disc or discs operating the valves has two raised sections diametrically opposed to each other, this applies to the other two raised sections on the other side of the disc or discs. The coupling between the piston and the disc is such that for each two cycles of the engine ie four reciprocation's (each reciprocation comprising a complete forward and return movement) of the piston or four complete turns of the crankshaft. The disc is turned no more than 360 degrees or one complete revolution. Of course with more raised sections, the rotation of the disc will be less than 360 degrees for each two cycles of the engine.

The force required to open a valve by means of the end of the rocker arm or the end of a push-rod going towards the discs axis, requires less effort than conventional valve timing gear.

Where the end of a rocker arm or end of a push-rod moves away from a camshafts axis.

A disc with two raised sections per side, (four raised sections per disc), as preferred has a slower rotational speed than a conventional camshaft, frictional forces, and surface wear will be reduced, this includes discs that are mounted to or part of a shaft.

An unexpected benefit of using this invention is a perceptible reduction in C02 emissions by alteration of the induction system, and without the use of a catalytic converter.

If a disc has one raised section a side ie two raised sections in total the said disc would rotate half engine speed. If a disc has two raised section a side ie four raised sections in total the said disc would rotate quarter engine speed.

If an internal combustion engine with conventional valve timing gear had four cylinders, eight valves and an idle speed of 850 revolutions per minute. The camshaft of the said engine would rotate at 425 revolutions per minute, which is roughly 7 revolutions a second, which is equal to the valves opening and closing 56 times a second in total. If the same engine had a speed of 2000 revolutions per minute the camshaft would rotate at 1000 revolutions per minute, which is roughly 16 revolutions a second, which is equal to the valves opening and closing 128 times a second in total. This takes a considerable effort any reduction in the force to operate the valve timing gear would be very beneficial.

Thus in accordance with the invention, there is provided one or more discs for indirectly operating the engine cylinder valves, each disc having one or more raised sections. If more than one disc is used the discs can be attached or actually part of a shaft. If a disc has two raised sections per side as preferred the disc or discs turn half as slow and easier than a conventional camshaft used to operate the engine cylinder valves, thus improving fuel economy, increasing performance, lowering emissions, and reducing wear.

Claims

CLAIMS 1. A valve timing arrangement for an internal combustion engine, the arrangement including one or more metallic or hard composition discs, a timing belt drive coupled to a shaft by a timing belt pulley, the shaft being the means to drive the said discs. The discs are positioned in the cylinder head, or cylinder block of an internal combustion engine petrol or diesel, and can be different sizes for different engines. They can also be different shapes for different engines, but generally they are similar in shape to that of a cross-section of a tube, pipe, or ring shaped. The discs rotate in a housing or bearing by means of the said shaft. The shaft is coupled to the discs by gear sections and there are gear sections on the shaft and on the discs. The gear sections can vary in size according to the speed that the discs are to be rotated. The rotational speed of the discs can also be changed by adjustment of the timing belt pulley arrangement which arrangement may include a timing chain rather than a timing belt or may include timing gears. Because the discs are similar in shape to that of a cross-section of a tube, pipe, or ring shaped, this means that they have an inner circle. On the inner circle there is one or more raised sections of predetermined profile, the peak of the raised sections go towards or go to the discs axis. (Axis being an imaginary line about which a given body or system rotates). The raised sections are for indirectly driving respective valves of engine cylinders, via rocker arms, push-rods or both. One end of the rocker arm, or push-rod is positioned in the inner circle of the disc. The other end of the rocker arm is positioned on the top of the respective valve. The other end of a push-rod is coupled to a rocker arm. Each disc can operate one or more valves and the timing belt drive means being arranged to rotate the discs via the shaft at such a speed that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle. If there is more than one disc, the discs can be mounted on one or more shafts, or actually part of a shaft so that the shaft directly rotates the discs as part of itself. In this case the shaft is rotated by a timing belt drive coupled to the shaft by a timing belt pulley. The rotational speed of the shaft and therefor the discs can be changed by adjustment of the timing belt pulley arrangement, which arrangement may include a timing chain rather than a timing belt or may include timing gears. The timing belt drive means being arranged to rotate the shaft at such a speed that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle.
2. A valve timing arrangement for an internal combustion engine, as claimed in claim 1.

The arrangement including one or more discs, wherein the inner circle of the disc can run through the discs from one side to the other, or the discs can have two inner circles one on either side of each disc.
3. A valve timing arrangement as claimed in claim 1 and claim 2 wherein if there is more than one disc, the discs can be mounted on, or actually part of a shaft so that the shaft directly rotates the discs as part of itself The shaft can rotate in a bearing or housing instead of the discs rotating in a bearing or housing, although this is optional. There is also no need for the discs to have gear sections. The timing belt drive means being arranged to rotate the shaft, at such a speed that each raised section on the discs inner circle indirectly operates the respective valve within the appropriate timing constraints of the engine cycle.
4. One or more discs for use in the valve timing arrangement, for an internal combustion engine as claimed in any preceding claim, wherein each disc having a plurality of raised sections of predetermined profile disposed equally around the inner circle of the said disc, the peak of the raised sections going towards or to the discs axis. The means to drive the discs at such a speed, being arranged that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle.
5. One or more discs for use in the valve timing arrangement, for an internal combustion engine as claimed in any preceding claim, wherein the discs having a plurality of raised sections on the inner circle for indirectly driving respective valves of the engine. Each raised section of predetermined profile disposed equally around the inner circle of one or more discs.
6. A valve timing arrangement as claimed in any preceding claim, wherein the number of raised sections on any one disc operating one valve comprises of two. The number of raised sections per disc operating two valves comprises of four, two raised sections on each side of each disc.
7. An internal combustion engine comprising at least one piston and cylinder having at least two valves. One or more discs as claimed in any preceding claim, for operating the said valves. Each disc having four raised sections two per side and each raised section opening and closing the respective valve on each pass of the end of a rocker arm or the end of a push-rod.

A means for coupling the crankshaft to drive the discs so that for every four complete turns of the crankshaft each discs rotates no more than once.
8. A valve timing arrangement substantially as described herein with reference to figures 1 to 7 of the accompanying drawings.

Amended claims have been filed as follows CLAIMS I A valve timing arrangement for an internal combustion engine, the arrangement including a timing drive means coupled to a shaft, which is the means to drive one or more discs, the discs are the shape of a cross-section of a tube, and so are ring shaped, which means they have an inner circle, on which there are one or more raised sections, the peaks of the raised sections go towards or go to the discs axis, the raised sections are for driving respective valves of the engine cylinders, via rocker arms, push-rods, or both, and the timing drive means being arranged to rotate the discs at such a speed that each raised section on the discs inner circle operates the respective valve within the appropriate timing constraints of the engine cycle, each disc can operate one or more cylinder valves in addition the discs can be mounted on one or more shafts, or actually part of a shaft so that the shaft directly rotates the discs as part of itself.

2 A valve timing arrangement for an internal combustion engine as claimed in claim 1 the arrangement including one or more discs, wherein the inner circle of the disc can run through the disc from one side to the other, or the disc can have two inner circles one on either side of each disc.

3 One or more discs as claimed in claim 1 and claim 2 wherein there are gear sections on 0 the said discs and on the shaft, the gear sections can vary in size according to the speed that the discs are to be rotated although there is no need for gear sections on the discs if the discs are actually part of a shaft.

4 A valve timing arrangement as claimed in any preceding claim, wherein if there is more than one disc, the discs can be mounted on, or actually part of a shaft so that the shaft directly rotates the discs as part of itself, in this case there is no need for the discs to have gear sections although this is optional.

5 One or more discs as claimed in any preceding claim, wherein the discs rotate in a I housing or bearing and are positioned in the cylinder head or cylinder block of an internal combustion engine.

6 A valve timing arrangement as claimed in any preceding claim wherein the number of raised sections on any one disc operating one valve comprises of two and number of raised sections per disc operating two valves comprises of four, two raised sections on each side of each disc.

7 An internal combustion engine comprising of at least one piston and cylinder having at least two valves, and one or more discs as claimed in any preceding claim, for operating the

said valves, and each disc having four raised sections (two per side of the disc), so that each al s raised section opens and closes the respective valve on each pass of the end of a rocker arm, or the end of a push-rod, in addition with a means for coupling the crankshaft to drive the discs so that for every four complete turns of the crankshaft each discs rotates no more than once.

8 A valve timing arrangement substantially as described herein with reference to figures 1 to 7 of the accompanying drawings.