Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2001-02-23
2002-09-03
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S090650, C123S308000, C123S432000
Reexamination Certificate
active
06443111
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a poly valve system for internal combustion engines. More particularly, the invention relates to a valve system which employs several independently operated intake valves and several independently operated exhaust valves per cylinder.
In an internal combustion engine, intake and exhaust valves serve a crucial function. They must each open at an appropriate time to allow combustible gases in or exhaust out, and remain tightly closed at all other times to maximize the power derived from combustion.
The performance of the engine is also closely linked to the valves. It is well known that the more an engine “breathes” the more power it will generate. It seems obvious that the more fuel and air that enters the combustion chamber, the greater the force of the explosion and the greater the power generated thereby. However, the ability of the engine to eliminate combustion by-products is also an important factor in performance. In fact the engine “redline”—the practical rev limit for an engine—is in large part determined by the speed at which the exhaust valves can no longer expel sufficient burned gases to allow efficient combustion to occur.
Traditionally, valve systems are fully mechanical systems. At least one cam shaft is used to precisely determine the times during the engine cycle when each valve is to be opened and closed. For each valve, a cam follower traces the movements of the cam shaft, and causes the valve “poppet” to open and close. One problem with this arrangement is the lack of flexibility. Once the cams are set, it is not possible to change the relative opening and closing times of the valves. In addition, the entire cam system itself comprises numerous moving parts which require maintenance and which to some extent detract power from the engine.
Over the last two decades, adding an extra intake and an extra exhaust valve per cylinder has become prevalent in automobile engines of all types. This change has thus lead to increased engine performance by simply increasing the inward and outward flow of the combustion chamber. In such engines, it has been the general practice to have both intake valves to open and close at the same time.
Experimentation with increasing the number of valves has revealed practical limitations. Having a large number of valves quickly increases the complexity of the cylinder head configuration, and causes porting problems. Some have sought to maximize the number of valves by conceiving variations of traditional cam operated valve technology.
U.S. Pat. No. 5,375,568 to Manolis et al. discloses a multi-valve internal combustion engine which has a cluster valve system, wherein four intake valves are mechanically ganged and all operate off a common cam follower. Four exhaust valves are also provided in a similar arrangement.
U.S. Pat. No. 5,111,791 to Onodera discloses a cylinder head and valve train arrangement for a multiple valve engine. Onodera discloses a six valve arrangement, wherein special attention has been given to solving the problem of positioning and synchronizing cam shafts to operate these valves. Care is taken to carefully synchronize the opening of all four intake valves even though two separate cam shafts are used for opening these valves.
U.S. Pat. Nos. 4,658,780 to Hosoi; U.S. Pat. No. 5,007,387 to Arao; U.S. Pat. No. 5,094,197 to Rosa; and U.S. Pat. No. 5,184,580 to Ascari all disclose multiple intake and exhaust valve systems. These patent references are all concerned with working out the mechanics of a multi-valve system using existing cam operated valves. They are generally concerned with synchronizing the valves where the use of multiple valves conflicts with the ordinary design constraints of standard single cam valve operation.
U.S. Pat. No. 4,587,936 to Matsuura et al. discloses a valve control system which employs traditional cam-based valve opening. Matsuura has provisions to mechanically deactivate one of the intake valves under certain engine conditions. However Matsuura is not able to provide any other flexibility or control over valve opening or timing, other than being able to simply disable one of the valves.
U.S. Pat. No. 5,669,341 to Ushirono et al. discloses a valve operating system which uses an electrically operated valve in addition to a mechanically operated valve. However, Ushirono et al. only employs the electrically operated valve during certain engine conditions.
While these units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter. In particular, these multiple valve systems all seek to employ a modified mechanical cam-based opening system. They are generally concerned with ensuring that all intake valves open together. However, some study has revealed that carefully creating turbulence in the combustion chamber can increase engine performance. But, the prior art systems are unsuitable for experimentation to optimize such effects, because they do not allow independent operation or opening timing between the various intake valves. In addition, internal stresses generated by the cam system inertia in itself limits rev speeds that the engine can achieve.
SUMMARY OF THE INVENTION
It is an object of the invention to increase the performance of an internal combustion engine. Accordingly, the invention is a poly valve system which employs several intake and several exhaust valves per cylinder.
It is another object of the invention to provide multiple valves per cylinder without requiring a complex cylinder head configuration. Accordingly, the poly valve system eliminates the cam structure ordinarily required in four stroke engines.
It is yet another object of the invention to create turbulence within the cylinder during the intake cycle. Accordingly, fully independent valve operation and freedom of valve placement allow the effects of intake turbulence to be optimized.
It is a further object of the invention to greatly increase the revolution limit of the engine. Accordingly, the use of multiple valves, and the lack of reliance on a mechanical system to open and close the valves greatly increases the allowable rotary speed for the engine. In addition, the lower mass and complexity of the poly valve system allows greater speeds to be achieved.
It is a still further object of the invention that practically random valve operation is achievable. Accordingly, electric, hydraulic, or pneumatic valves may be employed so that fully random selection of opening and closing times can be determined and executed in accordance with achieving maximum efficiency.
It is yet a further object of the invention to reduce the overall size of the engine. Accordingly, by eliminating standard camming mechanisms, a significant space savings can be achieved.
It is a still further object of the invention to optimize the shape of the combustion chamber. Accordingly, by having the ability to place numerous, smaller valves at flexible locations in the cylinder head, the piston need not be altered to provide valve clearance and thus can have a smoother shape.
The invention is a poly valve system for an internal combustion engine having at least one cylinder having a bore, a piston capable of reciprocal travel within the bore, a cylinder head adjacent the bore, and a combustion chamber defined between the cylinder head and the piston, comprising a plurality of independently operated valves. Intake and exhaust manifolds are located adjacent to the cylinder head. Valve seats comprise openings in the cylinder head between one of the manifolds and the combustion chamber. Poppet valves are situated in the valve seats to selectively allow communication between one of the manifolds and the combustion chamber. The valves are electrically, pneumatically, or hydraulically operated so that each valve, including one of several intake valves per cylinder, may be operated independently of each other.
To the accomplishment of the above and related objects the invention may be embodied
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