Stepless variable valve timing system

Abstract

A control system for changing permanently and stepless valve timing in engines with internal combustion. The system is based on the fact that camshaft turns two times slower then the crankshaft. The system contains a double gear that is pivoting around the camshaft gear. The pinion gear is coupled with the camshaft gear. The driver gear is connected to the crankshaft gear through satellite gears, chain or belt. Pivoting the system around the camshaft gear can change valve timing in large limits. There are two different cassettes, the first one (FIG. 3, FIG. 3b and FIG. 4) is for pushrod engines and helps eliminate the inertia of the moving parts. Its movement is controlled by the accelerator pedal. The second cassette (FIG. 5 and FIG. 6) is designed for OHC (over head camshaft) engines and it must pivot around the camshafts moved by actuators under the control of the car computer.

Description

Our proposition classifies under class 123 “Internal Combustion Engines”, subclass 90.15. Poppet valves operating mechanism “from the Classification US Patent and Trademark”.

The Search that we conducted in Official Gazette of Patents indicates that nobody before us has used such a system, that our idea us original and unique, and so we wish to patent it. Let's name our system: VaTi (Variable Timing).

REFERENCES CITED

5052350	October 1991	King
5111791	May 1992	Onodera
5163872	November 1992	Niemiec et al.
5199393	April 1993	Baldassini
U.S. Pat. No. 4,890,583	January 1990	Ohno et al.
U.S. Pat. No. 5,586,527	December 1996	Kreuter, Peter

Description of Related Art for the Last Two Patents:

1. U.S. Pat. No. 4,890,583, Ohno et al.

With multiple gears connected to the engine and with air cooling. Very heavy system.

2. U.S. Pat. No. 5,586,527 Kreuter.

With two camshafts which regulate the intake valves. Heavy and complicated.

In order to make an internal combustion engine work smoothly, quietly, and efficiently under all conditions and at the same time, to meet the emission control norms, it is necessary to have variable valve timing. If we want a real good engine, we have to vary separately the intake and exhaust valves.

For engines with camshaft that shifts jointly intake and exhaust valves we can use the cassette described in FIG. 6. This will exclude altering overlap, but will decrease the inertia at high RPM so, the final RPM can be higher which will increase the power and improve the emissions.

We submit four pages from the “Automotive Encyclopedia” to show the present situation.

Our idea is based on the fact that camshaft has to turn two times slower then the crankshaft. Using satellite gears in between and pivoting the satellite gears around the camshaft gear we can change continuously and stepless the valve timing.

Our system is simple, cheap and cannot only change valve timing but has many other advantages for example, the engine can be made more compact, because the camshaft gear can be made smaller.

Our idea is elaborated and explained in the following drawings and detailed descriptions.

DRAWINGS

FIG. 1 demonstrates a theoretical explanation of our idea.

FIG. 2 demonstrates a more practical solution. The device is between two plates (the front plate is removed for clarity).

FIG. 3 shows how to achieve bigger deviation of the timing mark.

FIG. 3b shows the connection between the cassette and the accelerator.

FIG. 4 shows the system from FIG. 3 from another point of view.

FIG. 5 shows another approach using the system and a chain.

FIG. 6 shows the cassette pivoting around the camshaft in detail.

DETAILED DESCRIPTION

The purpose of the mechanism described below is to provide precise control over the efficiency of the internal combustion engine, changing continuously and stepless the valve timing.

FIG. 1

Gear A is firmly attached to the crankshaft.

Gear D is firmly attached to the camshaft, or drives the camshaft with a gear, a chain or a belt. Gear C1 and C2 are driver and pinion firmly attached together.

Gears A and C1 have the same diameter.

Gear C2 has half the diameter of gear D.

Connecting rods provide the possibility to move gears C1, C2, and gear B between gears A and D.

Gear A drives gear B and gear B drives gear C1. Gear C2 drives gear D.

Let us assume that the engine is not working. Gear A is at a standstill.

Timing mark a on Gear A is aligned with timing mark d on gear D. Moving the system, gears B and C1, C2 to the right, from position N1 to position N2 will turn gear B around its shaft 120° C.W. Gears C1, C2 will turn around their common shaft 60° C.C.W. Gears C1, C2 will move from position N2 to position N3 and turn gear D 60° C.C.W. while gear C2 will turn gear D 30° C.W. As a result gear D will turn only 30° C.C.W. moving timing mark d, or we have 30° deviation on timing mark d.

We know that:

10. RPM camshaft equals ½ RPM crankshaft

20. Diameter gear A=Diameter gear C1

30. Diameter gear C2=½ Diameter gear D

Gears C1 and C2 are driver and pinion and turn with the same speed, so the actual size of the gears in equation 20 are not related to the size of the gears in equation 30.

We can choose smaller camshaft gear D and make the engine more compact. Also, smaller gears D and C2 will result in larger deviation of timing mark d.

FIG. 2

This is the same system but in a cassette. The front plate is removed for clarity. Gear A, D and C1 have the same diameter. Gear C2 is two times smaller than gear D. If we push the system left, gear B, which is two times smaller than gear A, will move from point 2 to point 1 and will turn around its axis 160° C.C.W., turning gear C1 80° C.W. Gear C2 will turn gear D 40° C.C.W., and in the same time, the system will move from point 4 to point 3, turning gear D 80° C.W. The result of these two movements will be that timing mark d will move 40° to the left or we have 40° variable valve timing.

FIG. 3

Gear A, B, C1 and D have the same diameter. Gear B drives gear C1. Gear B can move from point 2 to point 1 traveling 600 around gear A. Gear B will turn C.C.W. and will turn gears C1, C2 C.W. Gear C1, C2 will move from point 4 to point 3. The distance between 2 and 1 is equal to the distance between 4 and 3. Gear B will travel around gear A 60°. The distance M1 is two radius of gear A and B. The distance M2 is one and a half radius of gear D. So C2 will travel 850 around gear D. At the same time gear C2 will turn gear B 30° C.C.W. The timing mark d will move to position 55° C.W. We have 55° deviation of the timing mark. Moving the system, gears B and C1, C2 we can change timing mark from 0° to 55°. By changing the size of gears D and C2 we can change the deviation of the timing mark in large limits.

FIG. 3b

In our application FIG. 1 and FIG. 2 are theoretical explanation of our idea. FIG. 3 is more practical, but we had to give one more, with explanation how we see the simplest way to realization. This is our fault and we apologize.

FIG. 3b is the same like FIG. 3 but with the simplest way for application in pushrod engines. The double gear is in a cassette bolted to the engine in place to the chain. The spring S1 takes the double gear in position to start the engine. The double gear is connected with a wire to the gas pedal (accelerator). The spring S2 expands the first 1000-2000 RPM, and then the double gear begins to change the timing mark. This eliminates the inertia of the moving parts in the engine and gives the possibility of higher RPM and more power if the gears on the crankshaft and camshaft are changed appropriately.

FIG. 4

This is the system from FIG. 2 and FIG. 3 but from another point of view.

FIG. 5

For OHC (over head camshaft) engines we elaborate FIG. 5 and FIG. 6. The movement from the cassettes must be made with activators under the control of the car computer.

This is another way to apply the same principles in an engine with separate intake Din and exhaust Dex camshafts, using two cassettes as shown on FIG. 6, and a driving chain. Experiments show that if C1, C2 are pivoted around the camshafts, timing marks din and dex will be deviated 60°, 30° from the pivoting of the system, plus 30° from the turning of the gears C1, C2 created by the chain, when the system is deviated outside the lines L.

It is possible to achieve deviation of the timing mark from 0° to 80° or more without problems. When RPM increase, the two cassettes will move to the right. The chain near Dex will shorten and the chain near Din will expand. The movement of the expander E will be minimal.

The movement of the cassettes must be from actuators or from the car computer.

FIG. 6

This is the cassette used in FIG. 5.

Evidently, there are many ways to incorporate our idea in engine designs, but the principle is always the same: A double gear C1, C2 pivoting around gear D on the camshaft, coupled with gear D, can change continuously and stepless valve timing in large limits.

Claims

1. A cassette with a double gear bolted between the crankshaft gear and the camshaft gear and coupled with them, pivoting around the camshaft gear, change timing mark in large limits, by pushrod engines. The double gear is connected to the accelerator. A cassette with a double gear mounted over the camshaft and coupled with the camshaft gear, connected also through chain with the crankshaft gear, pivoting around the camshaft gear with actuators under the control by the car computer, change timing mark by OHC engines in large limits.