GB2280710A

GB2280710A - Rotating and reciprocating piston i.c. engine.

Info

Publication number: GB2280710A
Application number: GB9316191A
Authority: GB
Inventors: Keith Andrew Maclaughan
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-08-04
Filing date: 1993-08-04
Publication date: 1995-02-08

Abstract

The piston 5 is secured to the main shaft 3 and rotates and moves axially between the cylinder heads 2 within a cylinder liner 1. Each piston stroke provides 90 DEG of shaft rotation. Ports 4 are controlled by the piston 5 during its helical motion. <IMAGE>

Description

INTERNAL COMBUSTION ENGINE This invention relates to an internal combustion engine, hereinafter referred to as the engine.

Internal combustion engines are well known and have many uses and applications as a source of power. Internal combustion engines in current applications are predominantly of the piston and crank design ( simple harmonic motion ). Despite continued development of this concept they remain inefficient and detrimental to the enviroment.

According to the present invention a design of engine not employing the piston and crank is provided to build an efficient power source.

The engine design can be summarised as: - the piston and output motion of the main shaft is as near to pure rotary and achieves the required compression cycle ( stroke ).

- on a single cylinder basis, double acting, there are four power strokes per revolution of the main shaft.

- the manufacture and production of the engine is simplified compared to current engines with considerably fewer moving parts and inherent parasitic losses.

- mechanical torque is constant throughout the power stroke.

- the engine does not require valves.

- lubrication and piston sealing is not expected to be a problem like prior rotary designs.

The design concept of the engine will now be described with reference to the accompanying drawings in which: Figure 1, this is a line drawing to illustrate the essential components of the engine. The piston 5 is secured to the main output shaft 3 and free to rotate and move axially within a cylinder liner 1. The cylinder liner 1 has ports 4. The elevation shown is sectioned on X - X and the plan on Y - Y. The piston in turning 900 of rotation moves axially between the cylinder heads 2., the piston always rotates in the same direction of rotation. The exact path of any point on the piston 5, for a full combustion cycle, would move and be constrained to an approximate double helix. The path will hereinafter be described as helical.

There are many devices in use to convert this described motion to single plane rotation. The mechanical advantage of converting helical motion to rotary are obvious.

It should be noted that ports 4 are closed by the action of the piston in motion.

Figure 2, this is a schematic line drawing to support the explanation of the engine combustion cycle. The piston 5, is shown at rest. The piston is turned 90 and moved axially a distance between the heads 2 ( the stroke ) by an external force.

The piston closes ports 4 and compression begins, at a desired point after port closure, fuel is injected into the chamber A. The fuel/air ratio is further compressed and twin ignited between before or after top dead centre. Depending upon fuel used spark ignition may be substituted by compression ignition.

Upon ignition the expansion of the gas will tend to move the piston helically towards the opposite cylinder head.

As the piston moves under expansion of the burning gas, compression begins in opposing chamber.

0 Figure 3, shows the position of the piston after 90 of shaft rotation and axial movement from that shown in Figure 2a. As the piston moves helically as described above the ports in chamber B close and compression begins, fuel is injected and ignited, the piston now returns the the position shown in Figure 2a after a further 900 of piston rotation. The ports in chamber A are now open and air or a gas is blown in through one open port 4 and exhausted out the other, the chamber is therefore purged. This engine cycle like current two stroke diesels relies on an device separate to., but related to the engine for purging exhaust gases. The piston now moves helically from the position shown in Figures 2 to 3, the cycle is now self sustaining.

In summary: Figure 2 engine at rest Figure 3 piston after 90 of shaft rotation Figure 2 piston after 1800 of shaft rotation Figure 3 piston after 2700 of shaft rotation Figure 2 piston after 360 of shaft rotation The above summary demonstrates the four power "strokes" ( two on each end of the piston ), in one revolution of the main shaft/piston.

Figure 4, represents the cylinder head and piston crown profiles.

If a point on the circumference of a cylinder is rotated 900 and at the same time moved axially, the desired stroke. The line X is defined. Line Y is an appropriate radius scribed from the axis of the main shaft 3. The actual shapes and cylinder head/piston crown relationship can only be determined by experiment., but will approximate as drawn. Were upon the burning of the gases the piston tends to move along the "helical path" without reliance and losses on "path" constraints.

Figure 5, is a sketch showing the surfaces bounded by the lines X and Y. The construction of the engine would be such that the surfaces R are closer together than surfaces F. This would maximise the compressed gas volumes over F. Twin ignition over surfaces F will tend to move the piston helically with little or no negative expansion over the R surfaces. The ignited gases will expand and swirl around the main shaft 3.

0 Figure 6, shows the piston in four positions during 90 of shaft rotation. Twin ignition over the surface F will tend to move the piston along the desired path with minimal negative effect of gas burning over surfaces R. As can be seen from the four piston positions. The piston/cylinder heads volumes over F are expanding at a greater rate than the volumes over R. Over R the piston crown and head stay in close proximity.

Claims

1. an internal combustion engine were the gas, fuel/air, is compressed by a piston that rotates at the same time moving axially between cylinder heads.

2. an internal combustion engine whereby the cylinder head profiles and piston crowns are shaped such that upon ignition the expansion of the burning gases acts and tends to move the piston ( output shaft ) in a given rotation/axial movement away from one cylinder head towards the other.

3. an internal combustion engine that embodies all the claims above, but is double acting. The piston moves axially and rotates for each 900 of shaft rotation.

4. an internal combustion engine where to achieve useful rotation will require a flexible coupling.

5. an internal combustion engine that either relies on an external device to purge spent gases or the cycle is modified were the functions of induction, compression, ignition/expansion and exhaust are divided between each chamber.

6. an internal combustion engine that embodies all of the claims above, but can be designed to be either spark or compression ignition.