Six - Stroke Hybrid Engine

Six - Stroke Hybrid Engine

Abstract

The Beare Head is a completely new development of the internal combustion engine. Termed a six-stroke due to the radical hybridisation of two and four-stroke technology, the device achieves increased torque and power output, better fuel economy and cleaner burning with reduced emissions, longer service intervals, and considerably reduced tooling costs when compared with a conventional OHC four-stroke design.

The paper consists of an overview of the design of the six stroke Hybrid engine it explains briefly about the design and also compares the parallel technologies like four stroke and two stroke engines. The paper is been divided into the following chapters.

Introduction

The Beare Head is a completely new development of the internal combustion engine. Termed a six-stroke due to the radical hybridisation of two and four-stroke technology, the device achieves increased torque and power output, better fuel economy and cleaner burning with reduced emissions, longer service intervals, and considerably reduced tooling costs when compared with a conventional OHC four-stroke design. Below the cylinder head gasket, everything is conventional, so one advantage is that the Beare concept can be transplanted on to existing engines without any need for redesigning or retooling the bottom end. But the cylinder head and its poppet valves gets thrown away. To replace the camshaft and valves, Beare has retained the cam drive belt and fitted an ultra short-stroke upper crankshaft complete with piston, which the belt drives at half engine speed just as it previously drove the cam. This piston drives up and down in a sleeve, past inlet exhaust ports set into the cylinder wall, very much like on a two-stroke: these are all exposed during both inlet and exhaust strokes.

During the compression and expansion strokes, the upper piston seals off both ports, leaving the pressure contained between the two pistons, with the lower one a conventional flat-top three-ring design, while the conical upper one (so shaped to aid gas flow during both inlet and exhaust cycles by guiding it towards the ports) has two rings - one compression, one oil. In the combustion phase, twin spark plugs provide ignition via the stock Ducati CDI and a pair of Harley coils - one per cylinder - and not only does the engine run on pure petrol (no need to add oil, because all required surfaces are positively lubricated, in spite of the application of two-stroke technology), it's also happy on low octane unleaded fuel. Obviously there are no valve seats to suffer from lack of lead, the compression ratio can be increased significantly from the Ducati motor's 10.6:1 quite safely because

of the lack of hotspots, without problems with detonation. But there are other, much more significant apparent spin-off benefits from the Beare design. First of these is fuel economy: Beare engine is 35% more economical at low revs/throttle openings than an equivalent conventional engine and 13% less thirsty at high rpm/full throttle, in spite of the doubled-up carbs. That should mean fewer hydrocarbon and CO2 emissions, because you're using less fuel to achieve the same performance. Next there's improved torque at lower revs - on both his Yamaha and Ducati-based prototypes, the six-stroke version produces the same torque as a four-stroke 1,000rpm lower down the scale, as well as producing exponentially more torque as revs rose. But in a commercial application, perhaps the most attractive benefit is the reduced number of moving parts, compared to a four-stroke design, so the six should be cheaper to make. Not as few as a two-stroke, but what you appear to be getting here is improved performance and torque, coupled with the inherent advantages of a four-stroke, on the cheap. Finally, as the upper two-stroke piston is driven at half engine speed, it should have twice the life of the lower four-stroke one. Sounds promising.

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