HIGGS DIESEL TECHNOLOGY
Extended Mission Duration
Combined Cycle Spark Ignited
‘Combined Cycle Technology’ (CCT). This refers to the combined forced scavenge of the engine via the pump attached to the bottom of the piston and pre-charging of the cylinder. Removing the need for a separate supercharger or mechanical pump, this all takes place in a single action, hence “combined cycle”.
As we are a spark ignited engine and not a diesel, the compression is considerably lower, in the range of 6.5~7.5:1 (this being trapped compression ratio not full compression as measured on a four stroke engine). Unlike a ‘normal’ 2-stroke engine, we do not premix or use any oil with the fuel for lubrication. The lubrication is separate and is identical to most four cycle engine types. The pumping piston, attached to the bottom of the working piston only draws in air for combustion, this air is transferred to the working piston and fuel is directly injected into the cylinder avoiding any short circuit of fuel out the exhaust, which is a common trait of many 2-stroke engines and allows for a very clean burn engine.
As we are not a “diesel” engine, as in the form of a traditional Compression Ignition type (C.I), this allows us to design components that are considerably smaller and substantially lighter than a “traditional” diesel engine. The reduced weight of these components, combined with a reduction of part count as we have no valves, cams or supercharger etc, allows for a small and lightweight footprint than would otherwise not be viable with any other solution.
Inherent piston cooling characteristics of the combined cycle piston design offer a major durability advantage over conventional 2-cycle engines, allowing much leaner fuel delivery than can be sustained with traditional crankcase scavenging, where usually piston overheating and consequent seizure are common.
This technology operates without complex mechanical components such as cams, valves mechanisms and the other various precision components necessary to operate them.
The absence of these mechanical components eliminates a large number of moving parts, thereby considerably reducing the costs and maintenance requirements, whilst significantly increasing reliability and retaining the simplicity of the 2- cycle engine.
With this novel cycle engine technology, combined with the enormous benefits together with their appealing simplicity, a new generation of light weight high performance power plants can be achieved. Which until now would have been almost impossible.
The use of combined cycle pistons, for charge transfer and combustion, allows the key advantages of 2- and 4-cycle engines to be combined, with the elimination of disadvantages inherent in each of these engine types.
Using a combined cycle piston in we are able to completely separate the scavenging from the crankcase.
Isolation of the fresh charge from the crankcase is made possible by the provision of normal 4-cycle engine compression and oil control rings on the larger diameter part of the piston.
Gearbox & Accessory Drive
Comparitive Data Tables
Pratt & Whitney PT6
- Horsepower: 1,585hp
- Weight: 280kg
- Fuel Consumption: BSFC, 0.507lb/hp-h (308g/kW-h)
- Higher Operating Cost
- Higher Acquisition Cost
- 60% LESS Mission Range Increase
- Horsepower: 1,638hp
- Weight: 302kg
- Fuel Consumption: BSFC, 0.398lb/hp-h (231g/kW-h)
- Lower Operating Cost
- Lower Acquisition Cost
- 60% MORE Mission Range Increase
Fuel Type & Consumption
Designed to run on industry standard Jet fuel (Diesel (EN 590), Jet A, Jet A-1, JP-5, DEF STAN 91-86, JP-8, DEF STAN 91-91, JP-8+100, Chinese Jet Fuel No 3)
Will also run and perform on all gasolines where necessary, RON 80,87,91,95 including 100LL along with all bio derivatives.
BSFC, 0.398 lb/hp-h (231g/kW-h) Pratt & Whitney PT-6 Turboprop by comparison is 0.507 lb/hp-h (308 g/kW-h) (on approach and idle 0.825 lb/hp-h (502 g/kW-h))