Unmanned Systems Technology 016 | Hydromea Vertex AUV | Power management systems | Unmanned Space Vehicles | Continental CD-155 turbodiesel | Swift 020 UAV | ECUs | DSEI 2017 Show report

54 October/November 2017 | Unmanned Systems Technology Continental Motors CD-155 Turbodiesel aircraft engine I4 83 mm x 92 mm = 1991 cc Turbo-supercharged Diesel or jet fuel Aluminium block and head Linerless Five main bearings, plain Steel crankshaft, four pins Steel con rods Light alloy pistons; three rings Chain-driven double overhead camshafts Four valves/cylinder 12 degree included valve angle 28.5 mm intake valve, 25.4 mm exhaust Direct injection FADEC 18:1 compression ratio Maximum rpm 4000 The CD-155 is based on an all- aluminium I4 structure. A die-cast aluminium cam cover attached by 16 bolts forms the caps securing both camshafts (which run directly in the cylinder head, without bearings). The plenum is a low-pressure aluminium sand casting attached to the cylinder head by eight studs and having a metal gasket at the interface. The front cover is die-cast and conceals the chain timing drive. The uncoated double overhead camshafts are superfinished steel. The cam lobes operate the valves through fingers with sheet-metal-sandwiched, uncoated rollers. Each finger is mounted on a stand, the height of which is hydraulically controlled for tappet adjustment. The steel valves are solid, mono- metallic. The valve seats are powder metal with copper infiltration, and the valves run in bronze guides and have conventional retainers. Each valve is closed by a single steel spring. The crankshaft and con rods are steel. Main journals are 55 mm diameter and 18 mm wide. Big-end journals are 50 mm diameter and 20 mm wide. The diameter of the steel piston pin is 30 mm. The piston carries three rings. Top piston ring axial height is 2mm, as is intermediate piston ring axial height and oil control ring axial height. The cast iron top ring is barrel faced and has a small chamfer. The intermediate ring has a flat face. The piston rings are phosphate coated. An ancillary drive belt on the front of the engine powers the water pump and the alternator. The water pump sends coolant into the cylinder block, where it travels front to rear, then up into the cylinder head where it travels across to an exit at the front, and then to the radiator. The coolers are supplied by Docking Engineering. The cylinder head has dual water jacketing and reduces temperature around the exhaust seats and injector to less than 200 C. Water running temperature is normally 90 C with a maximum permitted 105 C. A thermostat regulates the flow through the water radiator to assist warm-up and protect the engine from shock cooling. When the thermostat is closed, the coolant is recirculated directly to the water pump. The low-pressure fuel pump is driven directly by the exhaust camshaft; the high-pressure fuel pump (a three-piston radial design) by the intake camshaft. The oil pump is located within the wet sump and has a dedicated chain drive from the crankshaft. The oil pump supplies the main gallery via a filter and the oil-to-water heat exchanger. From the main gallery there is a conventional crankshaft bearing lubrication system via each main journal. Anatomy: Continental Motors CD-155 The CD-155 seen from the timing and ancillary drive end

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