Perkins Adopt Direct Injection
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New 4.42-litre Oil Engine Shows Break from Perkins Traditional Policy
IIRECT injection has been adopted ' by F. Perkins, Ltd., Peterborough, a new four-cylindered oil engine which ; been developed initially for use in icultural tractors, combine harvesters, its and industrial equipment. The new ;Me is known as the FOLlf 270D and it the first direct-injection unit to have m produced by Perkins. A C.A.V. DPA tributor type fuel injection pump, ich is already being used on other kins units, is employed.
klthough the makers state that an omotive version of this engine is not templated in the immediate future— y say the indirect-injection principle more suitable for the higher speeds imon to automotive units—there ild be advantages in the use of this inc in a vehicle, particularly in respect fuel economy and easy coid starting.
Gross Power 62 b.h.p.
he new engine supplements the existL4 agricultural and industrial unit it has the same bore (4.25 in.) and ke (4.75 in.). It has a capacity of 5 cit. in, (4.42 litres) and its cornsion ratio is 16 : I. In its agricultural lication it is rated for a gross power )ut of 62 b.h.p. at 2,000 r.p.m., whilst marine rating is 58 b.h.p. at 2,000 n.
ontinuous industrial ratings range rt 32.6 b.h.p. at 1,000 r.p.m. to b.h.p. at 2,000 r.p.m., which are illy higher than those of the L4. Maximum torque output of the agricultural engine is 189 lb.-ft. at 1,000 r.p.m., whilst the industrial units have a maximum torque of 172 lb.-ft. at the same speed.
The combustion system follows conventional lines for a direct-injection engine. The combustion chambers are toroidal cavities formed in the piston crowns, and the four-hole injectors are located in the cylinder head at a slight angle to the vertical and are held in place by two nuts. These nuts and the main feed and leak-off pipe units are easily accessible, as is normally the case with Perkins engines, thereby making for easy removal and replacement of injectors.
High-duty cast iron is employed for the cylinder head and the joint between it and the cylinder block is sealed by a coppersteel-asbestos gasket. One inlet and one exhaust valve per cylinder are provided.
The high-duty cast-iron cylinder block carries centrifugally cast iron wet cylinder liners flanged at their upper ends and sealed at their lower ends by two synthetic rubber rings.
High-silicon aluminium-alloy pistons carry five rings—three compression rings and one scraper ring above the gudgeon pin and one scraper ring below it. The top compression ring is chromium plated.
The crankshaft is a chromemolybdenum steel forging, the main and big-end journals being inductionhardened. Thin-wall pre-finished steelbacked copper-lead-lined shells are used for the three main bearings and the bigend bearings.
Mechanical Governor
The C.A.V. pump is flange-mounted to the rear of the timing case and incorpor
ates a mechanical governor. The diaphragm fuel-lift pump is mounted vertically above it and is operated through a small push-rod from an eccentric on the fuel-pump-gear carrier hub.
A paper-element fuel filter is mounted on the cylinder head directly above the fuel-lift pump. The timing gears have 'straight-spur teeth and lubrication is provided by an intermittent feed from the idler gear hub and by splash and overflow from the main and camshaft bearings. A full-flow oil filter is provided.
As an agricultural-tractor version the engine has a dry weight of 680 lb., excluding starting motor, air cleaner, flywheel and starter ring, and flywheel housing. The industrial unit weighs 722 lb. Agricultural and industrial units are already being built and the marine engines are going into production shortly. Substantial orders are stated to have been placed.