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Description of engine components (A20NFT/LHU)

Description of engine components (A20NFT/LHU)

General

The LHU BioPower engine has engine components which have been adapted to run on ethanol fuel.

Cylinder block

The engine block is made from sand cast aluminium, with four in-line cylinders. The cylinders have embossed iron cylinder liners. The block has five crankshaft bearings, with the axial bearing in the second bearing location viewed from the front of the engine. The cylinder block is designed with a base plate which forms an upper and lower crankcase. This structure makes the cylinder block rigid and reduces noise and vibration.

Crankshaft

The main bearing journals are cross-drilled and the upper bearings are grooved. The crankshaft has a pinion with slip fit on the balancer shaft. Bearing 2 is the axial bearing. A vibration damper is used to limit torsional vibration.

Connecting rod and piston

The floating gudgeon pin is located in the connecting rod. The pistons are made from cast aluminium. The piston rings are of low-tension type in order to reduce friction. The upper compression ring is made from nodular iron with a molybdenum coating and phosphate-coated sides. The other compression ring is made from cast iron. The oil ring is a three-part, chrome-plated spring structure.

Oil pan

The oil pan is made from die-cast aluminium. The oil pan has a mounting which is screwed onto the gearbox to make the pan more rigid.

Balancer shafts

There are two block-mounted balancer shafts located on either side of the crankcase at the bottom by the cylinder bore. The balancer shafts are driven by a single roller chain which also drives the water pump. The chain is tensioned by a hydraulic tensioning device which is pressurised by the engine oil pump. This design brings about maximum efficiency for the balancer shaft system and noise and vibration are reduced.

Cylinder head

The top cover is made from semi-permanent, die-cast aluminium. Embossed valve guides and valve seat inserts made from powder metal are used. The injector nozzle is located below the intake port. The camshaft pins and camshaft cover are located in the cylinder head.

Valves

There are two intake and two exhaust valves in every cylinder. Valve rotators are used on all intake valves. The rotators are located at the bottom by the valve springs to reduce the oscillating mass of the valve mechanism. Positive valve spindle seals are used on all valves.

Camshaft

Two camshafts are used; one for all intake valves and one for all exhaust valves. The camshafts are made from cast iron.

Tappets

The valve mechanism uses a tappet which is controlled by a hydraulic clearance adjuster. The tappet reduces both friction and noise.

Chamshaft cover

The camshaft casing has a built-in steel baffle for crankcase ventilation. The camshaft casing has mounting points for the ignition system.

Camshaft drive

A single roller chain is used for the camshaft drive. On the slack side of the chain, there is a tensioner and active guide in order to control chain movement and noise. The chain drive gives the valve mechanism a long service life while also ensuring a low maintenance requirement.

Intake manifold and exhaust pipe

The exhaust pipe is made from cast iron. Inside the intake manifold is a distribution and control system for the positive crankcase ventilation (PCV). The exhaust pipe is of dual-plane design which gives good performance and good torque at low speeds.