More detailed talk on the 2AZ-FE

[Taido]

The 2AZ-FE incorporates many features of Toyota's dual-overhead-camshaft,
four-valves-per-cylinder engines, including the slant-squish combustion chamber,
offset cylinder and crank centers, and the VVT-i continuously variable intake valve timing system. The aluminum engine measures 626-mm (25-in) long, 608-mm (24-in) wide, and 681-mm (27-in) tall.

The 2AZ-FE obtains a total displacement of 2362 cm3 with 88.5-mm (3.5-in) bore
and 96.0-mm (3.8-in) stroke. The cylinder block is now an open-deck, midi-skirt die-cast aluminum type with cast-in iron liners and a die-cast aluminum lower crankcase and a stamped oil pan. The forged steel crankshaft is fully balanced with eight counterweights and supported by five main bearings. A helical gear pressed in No. 3 counterweight drives twin contra-rotating balance shafts
in the shaft housing within the lower crankcase. The balance shaft geartrain includes plastic Nos. 1 and 3 drive gears, meshing with steel gears.

The dual overhead camshafts are driven by a single-stage roller chain of 8.0-mm (0.3-in) pitch, enabling a narrow included valve angle of 27.5°. The camshafts act on four valves per cylinder via bucket tappets. As in the recent Toyota engine practice, no clearance adjusting shim is employed. Valve diameters are 34.0 mm (1.3 in) for intake and 29.5 mm (1.2 in) for exhaust, with 8.0-mm (0.3-in) lift for both intake and exhaust. The four-vane VVT-i device is fitted on the intake camshaft, altering timing by 50°.

Fuel is injected sequentially via an ultra-fine-atomization injector with twelve small injection holes, each 0.18 mm (0.01 in) in diameter. As in the smaller NZ engine, the new AZ adopts a plastic, built-up, and vibration-welded intake manifold integrating a large volume plenum chamber (3.5-L (214 in3) volume including a 1.3-L (79 in3) resonator).

Twin three-way catalytic converters, each with a 0.84-L (51 in3) volume,
are mounted immediately downstream of the stainless tubular exhaust manifold.
The front exhaust pipe, collecting from the catalysts, has a separator in the pipe that reduces exhaust gas interference and improves low- and mid-speed torque.

The 2AZ-FE engine is rated at 118 kW (160 hp) at 5600 rpm and 221 N•m (163 lb•ft) at 4000 rpm on a 9.6:1 compression ratio, requiring regular-grade, unleaded gasoline.

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