Toyota AZ engine

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Toyota AZ engine
2AZ-FE
ManufacturerToyota Motor Corporation
Production2000–present

The Toyota AZ engine family is a straight-4 piston engine series. The AZ series uses an aluminium engine block with cast iron cylinder liners and aluminium DOHC cylinder heads. The engine series features many advanced technologies including slant-squish combustion chambers, offset cylinder and crank centers, and the VVT-i continuously variable intake valve timing system. The aluminium engine measures 626 mm (25-in) long, 608 mm (24-in) wide, and 681 mm (27-in) tall.

The cylinder block is an open-deck, midi-skirt die-cast aluminium type with cast-in iron liners and a die-cast aluminium 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 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).

The AZ is the replacement for the S, and is designed to compete against the Nissan QR engines. It will be replaced with the new Toyota AR engine by 2010.

1AZ-FE

The 1AZ-FE is a 2.0 L (1998 cc) version. Output is 108 kW (145 hp) at 6000 rpm with 190 N·m (140 lb·ft) of torque at 4000 rpm.

Applications:

1AZ-FSE

The 1AZ-FSE is a 2.0 L (1998 cc) version. Bore is 86.0 mm and stroke is 86.0 mm. Output is 155 hp (114 kW) at 6000 rpm with 145 ft·lbf (192 N·m) of torque at 4000 rpm. The 1AZ-FSE features Toyota's D-4 direct injection system.

Applications:

2AZ-FE

The 2AZ-FE is a 2.4 L (2362 cc) version built in Japan and at TMMK in the USA, obtains a total displacement of 2362 cm³ with 88.5 mm (3.5in) bore and 96.0 mm (3.8-in) stroke, resulting in a compression ratio of 9.6:1. Output is 157 hp (117 kW) at 5600 rpm with 162 ft·lbf (220 N·m) of torque at 4000 rpm. The 2AZ-FE also has one-piece cast camshafts. Output for the 2007 Toyota Camry is 158 hp (118 kW) and 161 lft·lbf of torque. There is also a version of the 2AZ-FE engine with 161 hp (120 kW) and 163 ft·lbf (221 N·m) of torque made in Japan for the Scion tC. A 166 hp (124 kW) version is in the 2006 and newer Rav4. This engine is available for the Toyota Matrix and Pontiac Vibe twins as well as the Toyota Corolla beginning in the 2009 model year.

Applications:

The 2007 Toyota RAV4 produces 166 hp (123 kW) at 6000 rpm and 165 ft·lbf (224 N·m) of torque at 4000 rpm [1].

2AZ-FXE

The 2AZ-FXE is a variant of the 2AZ-FE. It has the same bore and stroke, but has a higher physical compression ratio of 12.5:1. The net result is that the engine has a greater effective expansion than compression – making it Atkinson cycle, rather than the conventional Otto cycle.

The reduction in cylinder charge means reduced torque and power output, but efficiency is increased. This combination makes the 2AZ-FXE suitable for use in hybrid vehicles, where peak torque and power demands can be met by the electric motor and battery.

Maximum output when used in the Camry is 147 hp (108 kW) at 6000 rpm with 138 ft·lbf (187 N·m) of torque at 4400 rpm.

Applications:

See also

References