2GR-FE Toyota engine

Introduction

Manufactured from 2005 and available in Australia from 2006, Toyota’s 2GR-FE was a 3.5-litre V6 petrol engine that effectively replaced the 1MZ-FE and 2JZ-GE engines. Key features of the 2GR-FE engine included its open deck design, alloy construction (for a service weight of 163 kg), variable intake and exhaust valve timing (dual VVT-i) and Acoustic Control Induction System.

For the TRD Aurion, Lotus Evora S and Lotus Exige S, the 2GR-FE was fitted with a supercharger (detailed below).

2GR-FE block

With its cast aluminium alloy cylinder block, the cylinder banks of the 2GR-FE engine had a 60-degree ‘V’ angle. The 2GR-FE engine had 94.0 mm bores and an 83.0 mm stroke for a capacity of 3456 cc; bore pitch was 105.5 (i.e. the distance between the centre of adjacent bores), while cylinder bank offset was 36.6 mm. Between the cylinder bores, passages existed for coolant flow.

The 2GR-FE engine had ‘spiny type’ cast-iron cylinder liners – the casting exteriors of these liners had irregular surfaces to enhance the adhesion between the liners and the aluminium cylinder block.

Crankshaft, connecting rods and pistons

The 2GR-FE’s forged steel crankshaft had four journals and five balance weights. The crankshaft bearings were made of aluminium alloy and, like the connecting rod bearings, the lining surfaces were micro-grooved for an optimal amount of oil clearance – this improved cold-engine cranking performance and reduced engine vibration. The crankshaft bearing caps were tightened using four (4) plastic region tightening bolts for each journal.

The 2GR-FE engine had forged connecting rods which used aluminium bearings. To reduce mass, the connecting rods and caps were made of high-strength steel and nutless-type plastic region tightening bolts. Furthermore, knock pins were used at the mating surfaces of the bearing caps to minimise movement during assembly.

The aluminium alloy pistons featured resin-coated skirts to minimise friction and the groove of the top ring had an alumite coating for resistance to wear. The piston crowns had a ‘tapered squish’ design to improve thermal efficiency and reduce the likelihood of engine knock (pre-ignition). The squish angle was shaped obliquely along the wall surface of the combustion chamber to improve airflow, promote swirl and enhance flame travel. Oil jets in the centre of the right and left banks of the cylinder block provided cooling and lubrication of the pistons.

Cylinder head

The 2GR-FE had an aluminium alloy cylinder head which consisted of three components: the valve cover, camshaft sub-assembly housing and cylinder head sub-assembly. The engine also had a steel-laminate type head gasket; to enhance sealing performance and durability, a shim was used around the cylinder bore of the gasket.

The 2GR-FE engine had upright, ‘Siamese’ inlet ports to reduce the overall surface area of the port walls to reduce wall wetting and hydrocarbon emissions, and a narrow included valve angle to create a compact combustion chamber shape.

Camshafts

The 2GR-FE engine had double overhead camshafts that were made of cast iron alloy. Both the primary and secondary timing chains used pitch roller chains with a pitch of 9.525 mm. The intake camshafts were driven by the crankshaft via the primary timing chain. The exhaust camshafts were driven by the intake camshaft of the respective bank via the secondary timing chain.

The primary timing chain used one chain tensioner (ratchet type with a non-return mechanism), and each of the secondary timing chains for the right and left banks used one chain tensioner. Both the primary and secondary chain tensioners used a spring and oil pressure to maintain proper chain tension at all times. Furthermore, the timing chains were lubricated by oil jets.

The 2GR-FE’s cam profile was designed with an indented radius to increase valve lift when the valve began to open and finished closing.

Roller rockers

The 2GR-FE engine had roller rocker arms with built-in needle bearings that reduced the friction that occurred between the camshafts and the roller rocker arms (which actuated the valves). The hydraulic lash adjuster – located at the fulcrum of the roller rocker arm – consisted primarily of a plunger, plunger spring, check ball and check ball spring. Through the use of oil pressure and spring force, the lash adjuster maintained a constant zero valve clearance.

Engine oil that was supplied via the cylinder head and the built-in spring actuated the hydraulic lash adjuster. The oil pressure and the spring force that acted on the plunger would push the roller rocker arm against the cam to adjust the valve clearance that was created during valve operation. As a result, the lash adjuster maintained constant zero valve clearance.

Valves and Dual VVT-i

The 2GR-FE engine had four valves – two intake and two exhaust – per cylinder. Of these,

• The intake valves had 38.0 mm diameters and 10.9 mm valve lift; and,
• The exhaust valves had 32.0 mm diameters and 10.7 mm valve lift.

The ‘dual variable valve timing with intelligence’ (Toyota’s ‘Dual VVT-i’) system adjusted the intake and exhaust camshafts within a range of 40 degrees and 35 degrees respectively (relative to crankshaft angle) to vary valve timing. For the XV40 Aurion at least, the 2GR-FE engine had valve overlap that varied from 1 degree to 76 degrees (relative to crankshaft angle); intake duration was 248 degrees, while exhaust duration was 244 degrees.

Oil passages on the intake and exhaust camshafts enabled the ECU to adjust camshaft advance and retard via:

• An oil control valve (mounted on the cylinder head); and,
• Vane-type actuators on the ends of the four camshafts. The intake side used a VVT-i controller with three vanes, and the exhaust side used one with four vanes.

The ECU also used signals from the camshaft position sensor and the crankshaft position sensor to detect actual valve timing, thus providing feedback control to achieve the target valve timing.

When the engine stopped, the intake side VVT-i controller was locked on the most retarded angle side by the lock pin, and the exhaust side VVT-i controller was locked on the most advanced angle side.

Intake

For the 2GR-FE engine, the intake air chamber was made of plastic and contained an intake air control valve for Toyota’s ‘Acoustic Control Induction System’ (ACIS). ACIS consisted of:

• A bulkhead to divide the intake manifold into two stages; and,
• An intake air control valve in the bulkhead which opened and closed to vary the effective length of the intake manifold according to engine speed and throttle valve opening angle.

When the engine was running at middle speed under high load, an actuator would close the intake air control valve to increase the effective length of the intake manifold and improve intake efficiency – at medium engine speeds – due to the effect of inlet pulsations. In any condition other than middle speed running under high loads, the intake air control valve was open to shorten the effective length of the intake manifold.

The 2GR-FE engine had a linkless-type throttle body in which the throttle position sensor and the throttle control motor were integrated. Furthermore, Toyota’s ‘Electronic Throttle Control System – intelligent’ (ETCS-i) controlled the throttle valve in accordance with the amount of accelerator pedal effort and the condition of the engine

The 2GR-FE engine had an aluminium alloy intake manifold, while the intake manifold gaskets had a rubber coating applied to their surfaces for durability.

Injection and Ignition

The 2GR-FE engine had an L-type sequential fuel injection system which detected the intake air mass with a hot-wire type air flow meter and a twelve-hole injector for each cylinder. The 2GR-FE used an ‘independent’ injection system in which fuel was injected once into each cylinder for each two revolutions of the crankshaft. Furthermore, there were two injections:

• A synchronous injection in which corrections based on the signals from the sensors were added to the basic injection timing so that injection always occurred at the same position; and,
• A non-synchronous injection in which injection was influenced by signals from sensors (regardless of the crankshaft angle). To protect the engine and improve fuel economy, the system could temporarily cut off fuel supply.

The 2GR-FE engine had a coil-on-plug ignition system, Toyota’s ‘Direct Ignition System’ (DIS), in which the spark plug cap was integrated with the ignition coil. Positioned in the centre of the combustion chamber, the 2GR-FE engine used long-reach iridium-tipped spark plugs so that:

• The top of the combustion chamber could be thicker than normal; and,
• The water jacket could be extended near the combustion chamber for better cooling.

Ignition timing was determined by the ECU based on signals from various sensors; the ECU corrected ignition timing in response to engine knocking.

The 2GR-FE engine had pentroof-type combustion chambers and a compression ratio of 10.8:1. The firing order was 1-2-3-4-5-6.

Exhaust

The stainless-steel exhaust manifold had an integrated three-way catalytic converter; the catalytic converter was an ultra thin-wall, high-cell density ceramic type. For the stainless steel exhaust pipe, ball joints were used at the exhaust centre pipe joint and between the exhaust centre pipe and tailpipe. Finally, dual main mufflers were fitted to reduce exhaust back-pressure and boost performance.

Supercharged 2GR-FE (2GR-FZE)

There have been three supercharged applications of the 2GR-FE: the TRD Aurion (solely offered in Australia), the Lotus Exige S and theLotus Evora S. Of these,

• For the TRD Aurion, the Eaton TVS (Twin Vortices System) four-lobe supercharger was driven by a V-belt off the engine’s crank shaft. Although peak torque was 400 Nm at 4000 rpm, more than 300 Nm was available from 1250 rpm; and,
• For theLotus Evora S andExige S, a Harrop HTV 1320 supercharger (with Eaton Twin Vortex compressors) was used. For these Lotus models, Toyota has referred to the supercharged 2GR-FSE engine as the 2GR-FZE.