Atlantis Speaks Again Book 1333 Mother Mary Maier

Introduction

The FA20D engine was a 2.0-litre horizontally-opposed (or 'boxer') four-cylinder petrol engine that was manufactured at Subaru'southward engine constitute in Ota, Gunma. The FA20D engine was introduced in the Subaru BRZ and Toyota ZN6 86; for the latter, Toyota initially referred to information technology equally the 4U-GSE before adopting the FA20 name.

Key features of the FA20D engine included information technology:

• Open up deck pattern (i.e. the infinite between the cylinder bores at the pinnacle of the cylinder block was open up);
• Aluminium alloy block and cylinder head;
• Double overhead camshafts;
• Four valves per cylinder with variable inlet and exhaust valve timing;
• Directly and port fuel injection systems;
• Compression ratio of 12.v:one; and,
• 7450 rpm redline.

FA20D block

The FA20D engine had an aluminium alloy block with 86.0 mm bores and an 86.0 mm stroke for a capacity of 1998 cc. Within the cylinder bores, the FA20D engine had cast fe liners.

Cylinder head: camshaft and valves

The FA20D engine had an aluminium alloy cylinder head with chain-driven double overhead camshafts. The four valves per cylinder – ii intake and 2 frazzle – were actuated past roller rocker arms which had built-in needle bearings that reduced the friction that occurred between the camshafts and the roller rocker artillery (which actuated the valves). The hydraulic lash adjuster – located at the fulcrum of the roller rocker arm – consisted primarily of a plunger, plunger leap, check ball and cheque brawl spring. Through the use of oil pressure level and bound force, the lash adjuster maintained a constant zilch valve clearance.

Valve timing: D-AVCS

To optimise valve overlap and apply exhaust pulsation to raise cylinder filling at high engine speeds, the FA20D engine had variable intake and exhaust valve timing, known as Subaru's 'Dual Active Valve Control Organisation' (D-AVCS).

For the FA20D engine, the intake camshaft had a threescore degree range of adjustment (relative to crankshaft bending), while the frazzle camshaft had a 54 degree range. For the FA20D engine,

• Valve overlap ranged from -33 degrees to 89 degrees (a range of 122 degrees);
• Intake duration was 255 degrees; and,
• Exhaust elapsing was 252 degrees.

The camshaft timing gear assembly contained accelerate and retard oil passages, as well every bit a detent oil passage to make intermediate locking possible. Furthermore, a thin cam timing oil control valve assembly was installed on the front surface side of the timing chain cover to brand the variable valve timing mechanism more compact. The cam timing oil control valve associates operated according to signals from the ECM, controlling the position of the spool valve and supplying engine oil to the advance hydraulic sleeping room or retard hydraulic chamber of the camshaft timing gear assembly.

To modify cam timing, the spool valve would be activated by the cam timing oil command valve assembly via a signal from the ECM and movement to either the right (to advance timing) or the left (to retard timing). Hydraulic force per unit area in the advance bedroom from negative or positive cam torque (for accelerate or retard, respectively) would utilize pressure to the advance/retard hydraulic chamber through the accelerate/retard bank check valve. The rotor vane, which was coupled with the camshaft, would and so rotate in the accelerate/retard direction against the rotation of the camshaft timing gear assembly – which was driven by the timing chain – and advance/retard valve timing. Pressed by hydraulic pressure level from the oil pump, the detent oil passage would go blocked and so that it did non operate.

When the engine was stopped, the spool valve was put into an intermediate locking position on the intake side by spring power, and maximum advance state on the exhaust side, to prepare for the next activation.

Intake and throttle

The intake organisation for the Toyota ZN6 86 and Subaru Z1 BRZ included a 'sound creator', damper and a sparse rubber tube to transmit intake pulsations to the cabin. When the intake pulsations reached the sound creator, the damper resonated at certain frequencies. Co-ordinate to Toyota, this design enhanced the engine induction noise heard in the cabin, producing a 'linear intake sound' in response to throttle awarding.

In contrast to a conventional throttle which used accelerator pedal endeavour to determine throttle bending, the FA20D engine had electronic throttle control which used the ECM to calculate the optimal throttle valve bending and a throttle control motor to control the bending. Furthermore, the electronically controlled throttle regulated idle speed, traction control, stability control and cruise command functions.

Port and direct injection

The FA20D engine had:

• A direct injection organization which included a loftier-pressure fuel pump, fuel delivery pipe and fuel injector associates; and,
• A port injection system which consisted of a fuel suction tube with pump and gauge assembly, fuel pipe sub-associates and fuel injector associates.

Based on inputs from sensors, the ECM controlled the injection volume and timing of each type of fuel injector, according to engine load and engine speed, to optimise the fuel:air mixture for engine conditions. According to Toyota, port and directly injection increased operation across the revolution range compared with a port-but injection engine, increasing power past upwardly to 10 kW and torque by up to 20 Nm.

Equally per the tabular array beneath, the injection organization had the following operating conditions:

• Cold start: the port injectors provided a homogeneous air:fuel mixture in the combustion sleeping room, though the mixture around the spark plugs was stratified by compression stroke injection from the straight injectors. Furthermore, ignition timing was retarded to heighten exhaust gas temperatures so that the catalytic converter could reach operating temperature more quickly;
• Low engine speeds: port injection and directly injection for a homogenous air:fuel mixture to stabilise combustion, meliorate fuel efficiency and reduce emissions;
• Medium engine speeds and loads: directly injection only to utilise the cooling effect of the fuel evaporating as it entered the combustion chamber to increment intake air volume and charging efficiency; and,
• High engine speeds and loads: port injection and straight injection for loftier fuel menses volume.

The FA20D engine used a hot-wire, slot-in type air flow meter to measure intake mass – this meter allowed a portion of intake air to flow through the detection surface area then that the air mass and menstruum rate could be measured directly. The mass air menstruum meter also had a built-in intake air temperature sensor.

The FA20D engine had a compression ratio of 12.5:1.

Ignition

The FA20D engine had a directly ignition arrangement whereby an ignition coil with an integrated igniter was used for each cylinder. The spark plug caps, which provided contact to the spark plugs, were integrated with the ignition whorl associates.

The FA20D engine had long-reach, iridium-tipped spark plugs which enabled the thickness of the cylinder caput sub-associates that received the spark plugs to be increased. Furthermore, the water jacket could be extended virtually the combustion chamber to enhance cooling operation. The triple basis electrode type iridium-tipped spark plugs had sixty,000 mile (96,000 km) maintenance intervals.

The FA20D engine had flat type knock control sensors (non-resonant type) attached to the left and correct cylinder blocks.

Exhaust and emissions

The FA20D engine had a 4-2-ane frazzle manifold and dual tailpipe outlets. To reduce emissions, the FA20D engine had a returnless fuel organisation with evaporative emissions control that prevented fuel vapours created in the fuel tank from being released into the atmosphere by catching them in an activated charcoal canister.

Uneven idle and stalling

For the Subaru BRZ and Toyota 86, there have been reports of

• varying idle speed;
• rough idling;
• shuddering; or,
• stalling

that were accompanied by

• the 'check engine' light illuminating; and,
• the ECU issuing fault codes P0016, P0017, P0018 and P0019.

Initially, Subaru and Toyota attributed these symptoms to the VVT-i/AVCS controllers non meeting manufacturing tolerances which acquired the ECU to detect an aberration in the cam actuator duty cycle and restrict the operation of the controller. To fix, Subaru and Toyota developed new software mapping that relaxed the ECU's tolerances and the VVT-i/AVCS controllers were later manufactured to a 'tighter specification'.

At that place accept been cases, however, where the vehicle has stalled when coming to balance and the ECU has issued error codes P0016 or P0017 – these symptoms have been attributed to a faulty cam sprocket which could cause oil force per unit area loss. As a consequence, the hydraulically-controlled camshaft could not reply to ECU signals. If this occurred, the cam sprocket needed to exist replaced.

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Source: http://www.australiancar.reviews/Subaru_FA20D_Engine.php

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