1VD-FTV Toyota engine

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Introduction

Toyota’s 1VD-FTV was a 4.5-litre 90-degree V8 diesel engine that had either a single turbocharger (for the 70-Series LandCruiser) or twin-turbochargers (for the 200-Series LandCruiser); this article will consider the twin-turbocharged version.

Commencing production in 2007, the 1VD-FTV was the first V8 diesel engine produced by Toyota. Key features for the 1VD-FTV engine included a nodular graphite iron cylinder block, aluminium alloy cylinder heads, double overhead camshafts, four valves per cylinder, direct injection and 16.8:1 compression ratio.
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1VD-FTV block

The cylinder block for the 1VD-FTV engine was produced from nodular graphite iron. The 4461 cc 1VD-FTV engine had 86.0 mm bores and a 96.0 mm stroke; the cylinder banks had a 22.0 mm offset, while bore pitch was 97.0 mm. To minimise vibration, the base of the cylinder block had stiffening plates, while four plastic-region tightening bolts were used for each bearing cap.

Crankshaft, connecting rods and pistons

The 1VD-FTV engine had a forged steel crankshaft with five journals, seven balance weights and aluminium bearings. All crankshaft pins and journals fillets were induction hardened, while the crankshaft pulley used an inertial weight to reduce noise and vibration.

The connecting rods were made from high-strength steel and the big-end bearings were secured with nut-less plastic-region tightening bolts. For correct alignment during assembly, knock pins were used at the mating surfaces of the bearing caps.

The 1VD-FTV engine had aluminium alloy pistons with combustion chambers in the piston crown. The pistons had an internal cooling channel, an Ni-resist cast-iron top ring carrier to improve wear resistance and a resin coating on the skirt to reduce frictional losses. Furthermore, oil jets at the bottom of the cylinder bores sprayed oil on the underside of the pistons to improve piston cooling and lubrication.

Cylinder head and camshafts

The 1VD-FTV engine had aluminium alloy cylinder heads with water jackets that featured vertical, two-stage construction for enhanced cooling. The 1VD-FTV engine had acrylic rubber cylinder head cover gaskets and plastic cylinder head cover sub-assemblies.

The 1VD-FTV engine had double overhead camshafts (DOHC) per cylinder bank. The intake camshafts were driven by gears and a timing chain, while the exhaust camshafts were driven by a cam gear that was attached to the intake camshaft. The timing chains used bush chains with a pitch of 9.525 mm and the ratchet-type chain tensioners had non-return mechanisms.

Valves

The 1VD-FTV engine had four valves per cylinder – two intake and two exhaust – that were actuated by roller rocker arms with built-in needle bearings which reduced friction between the cams and the roller rocker arms that depressed the valves.

The 1VD-FTV had hydraulic lash adjusters to maintain a constant zero valve clearance between the rocker arm and valve stem. Located at the fulcrum of the roller rocker arm sub-assembly, the valve lash adjuster assembly consisted primarily of a plunger, plunger spring, check ball and check ball spring. The oil pressure and the spring force that acted on the plunger pushed the roller rocker arm sub-assembly against the cam to adjust the valve clearance that was created during the opening and closing of the valve.

As per the table below, the 1VD-FTV engine had valve overlap of 4 degrees, intake duration of 199 degrees and exhaust duration of 233 degrees.
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Intercooler and intake

For the 1VD-FTV engine, inlet air passed through an air-cooled intercooler (i.e. air-to-air intercooler) that was mounted on top of the engine for compact packaging.

The 1VD-FTV engine had two link-less type throttle bodies in which a rotary solenoid-type throttle motor and non-contact throttle position sensor were integrated. The throttle position sensor converted magnetic flux density – which changed when the magnetic yoke (located on the same axis as the throttle valve shaft) rotated around the Hall IC – into electrical signals to operate the diesel throttle control motor.

For Australia, the 1VD-FTV engine was fitted with an air pre-cleaner.

Turbocharger

The 1VD-FTV engine had two low-inertia RHV4 turbochargers which had variable nozzle vanes and water-cooled bearing housings. The ECM controlled nozzle vane positions in the turbochargers via DC motors to obtain the turbocharger pressure appropriate for engine conditions. Target turbocharger pressure was calculated according to engine speed, injection volume, atmospheric pressure and engine coolant temperature.

At low engine speeds, the nozzle vanes would move towards the closing direction to increase the velocity of the exhaust gas flowing to the turbine and, hence, the speed of the turbine – this improve torque at low engine speeds. At medium to high engine speeds, the nozzle vanes would open and hold the targeted turbocharging pressure – this lowered back pressure and improved fuel consumption

Fuel supply and common rail D-4D direct injection

The 1VD-FTV engine had an HP4 type fuel supply pump which consisted of an inner cam (eccentric cam), outer cam (polygon ring), three plungers, Suction Control Valve (SCV) and a feed pump. Each plunger was placed outside of the outer cam. Please note that Australian models with the 1VD-FTV engine had a dual fuel tank arrangement which consisted of primary tank and sub tank.

The fuel pump supplied pressurised fuel to the common-rail where it was stored until injection. To control fuel pressure, signals were sent to the Suction Control Valve (SCV) of the fuel supply pump to regulate the pumping volume so that the pressure detected by the fuel pressure sensor matched target injection pressure. The common-rail contained a main hole and five intersecting branch holes; each branch hole functioned as an orifice that dampened fluctuations in fuel pressure. The common-rail also had a pressure sensor that mechanically relieved pressure if it rose abnormally.

The nine-hole fuel injector consisted of a nozzle needle, piston and solenoid valve. When the ECM sent an electrical current to the solenoid coil, the solenoid valve would retract. The orifice of the control chamber would then open, allowing fuel to flow out and fuel pressure in the control chamber would drop. Simultaneously, fuel would flow from the orifice of the control chamber to the bottom of the piston and raise the piston to enhance response. The piston would then raise the nozzle needle to inject fuel. The ECM calculated the target injection pressure (25 MPa to 175 MPa for Euro IV compliant models) based on engine conditions and inputs from the accelerator pedal position sensor and crankshaft position sensor.

The 1VD-FTV engine could also perform pilot injection, an auxiliary fuel injection that occurred prior to the main injection to gently start combustion of the fuel to reduce combustion noise.

The 1VD-FTV engine used a slot-in type mass air flow meter which allowed a portion of the intake air to flow through the detection area. By measuring the mass and the flow rate of the intake air, detection precision was improved and intake air resistance reduced. Furthermore, the mass air flow meter had an integrated atmospheric temperature sensor.

Ignition

For the 1VD-FTV engine, the glow plug was located between the inlet valves. Furthermore, the 1VD-FTV engine had a compression ratio of 16.8:1 and a firing order of 1-2-7-3-4-5-6-8.

Emissions control

For most markets, including Australia, the 200-Series LandCruisers had Exhaust Gas Recirculation (EGR) which reduced NOx formation by introducing a small amount of inert gas – water-cooled by the EGR cooler – into the intake manifold to reduce peak temperature. The ECM operated the linear solenoid-type EGR valve and diesel throttle control motor to regulate the amount of exhaust gas.

To reduce emissions, the 1VD-FTV engine was fitted with an oxidation catalytic converter.