2KD-FTV Toyota engine

Introduction

Toyota’s 2KD-FTV was a 2.5-litre four-cylinder turbo diesel engine. A member of Toyota’s ‘KD’ engine family, which included the related 1KD-FTV, key features of the 2KD-FTV included its:

• Cast iron block;
• Aluminium alloy cylinder head;
• Turbocharger with wastegate valve and actuator;
• Double overhead camshafts;
• Four valves per cylinder; and,
• Compression ratio of 18.5:1.

The 2KD-FTV engine was produced in standard and more powerful ‘High Version’ forms; the ‘High Version’ 2KD-FTV was distinguished by its 260 Nm torque output (compared to 200 Nm for the standard 2KD-FTV), tumble control valves and intercooler.

2KD-FTV block

The 2KD-FTV engine had a deep-skirt cast iron cylinder block with 92.0 mm bores and a 93.8 mm stroke for a capacity of 2494 cc. The block had a reinforcing rib to reduce engine vibrations, while the cylinder bores were liner-less.

Crankshaft, connecting rods and pistons

The crankshaft for the 2KD-FTV engine had eight balance weights and five journals, while the pin and journal fillets were roll-finished. The crankshaft bearings were made from aluminium alloy and had micro-grooved lining surfaces to optimise oil clearance for better cold-engine cranking performance and reduced engine vibrations; the upper main bearing had an oil groove around its circumferences. To reduce noise, vibration and harshness (NVH), the crankshaft pulley had a torsional rubber damper.

The high-strength connecting rods had aluminium bearings and plastic region tightening bolts. Furthermore, knock pins used at the mating surfaces of the bearing caps of the connecting rod to minimise shifting of the bearing caps during assembly.

The 2KD-FTV engine had aluminium alloy pistons with Ni-resist cast iron ring carriers. For cooling and lubrication, oil jets at the bottom of the cylinder block sprayed oil into the internal cooling channels of the pistons; these oil jets had a check valve to prevent oil supply when oil pressure was low. For ’emission regulation non-compliance’ models, the 2KD-FTV pistons had a Physical Vapor Deposition (PVD) coating for the surface of the no.1 compression ring.

Cylinder head

The 2KD-FTV engine had an aluminium alloy cylinder head which used plastic region tightening bolts. The cylinder head was mounted on a steel-laminate type head gasket, while a shim was used around the cylinder bores to increase the area of the sealing surface.

To reduce mass and noise, the 2KD-FTV engine had a plastic cylinder head cover. Inside the cylinder head cover, there was a baffle plate to reduce the consumption of engine oil through blow-by gas.

Turbocharger

Unlike the variable nozzle vane type turbocharger of the 1KD-FTV engine, the 2KD-FTV turbocharger had a wastegate valve and an actuator that operated mechanically to limit boost pressure.

The more powerful ‘High Version’ 2KD-FTV engines had an air-cooled intercooler which was located on top of the engine and intake air to increase its density and increase engine performance. The intercooler and the inlet tank were made of aluminium, while the outlet tank was made of plastic for mass reduction.

Camshafts

The 2KD-FTV engine had double overhead camshafts with a belt and gear drive. As such, the intake camshaft was driven by a replaceable rubber timing belt, while the exhaust camshaft was driven via a gear on the intake camshaft. To reduce noise, the gear had small diameter, flat teeth gears.

To increase abrasion resistance, the noses of each cam lobe were chill-treated.

Valves

The 2KD-FTV engine had four valves per cylinder – two intake and two exhaust – that were actuated directly by shim-less valve lifters that provided a large cam contact surface. Adjustment of valve clearance required the valve lifters to be replaced.

The 2KD-FTV engine had valve overlap of 2 degrees, intake duration of 213 degrees and exhaust duration of 210 degrees.

Intake and throttle

The 2KD-FTV engine had two intake ports for each cylinder which had different shapes to increase swirl in the combustion chamber. The ‘High Version’ 2KD-FTV engines had vacuum-actuated swirl control valves in one of the two intake ports for each cylinder. The swirl control valves consisted of a stainless steel shaft and an actuator which was integrated in the valve. At low engine speeds, the swirl control valve would close to increase swirl; for cold starts and high engine speeds, the valve would be open.

The intake shutter valve (throttle valve) was fitted with a rotary solenoid type torque motor, while non-contact sensors were used for both the intake shutter valve and accelerator pedal position sensors.

Common-rail injection (D-4D)

The 2KD-FTV engine had common-rail injection (Toyota’s ‘Direct Injection 4-Stroke Common Rail Diesel Engine’, or D-4D). The function of the common-rail was to store fuel that had been pressurised by the supply pump. The common-rail contained a main hole and five branch holes that intersect the main hole; each branch hole functions as an orifice that dampens the fluctuation of the fuel pressure. Furthermore, the common-rail had a fuel pressure sensor and a pressure limiter that mechanically relieved pressure if it rose abnormally (200 MPa).

The injectors consisted of a nozzle needle, piston and solenoid valve. When an electric current was applied to the solenoid coil, the solenoid valve would retract. The orifice of the control chamber would then open to allow fuel to flow out, causing fuel pressure in the control chamber to drop. Simultaneously, fuel would flow from the orifice to the bottom of the piston and the piston would rise. As a result, the piston would raise the nozzle needle to inject fuel. The injector was located in the centre of the combustion chamber.

For the standard 2KD-FTV engine with an intercooler, common-rail pressure ranged from 30 to 135 MPa; for the 2KD-FTV ‘High Version’ with intercooler, maximum pressure was 160 MPa. The 2KD-FTV engine used six-hole type injectors where the holes measured 0.14 mm. Furthermore, each injector was located in the centre of the combustion chamber.

The ECU calculated target injection pressure based on signals from the acceleration pedal position sensor and crankshaft position sensor. The ECU controlled the Suction Control Valve (SCV) opening to regulate pumping volume so that the pressure detected by the fuel pressure sensor matched the target injection pressure.

The 2KD-FTV engine could perform ‘pilot injection’ which consisted of a series of small injection phases prior to the main injection phase. Pilot injection was used to reduce:

• Ignition delay at the main injection;
• Noise and vibrations; and,
• Emissions by preventing sudden increases in combustion pressure.

The electronic injection system determined the volume, timing and count interval between pilot injections and the main injection.

For ease of starting, the glow plug was placed between the intake ports of each cylinder. Firing order for the 2KD-FTV engine was 1-3-4-2.

Exhaust and emissions

The 2KD-FTV engine used a ball joint to connect the exhaust manifold to the front exhaust pipe and an oxidation catalytic converter was used to clean exhaust gas particulates (HC and CO).

For models complying with Euro III and beyond emissions standards, the 2KD-FTV engine used cooled exhaust gas recirculation (EGR) to reduce recirculate a small amount of inert exhaust gas into the intake manifold, thereby reducing peak temperatures in the combustion chamber and NOx formation. On the 2KD-FTV engine, an EGR valve position sensor was used to directly measure the actual amount of the valve opening – this input was used by the ECU for precise EGR control.