Advanced new engine for Jag's F-Type
Jaguar has announced two new force-fed engines for its line-up, one of them specifically for the upcoming F-Type sports car.
The new three-litre V6 supercharged petrol engine has been developed from the existing five-litre V8, using key technology such as direct injection, variable valve timing, and all-aluminium construction.
The lightweight die-cast block has cross-bolted main bearing caps to increase rigidity and the four-valve cylinder heads are cast in recycled aluminium, while the valves are controlled by a dual independent variable cam timing system.
Spray-guided direct injection delivers precisely measured quantities of fuel directly into the centre of the combustion chambers at pressures of up to 150 bar, several times during each combustion cycle to create a more homogenous air-fuel mixture for cleaner and more efficient combustion.
AVAILABLE IN TWO STATES OF TUNE
Compression ratio is up from the 9.5:1 of the supercharged V8 to 10.5:1, and the Roots-type twin vortex supercharger in the V of the block is more compact than that of the V8, with a more efficient water-cooled intercooler.
It'll be available in two states of tune, 250kW/450Nm or 280kW/460Nm; and the company says that's the highest specific output of any Jaguar road engine - 93kW per litre.
In either case it will be mated to a new eight-speed automatic transmission from ZF, with an idle-stop system using a twin-solenoid starter that Jaguar says can start the engine quicker than the driver can move his foot from brake to accelerator pedal.
The 280kW version will only be available in the new F-Type sports car, but the 250kW version will replace the naturally-aspirated five-litre V8 in the XF and XJ sedans from next year.
TWO-LITRE TURBO FOUR
The two-litre I4 Ti 240 engine delivers a quoted 177kW at 5500rpm and 340Nm from 1800-4000rpm - that's more power than more torque than the three-litre AJ-V6 it replace, with significantly lower fuel consumption.
Yet it weighs only 138kg with all its ancillaries, making it the lightest Jaguar engine yet.
It'll line up north-south in the XF and XJ sedans, driving through the same eight-speed auto transmission as the V6 - although that doesn't rule out a transverse installation in later models.
The I4 Ti 240's turbocharger is fed via a lightweight thin-walled exhaust manifold that allows for a shorter engine warm-up period, further reducing emissions.
Chain-driven variable timing modulates both intake and exhaust valves, and specialised coatings on the piston rings and tappets reduce internal friction, while fuel is injected in precisely measured doses several times during each combustion cycle for the most efficient possible burn
Dual balancer shafts, active engine mounts and an acoustic cover with high-density foam insulation all contribute to smooth, quiet running.