Lexus is entering the 2016 model year with a three model strategy for its IS sport sedan: IS 200t, IS 300 AWD, and IS 350. The former IS 250 and IS 250 AWD are discontinued. The new IS 200t, available as RWD only, features a 2.0-liter twin-scroll turbocharged inline four-cylinder engine with intercooler paired to an eight-speed automatic transmission. Variable Valve Timing intelligent – Wide (VVTi-W) allows the engine to switch between the Otto and Atkinson cycles. (Earlier post.)
Atkinson cycle mode is used in extremely low load conditions, when the intake valve remains open for a fraction of time, after the compression stroke has set in, allowing part of the gas charge to be pushed back into the intake. As a result, the effective compression stroke is shortened. Pumping losses are reduced, since the pressure on the piston is lower, and also the throttle valve can be opened wider.
The engine cranks out 241 hp (180 kW) and 258 lb-ft (350 N·m) of torque at 1,650-4,400 rpm. Lexus developed the turbocharged engine in house, first integrated it into the NX luxury utility hybrid for 2015 model year, and modified it for IS 200t.
The IS 200t features a combination of water-cooled cylinder head, integrated exhaust manifold and twin scroll turbocharger for fast throttle response, performance and high torque at low engine revs.
The D-4ST direct injection system combines a high pressure fuel system for injection directly in to the cylinders with a low pressure system for injection into the ports. Injection is split between the direct and port injectors according to the engine load to help fuel economy.