SUBARU | Subaru Technology

Subaru firmly believes that the Horizontally-Opposed Engine is the optimum design for driving enjoyment. The pistons face away from each other in a 180º symmetrical layout around the crankshaft and work to balance out each other’s vibrations, delivering a smooth, shudder-free feel. This is because the engine can rotate freely at any given speed, delivering heart-gripping response to the driver. The length and height of this engine layout can be kept shorter than a traditional in-line engine, and it is also lighter. The engine can be mounted lower in the vehicle than other engines, and weight balance on the left and right can be made almost exactly the same. In this design, the low centre of gravity engine lowers the centre of gravity of the entire car. Similarly, a symmetrically balanced engine increases the symmetrical balance of the entire car. Both of these aspects combine to deliver a safer, more stable, and ultimately, more enjoyable experience on the road.

SUBARU BOXER DIESEL

The world's first commercial Horizontally-Opposed Diesel Engine developed for passenger vehicles is the SUBARU BOXER DIESEL. When petrol engines are converted to diesel, strengthening of the engine block usually makes the engine bigger and heavier. The SUBARU BOXER, however, was originally designed with rigidity in mind, allowing the 92.0 mm x 75.0 mm bore and stroke of the 2.0-litre petrol four-cylinder engine to be changed to a square 86.0 mm x 86.0 mm design. The result is a more compact combustion chamber and greater fuel efficiency, all while retaining the sporty engine feel of the SUBARU BOXER. The engine length has also been shortened, while weight has been kept similar to the petrol engine. Supplementing the powerful torque and low CO2 emissions that are characteristic of diesel engines, the smooth, almost vibration-free engine feel, high levels of silence and the breathtaking acceleration of the SUBARU BOXER have been retained to create a quiet, torquey diesel engine with swift and sporty response. These advantages are evidence of the vision that Subaru has in using the Horizontally-Opposed Engine.

(SUBARU BOXER 3.6-litre / 2.5-litre high-power turbo / New generation 2.0-/2.5-litre DOHC)

A system that continually changes the opening and closing timing of the intake and exhaust valves through a hydraulic mechanism. This increases combustion efficiency, improves fuel efficiency, delivers smooth torque from low engine speeds, and provides linear accelerator pedal response and acceleration.

(SUBARU BOXER 2.5-litre SOHC)

A variable valve system that controls the amount of valve lift and opening angle, and ultimately the amount of air flowing into the combustion chamber. At low engine speeds, lift in the left and right valves is alternated to generate a swirling flow (transverse vortex), resulting in efficient combustion even with minimal air and fuel use. A high valve lift is used for both valves at high engine speeds to generate a tumble flow (longitudinal vortex) for a greater amount of intake air. The result is outstanding fuel efficiency and large amounts of usable torque.