Higher Compression for Higher Efficiency
What is the advantage of a higher compression ratio? A longer stroke compresses the fuel-air mixture further, allowing you to get more energy out of the same amount of fuel. Higher compression engines traditionally faced the obstacle of “engine knock,” or premature ignition (as highly compressed fuel is more volatile and can ignite too soon).
The SKYACTIV engine introduces a solution to knock through an array of innovations that work to reduce temperatures in the combustion chamber and speed up the combustion process. This allows SKYACTIV engines to achieve an astonishing 13.0:1 compression ratio on 87-octane (regular) gasoline. To give you an idea of how impressive this is, the Ferrari 458 reaches only 12.5:1 on premium fuel.
4-2-1 exhaust system
Another tool in the belt of the SKYACTIV engine is a unique exhaust system that speeds up the evacuation of hot gases from the combustion chamber, helping keep temperatures down and stave off knock while improving efficiency.
Innovative piston cavity allows for delayed ignition timing
While the 4-2-1 exhaust system helps to prevent knock, it poses complications of its own. Because of the system’s length, the catalytic converter (which needs heat for proper operation) wouldn’t heat up quickly enough during cold starts. Mazda solves this with delayed ignition timing. However, too much delay can cause unstable ignition-the solution to this was to design a cavity in the top of the piston to improve stability, even with delayed ignition. The piston itself has a dome-shaped top to help achieve higher compression.
Super-High Pressure Direct injection system
Another way to reduce knock was to shorten combustion duration. To do this, fuel would have to be injected at lightning speed. That’s why Mazda uses an incredibly high pressure of 2,900 psi to shoot fuel through the six-hole injectors. This not only results in faster injection, but also improves fuel vaporization and cools off the air/fuel mixture to better distribute fuel in the cylinder.
Weight and mechanical friction reduction enhances efficiency
Nearly every engine part and component was trimmed down to eliminate unneeded mass and reduce friction.
- Adoption of compact electronic variable pressure oil pump (approx. 45% reduction in oil pumping loss)
SKYACTIV-Drive 6-Speed Automatic Transmission
A revolutionary engine needed a revolutionary transmission to get all of that power to the wheels with the minimal loss of energy along the way. The SKYACTIV-Drive 6-speed Sport mode automatic transmission’s “brain” delivers precise response and reliability while making for smooth shifting, steady acceleration and the quick feel traditionally associated with a manual transmission.
Mechatronic control module for precise response
Locking out the torque converter achieved our direct, connected feel and fuel efficiency goals. But getting fast, smooth shifts required speed and precision from deeper inside the transmission.
A new mechatronic module combines the transmission control computer and all the sensors and shift solenoids into one unit. Think of it as the transmission’s brain. Each module is individually calibrated when the transmission is assembled so the computer can learn the precise response characteristics of each part it has to control.
Innovative design helps to improve fuel efficiency by 4% to 7%
As a result of this innovative approach to automatic transmission design, SKYACTIV-DRIVE automatic operates more efficiently than conventional transmissions. It upshifts smoothly and directly like its DCT competitors, it rev-matches precise downshifts, and it yields 4% to 7% gains in fuel economy.
Best features of all types of transmissions combined
- Easy to control at low speeds like a conventional automatic
Torque converter and clutch together deliver smooth, direct feel
A conventional torque converter is still the smoothest, easiest way to control a car at slow speeds, but is inefficient at higher speeds. Mazda’s solution: use the torque converter only below 8 km/hour and use the SKYACTIV-DRIVE AT’s multi-plate clutch at higher speeds to efficiently transmit power.
SKYACTIV Body and Chassis
The SKYACTIV Body and Chassis improves body rigidity by 30% (for better handling) and sheds 220 pounds, all while improving crash safety performance. It was designed to make the driver and car feel connected at all speeds.
Chassis redesign delivers greater stability and agility
Our goal for improving suspension and steering seemed like a contradiction: Take that light, nimble feeling that Mazdas are known for and get more of it without losing stability. In fact, we wanted greater stability for that smooth-mover-on-the-Autobahn feeling.
The rear suspension given more toe-in with the front of the tires angled slightly toward each other to improve stability. While this adjustment would normally reduce handling, Mazda overcame this with a quicker steering ratio and electric-power-steering tuning.
To keep up high-speed maneuverability, Mazda increased front caster and trail to the highest of any front-wheel-drive sedan to give the steering more self-centering, stabilizing force for enhanced feel and performance, especially at high speeds. Simply put, it’s Autobahn-ready.
In the rear, trailing arm pivot points were raised by two inches to cushion bumps and improve stability under braking.
Body made 8% lighter but 30% more rigid
Mazda engineered a body 8% lighter but 30% more rigid. At the same time, they increased the amount of high-strength and ultra-high-strength steel alloys by 20%.
The body structure was made stronger and lighter through smarter geometry: By eliminating corners in each load path, Mazda created a straight frame from front to rear. The back half of the center tunnel was also reinforced so load directed to the floor can be carried there as well.
Smarter engineering for top crash safety performance
To improve crash safety performance, Mazda adopted a multi-load path structure that uses the whole body to absorb crash energy rather than just the floor. In a collision, this structure efficiently absorbs the load by dispersing it in multiple directions. The same approach was adopted for individual parts, allowing them to be made stronger without being made heavier.