introduced a pair of brand-new engines in Japan today, that it says will eventually spawn 14 different variants by 2015. Where these two engines stand out in today's world, is that neither mill boasts direct injection, and both are naturally aspirated.
The larger of the two is a 1.3-liter, while the smaller engine, a 1.0-liter, was developed in collaboration with Daihatsu. What makes these two unique is that they both use the Atkinson cycle. Now, we aren't going to bore you by explaining just what this is - there's Google
for that. Suffice it to say, Atkinson engines are highly efficient, but that efficiency comes by sacrificing power. That's why they're so popular in hybrids, which can offset the power losses.
This focus on fuel efficiency extends throughout the new engines, which also benefit from tweaks like a cooled exhaust gas recirculation system and a trick intake port, while the 1.3 employs Toyota's iE variant of variable valve timing. Both engines can be fitted with stop-start tech. According to Toyota, when fitted with stop-start the 1.3 should provide around a 15-percent bump while the 1.0-liter will increase economy around 30 percent, when they arrive on the road.
We're not going to lie, the non-hybrid Atkinson system is a question mark. But according to General Manager of Powertrain Planning Shouji Adachi, it shouldn't be an issue.
"There is always the challenge of lower performance in torque," Adachi-san told Automotive News
. "For the new engines, we were able to resolve these issues."
We're presuming that what Adachi is referring to is Toyota's use of high compression ratios on both engines - 13.5 in the case of the 1.3L and 11.5 in the 1.0L. Using a higher compression ratio allows the engine to develop more power thanks to increased thermal efficiency. In the case of the 1.3L, max thermal efficiency is at 38 percent, which Toyota says is quite good. The 1.0L is just a smidge behind, at 37 percent.
So, power concerns momentarily swept aside, where to do we think these engines will end up? According to AN, non-hybrid, JDM compacts will be the first to use the new engines. From there, though, it's really anyone's guess where these engines and their variants will end up. Scroll on down
for the short press release on the two engines, from Toyota.