You are using an older browser version. Please use a supported version for the best MSN experience.

Toyota’s Future Engines Employ Atkinson Cycle for Max Efficiency

Motor Trend logo Motor Trend 4/10/2014 Erick Ayapana

Toyota has just unveiled two new small engines that it says are more fuel efficient than previous engines thanks to a number of tricks and technologies pulled from its hybrid powertrains. The engines, which are estimated to be up to 30-percent more efficient, are slated to power a number of vehicles within the year and should spawn no fewer than 14 variations by 2015.

Research

The first engine is a 1.3-liter unit that runs on the Atkinson cycle, which until now has been reserved for Toyota’s hybrid powertrains. In fact, the automaker earlier this year announced it would employ the Atkinson cycle for the naturally aspirated 5.0-liter V-8 powering the upcoming 2015 Lexus RC F. As technical director Frank Markus stated in his report on the RC F, “the ideal Atkinson cycle captures and compress an amount of air that, when combusted and expanded throughout the entire power cycle, results in a cylinder pressure that’s near atmospheric at the bottom of the piston’s stroke, meaning the engine has wrung every bit of energy out of the fuel.” MotorTrend Image© Provided by MotorTrend MotorTrend Image

In addition to a high compression ratio of 13.5, Toyota’s new 1.3-liter mill will feature an intake port shaped to generate a strong air-fuel flow that tumbles in a vertical swirl, a cooled exhaust gas recirculation system, and Variable Valve Timing-intelligent Electric (VVT-iE) technology. Toyota engineers combated engine knocking by placing water jacket spacers around the cylinders to control temperature and by increasing combustion chamber scavenging.

Other technologies include plastic-coated bearings, modified piston skirt surfaces, more efficient oil pump, and a stop-start system. In all, the 1.3-liter engine will achieve a thermal efficiency rating of 38-percent and a 15-percent increase in fuel efficiency compared to the engines it will replace.

Meanwhile, the second engine is a 1.0-liter unit that features many of the engineering tricks as the 1.3-liter mill. Its compression ratio, however, is slightly lower at 11.5 and Toyota rates its thermal efficiency at 37-percent, but it is estimated to be 30-percent more fuel efficient.That said, Toyota will attempt to improve the engines in its future hybrid models, with a goal of increase the thermal efficiency in hybrid powerplants from 38.5 to 42 percent. MotorTrend Image© Provided by MotorTrend MotorTrend Image

Toyota’s Future Engines Employ Atkinson Cycle for Max Efficiency

Source: Toyota

Toyota 1 3 liter Engine© Provided by MotorTrend Toyota 1 3 liter Engine
AdChoices
AdChoices

More from Motor Trend

Loading...

image beaconimage beaconimage beacon