Toyota Maximizes Power in Yaris Minicar’s New Engine

An all-new 1.5L I-4 gasoline engine will power the latest-generation Toyota Yaris.

It will replace the minicar’s vehicle’s existing 1.3L I-4 and promises more power, more torque and faster acceleration, as well as improved fuel economy and fewer carbon-dioxide emissions.

Developed in anticipation of more stringent European Euro 6c emissions standards in the future and real-driving-emissions homologation requirements, the I-4 is a member of Toyota’s Economy With Superior Thermal Efficiency engine family.

The automaker says new technical features will reduce fuel consumption up to 12% under current New European Driving Cycle test criteria.

The new unit is manufactured by Toyota Motor Industries Poland as part of a €150 million ($161 million) investment program by Toyota Motor Europe.

The naturally aspirated engine develops a maximum 110 hp and peak torque of 100 lb.-ft. (136 Nm) at 4,400 rpm. Compared with the outgoing 1.3L unit, it is 0.8 seconds quicker from 0-62 mph (100 km/h) at 11 seconds, while midrange overtaking speed from 50 mph to 75 mph (80 km/h to 120 km/h) improves by more than a second, to 17.6 seconds.

Toyota claims the new engine’s 38.5% thermal efficiency value is among the best on the market, an achievement it credits to years of hybrid powertrain work. This is reached by using a 13.5:1 compression ratio, adopting a cooled exhaust-gas-recirculation system and extending the variable valve timing operation so the engine can switch from the Otto to the Atkinson cycle to gain optimum efficiency in different driving conditions.

A Toyota-first water-cooled exhaust manifold is employed to wring out efficiencies at high-speed highway driving. Reducing the temperature avoids the need for mixture enrichment to reduce combustion temperature at any speed, improving both fuel consumption and exhaust emissions.

“The announcement reflects the fact that the engine has passed its development stage and we have yet to hear when it will be first fitted to new Yaris models,” a U.K.-based​ spokesman for Toyota tells WardsAuto.