New bonsai 100 bhp Hybrid Synergy Drive for Toyota Yaris


February 6, 2012

The 1.5-litre Atkinson cycle petrol engine weighs 16.5 kg less and is 10 per cent smaller than the 1.8-litre unit used in the Prius and Auris.

The 1.5-litre Atkinson cycle petrol engine weighs 16.5 kg less and is 10 per cent smaller than the 1.8-litre unit used in the Prius and Auris.

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The littlest Toyota, the Yaris, is about to become hybridized too, and the engineering job to reduce the size of its Hybrid Synergy Drive system for the diminutive car is worth a look. The hybrid engines from the larger Toyotas such as the Prius and Auris were too large for the Yaris as they would have eaten into passenger space, and as the car's catchcry promotes a "small outside, big inside" character, a new powerplant was prescribed.

Toyota was obviously very keen to bring hybrid drive to the tiny Yaris, which is sold as the Vitz in some markets and the Diahatsu Charade in others.

The size of the motor has been reduced by 20 per cent and thePCU12 per cent, compared to those in Auris Hybrid; and the trans-axle has shed 11kg and is six per cent shorter.

The system uses a new 1.5-litre Atkinson cycle petrol engine that weighs 16.5kg less and is 10 per cent more compact than the 1.8-litre unit used in the Prius and Auris.

Likewise, other major components such as the electric motor, power control unit and trans-axle were also made lighter and smaller, but the power has remained robust at 99 bhp (74 kW)

The packaging challenge also demanded careful thought about the size and location of the nickel-metal hydride battery pack and the fuel tank, in order to minimize the impact on cabin space for rear seat passengers and the size of the boot. Both are positioned under the rear bench seat, which means the car's load space capacity, and rear passenger space is unaffected.

There have been no emission figures announced for the new power train yet, though the press release was carefully worded, claiming the Yaris hybrid would deliver "class-leading CO2, NOx and particulates emissions, together with excellent fuel consumption."

Most importantly, the hybrid Yaris will go on sale mid-year with very low fuel consumption, emissions, and ownership costs.

About the Author
Mike Hanlon Mike grew up thinking he would become a mathematician, accidentally started motorcycle racing, got a job writing road tests for a motorcycle magazine while at university, and became a writer. As a travelling photojournalist during his early career, his work was published in a dozen languages across 20+ countries. He went on to edit or manage over 50 print publications, with target audiences ranging from pensioners to plumbers, many different sports, many car and motorcycle magazines, with many more in the fields of communication - narrow subject magazines on topics such as advertising, marketing, visual communications, design, presentation and direct marketing. Then came the internet and Mike managed internet projects for Australia's largest multimedia company, (Australia's largest Telco), (Australia's largest employment site),,, and a dozen other internet start-ups before founding Gizmag in 2002. Now he writes and thinks. All articles by Mike Hanlon

Not a plug-in. Have been a Toyota buyer for many years but if they don\'t get off the mark on this will be buying something like the Nissan Leaf or the Chevy Volt as my next vehicle.

Max Kennedy

\"The littlest Toyota, the Yaris\"


The IQ and the Aygo are both smaller than the Yaris, guys...

Keith Reeder

Curb weight? Drag? MPG? Price? Is it too much to ask for the important stuff?


Sounds like a Prius C/Aqua to me!

David Alcantaro

You really do not need a hybrid system for the Yaris. Just modify the aerodynamics. I modified my Echo with an air divider in the front, drilled holes in the back bumper, covered the back wheels etc. and have 50 mpg. I cut plastic from plastic containers and that was enough.

Adrian Akau

I hoped they\'d solve this problem - It fits me (6\' 4\") like a glove - maybe the price will be right, too.

Jansen Estrup

@ Adrian A ___ You can modify most small cars for better mileage with the techniques you describe, but hybrid systems give such econoboxes an advantage for those not ready to buy a new car every five years or so. The hybrid system unloads the small engines that can deliver good mileage so that they last longer. I had a 1.5 liter five passenger car that was good for 39mpg in the nineties but was burned out far sooner than a 2 liter Toyota whose highway rpm's were 1000rpm lower. Piston speeds and acceleration stresses kill small engines. The acceleration help and ability to stop the engine at every lift of the accelerator pedal mean that that engine will go the distance a much more expensive car's overbuilt engine can go. To say nothing of the reduced brake wear on the typically skimpy small car brakes.

Paul Gracey
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