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Daihatsu develops e:S Technology for 30 km/l in JC08 Mode; equivalent to 71 mpg US or 3.3 L/100km

Daihatsu, the minivehicle specialist in the Toyota Group, has developed “e:S Technology (Energy Saving Technology) that it says will be at the heart of production of future motor vehicles with high fuel efficiency, low prices, and resource-saving features. In the process of this development, Daihatsu overhauled all aspects of the engine, the transmission, and the body structure, to maximize energy efficiency and achieve almost a 40% increase in fuel efficiency comparison with the Mira 2WD/CVT without idle reduction functions.

Daihatsu will introduced the new technology in a fuel-efficient vehicle model due to be released in September this year. The company anticipates that it will be the only gasoline-powered vehicle delivering fuel economy of 30 kilometers per liter (equivalent to 71 mpg US or 3.3 L/100km) in JC08 mode. This new mini vehicle will have an entry price of less than ¥800,000 (US$10,200).

The main features of :S Technology include:

  • A new engine with maximized combustion efficiency and minimized energy loss. Combustion efficiency has been boosted through eight main improvements, including an enhancement in the compression ratio from 10.8 to 11.3 and the downsizing of the particles sprayed from the injector.

    The engine uses an i-EGR system. It applies the ion current combustion control, in which ions in the combustion chamber are used to identify the state of combustion, to EGR control. Through close control according to engine characteristics, EGR gas is fed in larger quantities to massively reduce the pumping loss.

    Mechanical loss has been minimized by combining 11 improvements, including a reduction in chain tension by cutting the chain width, a tension reduction in the piston rings and modification of the oil seal.

    An electronic throttle body made of a lightweight resin has been utilized. Coordinated control of the engine and the CVT using the electronic throttle is performed precisely according to the speed range to maintain a state of the highest efficiency, irrespective of the gear ratio in the CVT.

  • Thermal management. The layout of the bumper openings and air cleaner ducts has been optimized and the air flow route has been improved to implement thermal management and lower the temperature of the intake air into the engine. A decline in air intake volume resulting from volume expansion of the intake air is suppressed to boost the engine combustion efficiency.

  • Continuously variable transmission (CVT) with higher power transmission efficiency. Power transmission efficiency has been increased by combining eight improvements, including utilizing a high efficiency oil pump and lowering the CVT control pressure. The engine load has been lowered by optimizing the transmission gear ratio on the basis of increased power transmission efficiency, reduced running resistance and vehicle weight cuts.

  • The shell body has been streamlined without impairing the body rigidity necessary for safety and onboard comfort. This has achieved a weight reduction of approximately 30 kg while maintaining vehicle length. As many components as possible have been made straight in form to reduce reinforcements.

    Weight reduction is achieved by redesigning every interior part. For example, a new structure sheet frame is utilized and the thickness of the instrument panel and door trims is reduced. The weight of the CVT unit for idle reduction is cut by utilizing a thinner-walled CVT case, an aluminum oil pump cover and an aluminum planetary carrier, and by introducing integrated molding for the secondary sensing gear and the piston.

  • Running resistance lowered. Rolling resistance has been lowered by utilizing low rolling resistance tires with new tread rubber, and by enhancing the drive parts. A CAE simulation and a wind tunnel test were conducted in the design phase to improve the forms of the front corners and slow the underfloor flow. Air resistance has thus been reduced.

  • Energy Management. The new car will be the first CVT vehicle equipped with the pre-stop idle reduction function, Daihatsu says. It applies a brake and stops the engine when the vehicle speed is 7 km/h or less to increase the idle reduction duration and improve fuel efficiency.

    Dedicated components for idle reduction systems have been decreased to achieve weight and size reductions. An ECU for the CVT has been incorporated into the idle reduction computer integrated with auxiliary power supply to prevent the navigation system from being reset upon engine restart.

    The function of converting the kinetic energy of the slowing vehicle into electric energy with an alternator and feeding it back into the battery has been enhanced. The power output of the alternator at the time of vehicle slowdown has been increased and the charge acceptance properties of the battery have been improved to substantially cut power generation from the alternator at the time of normal operation and acceleration, and to reduce the burden on the engine.



Hp? Weight? Torque? Displacement.. auto stuff?


Never mind what hp, torque, displacement etc. It is a mini car designed for city use and the comparison was done with other mini cars.

It is amazing to see was diligent applied engineering can achieve and could have realized decades ago. A mini car, made in Germany in the late 1950's, achieved almost the same level of efficiency.

Is it possible to achieve close to 100 mpg with this approach pushed to higher limits? That would about 1/7 the fuel consumption we get with out current gas guzzlers. It could drastically reduce crude oil imports for USA.


Apparently this press release is the first time you have heard, or thought, of the optimization of all parts.

Why do you assume this is not done on every car, by every manufacturer - and has been for decades?

What do you think the legions of designers do?

All this says is NOTHING BUT fluff.
Maybe there is something to this brainwashing theory after all.

And yes, what is the “Hp? Weight? Torque? Displacement.. auto stuff”?


The idea is to design and built a vehicle to effectively transport a few person (often one only) from point A to point B. It's not a question of hp, 24-foot long boats, championship acceleration, 400 + kpm etc.

That's what the majority forgot (willingly or purposely) how to do. We have been so deeply brain washed in the last 60+ years that many of us still believe the we really need 4+ton Hummers to drive to work and back. Even many of our kids strongly believe that they need a monster gas guzzler to drive to school with.

We have to be de-programmed before we will accept to drive common sense size vehicles. Extended financial crisis (a strong possibility?) and USD 10/gal/fuel (another strong possibility) may help the process.


The problem is that they dont price cars by the lb, very often a small 2 seater with a hyperefficient engine is as expensive as a 5 seater with 4 doors, guess which one people prefer?

Roger Pham

" ...40% increase in fuel efficiency comparison with the Mira 2WD/CVT without idle reduction functions." That's not good enough for you? Daihatsu is now owned by Toyota, and Toyota is the leader in fuel efficiency technology for the over a decade or more. Other car mfg's have been trying to catch up.

They don't price cars by the lb? You may be right!

"This new mini vehicle will have an entry price of less than ¥800,000 (US$10,200).
Let's say that this new mini vehicle weighs 2000 lbs, so by the lb, a 4000-lb vehicle ought to cost ~$20,000 entry-level.

But look around, lo and behold, 4000-lb class of vehicles usually cost ~$30,000 more or less. So, mini or micro vehicles in this case COST LESS per lb than their bigger counter parts.

Too bad, gasoline is still priced by the gallon. A typical fill-up in a 4000-lb -18-mpg vehicle will cost $60-70 USD. Ouch!!! A real pain in the pocket book!


I don't hav any objection to " ...40% increase in fuel efficiency" - I hope it comes to pass - this is just a press release.

I also don't object to a "Smart" class car seling for US$10,200, nor do I assume people will flock to it even at such a great price; but I hope I'm wrong.

The quality, features and specifics will make the difference.

You should be glad gas is priced by the gallon - rather than by the tank. Lest gas guzzler be reborn.


Right on Roger.


ToppaTom, "Hp? Weight? Torque? Displacement.. auto stuff?" refers to the specifications needed and expected in an automobile article.


I already pay upwards of $70 for a full tank of fuel (18.4 gallons, $3.979/gallon). OTOH, with my usual local driving I use less than 1 tank/month.


Peel P50 could do 100 mpg in the 70's. tHat weas very small (worlds smallest car) so could only car one person. Lets see how this compares.


This is a 4 seater Kei car of a class that they really only have in Japan.
It weighs 700 Kg.
It is a real car made by a real company and will be out in September (in Japan presumably).
Here is an article from 2 years ago about the concept car which presumably gives a hint as to what the production car will be like.

and remember, it is a city car, not a motorway cruiser.

I say well done to Toyota and Daihatsu.

william g irwin

Just as a point of interest - an 'outside the box' point - has anyone priced a street legal golf cart lately? Talk about low tech. Imagine a topless version of one of these Daihatsu bugs with turf tires! 'Auto start' comes standard now.

HarveyD need to downgrade what others are doing and we cannot do. With our high labor cost, the local unit assembly cost is much the same for one or three ton units. That's why we have so many 3 ton units.



Should read....that's why we build so many $30+K 3-ton units and so few $10K, one-ton units.


Wikipedia says the concept car was 660cc. So 71MPG is interesting, but not very relevant. What would be nice is to understand what a 1.4l high compression, start-stop engine could produce with a 2000lb Toyota Yaris equivalent. That car could be important to the US fleet.

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