Toyota boss Satoshi Ogiso says advances in battery, electric motor and petrol engine technologies mean the next Prius will be significantly more efficient
Matt Burt
28 August 2013

The next-generation Toyota Prius will usher in a substantially improved Toyota and Lexus family of hybrid powertrains, as well as a vastly improved chassis and interior refinement.

Toyota's main target with the next version of the Prius, which first went into production in 1997, is to improve on the 50mpg US combined average mpg (approximately 60mpg UK mpg) achieved by the current, third-generation model.

To attain this, it will use batteries with a higher energy density than those installed in the current Prius, as well as an electric motor that is smaller in size and features an improved power density and an internal combustion engine with a world-best thermal efficiency of more than 40 per cent – compared to the 38.5 per cent achieved by the 1.8-litre powerplant in the current third-generation car.

The current Prius electric motor provides four times the power density of the first iteration, and the next Prius's power density will be even higher.

Toyota Motor Corporation’s managing officer, Satoshi Ogiso, said: “These new hybrid powertrains will deliver significantly improved fuel economy in a more compact package that is lighter in weight and lower in cost.

“The performance of this new generation of powertrains will reflect significant advances in battery, electric motor and petrol engine technologies.

"It is part of Toyota’s larger strategy towards the electrification of the automobile, including plug-in hybrid, battery electric and fuel cell technologies. Toyota has a deep commitment to vehicle electrification and therefore, to advancing drive-battery technology."

Ogiso wouldn't be drawn on how much he expected the Prius's fuel economy would improve. He likened the difficulty of the challenge of making significant mpg gains to Usain Bolt shaving time off his 100-metre sprint world record, in as much that incremental improvements are more realistic.

The next Prius, which is expected to reach the market in two to three years, will also benefit from new mechanical underpinnings, said Ogiso, who was part of the team that started development of the original Prius back in 1993.

“To complement the substantial gains in powertrain development the next Prius will ride on a vastly improved chassis," he said. "It will feature the Toyota New Global Architecture (TNGA). It will have a lower centre of gravity and increased structural rigidity. This, along with many other improvements, will allow for beneficial gains in ride and handling agility and aerodynamics.

“Its interior will be roomier with significant refinements in design, layout and ease of operation, and it will introduce key advanced safety technologies."

Alongside the next Prius, Toyota is also developing a new Prius plug-in that can use cable-less wireless inductive charging between two coils, one placed on the ground and one in the vehicle. The Japanese manufacturer will begin verification of the system in Japan, the US and Europe next year. 

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Comments
10

29 August 2013

Significant improvements in powertrains and driving dynamics are welcome as long as they don't bring exaggerated prices.

29 August 2013

If Toyota can achieve a thermal efficiency of 40% from a petrol engine, then why bother with diesels?  And why is no other manufacturer producing an Atkinson Cycle engine, surely it can't be patented? 

29 August 2013

LP in Brighton wrote:

And why is no other manufacturer producing an Atkinson Cycle engine, surely it can't be patented? 

A lot of petrol hybrid cars use Atkinson cycle engines.  The Fords certainly do (just Google C-Max or Fusion hybrid and look at their technical specs).  I don't think that the Hondas currently use it but the Accord Plug-In is slated to have it.

 I would post links to the above information but Autocar thinks that by posting links I am a spammer!

29 August 2013

LP in Brighton wrote:

If Toyota can achieve a thermal efficiency of 40% from a petrol engine, then why bother with diesels?  And why is no other manufacturer producing an Atkinson Cycle engine, surely it can't be patented? 

The VW 1.9 litre pump Duse engine was advertised as having an efficiency of up to 43% many years ago. Many large marine and power plant diesels are over 50% efficient nowadays and are the worlds most efficient way of producing power from fossil fuels and bio fuels.

The current crop of cars fitted with Atkinson cycle engines are not really Atkinson cycle engines but ordinary otto cycle engines fitted with variable valve control in an attempt to replicate the benefits of an atkinson cycle engine without the required additional joint in the engines connecting rods plus other complications.

The easiest way to see how a true Atkinson cycle engine operates just look on Wikipedia.

maxecat

29 August 2013

I think that the forthcoming Jazz hybrid will be Atkinson cycle too.  As hybrid system costs continue to come down and efficiency goes up it is going to leave ever more complex diesels struggling to keep up.  Toyota made a gutsy move all those years ago and are really starting to reap the benefits.

Even my Gen 2 Prius has managed a solid 57mpg over the last 30,000 miles and there aren't many comparable automatic diesels that can top that.

29 August 2013

Thank you stavers and Clarkey for filling in my knowledge gap, I had no idea that other makers were pursuing the Atkinson Cycle. 

It would be interesting to know how well this type of engine would work in a lighter non hybrid application?  

 

 

29 August 2013

LP in Brighton wrote:

It would be interesting to know how well this type of engine would work in a lighter non hybrid application?  

 

The trouble with the Atkinson cycle is that it has lower torque than a regular petrol.  Also, in the Toyota case, it's been designed to have a low rev limit to allow the moving components to be lighter, reducing the amount of power available.

That all means that the electric motors are important to bridge the power/torque gap.  Without them, the Prius would be undriveable.

29 August 2013

Oilburner wrote:

LP in Brighton wrote:

It would be interesting to know how well this type of engine would work in a lighter non hybrid application?  

 

The trouble with the Atkinson cycle is that it has lower torque than a regular petrol.  Also, in the Toyota case, it's been designed to have a low rev limit to allow the moving components to be lighter, reducing the amount of power available.

That all means that the electric motors are important to bridge the power/torque gap.  Without them, the Prius would be undriveable.

 

Yes, and the Prius engine is effectively 'stuck in top gear' all the time - there is no way the amount of torque multiplication for the petrol engine can be varied in the Prius transmission.  The electric motor/generators make up this gap too.

13 May 2014
Thank You Very Much
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