Japan’s long-term diet plans
July 7, 2008 by George Skentzos
Honda is becoming slightly obsessive when it comes to improving fuel efficiency and cutting carbon emissions in its new cars, taking a pain-staking approach to weight reduction where every gram counts.
Kohei Hitomi, chief engineer of Honda’s redesigned Jazz, took apart a demonstration model to reveal where the excess steel in spot welded seams had been shaved off.
But it’s not just Honda who is putting itself on a diet, with Nissan, Toyota and Mazda all setting weight reduction as a priority for all new models in the pursuit of economy.
Nissan has set the benchmark, aiming to make its entire fleet at least 15 percent lighter on average by 2015 while Toyota is aiming for a 10 percent weight loss in its mid-sized cars by 2010. Finally, Mazda aims to trim 100kg from new vehicles starting in 2011.
“Generation by generation, we usually have to add more weight because of new safety regulations or emissions matters,” says Nissan’s Mitsuhiko Yamashita, head of Nissan r&d. “But our philosophy is not to increase vehicle weight. That’s why I’m proposing the 15 percent reduction.”
Now obviously whilst shaving grams off here and there is thoughtful, it will certainly take more than this to achieve each company’s goals.
To generalise the process, the Japanese carmakers will focus on three key areas: using lightweight materials, developing more efficient engineering and design methods and finally decreasing the overall size of vehicles.
“Unless you really reduce weight, you will never be able to reduce auto emissions. We therefore intend to bend over backward to achieve this,” Toyota R&D chief Masatami Takimoto says.
The Prius is getting special attention from Toyota, with the next generation featuring a motor one-sixth as heavy as the first generations and a battery only half as heavy.
Cost is the obvious constraint, with materials such as aluminium, magnesium and carbon fibre costing far more than steel, however spiralling steel costs are whittling away the metal’s price advantage – as seen with the Tata Nano.
The Japanese diet has already begun, with phrases like hybrid and power-to-weight ratio overtaking traditional performance adjectives like horsepower and torque for cars like the Honda CR-Z, Nissan FF Coupe and Toyobaru.
Print it: 
Reducing the weight of the vehicles themselves is laudable, but in the face of increasing weight of the occupants it would seem to be counter-productive. It’s a massive (excuse the pun) challenge to make lighter vehicles which can handle the vastly increased inertia of overweight occupants in a crash. Has anyone seen a 140kg crash-test dummy?
Captain M…..thats something I didn’t think of when I chose to make comment…..but you are soooo correct ;)
It certainly is an exciting and highly dynamic change we are seeing in the auto industry. Those that thought a big fat heavy guzzler would still be a good thing (aka Ford/GM) are now wiping the egg off their faces….while all those little buzz-box Japanese makes are once again favourable again.
The things that we will see in the next few years will be def interesting and as manufacturing materials that were once expensive give rise to alternatives never before thought possible.
Of course we will have to wade through all the buzz and hype to avoid wasting our time and ending up with another short lived model that will only become famous via some article in the press…”What were they thinking?”
But efficiency is def the name of the game now….
Its about time.
But i think you’ll see a few things that aren’t so great as fancy pants welds or carbon fibre cup holders.
Car companies will rip out sophisticated suspensions and use “ye old” world torsion beams etc. Of course, they’ll site it as weight saving technology. When in fact its nothing more than cost cutting.
The Corvete uses “ye olde” suspension technology and it goes around the ‘ring pretty quick. Imagine what it could do with modern suspension.
The Honda Civic type R tested by Top Gear last night has had the independent rear suspension replaced with a lighter, cheaper, poxy beam axle like you would find on a Barina.
The result is a car that screams its head off and doesn’t handle, whereas the previous model used to scream its head off but did handle well.
Oh, and if Honda wants to bleat about efficiency, it could start with the honda.co.uk web site, which is a pox of a thing to browse through, waiting for things to load.
Honda can switch to using aluminium engines and aluminium car bonnets, to reduce weight.
Tony, where the hell have you been? Honda (and most others) have been using aluminium engines for the last 20 years or more. Even Honda’s European-market diesel is aluminium.
The corvette uses a transverse leaf. I think but cant be bothered to look that it still runs multilinks.
Besides, its rubbish on roads. Thats the trade off you get with compromised engineering.