• Sep 10th 2010 at 2:00PM
  • 14
Lexus CT 200h aerodynamics – Click above for high-res image gallery

Aerodynamic performance is getting increasingly important for every new vehicle as automakers strive to improve fuel efficiency and reduce noise. That's especially true for hybrid vehicles as manufacturers aim for MPG bragging rights – and it's the main reason the Toyota Prius looks the way it does.

The next hybrid-only model from Toyota is the new CT 200h from Lexus and, while it doesn't feature the overtly low-drag styling of the Prius, it's spent its fair share of time in the wind-tunnel and on the CFD workstation screen. The smooth under-body and thoughtful tweaking of the bodywork around the front and where the air-flow separates has resulted in a drag coefficient of 0.28. The back end of the greenhouse has been carefully tapered and augmented with a spoiler extending back from the roof over the rear glass. Lexus claims that's the lowest figure in the compact luxury class. The production CT 200h will debut at the Paris Motor Show soon and goes on sale next year.



[Source: Lexus]

PRESS RELEASE

LEXUS CT 200h ACHIEVES AERODYNAMIC EXCELLENCE
  • Full hybrid Lexus CT 200h most aerodynamically efficient car in its class, with Cd 0.28 (coefficient of drag)
  • Detailed treatment of upper and lower body to achieve smoothest possible airflow
  • Aerodynamic quality supports fuel efficiency, ride comfort, handling and high-sped stability
The aerodynamic quality of the new Lexus CT 200h is fundamental not only to supporting the efficiency of its full hybrid powertrain, but also to the quality of its handling, ride comfort and stability at high speed.

Lexus engineers used extensive computer aided design and wind tunnel testing to ensure every detail of the car's body – including the underneath – contributed to achieving the smoothest possible passage through the air, while retaining distinctive, contemporary styling. Their success is reflected in the lowest coefficient of drag in the small luxury car class – Cd 0.28.

Every aspect of the upper bodywork has been detailed for airflow management. The deep front bumper, sharply sculpted front air dam, optimised bumper corner angles and door mirrors styled like those of the ultra-exclusive LFA supercar, have been designed to smooth the flow of air over the front and down the sides of the vehicle, minimising turbulence in the wheelarches.

The flow of air away from the rear of the CT 200h is carefully controlled by the tapered shape of the cabin sides, a deep roof spoiler, aerodynamic fins at the corners of the rear windows and the sharp, near-vertical junction of the rear wing and bumper.

Equal attention has been paid to underbody airflow management, minimising the vehicle's coefficient of lift to secure optimum fuel efficiency and handling stability.

The aerodynamic underbody elements include a front lower absorber, under covers for the engine, centre floor, tank side and rear floor, front and rear wheelarch spats and rocker mouldings. Diffuser fins have been added to the front under cover, and even the installation of the main exhaust silencer and the shape of the rear bumper cover have been designed to create the smoothest possible airflow.

The production-ready full hybrid Lexus CT 200h – a new gateway model for the Lexus range – will be unveiled at the Paris motor show on 30 September, with UK sales scheduled to start in early 2011.


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 14 Comments
      • 4 Years Ago
      although let's invoke the heinous Tatra. try the GM Utralite instead. or Loremo
      • 4 Years Ago
      When you think about it, 0.28 is pretty good for a hatch. The Volt drops in at 0.26 and it's a sedan, and the Prius is 0.26 as well with it's Kammback design.

      Looks like it could really benefit from a better diffuser path in the rear...that little hump sticking down from the bumper looks like it's creating a separate area of low pressure that doesn't need to be there...
        • 4 Years Ago
        Still, it's damn good for a car that doesn't totally look like an egg with a chopped off butt.

        They did a good job of hiding the kammback factor.
      • 4 Years Ago
      Don't forget that its drag ratio x frontal area though. That is one of the main reasons that my horribly unaerodynamic VStrom gets 55mpg, its low frontal profile.

      Length actually improves aerodynamics, all else equal, so I'd love to see a low, narrow, and long passenger vehicle. Wide enough for two front shoulder to shoulder, two rear, and a long tapered hatchback rear trunk. Narrower cars are less stable, but a low height lowers the CG while reducing the frontal area even more, balancing things out.
        • 4 Years Ago
        although let's invoke the heinous Tatra. try the GM Utralite instead. or Loremo
        • 4 Years Ago
        The added length is to compensate for reduced width so that it still has a decent internal volume.

        ME major at UT, books all say that a long cylinder has a considerably better drag coefficient than a short one. I'm no genius, but that was first year material, heh! Skin drag is insignificant next to pressure drag.
        • 4 Years Ago
        Actually, here is something you may be better able to relate to.

        Go to a Mercedes dealership and sit in a Smart Fortwo. There is a gap between the two seats in this car and a center shifter, but its not huge. Then imagine another two seats just like the front behind you, and a large hatchback trunk area. Basically, a 60" wide station wagon.

        Now just imagine the hoodline lowered and a more reclined lower seating position such as in the Corvette.

        Combined the width and height reduction greatly reduces the frontal profile of the vehicle, with great aerodynamics, while still having room for four adults and groceries. There is no technical reason this can't work, just consumer preference such as women who prefer to sit up high to "feel" safer. =)
        • 4 Years Ago
        Sorry to SPAM, but EUREKA! There is actually a vehicle somewhat similar (actually larger) to what I am describing... made back in the 1930s:

        Google Tatra T77. It was marketed as "the car of the future" with a low frontal profile and drag coefficient of 0.212.

        Thats right, WWI era technology large 6-seater blowing away our supposedly ultra-aerodynamic SUVs of today.
        • 4 Years Ago
        Ducman69, nice to see someone else who has some understanding.
        reclined seating, no center console, can even raise the feet to ass height. and of course even the Cd can easily be much better than this unimpressive .28
        the difference is dramatic. and easily achieved. but carmakers and intelligent design.. so far unlikely.
        • 4 Years Ago
        "Length actually improves aerodynamics, all else equal"

        Pretty sure it doesn't. More surface area = more skin friction = more drag. More length also increases weight.

        Now if that increase in length happens to drastically reduce the turbulence aft of the vehicle, then you might see significant gains. But you still have to take into account the added surface area and weight, because those are going to offset some of the gains you've made by reducing form drag.
        • 4 Years Ago
        Hmm, looks like you're right on the basic principle. However, I still think there's a limit where increasing the length doesn't help you anymore, and begins to hurt you skin-friction and weight-wise.

        http://www.roymech.co.uk/Related/Fluids/Fluids_Drag.html

        On the bottom of that page, it outlines the Cd of different L/d ellipses...and you'll see that for low L/d ratio, you're right. But as you go to larger L/d ratios, the effect tapers off. I think for most vehicles, you're probably already long enough to the point where it's not going to help you much to increase the overall length unless you're doing so specifically to reduce form drag.
        • 4 Years Ago
        Have you ever flown in any general aviation aircraft?

        They are almost all laid out that way (2 front, 2 back, no divider) since the 1930s, simply because its aerodynamically efficient.

        Its not really cramped (even cross-country fliers are designed like this), just different not having a large center console or seat for a third person in the back. The amount of shoulder and leg room for each individual is normal.
        • 4 Years Ago
        If that's what you want you should buy the Aptera. For the rest of us Joe Sixpacks that kind of car isn't what we want. We'd prefer to NOT ride cramped up in our coffin. I'll take the Plug-in Prius please.
      • 4 Years Ago
      Now scale it down to about 70%.
    • Load More Comments
    Share This Photo X