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Mazda to debut next-generation midsize sedan diesel concept and CX-5 SUV with SKYACTIV Technology at Tokyo Motor Show; new push on clean diesels in Japan market

Takeri
The Takeri diesel concept. Click to enlarge.

Mazda Motor Corporation will showcase the global premiere of the Mazda Takeri next-generation midsize sedan concept car at the upcoming 42nd Tokyo Motor Show. Mazda will also hold the Japan debut of the new CX-5 crossover SUV. Both vehicles are equipped with the full array of Mazda’s SKYACTIV Technology (earlier post).

The TAKERI features the new SKYACTIV-D clean diesel engine, as well as Mazda’s idling stop system i-stop, and a new regenerative braking system. The regenerative braking system converts kinetic energy to electricity during deceleration, stores it in capacitors and then uses it to power the vehicle’s electric equipment, thereby reducing load on the engine and saving fuel.

Regen
Mazda regenerative braking system. Click to enlarge.

Mazda says that the regenerative braking system represents Step Two of its Building Block Strategy. After renewing existing technologies, such as engines and bodies, Step One of the Building Block Strategy is idling stop technology (i-stop), Step Two is regenerative braking technology, and Step Three is electric drive technology (hybrid, etc.).

CX-5. The Mazda CX-5 is the first of Mazda’s next generation products that will feature the complete range of SKYACTIV Technology, including powertrain, body and chassis. The CX-5 will be Mazda’s first production model equipped with the new SKYACTIV-D clean diesel engine.

The CX-5 will also be the first passenger vehicle in Japan to combine a clean diesel engine with an idling stop system. It will deliver maximum torque of 420 N·m (309 lb-ft), more than some 4.0-liter V6 gasoline engine vehicles, and the best fuel economy of any SUV on the Japanese market at 18.6km/L (43.8 mpg US, 5.4 L/100km) on the JC08 mode test cycle.

CX-5 customers can also select the direct injection SKYACTIV-G gasoline engine. Equipped with the new SKYACTIV-DRIVE automatic transmission and i-stop idling stop system, SKYACTIV-G FWD models achieve 16.0 km/L (37.6 mpg US, 6.25 L/100km) on the JC08 mode test cycle, with Mazda in-house measurement.

Mazda’s diesels. Mazda Motor Corporation will progressively introduce clean diesel vehicles to the Japan market, beginning with the new Mazda CX-5 crossover SUV in spring 2012, powered by the SKYACTIV 2.2-liter diesel engine. The SKYACTIV-D 2.2 is the first passenger vehicle diesel engine to pass Japan’s Post New Long-Term Emissions Regulations without the need for NOx aftertreatment technology. Although popular in Europe, current clean diesel vehicles have struggled to gain traction in Japan because they require expensive NOx aftertreatment technology to meet the exhaust gas regulations.

Mazda says that its diesel customers in Japan will be able to enjoy the price advantage of diesel over gasoline, approximately twice as much torque as similar sized gasoline engine vehicles, and 30% better fuel economy. Mazda expects that its clean diesel vehicles will become a core part of its product lineup in Japan.

Mazda has also redeveloped its unique idling stop system, i-stop, for use with the SKYACTIV-D 2.2 engine. Unlike other diesel engine stop-start systems that require two engine cycles to restart combustion, i-stop restarts in a single cycle by careful positioning of the pistons as the engine stops. At less than 0.4 seconds, i-stop achieves what Mazda characterizes as the world’s fastest diesel engine restart time. The result is a smooth restart that is barely noticeable, as well as an improvement in fuel economy.

Comments

Peter_XX

Again, we could give our recognition to Mazda for meeting stringent NOx emission limits with their SKYACTIVE diesel engine without aftertreatment. In a recent article, we saw that Hyundai also meet Euro 6 without aftertreatment. The Hyundai engine mainly rely on low-pressure exhaust gas recirculation (EGR) for NOx reduction (they are not first with this technology), while the Mazda engine achieves Euro 6 via low compression ratio and low power density (anti-downsizing). Both options cost much less than aftertreatment alternatives (e.g. urea-SCR or NOx-adsorber catalyst).

In the debate about the recent article about the Mazda SKYACTIV engine, the potential for downsizing was discussed. I tried to prove - but was not very successful in convincing everybody on his forum - that there would be further gain in fuel consumption if the engine was downsized and the specific power and torque was raised to compensate for the reduced size. Now, there is no need to debate this further. In an article in the MTZ journal, Mazda showed the (substantial) potential for downsizing. The rationale for not doing that was the corresponding increase in NOx emissions. It is well-known that NOx emissions increase at high load when conventional high-pressure EGR is used. Now we also know that Mazda is not using low-pressure EGR, which is particularly effective for NOx abatement at high load. As said, the mentioned Hyundai engine uses low-pressure EGR for meeting the Euro 6 NOx limit and this could be applied to the Mazda engine as well.

It was interesting to see the improvement of the start/stop system in addition to all the other information we have received. However, I would still like to see absolute numbers on fuel consumption and efficiency on this engine. All diagrams provided by Mazda so far are only relative, i.e. without any absolute scale on the y-axis.

Finally, we could draw the conclusion that a combination of, for example, advanced combustion (e.g. Mazda SKYACTIV), low-pressure EGR (e.g. Hyundai, Renault) and aggressive downsizing (e.g. BMW and Mercedes) could give a significant contribution to further reduction of fuel consumption. We do not have to invent any new technology or even increase the cylinder pressure capability (with corresponding weight increase) to do that and the marginal cost would be low. In fact, the cost might even decrease somewhat due to the use of a smaller engine. Needless to say, a cost-effective mild hybrid system could extend this potential further.

http://www.greencarcongress.com/2011/10/hmg-20111019.html

http://www.greencarcongress.com/2011/08/skyactiv-20110804.html

Dollared

Totally agree, Peter. The 50 MPG, 1750kg mainstream vehicle is 5-7 years away, probably with mild hybrid or KERS. And if regulations forced vehicles toward 1500kg, we could do it with ICEs with start/stop and no more.

Peter_XX

@Dollared
Well, you could say that the BMW 520d EDE (Efficient Dynamics Edition) is almost there already. Thanks to lightweight materials, it weighs “only” 1 695 kg. The fuel consumption is 4.5 l/100 km and the corresponding CO2 emissions are 119 g/km. This is equivalent to 52 mpg diesel and 47 mpg in gasoline equivalent mpg (US gallons in both cases). Volvo V70 Drive is another example of a car with similar fuel consumption. However, this car has a 115 hp 1.6-liter engine. In contrast, the BMW has a 2-liter engine rated at 184 hp / 380 Nm and accelerates 0-100 km/h in 8.2 seconds. For those who want more power, there is a twin-turbo version of the engine at 218 hp / 450 Nm and 0-100 km/h in 7.0 s. However, then the fuel consumption jumps up to 5.0 l/100 km for the manual transmission and 4.8 l/100 km for the automatic transmission (note the lower FC for the AT). Surprisingly, the 520 EDE is not (yet) available with an automatic transmission. It will be interesting to see the fuel consumption of a Mazda car of comparable size and weight.

Of course, none of these cars are available in the USA.

DFGeneer

@Peter XX
Those numbers you cite are irrelevant. They are obtained through NEDC test cycle which is 30-50% away from the real world numbers.
A quick search in a fuel economy database shows 2010-2011 BMW 520d has average consumption of 6.76 L/100 km (35 US mpg). 50% off from 52 mpg.

http://www.spritmonitor.de/de/uebersicht/6-BMW/38-5er.html?constyear_s=2010&exactmodel=520d&powerunit=2

Carl

@ DFGeneer

That may be true, but the USEPA 5-cycle test is nearly that unrealistic in the other direction.

A study recently published by Oak Ride National Laboratory (Lin, Z., and Greene, D. "Predicting Individual Fuel Economy." SAE Technical Paper #2011-01-0618, © 2011) calculates that the 5-cycle UNDERESTIMATES real-world mileage of diesel LD vehicles sold in the U.S. by about 25%, gasoline vehicles by about 20%, and hybrids by about 10%.

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