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Daimler and Mercedes-Benz Japan made available the most up-to-date Smart car automotive technologies for the Japanese market. Beginning this month all Smart cars purchased in Japan will be equipped with the MHD technology as standard equipment. This inventive technology is christened MHD or "micro hybrid drive.”

The MHD drive has been available in Europe for several months, is now the "standard engine" for all Daimler and Mercedes-Benz's 2009 models, except for here in the good old U.S.A.!

The Smart ED: electric drive Smart car, 62mph (0-30mph in 6.5 seconds), 72 mile (115km) range, Smart claims it has a 300 mpg (118.9km/liter) equivalent consumption – that amounts to a saving of up to 80% compared to the Smart ForTwo.

Mercedes-Benz Brings Idling Stop Function to Smart Fortwo

Mercedes-Benz Japan Co Ltd launched Dec 2, 2008, the "Smart Fortwo Coupe mhd " and the "Smart Fortwo Cabrio mhd," both of which are equipped with an idling stop function called "micro hybrid drive (mhd)," in Japan.

In this article, I will explain the impression that I got from the test-drive event for the press as well as technological features of the vehicles.

I got into the car and turned the key to start the engine. At this point, the idling function is activated if you press the "ECO" switch located in front of the shift lever on the center console.

When the vehicle is being starting, the orange-colored ECO lamp to the right of the meter panel is blinking and idling stop does not occur because the water temperature is low. Once the water temperature reaches 60°C, the ECO lamp lights up in green, indicating that the idling stop function is available.

The engine shuts down when the brake is applied and the vehicle speed drops below 8km/h.

It does not stop when the driver releases the gas pedal and the vehicle coasts to a speed below 8km/h because the engine shuts down by detecting the brake pedal operation.

When the engine stops detecting the application of the brake pedal, it will restart in 0.35 seconds after the brake pedal is released, even if the vehicle speed does not reach zero.

This function could be a little annoying when you need to frequently switch between the brake pedal and the gas pedal, for example, in a stop-and-go driving. The engine stops as soon as the brake is applied and starts soon after the release of the pedal, transmitting uncomfortable vibration caused by the starting process to the driver.

You can turn off the ECO switch if the engine stop function bothers you in a slow-moving traffic jam or in a parking lot. With the mhd, the fuel consumption in the 10•15 mode was improved by 24% to 23.0km/L compared with that of the previous models. The CO2 emissions are 101g/km.

In order to incorporate the idling stop function, Mercedes-Benz Japan used an integrated starter-alternator and a high-capacity lead secondary battery. Also, the ECU (electronic control unit) was improved.

The starter motor was removed and replaced with a belt-driven starter/alternator to reduce the vibration generated at the time of starting the vehicle.

As for the lead battery, the company employed the AGM (Absorbent Glass Mat) type, which uses a glass mat as a separator and does not require refilling of water. The battery capacity was enhanced from 45Ah to 60Ah.

The prices are ¥1.84 million (approx US$20,238) for the Coupe mdh and ¥2.13 million for the Cabrio mhd (including tax), which are ¥ 80,000 higher than previous models . However, the "idling stop vehicle subsidy" of up to ¥35,000 is provided by the Energy Conservation Center, Japan, according to Mercedes-Benz Japan.

Source: Nikkei Automotive Technology by Tatsuhiko Hayashi

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