Best tank on my dsl smart car

[ma4t]

Totally insane. I can't wait for those to be available in the US on a wide scale.

m

[Mike T]

smart fortwo cdi hybrid drive (prototype)
Courtesy DaimlerChrysler Media Services

The combination of an electric motor and a combustion engine makes the smart fortwo even more economical and environmentally friendly than ever. The hybrid concept reduces consumption and emissions for both the diesel and the petrol version by around 12 percent. For example, the standard consumption (NEDC) of the smart fortwo hybrid drive diesel is reduced from 3.3 litres to 2.9 litres per 100 kilometres. Carbon dioxide emissions fall from 88 to 77 grams per kilometre. This means that the CO2 champion is setting new standards for the "three litre" car. No other diesel car is more fuel-efficient and climate-friendly.

The smart fortwo hybrid drive has a 33 kW/45 bhp combustion engine and a 20 kW/27 bhp electric motor that is driven by a nickel hybrid battery (1 kWh). Both motors can work together or separately. This strategy leads to a double advantage. The exclusive use of the electric motor enables fuel-saving and completely emission-free driving in urban traffic i.e. zero emissions and no noise. The combined use of both motors provides for a considerable increase in power and torque. In figures, this means that the combustion engine delivers power of 33 kW/45 bhp and maximum torque of 110 metres, whilst the electric motor has power of 20 kW/27 bhp and maximum torque of 50 metres. Together, these add up to an exceptional 53 kW/72 bhp power pack. The torque interruptions when changing gear, especially when changing from first to second gear, are compensated by simultaneous use of both drives. This enables the smart fortwo hybrid drive to accelerate from zero to 100 km/h approximately four seconds faster than the smart fortwo cdi. In this way, the hybrid concept offers a unique combination of driving fun, economy and environmental friendliness.

All new components have been integrated in the existing smart cable harness and databus architecture. The electric motor is connected to the axle drive. The battery is housed under the driver's seat and is charged via the motor and by recuperation of the braking energy. This means that the hybrid drive is a fully independent system.

The most important technical data on the smart fortwo hybrid drive at a glance:

Cylinders/valves R3/2 valves per cylinder
Engine capacity 799 cc (diesel)
Bore/stroke 65.5 x 79 mm (diesel)
Rated output 33 kW/45 bhp combustion engine 20 kW/27 bhp electric motor combined: maximum 53 kW/72 bhp
Max. torque 110 Nm at 2,000-2,500 rpm (combustion engine)
50 Nm (electric motor)
0-100 km/h 15.8 s
Maximum speed 135 km/h
Fuel consumption* 2.9 l/100 km (diesel)
Fuel saving approx. 12 %
CO2 emissions 77 g/km (diesel) 0 g/km (when the electric motor is exclusively used)

*NEDC

2.9 L/100 km is the overall fuel consumption figure in EC cycle tests, equivalent to 81 US MPG overall average. Let's hope this is produced and sold in North America....

[Erdrick]

Congratulations. That is pretty amazing, as in REALLY amazing! Basically with no mods, being able to break the 100 barrier. Just think what you could do if you now started to work on car, and kept your awesome driving technique in place...!

[Lug_Nut]

"Rated output: 33 kW/45 bhp combustion engine, 20 kW/27 bhp electric motor,
combined: maximum 53 kW/72 bhp
Max. torque: 110 Nm at 2,000-2,500 rpm (combustion engine), 50 Nm (electric motor)"

The italics are mine. That type of addition works only if the peaks coincide. At what rpm is the electric motor's peak torque? If it has 50 Nm torque when the diesel is turning between 2k and 2.5k, then the addition is correct.

[omgwtfbyobbq]

Don't electric motors have flat torque curves?

[Bill in Houston]

It is highest at 0 rpm. Not sure how quickly it drops off... I.e. is it relatively flat or does it drop precipitously.

[GasSavers_Antoine]

Originally Posted by Erdrick

Congratulations. That is pretty amazing, as in REALLY amazing! Basically with no mods, being able to break the 100 barrier. Just think what you could do if you now started to work on car, and kept your awesome driving technique in place...!

Well, it is just around 50% over manufacturer's declared fuel consumption. Some people here have done much better, like CO ZX2 recently, with + 239.5% over EPA.( His effort deserve much more merit). The fact is this light car by itself is a low burner with its small efficient diesel engine.( I am lazy, I buy the economy instead of making it). The 50% over EPA is done with basic driving techniques of low constant speed in high gear and acute control of acceleration, deceleration, anticipation of geographycal relief and traffic pattern.

The basic car is efficient but it is difficult to improve by a high percentage. More advanced driving techniques like P&G or EOC or WOT seem impossible with this car. The semi-automatic transmission doesn't allow lower speed. EOC is impaired by the fact the car cannot be restart without stopping first. WOT for more efficiency on gas engine is contrary to diesel fundamentals lean burning at regular slow rpm.

I was thinking about fairing the CO ZX2 way. Even then it is difficult, just thinking the wheels are wider apart form the side of the car (protuding somewhat). The best would be to make the back more aerodynamic, like a water droplet, since this car is so boxy, and CO ZX2 says that ? negative pressures and turbulence at the rear may produce as much as 85% of total aero drag ?.

I continue studying what GS members have done and will be happy having your opinions on ways to improve FE on a diesel.

[CO ZX2]

Antoine, I made most of the gains in reducing negative pressures at the rear of my car by working with the front end.

Is the air inlet below the number plate to cool the engine? How about the grille opening? I would like to see you block as much of the air openings in front as you can. Make sure they are sealed well. These two temporary mods I mention can be made in a few minutes with cardboard and duct tape.

Below your front bumper appears to have a lot of space to the ground. Try taping a piece of cardboard on to the bottom of your bumper to within 2-3 inches of the ground. Try to curve it some on the ends extend it at least to the outside edge of your tires. If that works, you can look for a flexible material to make it permanent. I used plastic lawn edging for mine. Again, make sure to seal well where you fasten it. Duck tape works wonders for experiments.

Aerodynamics at low speeds are considerably less important. I did measure three sensitive spots on my car recently at 30 mph and my pressures were about 1/3 of the pressures measured at 60 mph. These pressures were measured on my car with the mods it now has but I would expect the percentages to hold fairly true on your car.

I also wonder if your transmission control could be electronically modified to do a better job. I have no answers for this question but surely would be investigating the possibility if I owned your car.

Hope these ideas are of some help. CO ZX2

[88HF]

Your smart has boa-tail written all over it!

[GasSavers_Antoine]

I am really a new-comer to all this aerodynamic fairing CO ZX2. I am surprised that you « made most of the gains in reducing negative pressures at the rear of my car by working with the front end. ».
The middle part of the air inlet below the number plate is to cool the radiator ( engine is at the back). The upper grille serve the same purpose. I use to block it in winter to keep the engine warmer but on the inner side of the opening. Since this opening is 2 inches deep, it might be better to block it flush with the outside edge. I thought you guys blocked these opening so to make the engine run warmer ? not to reduce drag at the rear !!! Further more, my added wooden bumper might interfere with air flow. Might be better off, or... use it to hold a larger fairing.
Well modifying the electronics of the transmission control is out of my reach. That would be great ( also for disabling the power down on traction control).

88HF, I don't know what is boa-tail written over my smart, but it make me think that snake skin or fish scale would make better aerodynamics.