Re: Scooters
Riding a bike on the sidewalk in St. Louis will get you fined. Riding it on the street will get you killed. Sadly, I speak from experience. Luck...
I'm not particularly fond of most scooters because they aren't designed to maximize the efficiency they could obtain. 90 mpg might seem like a lot, but it is possible to get a compact car to achieve that if you use composite materials to lower weight, heavily streamline the aerodynamics, use low rolling resistance tires, and use an efficient diesel engine(The GM Precept prototype got 80 mpg, did 0-60 mph in 11 seconds, and was the size of a Ford Taurus sedan. The Loremo AG can exceed 150 miles per gallon, tops out at 100 mph and seats 4 people). A scooter? If someone made a streamlined scooter that used a 500 cc diesel engine(which is ****ing huge for a scooter), 200+ miles per gallon wouldn't be out of the question.
Horsepower to overcome rolling drag is proportional to weight and varies linearly with speed. Horsepower to overcome aerodynamic drag is proportional to frontal area and varies as a cube of the speed. The more horsepower used to maintain a given speed, the more fuel will be used to maintain that speed. After about 25 mph or so, aerodynamic drag, and not weight, is the biggest factor in fuel consumption. Scooters have very, very crappy drag coefficient, like in the 0.8-1.0 range. A typical midsize passenger car is around a .32 drag coefficient(which, if you were to lower it to about .16 through aerodynamic improvements, could yield 50 mpg midsize cars with no other changes and no loss in size, comfort, or performance).
The reason the scooters get the good fuel economy they do compared to cars is mostly because of low weight and horsepower starved engine. The low frontal area helps cancel out the negative impact of the high drag coefficient, and they often use efficient two-stroke engines which have the adverse effect of increasing air pollution. An internal combustion engine tends to be most efficient at low RPMs and a load between 1/2 and 2/3 of full throttle, peaking at about 25-30% thermal efficiency. Most passenger cars are using only about 1/10th their peak horsepower to maintain highway speeds, so they are usually operating at about 10-15% thermal efficiency. Since scooters have such small, power-starved engines, and are running higher compression ratios than most passenger car engines(look up Carnot's equation to see how this effects thermal efficiency) you'll usually need to be using a higher percentage load than most passenger cars will use, and therefore you will see a higher percentage thermal efficiency in normal operation of the engine. If you don't believe me, look at a brake specific fuel consumption map of an Otto cycle engine and a two stroke engine.
What especially bothers me about scooters is poor pollution control systems(motorcycles have this problem too). Most models lack a catalytic converter and the high compression ratios of the two-stroke engines make pollution control difficult. These factors conspire to increase the amount of CO, NOx, particulates, HCs, and VOCs emitted is to be roughly 60-100 times more than a passenger car per unit of fuel used(depending on study cited).
However, I must commend you for choosing to use a vehicle that uses about 1/4th the gasoline per unit of distance as a typical passenger car. That's more than I'm doing to lower oil consumption considering my electric car is not on the road yet. I definately rate scooters above poorly maintained passenger cars.
If I were to ever have a two-wheeled vehicle, I'd find me a used motorcycle, showhorn a 100 horsepower Volkswagen diesel into it, and slap a Craig Vetter faring on that *****. Instant 300+ mpg coupled with crotch-rocket like acceleration and top speed(with the right gearing).
If you wish to increase the top speed and fuel efficiency of your scooter, I'd strongly recomend building a custom faring for it. If engine RPM is the limiting factor to top speed, then aerodynamic improvements alone won't improve it; you'll need taller gear ratios or a bigger tire size too. Since you're using a CVT, swapping gear ratios isn't possible, but if it has a minimal amount of electronics controlling it, the CVT may actually adjust its ratio sufficiently to allow the lower drag to impact top speed.
Riding a bike on the sidewalk in St. Louis will get you fined. Riding it on the street will get you killed. Sadly, I speak from experience. Luck...
I'm a very big supporter of this mode of transportation and I'm very excited about this scooter. Lately, I have seen more and more scooters on the road than I have in previous years, so I am assuming they are increasing in popularity. However, it seems as though most people tend to scoff at the functionality of such a vehicle while they dump 24 gallons of gas into their H2, perhaps because they view scooters more as toys. While scooters are significantly more fun to ride, I definitely wouldn't consider them play things. Personally, living in the city, using the scooter is a far more convenient way to reach destinations than using my car has been, especially with local highways being rendered useless from constant construction (Google Maps even has a feature that gives me directions without using highways). It's much easier to navigate through congested traffic and parking is much easier when I can just pull up the sidewalk for short stops. The scooter I have gets over 90 mpg as well and scooters with smaller engines can get over 100. I guess I just like scooters, so what do you think?
Horsepower to overcome rolling drag is proportional to weight and varies linearly with speed. Horsepower to overcome aerodynamic drag is proportional to frontal area and varies as a cube of the speed. The more horsepower used to maintain a given speed, the more fuel will be used to maintain that speed. After about 25 mph or so, aerodynamic drag, and not weight, is the biggest factor in fuel consumption. Scooters have very, very crappy drag coefficient, like in the 0.8-1.0 range. A typical midsize passenger car is around a .32 drag coefficient(which, if you were to lower it to about .16 through aerodynamic improvements, could yield 50 mpg midsize cars with no other changes and no loss in size, comfort, or performance).
The reason the scooters get the good fuel economy they do compared to cars is mostly because of low weight and horsepower starved engine. The low frontal area helps cancel out the negative impact of the high drag coefficient, and they often use efficient two-stroke engines which have the adverse effect of increasing air pollution. An internal combustion engine tends to be most efficient at low RPMs and a load between 1/2 and 2/3 of full throttle, peaking at about 25-30% thermal efficiency. Most passenger cars are using only about 1/10th their peak horsepower to maintain highway speeds, so they are usually operating at about 10-15% thermal efficiency. Since scooters have such small, power-starved engines, and are running higher compression ratios than most passenger car engines(look up Carnot's equation to see how this effects thermal efficiency) you'll usually need to be using a higher percentage load than most passenger cars will use, and therefore you will see a higher percentage thermal efficiency in normal operation of the engine. If you don't believe me, look at a brake specific fuel consumption map of an Otto cycle engine and a two stroke engine.
What especially bothers me about scooters is poor pollution control systems(motorcycles have this problem too). Most models lack a catalytic converter and the high compression ratios of the two-stroke engines make pollution control difficult. These factors conspire to increase the amount of CO, NOx, particulates, HCs, and VOCs emitted is to be roughly 60-100 times more than a passenger car per unit of fuel used(depending on study cited).
However, I must commend you for choosing to use a vehicle that uses about 1/4th the gasoline per unit of distance as a typical passenger car. That's more than I'm doing to lower oil consumption considering my electric car is not on the road yet. I definately rate scooters above poorly maintained passenger cars.
If I were to ever have a two-wheeled vehicle, I'd find me a used motorcycle, showhorn a 100 horsepower Volkswagen diesel into it, and slap a Craig Vetter faring on that *****. Instant 300+ mpg coupled with crotch-rocket like acceleration and top speed(with the right gearing).
If you wish to increase the top speed and fuel efficiency of your scooter, I'd strongly recomend building a custom faring for it. If engine RPM is the limiting factor to top speed, then aerodynamic improvements alone won't improve it; you'll need taller gear ratios or a bigger tire size too. Since you're using a CVT, swapping gear ratios isn't possible, but if it has a minimal amount of electronics controlling it, the CVT may actually adjust its ratio sufficiently to allow the lower drag to impact top speed.
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