Put Your Car on a Diet to Save on Gas

Every pound of weight your car's engine has to haul around costs a little bit more gas. The video shows the results of weight reduction on a car's acceleration. You can see the improvement with less weight. The same works for fuel efficiency: with less weight, instead of generating more acceleration, the engine can achieve the same acceleration as before by using less fuel.



Next time I write on this blog I will be talking about infinitely variable geared transmission. Not possible you say? Well then stop by tomorrow and find out about the D drive.

Carbon Fiber Do It Yourself

Carbon fiber and other composites are lightweight materials which can replace metal in many applications in vehicles. Panels made of carbon fiber are strong while saving on weight. Every extra pound costs the engine a little more gas to haul it around. To many people, carbon fiber seems like an alien technology, beyond the capacity of mere mortals to understand or use. But in fact it is not difficult ... you can make carbon fiber panels at home! This video shows you how.



Lighter cars are more fuel efficient cars, and tomorrow I'll be writing about that. If you like to see real life proof that these strategies to save on gas work be sure to read my blog post tomorrow.

World's Smallest Car

The world's smallest car. It may be small, but for local intracity travel, it is really all you need. It is something like a covered motorcycle so you will not get wet in the rain. And it gets 100 miles to the gallon, or expressed in gallons per hundred miles, it only uses 1.00 GPHM. Just right for getting about the neighborhood without spending a fortune on gas. This particular vehicle was manufactured in the 1960's on the island of Peel, so they are not for sale now. But the concept of a small, very lightweight vehicle for local travel is something the modern world is going to become very familiar with as we look for ways to stay mobile in a world of expensive gasoline.

Moonbeam a Micro Car

One way to get better gas mileage is to choose the right vehicle for the job. And to save on gas, the right vehicle is the smallest, lightest, lowest horsepower and most streamlined one that can possibly work. Most local trips within a neighborhood don't need much more than a motorcycle. A Micro Car is essentially a motorcycle fitted out with a body. The resulting low weight allows for amazing gas mileage. For example, the Moonbeam introduced in the video gets 200 miles on a 2 gallon tank of gas. It uses only about 1 gallon per hundred miles! And if you only want to go ten blocks to visit a friend, it is absolutely perfect.

Four Wheel Drive Guzzles Extra Gas

One of the main enemies of fuel economy is vehicle weight. The heavier a vehicle is, the harder the engine will have to work to manage the same acceleration. That in turn means the engine will burn through more gas. This means that four wheel drive vehicles will be less fuel efficient than their two wheel drive models. The extra drivetrain assembly needed for four wheel drive adds weight. That weight is always there, whether or not the vehicle is actually using four wheel drive. For this reason the two wheel drive will always use fewer gallons per hundred miles driven.

Additionally to this permanent weight penalty that applies whether or not four wheel drive is engaged, actually engaging all four wheels adds yet another fuel penalty. The engine will have to work harder to overcome the extra friction and resistance in the drivetrain introduced by the engagement. Additionally, the extra load on the engine will induce larger losses internal to the engine, such as crankcase losses.

If you need four wheel drive in your working vehicle, go right ahead and get it. If you need it, you need it. If you are looking for a recreational vehicle that you will use for playing off road, go right ahead. But if you are thinking about buying a four wheel drive vehicle without really knowing when you would use it just because it sounds like it would be "nice to have", remember that you will be paying extra at the pump for the rest of your ownership. It may be "nice to have", but so would be the gas and money you could have saved.

Online Route Planner

The TomTom website is an interface to some pretty sophisticated route planning software. They maintain an up to date map of road networks in several countries and are able to combine that with real time traffic data to show you what they consider the best route between two points. They use the traffic data to find the shortest time route based on the predicted travel speed. The video shows off the website.

Two potential pitfalls with the route planner are 1) it is based on minimum time and 2) it offers only one choice of route. Many or possibly most drivers are indeed looking for the minimum time path between the start and the destination. However, minimum time might not be minimum distance or minimum fuel consumption. For example, a high speed low traffic route which goes over several large hills will get you to the destination quickly, but those hills could really harm fuel efficiency. A different route which avoids the hills could take a little more time but save on gas.

Providing only one route to the driver is also quite limiting. There could easily be several routes to a destination which differ only minutes in time. The website seems to always pick the single route it considers absolutely shortest. Imagine a situation where there are half a dozen routes between two places, with predicted travel times ranging from 2 hours 5 minutes to 2 hours 20 minutes. A difference of 15 minutes on top of a 2 hour drive is not very much. However, there could be other factors to choose from between the routes which are very different. For example, some routes could include toll roads and others not. Some routes might go through dangerous neighborhoods. Some routes might include a lot of hills. Some might be more scenic than others. Some might have more potholes or rough pavement.

All of these factors are things the website does not know about. Different people would weight these factors differently anyway. For example, some people would be happy to drive an extra 5 minutes to avoid paying a toll and others would not. Given these other factors, I believe it would be better to have a route planning software that offered a selection of all routes with approximately the least time. Then each driver could choose among these routes to find their best trade off between minutes and everything else.

Road Map to Save on Gas

This University of Oxford study suggests that over the next ten to fifteen years the best way to achieve better fuel economy is to do it the old fashioned way: make vehicles smaller and lighter. High technology items such as hydrogen power or electric vehicles are not going to be commercially available at mass market levels before that says the study. Given that we cannot wait a couple of decades during which we continue to guzzle gas, another way must be found.

Fortunately the low technology techniques of size and weight reduction are simple to implement and very effective. In fact, the possible increases in fuel economy from downsizing are much greater than what advanced technology offers. Many times going back to the basics is the best solution and it works to save on gas as well.

Super Lightweight Car

The more weight that a vehicle has, the more kinetic energy it needs to reach a given speed. Kinetic energy that is all lost again when the vehicle brakes to a stop. Weight reduction is one of the most important and effective ways to make a car more fuel efficient. The University of South Australia developed an ultralight car that has space for two people. The car has a mass of only 64kg, which corresponds to a weight of only about 140 pounds! Imagine that. In a normal car, almost all of the weight is just the car. In this case, the majority of the kinetic energy is going to move the passengers and not the car. And after all the point of a car is to move people, not metal.

This low weight was achieved by building the car using panels made of layered fiberglass and aluminum. These panels were used to build a basic box like shape. Then an aerodynamic form was constructed by layering styrofoam cut to an aerodynamic shape on top. A layer of fiberglass was then placed over the styrofoam to secure and protect it.

This is another example of a vehicle that would be perfect for neighbourhood driving or one person commutes. The heavy steel cars we drive are overkill for a lot of uses to which they are put. This overkill has a cost that shows up at the gas pump. Choosing the smallest, lightest vehicle that can serve a given function is one of the best ways to save on gas.

Snazzy Motorcycle Sidecar

A motorcycle can save a lot of gas relative to a car. This is fundamentally because it is much lighter. Choosing the right vehicle for the job can be a great strategy to up your fuel economy. A lot of people hold back on a motorcycle due to two big issues: safety and space.

As far as safety goes, if you use your motorcycle for local trips and avoid heavy traffic situations it will not be as risky. For passenger and cargo space, a sidecar could be just the thing. Now a lot of people say they do not like sidecars, that they look bad. Well, just to dispel this excuse, I have posted here a picture and a video of a motorcycle with a tricked out sidecar. This sidecar looks like a car!



Here you go: proof that a motorcycle can carry passengers or light cargo and look snazzy doing it! So consider using one when appropriate to save on gas.

Drive a NEV

Ok you need the gas-guzzling SUV to take the kids and the dogs and all your equipment to go camping. But do you need such speed and range to do errands around town?

You might want to consider buying an Neighborhood Electric Vehicle (NEV) as a second car for your family. Basically it's an electric golf cart that meets the basic requirements to be an on-road vehicle. They are much cheaper than cars, both in up-front costs and maintenance so you probably can afford one as a second vehicle even if a Prius is out of your price limit.

Electric golf carts use a bank of standard lead-acid batteries. They're designed to be used all day then recharged all night. That means that at the end of the day you plug them into a standard power outlet. If you won´t have such a steady use pattern you can look for a NEV that supports "opportunity charging," which allows you to simply plug in whenever you're not using it.

They may seem simple, but NEVs pack a lot of technology into a very small package. Stripped-down personnel carriers can be found for as little as $3,000, while fully configured burden carriers can reach $20,000. Pricing for new golf cars starts at around $4,000 for a bare-bones model. More typical are prices of $6,000 to $9,000. High-end models with all the extras can cost upwards of $10,000. These luxury models include upgraded upholstery, fancy wheels, lights, and details like radios and cell phone chargers.

The more options you add, the more you’ll pay. Some two-seater golf cars can be outfitted with a rear-facing bench seat that lets them carry four people. Some models are open-topped, some have a roof, and some have a roof and a windshield. Expect to pay $200 to $400 for a top and that much again for a windshield. A rain enclosure – usually roll-down plastic sides – can be a nice extra in wet climates.
Don’t feel compelled to purchase every accessory at the outset: in most cases, you can buy a basic model at first, then make the upgrades as you see fit.

An economical choice is buying a used golf cart. Many dealers sell refurbished carts with 30 day warranties. Used utility vehicles can be found for as little as $2,000. You’ll rarely find anything for much less than that – at least, not anything you’d want to depend on for transportation.

Modern NEVs have greatly increased range and power over models available five or ten years ago. They have features like regenerative braking, which helps recharge the batteries as the car slows or goes downhill. Imagine a gas burning car where the tank fills up every time you stop at a red light.

A distinct advantage of electric golf carts is their cost to operate: it can be five or 10 times cheaper than a gas model. Proof that the technology is good can be seen in golf courses with large fleets: gas-powered utility vehicles are no longer as popular as electric golf carts.

Maintenance is an important consideration for any vehicle. Electric vehicles need to have the water level in their batteries checked regularly, which is a simple but critical task. More significantly, the batteries in electric vehicles need to be replaced every couple of years at a cost of $400 to $500. The overall maintenance costs work out to be fairly similar to gasoline engines - combustion engines spread the cost out more, but require more frequent servicing.

Having basic maintenance done regularly – on the schedule recommended by the manufacturer – can drastically extend your vehicle’s lifespan and improve its performance. Something as simple as making sure there’s enough air in the tires can help safeguard your investment. With proper maintenance, you can expect about 10 years out of an electric motor – but manufacturers report vehicles lasting 15 or even 30 years in some cases.

One thing you need to be careful about: Laws governing the use of NEVs are different to those applying to golf carts. You should check with your local authority for information that is relevant to where you intend to be driving your golf cart/NEV. There are differences regarding use of windshields, headlights, brakes etc. There are also differences regarding where exactly you are allowed drive them.

If you think you might want to upgrade your golf cart to a NEV, contact a licensed dealer, as it makes the registration process simpler for you. A dealer can do the paperwork for you, but only if she or he is licensed.

Lightweight Electric Fans

Does your vehicle have an engine-driven fan? Many trucks, vans and SUVs have a heavy metal cooling fan that is run off the engine crankshaft by a belt. These fans are heavy and have a lot of inertia. It takes a lot of rotational kinetic energy to get them going which is just lost when they slow down. That translates to more gallons spent per hundred miles of driving. Think about replacing it with a much lighter, plastic electric driven fan. The weight savings will give a fuel savings. And many modern electric fans are designed to be more efficient than engine driven ones because they have a computer which can control their speed independently of the engine speed. You will get a fuel economy boost and a litle extra horsepower too!

Carpool When You Can

Carpooling can be a simple change in your habits that might lead to a big savings on gas. A vehicle with four people is much lighter than four vehicles with four people. This alone means a large gain in fuel economy. If you have a regular commute look around to see if any neighbours are heading in the same direction and split the gas bill. Also if you find yourself driving all over the map to visit friends, meet clients or take care of other chores consider offering rides to friends and associates. Then split the gas bill. Both of you will save something on gas. Carpooling can easily be a win win situation!

Do You Need a Bigger Car to be Safe?

One reason for choosing a big vehicle in spite of the gas savings hit is safety. Most people feel that a big vehicle will be overall safer to drive. Is that true? The Monash University Accident Research Centre tried to find out and the result was this report.

They looked at two measures of vehicle "bigness": the mass and a measure of the physical size such as volume or wheelbase length. The Monash study was one of those "study of studies" where they reviewed many other studies in the literature looking for common factors and data. The aim was to find how size and mass are related to occupant safety. There were problems getting definitive results due to the variability of the data. For example, some studies used interior cabin volume to measure size and others used wheelbase. But overall?

Overall they found that in multi-vehicle crashes (things like head on collisions, rear ending, sideswipes, anything with a least two cars involved) the bigger the vehicle mass, the safer the occupant. On the other hand, in single vehicle crashes (rollovers, hitting a tree, crash into a wall) the bigger the vehicle size the safer the occupant.

In multi-vehicle crashes it makes sense that bigger mass will help more. Physics says that the bigger car will always be least effected in a 2 way crash. It also makes sense that mass doesn't help much in single vehicle crashes. If you hit a wall or embankment, it doesn't matter how much mass you have in your car: the obstacle will always outgun you. On the other hand, if there is a lot of interior space, there is room for the vehicle to crumple, compress and slow down gradually without the driver's body being impacted by something.

How can we relate this to saving on gas? Well, careful design of interior cabin space can give us vehicle inner volumes that are as close as possible to the outer volume (no wasted space). Careful aerodynamics will let us make larger volume, light mass vehicles with little air drag. So in that respect, we can have safety and gas savings at the same time. But we need Detroit to play along and start designing vehicles accordingly.

With regard to mass, it is the direct enemy of fuel economy and they can't really be made to live together. But if all the vehicles on the road are lighter, being made of composites and modern light alloys, then what counts as a relatively "massive" vehicle in a two-way collision will also be lighter. We might see that over time, the "heavyweights" of the road become quite light compared to our heavyweights of today. That would open up the choice of driving a "heavy" car for safety and still saving on gas.

Smaller Vehicles Designed for Maximum Utility

We are at the last in our series. The purpose of a car is to move passengers and their cargo. If we can design the smallest, lightest car that does this, we will get better fuel economy. However to meet standards of comfort and provide sufficient cargo capacity it is not possible to just miniaturize everything. The idea is to rearrange the interior space of the car to make the space inside as usable as possible while keeping the overall shape as tightly fit to the interior as possible. Some of the techniques that can be used are illustrated in the Mazda Washu concept.

The Washu has features such as steer by wire, which allows reduction of the steering column. Additionally the steering wheel can stow away to provide even more space when parked. The beltline is widened outwards to give more interior space. The feel of roominess is enhanced by putting windows everywhere possible. The rearmost seats can be efficiently folded down to carry long cargo. The rear cargo door consists of a combination of a hatchback and a tailgate that slides straight down vertically (instead of swiveling on a hinge to be parallel with the ground) to make it as easy as possible to load bulky freight. The cabin roof is arched to open up a little more volume.

Design attention like this can open up more space for passengers and cargo without needing to make the overall vehicle larger. This means that there is less structure per usable functionality, and that in turn means carrying around less metal with you. The result is a savings on gas.

Lighter Construction with Composites and Lighter Metals

Here is number six in our series looking at fuel economy technologies. If a vehicle can lower its weight it will be able to run with less fuel. There are two main reasons for this. One is that the mechanical friction suffered by the vehicle is proportional to the weight. A heavier vehicle has to spend more fuel fighting more friction. Note that this does not apply to the aerodynamic air resistance friction that begins to really bite at higher speeds. The air resistance does not increase with vehicle weight, assuming the shape of the body stays the same. The other is the investment in kinetic energy to speed up the vehicle. The amount of kinetic energy needed to reach a given speed is proportional to the mass. So to speed up a heavier car, you have to burn more fuel. Then when the car slows down or stops, all of this energy is lost, mainly as heat in the brakes. Heavier car equals greater loss in this way.



The video above explains the Rocky Mountain Institute's Hypercar concept. It is a car made of only fourteen panels of carbon fiber composite. The carbon fiber has half the mass of steel. Because there are only 14 pieces the overall strength of the body is greater than if it were made of steel. The result is a much more fuel efficient vehicle.

Shed Pounds to Save on Gas

Every pound that your car has to haul around costs you gas to do it. The friction or resistance that your car has to work against generally goes up proportionally to the weight of the car. You can see a similar principle at work down at the drag strip. Drag racers cut away extra weight so they can get better acceleration for a given horsepower. In our case, we want to get better mileage per gallon for a given engine, but the basic idea is the same. For low speed driving, the amount you can improve your gas mileage depends on the weight you shed relative to the weight of your car. If you have a 1000 pound car and shed 50 pounds, that is 5% of the car's weight. In this example you would get up to a 5% increase in mileage.

You can't put your car on a diet, so how to shed those extra pounds? You could replace your rims with light aluminum ones. Replace steel body panels or the hood with a modern, lighter composite material. Throw out all of the junk in the trunk. Don't carry around bags of salt in the summer. If you have a huge toolbox that you never use, consider leaving it at home. This is maybe going over the top, but the fanatics out there could even leave behind the spare tire.