Electric Vehicles

"recoverable" levels of electricity. However, this low-grade electricity can be channeled into resistive coils (like those found in floor heaters) to continue the braking effect. This is called dynamic braking. The use of dynamic braking minimizes the amount of hydraulic braking required to slow the vehicle. Also, both drum and disc brakes release asbestos dust to the environment as the brakes wear. Dynamic braking decreases asbestos pollution by reducing the rate of brake wear. Your pocketbook will appreciate the greater time between brake jobs, too!

Both the regenerative and dynamic braking circuits are made to work off the standard brake pedal in the MBG. As the pedal is depressed, it moves through various detents. The regenerative braking circuit uses the first two (1 and 2) detents and dynamic braking uses the following two (3 and 4). Further pedal depression engages the vehicle's hydraulic brakes. Indicator lights on the MBG dashboard will inform the driver when regenerative, dynamic, and hydraulic braking modes are engaged. The braking effort, then, is completely under the control of the driver; he or she simply presses the pedal until the desired degree of braking effort is reached.

POWER SOURCES

PVs values, and display the errant reading for further evaluation. I prefer this system to idiot lights or gauges since I always seem to notice them too late! This may be too costly to include in a production version.

Aerodynamics

A standard car, speeding down the highway at 55 MPH requires fully 50% of its propulsive effort to move air aside. As more attention is given to the ways a vehicle can slip through the air, this power consumption is reduced, as is the need for the size of propulsive machinery. There is no mystery to this (we wouldn't have aircraft that could do 2,000 MPH if there were) but, for a long time, Regen. solid aerodynamics has been

Braking lacking in most cars. The main culprit is "style", truly aerodynamic vehicles are thin and taper at each end. Since we are quickly reaching the point where conspicuous consumption of fuel is no longer possible, the "style" is getting cleaner, softer edges, lean lines, recessed fixtures, and more attention to detail. However, there's a lot more "trend" than "slick" in most manufactured bodywork.

BATTERIES Propulsion, Instrumentation, & Regeneration

INSTRUMENTATION & CONTROL

There's one more feature here: coast versus slow down. In standard cars, when you take your foot off the accelerator pedal, some vehicle slow down occurs automatically. This is due to "compressive braking", an engine-related retardation of timing. This is pollution intensive, but a good safety feature because it acts like a "dead man switch". An electric motor cannot be compressively-braked. To duplicate this slow down feature, the MBG's motors are automatically put into a dynamic braking mode when the accelerator is released.

Long-time EV Owners advocate the benefits of "coasting" in electric vehicles. Little wonder! It certainly increases vehicle range! It takes practice to anticipate traffic and stoplight timing, letting off on the accelerator pedal to take upmost advantage of this effect. But it pays off. I like this feature, too. So, the MBG will have a dash-mounted switch to defeat the "auto-slow" circuit described above. When selected, it permits the maximum coasting effect, letting vehicle speed bleed off to the natural resistance of bearings, tires rolling on a surface, and general aerodynamic losses.

Instrumentation & Controls

The MBG prototype will be equipped with lots of monitoring capability. So that the dashboard doesn't look like the cockpit of a Boeing 747, a microprocessor will be used to automatically scan through all of the onboard sensors (i.e., voltages, currents, temperatures, etc.). An audio and/or visual indicator will alert the driver of any parameter that moves outside the range of preset

PROPULSION

What are the important aerodynamic considerations in landborne vehicles? A brief but accurate list includes four factors: shape, frontal area, closure, and ground effect.

The ideal SHAPE of vehicles in the 0-60 MPH range is a teardrop, rounded at the front and slowly tapering to a point in the rear. FRONTAL AREA is the number of square feet of silhouette when the vehicle is viewed "head on". You want this as low as possible, suggesting that the vehicle be a thin teardrop. Exhaustive tests have concluded that unless the CLOSURE (the way the vehicle tapers in the rear) stays at less than a 14 degree angle (7 degrees each size of a centerline through the vehicle), you might as well chop it off abruptly. Rattail-looking vehicles have limited appeal, so you'll see mostly sharp cutoffs.

GROUND EFFECT, in this context, defines a natural relationship between a road surface (or any surface) and the sky. A vehicle interacts with, and generally messes up, this intimate relationship in a way that defies easy description or remedy. It gets progressively worse with speed. Vehicles minimize the resultant drag with SKIRTS (shrouding that dips down to the surface to keep air from getting under the vehicle), UNDERPANS (smooth bottoms that minimize the yo-yo'ing of air between vehicle and ground), and ISOLATION (maintaining an elevation above the road surface that fools the road surface into thinking your car is an airplane).

A measure of a vehicle's aerodynamics is its drag coefficient. (This is not directly affected by the vehicle's propulsive power or its weight.) The desirable value of drag coefficient is low.

Streamlining is the art of achieving a low drag coefficient but it is thwarted by the air's propensity to cling to a surface. When it does, the air is turbulated at the parting, rolling and dodging, producing a thing called a vortex that's a real drag to the vehicle that experiences it. Careful attention to the four factors above, a clean shape, low frontal area, good closure, and minimal ground effect, will help.

The MBG vehicle chops the typical frontal area of a passenger vehicle in HALF. One MBG prototype will be a single-seater, so no explanation is required for how this is achieved. However, the second MBG will be a twin-seater (one driver, one passenger). It will also have HALF the frontal area of a standard car because the passenger is positioned behind the driver. This is called tandem seating. An alternate arrangement is "offset tandem", which places the passenger behind and slightly to the right of the driver. This would result in a slightly greater frontal area but afford the passenger a direct view ahead instead of a "view of a head".

The MBG prototype will have a low drag coefficient because of a painstaking attention to detail. For example, there will be no scoops. A scoop is a protrusion that is intended to force some of the air moving past the vehicle to enter and, hopefully, move through some portion of the vehicle. Scoops are used for ventilation (of driver and passengers), combustion air (for engines), and cooling air (thermal management) -- the latter application typically requiring the highest CFM (cubic feet per minute) of airflow. Scoops interfere with aerodynamics. An alternate technique is to identify high and low-pressure points on the vehicle's body, and position inlets and outlets at these points for any internal cooling needs. As well, one test bed will investigate an alternate cooling technique for engine, motors, and batteries to eliminate most inlets/outlets.

Various aspects of the specific body layout also help to keep the drag coefficient low in the MBG vehicle. However, since these are side benefits of the vehicle's crashworthiness, they are better revealed in the next section.

Crashworthiness

If a transportation system were proposed today that killed 25,000 people worldwide each year, and injured or maimed another 2 million human beings annually, we'd reject it out of hand, right? I guess not. That describes our current system using automobiles! A major concern and design effort must be expended in scratch-built vehicles in the area of crashworthiness -- the effect of collision from the front, side, or rear of the vehicle. This could be a two-vehicle interaction or a collision involving the vehicle with a stationary object.

Although this subject important in the design of ANY type of vehicle, it is especially important in lightweight vehicles because it is a basic LAW of physics that more of the energy of a collision is transferred to the lighter of two vehicles. Weight is a linear function.

Hydrogen Production Workshop

Speed is a square function. At twice the relative speed of collision, the effect of the collision is four times as great.

In view of this, if you're neurotic, you don't drive. If you're sane, you drive as little as possible. If you're cautious, you drive something slow and heavy. If you concede that life is all about risks, you drive small and lightweight and stay very, very alert. If you're building your own, stay aware of things that help: strength, collapse distance, and design.

In vehicles, STRENGTH is often confused with weight, massiveness, and metals. Carbon fiber and fiberglass materials, and composite construction (fiberglass sandwiching) techniques make a lightweight vehicle tough. Stronger, in fact, than a vehicle several times heavier.

COLLAPSE DISTANCE recognizes the importance of spreading the impact of a collision over the greatest amount of time possible, decreasing the RATE of energy transfer. All that sculpting of metal that occurs in vehicle crashes actually helps the occupants. It dissipates energy. It slows things down. It converts energy into noise, heat, and motion. The idea is to absorb energy that a softer body, like a human being, dissipates in a more messy and irreversible fashion.

Good DESIGN confronts the possibility of a collision from any direction. It figures out how to be tough, malleable but rigid, dissipating and slowing energy. You do NOT worry about what happens to the vehicle. Every reasonable effort is made to keep a careening car or a telephone pole from penetrating or malforming the driver/passenger space AND it occupant(s).

Lightweight EVs, with their fiberglass materials and long aerodynamic bodies, are typically a designer's nightmare when it comes to crashworthiness. Front and rear impact are relatively easy directions to fortify. Side impact is the tough guy. How can you be slim and still withstand a side impact?

The MBG vehicle incorporates a TRIKE layout, as shown. In my opinion, this is one of the very best when it comes to overall collision protection and, most importantly, side impact protection. The MBG vehicle (see diagram) borrows heavily from the Amick windmobile (pictured in last month's issue).

Note that, in this layout, a side-impact will first contact the vehicle some 1-1/2 to 2 feet away from the driver. Due to the vehicle's unique wing-like structure and the rear wheel housings, this would be a tough distance to collapse. At least, it will dissipate much of the collision energy. Then, simply because the vehicle is so lightweight, the vehicle will start sliding. Certainly, at lower vehicle speeds, this will occur before cabin penetration. The end result is a greater degree of survivability, since the collision energy is spread out over both distance and time.

Note: One individual challenged this last statement, questioning the use of the word "survivability" since, almost assuredly, the vehicle in question would go careening off to collide with something else. Without any thought at all, I responded, "That's okay. I'd love to be in a position to worry about the second collision!" I don't expect absolutes and, like life, I'll take things as they come.

The MBG, then, uses a Trike arrangement, utilizing twin motors, one at each of the rear wheels. This eliminates the differential -with its attendant weight and inefficiency -- as required in vehicles using one propulsive source, i.e., an engine. It's likely that the MBG motor/wheel assemblies will use fixed gear ratios, eliminating the weight and inefficiency of a transmission. The motors act independently of one another. So, one motor will bring you home if the other decides to play dead.

The MBG vehicle is similar or different to the Amick windmobile in several ways. More specifically, the MBG prototype:

1. is NOT designed to use wind as an energy source. In the area I intend to operate the vehicle, there just isn't enough side wind to justify using it. Accordingly, the arch is lower. This will keep the wind's effect to a minimum and decrease the frontal area.

2. has a vertical fin between the uppermost point of the arch and the vehicle body. The arch is already a natural roll bar, and this fin strengthens this feature. It also stiffens overall structural support, increasing the side-impact protection. While this will affect the aerodynamics a bit, it also means that a side-impact must collapse the horizontal lower wing (compressive), the arched upper wing (compressive), the vertical fin (shear), and the wing which is attached to the outermost point of the horizontal wing on the other side of the vehicle (expansive).

3. has a narrower fuselage. As much as 9-12 inches in the width of the center vehicle body is removed since no true collapse distance need be added around the driver. This would decrease frontal area, assist with a proper tapering closure, and lower the drag coefficient.

4. has a flattened arch. This makes it able to accommodate rigid photovoltaic modules.

5. has, when viewed from the side, the arch angled backward. This retains the crashworthiness of the horizontal low-wing positioning (aligned to the driver) but permits better side visibility for the driver.

6. employs the arch as a means of promoting high visibility of the slight-figured MBG body. The overall MBG design, incidentally, helps drivers "see" in front of the MBG because there's so little of the MBG body to interfere with their view!

7. may use the arch as a "radiator" in MBG proprietary thermal-management system.

How safe is safe? Buying a big, heavy car might exorcise your fears about collision, but ... will it? In any car, how much distance is there between the driver and the front end of a car that hits the vehicle on the left side? Think about it. A few inches. It may be good steel but there's going to be "penetration" and all of its nasty consequences. In this case, all of that fine steel everywhere else in the vehicle is working against the driver because it "plants" the vehicle massively (no pun intended), resisting the forces that would, for a lighter vehicle, cause it to start sliding.

Final Comments

I could go on and on. But -- it's time to zip this off to the Home Power folks. Besides, I've logged 22 hours on the Mac in three days doing this thing, and the key cooling system is going to come on at any second. It's writ-and- rewrit, edited and rearranged. A blackout right now would ruin the elation I feel in doing & finishing it.

I've given up a lot of my gameplan for the MBG in this article and that makes me happy and sad. Happy because experience, like love, is something you can share without using any of it up. Sad because I'd like to make a million dollars and finish the MBG, and I can't sell what's in the public domain. Oh, well.

The first article in Home Power #8 generated bushels of mail. Thanks! That's a welcome stroke. (I sometimes wonder if I sail strange seas of thought alone.) The EV networking newsletter is evolving into what may be a magazine (tentative title is Alternate Transportation Magazine.) EVs and HPV (human-powered vehicles), airships and ultralights, solar cars and waterbuggies. Shooting for a March release, newsletter or mag, of the 1st issue.

Do you feel teased into building your own hybrid EV. Great! Give it LOTS of thought, glean every bit of info you can from anyone who is doing anything that looks interesting, and go at it. Please -- be careful. Too little knowledge is SO dangerous. None of what is written here is gospel truth. I'm talking at the edge of integrating all this technology & I could get something wrong. Feel free to correct me, if you think I've done that. Be gentle; I have good intent. The final arrangement of this stuff -- into something you'll drive down the road -- is a process. Winnow through the factors and see what fits. Good fortune.

Wait! Lead-acid batteries always take it on the chin when it comes to propulsive power packs. Okay, so they do have low electro-mechanical efficiency and low energy density. In a hybrid EV, they work adequately because there's less to do, and storage isn't an issue like it is in pure EVs. In the MBG, there is an OCU there to recharge them immediately. These factors tickle the thought that standard SLI (Starting-Lighting-Ignition) batteries COULD be used for the battery pack. Although not intended for deep-cycle, they are adept at the higher charge/discharge currents involved, and good performance may justify more frequent battery replacement. It's worth investigating!

Want more info on electric vehicles? Here's some options: 1. Electric Vehicles: Design and Build Your Own , Michael Hackleman, 214 pages, 1977. $10 from Earthmind, P.O. Box 743, Mariposa, CA 95338.

2. EV Sources & References. Lists publications, catalogs, manufacturers, and sources for components related to EV vehicles. Send $3 to Michael Hackleman, P.O. Box 1161, Mariposa, CA 95338.

3. EV Mailing List. Get on my mailing list for information on Alternate

Transportation Magazine, Video Lending Library of EV films, and EV documentary film (now in postproduction). Send an SASE or postal money to Michael Hackleman, P.O. Box 1161, Mariposa, CA 95338.

Sweet, colorful, detailed visions! Michael Hackleman

ELECTRIC VEHICLES

DESIGN & BUILD YOUR OWN Second Edition!

by Michael Hackleman

214 pages of solid information about electric vehicles. Contents include: Functions, Mechanical Power, Electrical Power, Frame Works, Vehicles, and The Hybrid EV. Many diagrams and illustrations. Listings of EV parts and information sources.

$10 from Earthmind

P.O. Box 743 Mariposa, CA 95338

Real Goods

Three types of electric lights are used for indoor illumination. Each one has its place in the energy-efficient home. The efficiency and economy of your lighting depends on your choice of the right light for each application AND on the way the light is installed. Wise choices in lighting design can reduce energy requirements by 40-80%! Every $100 spent on high efficiency lighting can save $300 or more in system cost (for a typical photovoltaic system). There are two ways to power an alternative energy lighting system, LOW VOLTAGE DC from your battery bank (12 or 24 volts) and 120 VOLTS ac from your inverter or generator. (Readers who are not remote from the utility lines should follow our suggestions for efficient ac lighting.)

Hybrid Cars The Whole Truth Revealed

Hybrid Cars The Whole Truth Revealed

Hybrid Cars! Man! Is that a HOT topic right now! There are some good reasons why hybrids are so hot. If you’ve pulled your present car or SUV or truck up next to a gas pumpand inserted the nozzle, you know exactly what I mean! I written this book to give you some basic information on some things<br />you may have been wondering about.

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