HYBRID ELECTRIC VEHICLES
|Personal transportation has come to mean almost total mobility, that is, we want to go anywhere we wish anytime we wish. A system with limited range or mandatory down time for recharging or special requirements at a base station is less than satisfactory. For these, and other reasons, the hybrid vehicle is of much interest. The hybrid, in this case, means crossing an electric with a liquid fuel vehicle. The primary advantages are the possibility of averaging the power requirements over a period of time and recapturing the power expended in accelerating and hill climbing.|
The dictionary says hybrid is something of mixed origin or makeup.
We’re used to hybrids in the animal and vegetable kingdoms, usually they improve the product in some way. In the automotive field hybrid has become a buzz word with everyone trying to get on the bandwagon. If you put an electric motor in the drive train of a standard vehicle and add a lot of batteries in the trunk, you can call it a hybrid, but from an engineering standpoint it’s definitely not an improvement. The current vehicles on the market are not a demonstration of the performance a true hybrid is capable of.
We could start by analyzing the uses and needs of personal transportation, and probably solve the problem by mandating logical use. But let's assume that personal mobility is desirable and justifiable and go on from there. Let's also assume that our study will be toward a more efficient means of obtaining this.
Let's start with a clean sheet of paper. How much power does it really take to move a car? At a constant speed on a leval road the power has to overcome only rolling resistance and aerodynamic drag.
We can calculate the power it takes to keep our design moving at a constant speed on leval ground, but how about getting up to that speed and over hills and mountains? We can regain some of the power needed to accelerate to speed and get over the mountain with regenerative braking, turning the motors into generators to slow down and stop the car. We can't get it all back, of course, but probably around 60 percent.
This vehicle should have the lightest Weight, the lowest aerodynamic drag, the smallest rolling friction, the most efficient propulsion system, and the lowest costs we can come up.
About thirty years ago I presented a design study on hybrid electric vehicles to a concerned citizens group. We had experienced an oil embargo by Opec that left some of us sleeping in our cars in closed gas stations waiting for fuel to arrive. The national speed limit was 55 MPH.
|The paper was a retirement hobby that was my creativity outlet, but several friends got excited about it and talked me into building a prototype.|
We passed the state inspections and got license plates. We used the car for local trips as a plug-in electric and had about a 30 mile range before we had to start the engine and recharge the batteries. We were getting excellent miles to a gallon as a hybrid but most of the milage was local. The design was intended as an example that would fulfill 90 percent of the average vehicles use. The information and ideas in that study are more valid today than they were then. So here it is, circa 1980, only edited slightly from the original.