Horst Berger’s Blog


Why you cannot buy a 120 miles/gallon car yet - but soon will

Thursday, August 28, 2008


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Click on www.hybridcenter.org/hybrid-center-how-hybrid-cars-work-under-the-hood-2.html illustrations of how they work. In parallel hybrids the two motors - gasoline and electric - work in parallel to drive the wheels. Most hybrid cars on the market today are parallel hybrids, leaving most of the work to the gasoline motor. The best of them, Toyota’s Prius, gets 45 to 50 miles/gallon on average. I know, because I drive one.

Two years ago a British electric motor company, PML Flightlinks, demonstrated the superiority of  a series hybrid motorcar. They build the modern version of Porsche’s 1900 cars by converting a Mini Cooper. You get the details under http://www.treehugger.com/files/2006/08/the_hybrid_mini.php. . The car is driven by four electric disc motors located in the four wheels. A small gasoline motor generates electricity. This car gets 80 miles/gallon. Because it has four 160 hp electric motors, it gets from 0 to 60 in 45 seconds. Also, there is no separate brake. The electric motors do the braking, thereby re-loading the battery in the process. There is no doubt in my mind that this car would be less expensive to built, since it has no clutch, no transmission, no differential. The four electric disc motors weigh half as much as the commercial Mini Cooper’s gasoline motor and the constant speed gasoline motor and generator are tiny. There is no magic here. And the facts have long been known to automotive engineers: electric motors have more than 90% efficiency, independent of speed. Gasoline motors, running at their best speed, may reach 70% efficiency, but as a car engine going through the variations of normal traffic their efficiency drops to about 20%.


    One direct result is the new Tesla luxury sports car. It is to come on the market this year. And, in spite of its price of over $105,000 it is sold out. But it has dropped the most interesting part of the hybrid Mini Cooper conversion car: its no longer hybrid. It is a straight plug-in electric car. At the cost of a $ 30,000 lithmium battery. And its cruising range is limited to something like 250 miles. Is anyone going to produce a series hybrid for passenger cars? (They are becoming popular for city buses). There are many announcements. Not from any of the big car manufacturer, except, maybe, Mitsubishi-Renault. Is GM going to wake up? Here is the real chance.

There is no doubt that cars need to go electric, especially in the US. With 4.5% of the world’s population we use up 25% of the world’s energy. That’s absurd and irresponsible. It is also economically unwise. For decades we have had a huge export/import deficit, which is still growing. A huge part of the deficit comes from our oil consumption, nearly half of which is caused by our inefficient cars. Another substantial part of the deficit comes from the fact that 40% of the cars bought in this country are foreign. So here is a critical area for change: move to drastically more efficient cars, and begin to make these cars in this country. If we can do this, we might be able to make a significant contribution  towards avoiding the worst of the global warming disaster while reducing or eliminating our export/import problem. And we might begin to put our economy on a saver basis.

The State of California shows us what government can do: the state’s mandate for automakers to make 7,500 zero-emissions cars by 2014 has most recently produced a number of interesting responses: Volkswagen has announced that it would make a limited number of its 1-Liter 282 MPG car, and BMW is rumored to plan production of 500 electric Mini Coopers, 490 to be leased to California drivers, 10 to be used for demonstration purposes. So, maybe, this is be beginning of the big change.

Of course, changing the drive system is not the entire answer. Making the car lighter and smoother are other important steps. I have been dreaming of a fabric car (with a strong rigid frame for safety like in race cars) to drastically cut the weight and knock out much of that wasted and expensive steel. I found I am not alone. In 1991 BMW promoted this concept car: the BMW Gina. No plans to actually do this, they said then. Maybe they are ready to change their minds. This is a new world. The dangers are real. And we need to use every trick we can think of to help us survive.


My blogs deal with various concerns of mine, not only architecture and the role of structural form. Of major interest are the forces in the economy which prevent us from regaining a sustainable environment and finding ways of overcoming them. As a concerned technologist I want to see technology utilized to regain harmony in a peaceful world. I believe in the possibility of an undivided world in which technology and the arts are in tune, utility and beauty are not enemies, the ideal is the goal for the practical. I have tried to express this conviction in my life including my work in architectural structures. They span spaces with an uncanny lightness, admitting soft daylight, their gentle grace revealing nothing but their structural nature and form itself.


    In a pure gasoline car, thats what you get. In a parallel hybrid  that efficiency reaches 35% to 50%. A series hybrid, combining electric motors driving the car, with a small, constant speed gasoline motor making electricity, can reach 70% efficiency. That’s why the converted series hybrid Mini gets 80 miles/gallon. Now, make the lithium battery larger so it can be plugged into an electric line between trips, and the overall efficiency can be further increased, lets say to the equivalent of 120 miles/gallon.

    So, why is nothing like the series hybrid Mini Cooper on the market?! Why is my Toyota Prius a parallel hybrid? Amazingly, the answer is not technical or even logical. It is in a sense ‘fundamentalist’ in character. As the top technologist of a leading car company said in a symposium not long ago: ‘Gentlemen, after all our task is the refinement of the gasoline engine’. This is the explanation for GM destroying their electric cars, for Toyota choosing the wrong hybrid, when the right one is less expensive to built and much more efficient. So what has happened since the appearance of the hybrid Mini Cooper? A number of companies have begun to develop cars along a similar line.

By now most of us understand that we need to take giant steps to deal with the problem of global warming. Automobiles are one important part. And here - as in most areas - the needed technology has already been invented. But it needs to be implemented. Let me tell you about it.

    In 1904 Ferdinand Porsche’s hybrid race car won most car races.  Because it was a hybrid car, the right kind of hybrid car. Electric motors located in the front wheels drove the car. You can see them in the photo. The electricity was made by a small gasoline motor running a generator. The race car was a variation of a Lohner-Porsche motorcar, 300 of which were sold between 1898 and 1906 in Vienna, Austria. It was Porsche’s first car design. He went on to become the most prominent automotive engineer of the twentieth century.

    There are several types of hybrid cars, the most important being serial hybrids and parallel hybrids. You find excellent illustrations on the “Hybrid Center”.