Sunday, December 24, 2006

Why not modern steam powered cars?

Maybe anything that will burn can produce steam. The power and torque of a steam engine is legendary. If the per mile cost were way cheaper than gas and trash, methane from dumps and agriculture, fuel oils, wood, coal, and other energy sources could be burned cleanly, maybe we could tell the fossil fuel produces to go screw.

Excerpt:


Here is where the steam car really shines.

The steam engine develops maximum torque at minimal revolutions, right from the start, therefore, no clutch or transmission is needed. This torque is not inconsequential either. The simple Stanley 20 HP two cylinder engine develops at maximum, some 640 lbs/ft of torque. The legendary Doble at maximum pressure develops 2200 lbs/ft of torque on the crankshaft. These levels can not be matched by anything in any normal automobile, plus, the engines just loaf along at highway speeds. Their gear ratios between the engine crankshafts and the axle shafts is usually 1-1/2 to one, bringing silent and vibrationless operation, and also delivering extremely long engine life.

This massive torque produces high acceleration rates, not easily equaled by their contemporary gasoline engined cousins. Their performance is exemplary.

The only driver input is the throttle position and whether the car is to be driven forward or backward. No other driver decision is required in the later steam cars.

The control of the power system has been fully automatic since 1907 in the better makes of steam cars, notably the White. Today, the driver of such a modern steam car would only need turn on the key switch and moments later drive away.

The car takes care of itself in all respects of steam pressure and temperature. You could simply ignore it.

This does not also imply that some highly complex multi computer system is demanded, such complication and expense is not needed nor wanted. Simple relay logic controls are well developed and have been used for the past seventy five years in steam cars with complete success.

Microprocessors and limited computer control systems can be applied to the steam car to provide totally automatic operation and complete operational safety if really desired; but it would be a minimal involvement. There is no need to incorporate some complex computer controlled system, when a much simpler version will perform all the necessary functions with reliability.



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The Wankel Rotary Engine.

This engine has very interesting possibilities if given sufficient development. It does offer a powerful package in a small volume and mechanical simplicity and good balance. It is an expensive engine to have to construct from scratch; but not if one started with a production Mazda Wankel 13-B or three rotor 20-B basic engine.

As a gasoline engine with a turbocharger added, it is capable of very high power output, high torque and a reasonable speed range. The racing activities of the Mazda Corporation has produced seal materials that withstand full power output for long periods. After all, they did win the 1991 LeMans 24 hour race with a Wankel engine. This four rotor engine developed over 700 HP and over 450 lb/ft of torque while being highly turbocharged. This shows that the modern Wankel engine with available racing seals and strengthened hub and rotor gears works at a very high BMEP, actually higher than would be needed in a steam car application. This special racing hardware is easily available off the shelf, making the development of a steam conversion a relatively easier matter than if one had to develop special hardware from scratch in order to make it survive while giving high power and massive torque.

Case distortion due to the high steam temperature would also require careful analysis. The Mazda rotary engine when used in racing has a reputation of fatal distortion problems if allowed to severely overheat. One may observe the rather large oil cooling radiators used in such cars. However, analysis of the heat distribution and modification of the clearances used, could provide a solution, as the ultimate temperature when used as a steam expander is considerably below what would be reached in an I.C. engine with failed oil cooling. There are also good material changes that would benefit the use of the Wankel engine as a steam expander. This appears to be an easily solvable design problem.

If converted to steam, it requires a good inlet valve design that would work at one-third output shaft speed. Again, a double-seated balanced poppet valve is ideal.

However, being a positive displacement design, the output shaft speed can be kept to under 4,000 RPM and permit a more normal cam operated inlet valve, while still delivering optimum power for the displacement.

The rotor in the Wankel engine turns at one third the speed of the output shaft. In one aspect, this is a very good thing in that the apex seal rubbing speed is only one third what it would be if it ran at shaft speed.

Several investigators have proposed that the Wankel engine be used with two inlet valves and two exhaust ports per working chamber. If one examines a dismantled Mazda 13-B engine, it will be seen that to use the maximum chamber volume for expansion, the inlet and exhaust ports would be slightly in excess of 180° apart. This indicates that trying to incorporate two inlet and exhaust ports would by necessity either reduce the working volume, or cause some serious timing overlap that would let the incoming steam rush directly out of the exhaust port. Both of these conditions would seriously reduce the potential expansion ratio and thus lower the final water rate. This is not acceptable for obtaining the highest efficiency that the Wankel is capable of delivering.

2 Comments:

Anonymous Kathleen M. Dickson said...

Steve,

You have to burn something to make the steam. Nuclear power plants heat up the steam. Steam turns a turbine in a steam engine. Something makes the steam. It's just an extra step.

You have to understand the laws of thermodynamics to know what you are talking about when it comes to energy.

Monday, December 25, 2006 11:08:00 AM  
Anonymous Lane Lombardia said...

By itself, a steam engine has an achilles heel of needing to heat up before it can do anything. As part of a waste heat recovery system in a cogenerating internal combustion engine, it makes perfect sense. There already is enough heat being vented to the ambient environment that could be captured and used. An example of such a system is BMW's turbo steamer in which steam created with waste heat drives a turbine. In a diesel application, steam could also be used to drive a compressor, allowing pressurized and leaner operation even from idle, which a conventional turbo diesel is not able to do.

Thursday, September 11, 2014 12:50:00 PM  

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