A Powerful Cross-compound Double-acting Reciprocating Engine That Could Save Lives

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About: Began studying automotive technology in high school for 2 years. Retired as Chief Engineer at Process Fab Inc, Santa Fe Springs, California

I was surprised that air pollution kills 40,000 people a year in England alone. That was announced by Jeremy Corbin leader of the opposition party on July 17, 2019, in "Questions to the Prime minister". The Government will not be able to fix the problem until 2099. (3,200,000 deaths later).

This matter is serious enough to look into alternative propulsion systems. It seems that acceptable pollution levels can not be attained without a great deal of mechanical complexity and cost penalties.

Investigators conclude that the reciprocating steam engine is at least a reasonable alternative to IC engines for automotive applications after carefully weighing the pros and cons of many potential systems, such as the Fuel-cell systems, Battery systems, Gas Turbine engine, and Stirling engine.

The Rankine-cycle reciprocating steam engine is somewhat less polluting than either the gas turbine or the Stirling engine, quiet, and not too complex. It has the multifuel capability, high specific power and energy, moderate efficiency, and a very favorable torque-against-speed curve.

I made a video of such an engine as shown in steps 1 to 7 in this instructable. One of the many reasonable alternatives to IC engines for automotive applications. It was modeled similar to the Stanley Steamer using standard off-the-shelf items. If you are interested in building the entire system including the boiler, pump motor, and condenser. I wrote a self-published e-book or paperback in KDP Amazon on how to build the system for yourself with instructions and detailed calculations for support.

The engine is adaptable and may be installed in many configurations, with or without transmissions in a transverse engine front-wheel drive, rear-wheel differential drive or as a direct-drive config with the built-in reverse linkage option.

The direct-drive config may be used as a generator for home backup power.

A wooden paper mockup or a 3D printed model may be made to get a better understanding of the model prior to making the real deal.

The primary purpose of this instructable is education - for the student, the designer, and the individual whose interest and the aim is to design and build his or her propulsion system using steam energy. The material selected for the presentation has been carefully prepared to give the reader a basic understanding of the requirements for the new steam-power propulsion design.

Supplies:

The engine material parts are called out in the assembly and detailed drawings in steps 1 to 7. Click-on the image and you should see the material and finish call-out in every detail with overall sizes.

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Step 1: Cylinder Head Assembly

The first step is making the cylinder head assembly. The design concept cylinder-piston assembly includes two cylinders, two pistons, two sliding valve assemblies, one input and output steam chest with steam pipe connections. Some brazing is required to secure the feed and exhaust ports.

The two power cylinder-piston assemblies and two sliding valves assemblies are mounted on the front closure panel. The input and exhaust chest are also mounted on the panel with standard NPT type fittings.

The pipe components I used were from McMaster-Carr catalog. Another source of supplies may be purchased from your local plumbing supply house. They may have to order some parts per required drawing pressure ratings. Most of the welding and brazing for this project is done here.

Detail 23 plate, may be made from a flat pattern sheet metal. The radius corner flanges may be eliminated for the flat pattern option.

Valve assembly

The slide valve is a valve which controls the inlet and exhaust of steam by sliding across the ports. A method for fine-tuning is available by turning item 7 in quarter-turn increments in the clockwise or counterclockwise direction. After the engine is assembled, it is connected and driven with standard shop air for final adjustments.

Input chest assy

The input chest assembly includes 3 standard pipe fittings. The 4512k62 fitting is threaded on each end of the 44615k474 fitting. The 44615k474 fitting is modified with 2 through holes as shown in the illustration.

Step 2: Stephenson Linkage

The second step is making part of the internal assembly known as the Stephenson linkage. During the 1830s the most popular valve drive for locomotives was known as gab motion in the U.K. and V-hook motion in the U.S.A.

In 1841 two employees in Stephenson’s locomotive works, draftsman William Howe and pattern-maker William Williams, suggested the simple expedient of replacing the gabs with a vertical slotted link, pivoted at both ends to the tips of the eccentric rods. To change direction, the link and rod ends were raised or lowered employing a counterbalanced bell crank worked by a reach rod that connected it to the reversing lever.

Step 3: Crosshead Assembly

The next step is making two crosshead assemblies. The drawing shows one side. Remember there is an opposite assembly as well. Same pieces but arranged in an opposite configuration.

The slide portion is made from Grade 142 Rulon which is bronze filled and often used to fabricate linear slides and piston rings

Temperature Range: -400° to 550° F

Tensile Strength: 2,000-3,100 psi

Impact Strength: 6 ft.-lbs./in. (Excellent)

Hardness: Not Rated (Medium)

Rulon PTFE, a PTFE material that’s been modified with an epoxy-coated fiber. In addition to having the superior chemical and temperature resistance of PTFE, they have excellent impact resistance and a super-slippery surface that resists wear. These easy-to-machine sheets are nonabsorbent, so they won’t swell when exposed to water.

Step 4: CrankShaft Assembly

This step includes making the components for the power shaft.

The crankshaft assembly includes a 4.2 diameter spur gear, 4 cams ( items 27,29,30 and 31), and 2 flywheel weights mounted on a 7/8 diameter keyway shaft. The power-transmission elements and cams are located close to the supporting bearings.

The gear manufacturer is RushGears.com. The part number is F1040 with a pitch type DP. Also, pitch is 10, PD is 4, number of teeth is 40, pressure angle is 20 degrees, the outside diameter is 4.2, the face is 1.0 inches, the bore is 0.875 diameter, keyway width is 0.1875, depth is 0.0938, the service factor is 1.25 and the duty cycle is continuous. The material is 440F SS.

Step 5: Main Drive Shaft Assembly

This step includes making the components for the main drive shaft.

The driveshaft assembly includes a 6.2 diameter spur gear, 3 pulleys, and hub adapters all mounted on a 7/8 diameter keyway shaft. The power-transmission element is located close to the supporting bearings.

The gear manufacturer is RushGears.com. The part number is F1060 with a pitch type DP. Also, pitch is 10, PD is 6, number of teeth is 60, pressure angle is 20 degrees, the outside diameter is 62, the face is 1.0 inches, the bore is 0.875 diameter, keyway width is 0.1875, depth is 0.0938, the service factor is 1.25 and the duty cycle is continuous. The material is 440F SS.

Step 6: Internal Assembly

The next step is assembling the internal sub-assemblies per drawing.

The Internal assembly includes the Crankshaft, Stephenson Linkage, Driveshaft, Crossheads, Propeller adapter, and Rear panel.

Four standard threaded rods, 5/8-11 UNC-2A x 23 inches long are used to secure all the subassemblies in the proper orientation. The Internal assembly is easily attached to the Cylinder-piston assembly with fasteners provided.

Step 7: Final Assembly

The final step is to assemble all the subassemblies.per drawing. After the final assembly, you may use standard shop air to power the unit and adjust the assembly if required. Adjustments are made by turning the cylinder input connections (item 7) clockwise and/or counterclockwise as required.

Based on the following conditions, grease shall be used as the primary lubricant:

1. The temperature in the casing is not expected to go over 200 degrees F

2. The speed is low

3. Unusual protection is required from the entrance of foreign matter

4. Simple bearing enclosures are desired

5. The operation for long periods without attention is desired

Step 8: Engine Shown Installed

The Rankine cycle engine must also include 3 additional components for energy and transfer. The boiler (burner), radiator(6-inch core) and a water motor/pump. A midsized pickup with a standard rear-drive differential (3:1 ratio) is shown as one idea for integration. Transmissions are not used. The Cross-Compound Double-acting Reciprocating Engine is shown installed on the vehicle chassis. A propeller shaft is connected to the drive shaft via a standard spline. The input and exhaust piping are shown connected to the steam chest. The fuel selected is propane at 1,400 Kelvin with 100-percent theoretical air produces 23.8 MJ/kg fuel.

The engine may also be installed directly onto a flywheel if a transmission is preferred. The flywheel is installed on the torque convertor inside the transmission.

Another option may be used for the Transverse-engine front-wheel drive as well. As shown in the illustration from Wikipedia.

Thank you for watching and good luck.

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    3 Discussions

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    davy2285

    4 weeks ago

    I would like to add a comment regarding gear ratios for a direct drive configuration. Steam-driven engines have fantastic torque values. Therefore, rear differential gear set ratios are not required to boost the torque values as needed for the IC engines. Since all rear differential gear sets include gear ratios designed for IC engines then the internal gear set in the steam engine must be made to accommodate.
    For example, if a 9 inch Ford differential is used with a 3.75 ratio, and the given steam-driven engine rotation speed is 600 rpm, then an internal gear set in the steam-driven engine must be used to match. Otherwise, you may not be traveling as fast as you would like. Yes, you would have plenty of power but not the speed.
    With this design, simply replace the internal gear set with the preferred number of teeth (gear ratio). Also, switch the existing differential gear ratio to the lowest set offered, such as 3.75:1 to 3:1.

    Note, the engine is adaptable. If a rear-wheel or transverse engine front-wheel-drive configuration is used with a transmission, then the engine may be attached to the flywheel similar to were the IC crankshaft was attached.

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    russ_hensel

    4 weeks ago

    Do not quite get where the steam comes from. How big would a 200 Hp boiler be?

    1 reply
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    davy2285russ_hensel

    Reply 4 weeks ago

    Hi Russ

    The steam comes from a mono-tube boiler. Which was not part of this presentation. For a 200 hp boiler, the size would be 1.1 ft diameter x 1.68 ft high. The tubing diameter would be 1/2 inch OD, 6 coils per row, 40 rows with a transverse pitch of 1.0 and longitudinal pitch of 1.4 The weight would be 97 lbs. Heat transfer rate would be 190,000 btu/hr. Please refer to NASA TN-D-5813 table 2 for more details. For details on a complete propulsion system please refer to the Paperback or kindle ebook .
    Best regards
    Dave