THE STIRLING ENGINE COMES OF AGE

The search for new power sources for a fuel-hungry and environmentally conscious world has focused on the Stirling enginetechnology has now made this remarkable powerplant one of the most attractive alternatives to the internal combustion engine.

External combustion: quiet, multifuel, versatile The Stirling is an external combustion engine that converts heat into driving power by continuous heating and cooling of a captive working gas. It can be adapted to run on almost any fuelliquid, solid or gasor even solar energy.

Continuous combustion at high temperatures results in complete combustionvirtually pollution-free. Nitrogen oxide levels are very low. Carbon monoxide and unburned hydrocarbons are almost nonexistent. And, without the rapid-fire explosions

that take place in reciprocating inter-nal combustion engines, the Stirling runs whisper-quiet.

Potential uses are almost limitless. Stirling engines have been tested in automobiles and boats. They can also be used to power portable electric generating sets, water pumps, heat-ing systems and refrigeration units.

A Stirling engine is the heart of a new total energy systemthe Stirling Power Pack. It provides a clean, quiet and completely independent source of power for electrical equipment, lighting, heating and cooling.

N. V. Philips generator set, 1952. Swedish Stirling Engine generator set prototype, 1972.

Rider water-pumping engine, about 1900. Robert Stirling's design, 1816.

1816: Stirling power is born Reverend Robert Stirling, a noted 19th Century Scottish engineer and theologian, invented the engine that bears his name.

He patented the engine in 1816, at the age of 26. Two years later, a large Stirling engine was built to pump water from a quarry at Ayrshire, Scot-land.

Throughout the 1800s and well into the 20th Century, various adaptations of the Stirling engine appeared in many applications. They pumped water in the arid western U.S. cattle ranges, on the railroads, in mines and supplied water for numerous resi-dences and estates. Small Stirling cycle engines powered dentists' drills, household fans, sewing machines and popcorn shakers. Larger models were used to power winches and in other industrial appli-cations. Liquid, gas and solid fuels were used. Lake Breeze fan, 1918.

Several of those early engines were developed by a Swedish inventive genius named John Ericsson, whose best-remembered project was the ironclad fighting ship "Monitor" of U.S. Civil War fame. Ericsson developed many engines on the Stirling principle for business, industry and agriculture. With an eye to the then-distant future, he even built a Stirling "sun motor" powered by solar energy.

The Stirling was limited by turn-of-the-century metallurgy, however. The newly developed gasoline engine and electric motor quickly gained popular-ity, and the Stirling engine was all but forgotten by the 1920s,

Interest was rekindled in 1938, when N.V. Philips, of Holland, began development of a small Stirling en-gine. Philips, a manufacturer of port-able radio equipment, used the en-gine as a compact, quiet power source whose spark-free operation created no radio interference.

In 1968, the Swedish FFV Group formed a joint venture with other Swedish companies to explore the possibilities to develop advanced production versions of the modern Stirling engine. The new joint venture was called United Stirling. Based on a license from United Stirling, the FFV Group developed a specific version of the Stirling engine, today's V160 engine.

Many organizations have been in-trigued by the Stirling engine's poten-tial in transportation. Evaluation of the engine for automotive power con-tinues today under the sponsorship of several companies and governmental agencies including the U.S. Depart-ment of Energy. The engine is being considered both as a direct automo-tive power source, and for use in "hybrid" Stirling/electric vehicles. How it works. The Stirling engine operates on the principle that gas expands in volume when heated, and contracts in volume when cooled.

Like a reciprocating internal com-bustion engine, the Stirling engine has pistons that move up and down in en-closed cylinders. The Stirling engine, however, uses continuous heat from an external combustion chamber rather than burning fuel within the cylinders.

The heater tubes within the com-bustion chamber heat the working gasusually helium or hydrogen which moves back and forth between the "hot" and "cold" sides of the en-gine. The working gas is completely enclosed. A regenerator between the two sides captures heat from the gas when it moves from the "hot" side, and releases heat to the gas when it moves in the other direction.

As shown in the simplified illustra-tion below, expansion of the gas on the "hot" side pushes the piston and produces power.

1-2: Compression. Working gas is com-pressed on cold side.

2-3: Displacement. Gas moves from cold to hot side.

3-4: Expansion. Pressure increases, heated gas expands.

4-1: Displacement. Gas moves from hot to cold side.

EFFICIENT POWER, WHEN AND WHERE YOU NEED IT

Today's production model Stirling V160 engine was designed to fill the need for a small, quiet, multifuel powerplant.

It is engineered to take full advan-tage of the basic Stirling engine at-tributes:

Low noise and vibration levels Multifuel capabilities Low exhaust emissions Low lubrication oil consumption Those design objectives are met by

the V160 Stirling engine, developed and manufactured by the Swedish FFV Group.

The V160 is a 90 degree, two-cylinder, V-type engine. It is a "single-acting" Stirling engine, with one compression piston and one ex-pansion piston. Between the cylinders are the combustion chamtjer, re-generator and gas cooler. The model number is derived from the engine's 160 cc swept volume.

STIRLING ENGINE V160

When compared with the standard Otto-cycle engine, the Stirling V160 is superior in several important areas: noise levels, exhaust emissions, odors, vibration and fuel economy.

Because fuel is burned in an exter-nal-combustion chamber, combustion by-products don't contact pistons or cylinders. Engine oil is not contami-nated. This contributes to engine re-liability and service life, and virtually eliminates the need for oil changes.

Cylinder block

Expansion plug

Water pump

Oil cooler

Regenerator

Cooler

Compressor plunger Compression piston

Oil filter

Reduction valve with spring

Oil sump

Magnetic plug

Water pipe

Compressor housing

r

Heater unit

Swept volume 160 cc (9.76 cu. in.) Cylinder bore 68 mm (2.68 in.) Stroke 44 mm (1.73 in.) Power (max.) 15 KW (20 hp) @ 3600 rpm Weight 100 Kg (220 lbs)

Starter motor Engine type 2-cylinder V-type, 90 degree

Pre-heater

Fuel tank

Helium compressor

Piston rings Sealing unit Cross-head with piston rod Oil jet

Crankshaft Connectingrod STIRLING V16CJ ENGINE

SPECIFICATIONS

Thermocouple

Heater tubes

Dome

Expansion piston Electronic unit

AIR-FUEL SYSTEM STIRLING ENGINE V160

Airflow meter

Generator

Discharge valve

Phase regulation valve

Filling valve

Fuel valve

Flame guard

Helium tank

Fuel pump

POWER CONTROL SYSTEM STIRLING ENGINE V160

Fuel filter

Non-return valve

Thermocouple

i