Rudolf Diesel’s lesserseen engines—energy cell engines

LANOVA: CUSHIONED POWER

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If you’ve regularly read the “Vintage Smoke” or “Tractor Talk” columns in this magazine, you’ll remember that Lanova has popped up more than a few times. From the 1930s to almost the 1970s, Lanova diesels were a major part of the worldwide landscape. You are about to learn why.

The Lanova is a variation of the air cell class of diesel first conceived, although never built, by Rudolph Diesel. Strictly speaking, the Lanova is an energy cell diesel, not an air cell. The difference is that an energy cell engine injects a certain amount of fuel into the cell; an air cell does not. In the energy cell combustion chamber, when that smaller charge ignites, it blasts out into the main chamber, creates turbulence and helps the main charge mix better.

With an air cell combustion chamber, the air cell merely stores a certain amount of the air from the compression stroke. As combustion begins, the piston moves down the bore, cylinder pressure begins to drop, and the air is released into the chamber, promoting more-complete combustion by better mixing the fuel and air. Clessie Cummins introduced this feature into the Model U diesel, calling it the “Sneezer.” Several series of Cummins engines had them.

You can see how the Lanova cell works in the illustration on the facing page, but both types have a small chamber off the main combustion chamber that are connected by a small passage. The volume and size of the air/energy cell were carefully calculated, as was the size of the passage that connected the cell to the main chamber.

While direct injection was known back in the day to be more efficient, the engine-building technology of the day was insufficient to utilize it economically in smaller, automotivesized applications. The early low-pressure fuel-injection systems delivered marginal atomization, and poor air/fuel mixing made ignition erratic. Fuel had to be injected early in the compression stroke, and when the fires lit, they lit hard, noisily and somewhat unpredictably. This required robust engines that were difficult to downsize at the time. The available fuel of the time, which was generally of inconsistent quality compared with today’s, greatly added to the trouble.

The key benefit of the energy cell engine—the Lanova being one of the best refinements of it—was that the combustion process was very controlled. Instead of the sharp hammering of a DI system, it was a slow, but strong, push. A lower compression ratio could be used, further easing the engineering requirements and enhancing smooth operation.

Some Lanova engines were conversions of HD gasoline lower ends, and they did well. Reputedly, the Lanova engines, being more or less direct injected, cold-started better than the IDI pre-chamber engines on the market at the time.

Papa Lanova

The Lanova energy cell was the brainchild of Franz Xaver Lang (1873–1956), whose history with diesel engines

goes right back to the beginning. Lang had apprenticed as a locksmith in his hometown of Altomünster, Bavaria, Germany, but internal combustion drew him away before he started that career.

In 1898, Lang went to work for MAN (Maschinenfabrik Augsburg-nürnberg), where Dr. Diesel was doing his ground-breaking work on compression ignition engines. In a career-enhancing stroke of luck, Lang was assigned to work with Diesel on those projects and became one of his most trusted engineers. During those pivotal days, Lang was in charge of setting up new engines and testing them. Diesel said of Lang, “He has the feel of an engine.” While Rudolph Diesel is often thought of as more a theorist than a hands-on engineer, Lang became both.

Like many of his peers, Diesel included, Lang realized the limitations of the air blast fuel systems (high-pressure air to atomize and inject fuel) used on the first diesels. This realization came with the knowledge that it was very difficult at the time to build a device to inject liquid fuel directly into a highly compressed cylinder. Even when that was done, the combustion process was difficult to control and violent in an open chamber, requiring a heavily built engine to reliably convert combustion into power. When his time working for Diesel was finished, Lang set his sights on developing a system that addressed these issues.

Lang continued to work at MAN, learning his craft, in the early years of the 20th century. In his spare time, he experimented and, in 1910, he built in what was then the smallest working diesel engine—a tiny, 7.55-cubic-inch engine (1.5625 x 3.9375-inch bore and stroke) with indirect liquid injection. By 1914, Lang had 26 patents in his name, mostly for fuel injectors or injection pumps. Along with Knut Hesselman (see part 1 of this article in the June Diesel World issue), he was one of the first two engineers credited for

developing the now-familiar barrel-and-plungerstyle injection pumps.

By 1922, Lang had left MAN to open his own technical development company. By 1923, he had designed a full-scale air cell system. It was introduced worldwide with the help of Albert Wielich (1879–1942), a businessman, financier and friend. Wielich, a transplanted German living in the United States, had global connections, and his business acumen left Lang able to focus on the technology.

The new design was featured in U.S. periodicals, but nothing came of that right away. An engine based on it was developed and licensed by Acro of Switzerland. Known as the Lang-acro, it featured an air cell contained in the piston and an advanced liquid-injection pump.

Both the Acro and the injection pump it used came to the attention of Robert Bosch (1861– 1942) in the early 1920s. Bosch had dominated the spark ignition market in Europe with several pivotal advances and wanted to do the same in the burgeoning diesel injection market. Bosch hired Lang and bought the Acro patents in

1925. Lang contributed to Bosch developing the first practical high-pressure injection pumps and further refined the air chamber design. However, “creative differences” and disputes over patent rights led to Lang parting ways with Bosch in October 1926.

On his own, Lang made additional refinements to the air cell design and contemplated marketing and licensing the strategy. Patent disputes held back implementation; but, in a relatively short time, Bosch and Lang reached a satisfactory agreement. Lang again teamed up with Albert Wielich to form a new company in Liechtenstein to license his air cell technology in Europe under the trade name Lanova (“Lan” for Lang and “nova”—latin for “new”). Several companies in Europe, including the gigantic Henschel & Son, licensed it.

Lanova in America

Not ignoring the U.S. market, Lang and Wielich filed numerous patents on the related technology here, formed the Lanova Corporation in 1931 and built a technology center in New York. They made the rounds of U.S. companies and had almost immediate success with the Buda Engine Company.

Working with Buda, who had previously produced some diesels using MAN technology, they successfully converted an existing Buda engine to the Lanova system. Buda released the first designs into production in 1934, calling them Buda-lanova diesels. Buda used the Lanova system for the rest of its time as a company. Buda was absorbed by Allis-chalmers in 1953, and the new owners continued to use Lanova technology into 1967 before completely moving to direct injection.

Mack came next in 1935 and began designing a new diesel engine around the Lanova system. It came to the market in 1938 as the Mack-lanova and was used into 1953 before being replaced with the legendary Thermodyne diesels.

Chrysler licensed the Lanova system for its short-lived line of Dodge diesels built from 1937 to 1942. Atlas Thornburg licensed it for a line of small diesels, as did Stover and Kohler.

Buda was ultimately the biggest producer of Lanova diesels, and Buda-lanova engines were used by many tractor and truck makers. Waukesha built a Lanova diesel for Oliver tractors, even though its own diesels were pre-chamber types. Case adopted the Lanova system in tractors for 1948, used it to 1969 and was the last engine builder to make Lanova engines in North America.

Lanova: Beyond its Prime

Lanova had its limitations. Power potential was low compared to direct injection, but that wasn’t a problem until better direct- and indirect-injected engines were developed. Lanovas were more economical than IDI, although not on par with DI. But they were very sensitive to changes made to the injection systems or combustion chambers. When a farmer cranked up his pump, the results were often counterproductive. Carbon buildup in the air chamber could also cause problems, so occasional removal of the chambers for cleaning was good maintenance.

Better technology, good diesel fuel and highpressure injection systems eventually made the DI engine more downsizable. Those same advantages helped Idis—most notably, the Ricardo system—to move ahead of the Lanova, and both proved to be more flexible and tunable in the modern diesel landscape.

One of the bigger downsides of the Lanova was its poor response to forced induction. There were several supercharged and turbocharged Lanova engines over the years, but they required a big investment in tuning while yielding only modest power increases, compared with DI or IDI diesels.

So, the bottom historical line is that Franz Lang and the Lanova system gave automotive diesel the short-term “crutch” it needed to downsize for road applications, and it worked well enough to keep the automotive and industrial diesel market moving ahead as technology caught up to provide better products.

This four-cylinder engine from 1923 was a conversion of a German gasoline engine to the Lang-acro system—a precursor to the Lanova developed later. The injection pump developed 650 psi and sprayed into a relatively low-pressure cylinder of about 200 psi (about 12:1 CR). This engine was brought to the United States by Lang and Wielich in one of the first foundation steps of introducing air cell technology here. This, along with a one-cylinder test engine, got Bosch interested in the Lang-acro technology.

The Lang-acro combustion chamber featured an air cell in the piston crown. Mercedes-benz, Perkins, MAN, Cummins and Kreutzer, among others, used an air chamber system of some type, although they were just different enough to escape patent violation charges. After Robert Bosch hired Lang and bought Acro, the design was modified, and the Acro-bosch system was the result. Truck maker A.E.C. of England licensed the Bosch-acro and produced a number of engines using it. However, this company moved on to Ricardo-designed engines because the Bosch-acro licensing was too costly.

The Lanova cycle was extraordinarily gentle combustion, allowing engine manufacturers to make engines smaller and lighter. The injector sprayed across the cylinder into the air cell, and a percentage of the charge went into it. Ignition occurred at the peak of compression pressure and was often simultaneous in both the main chamber and the energy cell. When the fuel in the energy cell ignited, it would blow out into the main chamber and create turbulence, helping to mix the air and fuel better. In some versions of the Lanova, a barrel valve could close off the energy cell, thus raising the compression ratio and aiding cold starts.

The Mack-lanova diesel was a mainstay for Mack into the early 1950s. This one is a 1942 END-519, one of three displacements of the time. They were built for automotive applications and, for a brief time in the 1940s, Mack offered a marine version. They came in 405ci (4x4.375-inch bore and stroke), 519ci ( 4.375x5.75-inch) and 605ci (4.625x6.000) displacements. Power and torque were 107 at 2,200/308 at 1,200, 131 at 2,000/382 at 1,300 and 144 at 2,000/455 at 1,100, respectively. Many considered them benchmark engines of their day.

 This is a 1937 6LD-275 Buda-lanova automotive engine, which could be found in medium-duty trucks of many makes from 1936 to 1939, as well as in marine and industrial applications. It made 274.2ci from a 3.50x4.75-inch bore and stroke, cranking out 72 hp at 2,400 rpm and 216 lb-ft at 1,300. The compression ratio was 13.5:1. It was a smaller-bore adaptation of a gas engine.