Happy Birthday, Hybrids! You may not have known it, but March 2 is the 100th anniversary of the granting of the first US patent for what was called the “Mixed Drive for Autovehicles.”
Henri Pieper, a German-born inventor and gunmaker in Belgium, submitted his application on November 23, 1905—and was granted a US patent on March 2, 1909. Its opening paragraph says:
“Be it known that I, Henri Pieper, a subject of the King of Belgium, residing at 18 Rue des Bayards, in Liege, Belgium, have invented new and useful Improvements in Mixed Drives for Autovehicles…The invention…comprises an internal combustion or similar engine, a dynamo motor direct connected therewith, and a storage battery or accumulator in circuit with the dynamo motor, these elements being cooperatively related so that the dynamo motor may be run as a motor by the electrical energy stored in the accumulator to start the engine or to furnish a portion of the power delivered by the set, or may be run as a generator by the engine, when the power of the latter is in excess of that demanded of the set, and caused to store energy in the accumulator.”
Voila: the gas-electric hybrid!
Today, hybrids are celebrated as fuel-saving marvels of the high-tech age—but as shown by Pieper’s US patent, the basic concept is more than a century old. And yet M. Pieper was not the first engineer to create a hybrid car.
In 1898, the 23-year-old Ferdinand Porsche built his first car, the Lohner Electric Chaise—the world’s first front-wheel-drive vehicle. Porsche’s second car design was a series hybrid (like the Chevrolet Volt, due out in 2010) in which a combustion engine ran a generator that powered electric motors in the wheel hubs. Its battery could take Porsche’s hybrid car nearly 40 miles—the same as promised by the Volt. Plus ça change…
Pieper applied for his patent a year or two after Porsche built his hybrid. The patent describes processes that are now well known to hybrid engineers and mechanics—including the parallel-hybrid design, and electric assistance for the engine under load:
“As long as the amount of power required falls short of that developed by the engine, the excess is utilized in charging the secondary battery. As soon, however, as an increase in propulsion power is required, as will happen, for example, whenever the car encounters an up-grade, the slackening of the speed causes the dynamo to work as a motor, thus supplying the engine with the additional power which it requires to keep an approximately uniform speed.”
Pieper even developed a rudimentary battery- and engine-management system. He writes in the application, “I have devised an automatic regulator…for preventing the battery from being overcharged, or improperly charged, and for regulating the volume of the explosive charged in proportion to the work which the engine is called upon to perform.”
Unlike today’s hybrids, the driver of Pieper’s vehicle changed modes using a hand lever. Drivers also controlled a magnetic-disc clutch that connected the engine to a DC motor-generator, or dynamo, which in turn was connected to a gear-set that turned the rear wheels via chain drive.
The driver’s hand lever moved through positions that operated a series of mechanical switches and relays. Mode One used the dynamo as a starter motor to fire the engine, which normally powered the vehicle alone. Another mode used road motion to charge the battery—what we would call “regenerative braking.” A further mode sent battery power to the dynamo to supplement engine torque. And a last mode spun the dynamo backward, providing an electric reverse gear.
In every case, the engine’s fuel-air mixture and spark timing were controlled automatically based on the lever position. In addition, the driver could disengage the clutch, shunting all engine power from the final drive to the dynamo, to charge the batteries.
Timing is Everything
From 1906 to 1910, a few Auto-Mixte vehicles using Pieper’s hybrid system were built in Liege. Most were delivery and commercial vehicles, though at least one car chassis was shown at motor shows in Belgium.
But while Henri Pieper may have been a brilliant inventor, his timing was horrible. The year before his patent was granted, Henry Ford built the first assembly lines in Detroit to produce the Ford Model T—the first affordable, mass-production car. It would cement the primacy of the gasoline engine to power road vehicles.
The rest, as they say, is history. Steam and electric cars gradually faded from view, and by the 1930s, production of hybrid and electric vehicles—a few based on Pieper’s patent—had screeched to a halt.
One hundred years and a gazillion gallons of gasoline later, the hybrid gas-electric car has reemerged as an effective and feasible alternative to gas-only internal combustion vehicles. More than 1.5 million hybrid cars can now be found on roads around the world.
The basic concept of a parallel hybrid—still put to use in today’s hybrids like the Toyota Prius—hasn’t changed much since Pieper got his patent, but the world is a very different place. Global warming, air pollution, and erratic oil prices pose new threats. Ironically, clues to the way forward can be found by looking back a century: to the words and drawings of Henri Pieper.