Benz Patent-Motorwagen

The Karl Benz Patent-Motorwagen (or motorcar), built in 1885, is widely regarded as the first automobile, that is, a vehicle designed to be propelled by a motor.
The vehicle was awarded the German patent, number 37435, which Benz applied for on January 29, 1886. Following official procedures, the date of the application became the patent date for the invention once the patent was granted, which occurred in November of that year.
Benz officially unveiled his invention to the public on July 3, 1886 on the Ringstrasse (Ringstraße) in Mannheim, Germany.

After developing a successful gasoline-powered two-stroke piston engine in 1873, Benz focused on developing a motorized vehicle while maintaining a career as a designer and manufacturer of stationary engines and their associated parts.



The Benz Patent-Motorwagen was a three-wheeled automobile with a rear-mounted engine. The vehicle contained many new inventions. It was constructed of steel tubing with woodwork panels. The steel-spoked wheels and solid rubber tires were Benz's own design. Steering was by way of a toothed rack that pivoted the unsprung front wheel. Fully elliptic springs were used at the back along with a live axle and chain drive on both sides. A simple belt system served as a single-speed transmission, varying torque between an open disc and drive disc.
Karl Benz - detail from gravestone
Working replica of the 1885 Benz Motorwagen in Frankfurt, 2007

The first Motorwagen used the Benz 954 cc single-cylinder four-stroke engine. This new engine produced ⅔ hp (½ kW) at 250 rpm in the Patent-Motorwagen, although later tests by the University of Mannheim showed it to be capable of .9 hp (0.7 kW) at 400 rpm. It was an extremely light engine for the time, weighing about 100 kg (220 lb). Although its open crankcase and drip oiling system would be alien to a modern mechanic, its use of a pushrod-operated poppet valve for exhaust would be quite familiar. A large horizontal flywheel stabilized the single-cylinder engine's power output. An evaporative carburettor was controlled by a sleeve valve to regulate power and engine speed.

Benz later built more models of the Motorwagen, model number 2 boasting 1.5 hp (1.1 kW), and model number 3 with 2 hp (1.5 kW), allowing the vehicle to reach a maximum speed of approximately 10 miles per hour (16 km/h). The chassis was improved in 1887 with the introduction of wooden-spoke wheels, a fuel tank, and a manual leather shoe brake on the rear wheels.