Benz Patent Motorwagen

From Wikipedia, the free encyclopedia

Benz Patent Motorwagen

Manufacturer:	Rheinische Gasmotorenfabrik Benz & Cie.
Production:	1886–1893
Successor:	Benz Velo

After developing a successful gas-powered two-stroke piston engine in 1873, Karl Benz focused on developing a motorized vehicle. His Patent Motorwagen (or Motor Car), introduced in 1886, is widely regarded as the first purpose-built automobile, that is a vehicle designed from the ground up to be motorized. Benz unveiled it officially on July 3, 1886 on the Ringstraße in Mannheim, Germany. The vehicle was patented with German patent number 37435, which Benz applied for on January 29, 1886.

[edit] Specifications

The Patent Motorwagen was a three-wheeler with a rear-mounted engine. It was constructed of steel tubing with woodwork panels, and 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 kind of single-speed transmission, varying torque between an open disc and drive disc.

The first Motorwagen used Benz's 954 cc single-cylinder four-stroke engine. This new powerplant produced &frac23; hp (½ kW) at 250 rpm in the Patent Motorwagen, though Mannheim University's later tests showed it to be capable of .9 hp (0.7 kW) at 400 rpm. It was an extremely light engine for the time at 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 Motorwagens, number 2 boasting 1.5 hp (1.1 kW), and number 3 with 2 hp (1.5 kW). The chassis was improved in 1887 with wooden-spoke wheels, a gas tank, and a manual leather shoe brake on the rear wheels.

[edit] Bertha Benz's trip

Benz's wife, Bertha, publicized the Patent Motorwagen in a unique manner — she took the car without her husband's knowledge and drove on the first long-distance automobile trip. In August, 1888, Bertha and sons Eugen and Richard (15 and 14 years old) drove through Weinheim, Heidelberg, Wiesloch, and Durlach, to Bertha's home town of Pforzheim. She acted as mechanic on the drive as well, cleaning the carburettor with her hat pin and using her garter to insulate a wire. She refueled in Wiesloch, and replaced the brake lining several times along the journey. She returned home the next day, with the trip covering 180 km (112 mi) in total.