Benz Patent-Motorwagen - Specifications

Specifications

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.

The first Motorwagen used the Benz 954 cc single-cylinder four-stroke engine. This new engine produced 2⁄₃ horsepower (0.50 kW) at 250 rpm in the Patent-Motorwagen, although later tests by the University of Mannheim showed it to be capable of .9 hp (0.67 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. The first model of the Motorwagen had not been built with a carburetor, rather a basin of fuel soaked fibers that supplied fuel to the cylinder by evaporation.

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 mph (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.