Benz Patent-Motorwagen

The Benz Patent Motor Car No. 1 was the name of the first built by Carl Benz automobile with an internal combustion engine. The patent for this tricycle was submitted by Benz on 29 January 1886, issued as DRP No. 37435 on November 2, 1886. On July 3, 1886 Benz introduced the first public test drive with this vehicle by in Mannheim. It is considered the first practical power cars in the world, thus following the birth of the modern automobile.

Technology of the motor car

The engine

Centerpiece of the car was a single-cylinder four-stroke engine with a displacement of 0.954 liters. This had some details that still count among the pillars of any internal combustion engine: the crankshaft with counterweights, electric ignition and water cooling. He made according to the measurements of Benz PS/490 0.67 W at a speed of 250 rpm. ( Later measurements of the Technical University in Stuttgart showed PS/662 0.9 W at 400 rpm. )

The rotational speed of 250 rpm of the engine sufficed Benz perfect, after all, this was already about twice as many as in his two-stroke gas engines. Other points of view of for that time with about 100 kilograms "light" engine had cylinder with open crankcase, controlled via an eccentric inlet slider and the outlet poppet valve, actuated by cam, bumper and rocker arms as well as the lubrication via drip oiler. The large flywheel Benz designed for installation in the chassis lying because he was afraid that in vertical arrangement, the steering and the stability of the vehicle is affected in tight corners due to the gyroscopic effect.

The mixture system was developed by Benz surface carburetor, which also contained a gasoline supply of 1.5 liters. Where it was not gasoline in today's style, but rather an alcohol - gasoline mixture ( ligroin ) also known as benzine, which was available in pharmacies. For the precise composition of the fuel -air mixture caused a sleeve valve, which more or less covers the holes for the additional suction and so regulated the power output. In the vehicle, this tab was easily accessible underneath the driver's seat.

The ignition devoted Benz several attempts until he found a solution that was adjusted to the then low power of the battery current. He transformed the power using a model developed by Heinrich Daniel Rühmkorff spark coil to a higher voltage. The spark plug was developed in-house. Later research showed that the material of its electrodes largely coincided with the commercial spark plugs of the thirties of the 20th century.

The cooling of the engine was a special problem, because it could not be like a stationary engine simply connected to a cooling water pipe. Benz hit upon a simple evaporative cooling, which proved to be effective and adequate for the low performance.

The engine has been let through courageous turning the flywheel. The fact that the fuel level in the carburetor was not enough for a longer distance, Benz does not interfere with the Patent Motor Car on. After all, the drive of the vehicle took around 10 liters per 100 kilometers of what was then still regarded as dangerous ligroin.

Frame and body

The frame was bent from steel pipes and welded. Since the car should have rear-wheel drive, was thus pushed from behind, appeared to the problem of steering, which had to be constructed differently than in a chariot drawn. The otherwise common in carriages turntable steering was out of the question, and after his two-wheeled experience, Benz for lightweight construction and a Tricycle decided, a three-wheeled velocipede ( see patent text). The front wheel hung in an unsprung fork and was driven by a crank connected to a rack. ( It was not until 1893 Benz used a knuckle - steering). The three frosted with solid rubber spoked wheels made ​​Benz itself, only the rims were " external procurement " of the Adler bicycle factory in Frankfurt. The front wheel ran, as it did in bicycle usual, in a ball bearing, the rear wheels in white metal bushes.

The car was driven with a left and right of each chain of the countershaft via the rear wheels, which were in turn connected via a rigid axle and Vollelliptikfedern to the frame. It was at this first automobile on the countershaft only one gear in the form of a mounted drive pulley including a built differential, along with another idler pulley. So no transmission with two or more gears, nor a reverse gear. The flat belt between the motor and countershaft had, thanks to the idler pulley, at the same time as the clutch. The flat belt was simply moved to the start of the Lot to the hard disk. The car's speed was controlled by the sleeve valve underneath the driver's seat. About the engine was enthroned the reservoir for the cooling water. Was slowed by a hand lever, who worked on the countershaft pulley. A foot brake did not exist.

The bench was in front of engine on curved springs directly to the frame and upholstered with stitched leather. Firm grip gave a low, leather-trimmed railing in the back and on the sides.

Worried prepared the chains: The bicycle chains were still deficient, usually too soft and therefore very stretched, jumped out of the gears or torn. But since there was none better, Benz had to make do with the available material.


The first test runs took in 1885 for reasons of secrecy in the factory yard instead, and ended at the factory wall. Also, the first " trip " on the open road - at night - took only a few minutes. After a hundred meters, the car stopped. In numerous experiments, but could be gradually improved the range.

On January 29, 1886 Finally, the vehicle was registered with the Imperial Patent Office under the number 37435. In the first public and documented by newspaper article exit on 3 July 1886 the Ringstrasse in Mannheim his son Eugen runs with a bottle of gasoline on the side "to nachzuschütten when the fuel runs out ."


The car remained a one piece, as well as its direct successor Patent Motor Car number 2 He was first converted into a four-wheel carts and exploited later. In 1903, he was reconstructed. This Benz patent motor car # 1 is today within the transportation hub of the Deutsches Museum in Munich.

World Heritage

In 2011, the patent was included in the UNESCO World Documentary Heritage.

Technical data of the Benz Patent Motor Car No. 1

  • Reclining Single cylinder with horizontal flywheel
  • Gas exchange via inlet slide damper controlled by eccentric
  • Standing exhaust valve controlled by cam, rocker arms and bumper
  • Mixture preparation Benz surface carburetor
  • Evaporative cooling ( thermosiphon )
  • Lubrication via drip oiler with grease jack
  • Electric high-voltage ignition Summer
  • Tubular steel frame
  • Front suspension to control fork without suspension
  • Rear suspension on rigid axle with Vollelliptikfeder
  • Rack and pinion steering, steering crank in the center of the car
  • No foot brake, hand brake acts on countershaft pulley
  • Three wire spoke wheels, diameter front 730 mm, rear 1125 mm, each solid rubber tires
  • A flat belt from the motor to countershaft with loose and fixed disk and integrated differential
  • Per a chain of the countershaft to the two rear wheels

Drive pulley