What used to require serious muscle power is now just a push of a button: Starting a car engine. Security aspects made the ignition key an integral part of the system.

1 – Starting procedure: The hand crank was used to start a combustion engine by hand. Switch on the ignition – turn the crank – the engine starts. The underlying technical principle is simple and, interestingly enough, pioneers Gottlieb Daimler and Carl Benz, who developed their motorcars almost simultaneously, chose two very different starting variants for their first vehicles: Benz initially had a horizontally mounted flywheel while Daimler used a hand crank. But the procedure was by no means a simple matter. Crank-starting a car looks easy, but it is, in reality, really heavy work. Turning over an engine requires considerable physical effort. In addition, the motorist must be prepared for a possible backfire, to avoid arm injuries such as the dreaded “chauffeur’s fracture”.

2 – Security level: Around the year 1910, the procedure began to change a bit. Cars began to be fitted with a key switch, which completed the circuit for the ignition system and, at the same time, protected against theft of the vehicle. However, this system was still far removed from an ignition key because after switching on the ignition, the engine still had to be cranked.

3 – Electrically powered assistants: Because cranking a car engine was dangerous and awkward, the electric starter became more and more common around this time, beginning with high-performance models. A permanently mounted, compact electric motor started the engine reliably. The motor was powered by a battery. The driver closed the ignition circuit and briefly turned on the starter. This improved simplicity helped motorcars with internal combustion engines to achieve a breakthrough. However, the hand crank was often still included with a car’s tool kit even into the 1950s – just in case it did not start with the starter motor.

4 – A turn for the better: From the 1920s onwards, the combined ignition and starter switch became increasingly popular; at that time it was considered a high-tech product. By turning the key, the driver closed the circuit and ran the starter motor in one go. In addition, the ignition-start switch was another anti-theft feature because after the key was removed, the steering wheel locked in a fixed position. In addition, now that increasing numbers of cars had closed bodies, their doors could also be locked with a separate key.

5 – Two into one does go: The ignition-start switch was standard for many decades. Through to the 1960s, it remained common practice to have several keys for the car. It was a real step forward when the keys for the doors and the ignition lock were merged into a single combination key.

6 – Symbol of mobility: The ignition key is an expression of mobility as it symbolises both access to the car and a certain independence. Sometimes there are special keys for special cars: Queen Soraya of Persia was presented with an ignition key made of solid gold when she took delivery of her Mercedes-Benz 300 SL Gullwing (W 198).

7 – Additional functionality: The next step was the central locking system. From 1963, Mercedes-Benz offered this system as a pneumatic version in the representative 600 (W 100). It had already been available as an optional extra in the 300 SE LWB (W 112) and, from 1972, it was available for the S-Class (model series 116). The need to walk right round the car to check that the doors were locked and pushing the buttons inside to lock them was a thing of the past. In the 1990s, the car key with built-in electronic circuitry could even be used as a remote control transmitter: unlocking or locking the car was a simple matter of pushing a button.

8 – Open sesame: In 1999, Mercedes-Benz introduced the KEYLESS-GO system in the S-Class. The doors could be opened as soon as one stood beside the vehicle and the state-of-the-art key stayed in one’s pocket. A start-stop button replaced the ignition lock, and the engine was started and stopped with a finger tip. And that was not all, because the motorcar had generally become more complex: that push of a button was the start signal that initiated all the underlying electronic systems in the background.

9 – Shaping up for the future: Over the decades, the ignition key not only lost its bit – it also changed its appearance as a whole and became, for example, credit card shaped. Today, there are compact smart keys – and smartphones can replace them completely. In the latter case, a virtual key is stored on the mobile device, which sensors in the car recognise as being a key and allow access to the vehicle.

10 – Motorsport: Starting the engine in racing cars has undergone a similar development. In the early years they were also started with a hand crank. Starting in the 1930s, the Silver Arrows were equipped with an external starter motor that was only used for starting the car and was then removed and stored in the pits. This is because a permanently installed starter would increase the vehicle weight unnecessarily. The external starting device is still standard in motorsport today. Before it is applied, the mechanics use their laptops to monitor whether all systems are “go”. Understandably, these cars do not need conventional anti-theft protection.

Source: Mercedes-Benz Classic