This article is inspired by one of my customers/readers. They asked me how starting an automobile has changed over the years. I found this to be an interesting question.
Before we get started, I will give a quick breakdown on how an engine starts. Engines need three things to start: air, fuel and compression. We will focus on four-stroke engines to keep it simple. On the first stroke (intake), the piston is moving downward. While it is moving down, the intake valves open to allow air and fuel to be pulled into the cylinder. During the second stroke (compression), the exhaust and intake valves are closed and the piston moves upwards. While it is moving upwards, the air and fuel are being compressed. At the top of the compression stroke, the air and fuel are ignited and there is an explosion. This explosion is the beginning of the third stroke (the power stroke). As the piston nears the bottom of the cylinder, the exhaust valves begin to open and start the fourth stroke. The fourth stroke is the exhaust stroke. As the piston moves upward, it pushes the burn fuel/ exhaust out. Intake, compression, power and exhaust.
To begin the rotation motion of the engine, the crankshaft has to be turned. Since the pistons create high resistance it is difficult to turn the crankshaft. At the turn of the century, engines were started with a hand crank. The hand crank would be inserted through the front grille into the front crank pulley. The driver would then turn the fuel on, make sure the car was in neutral and start to crank over the engine manually. This was a very difficult and dangerous procedure as the engine could backfire or the crank could possibly get stuck in the motor. Needless to say everyone was happy for the first electric starter motors.
The first electric starters were introduced around 1915. The early starter motors were very basic. There was a power supply, starter switch and starter motor. This type of basic system filled a need, but was not always reliable. This reliability not only has to perform electrically but also mechanically.
Starting a car demands very high amperage. For example, if you are driving down the road and you have your headlights on, radio on, blower motor on, wipers on and are charging a phone, the car is pulling about 20 amps with the help of the alternator. Yet when you start your car you could pull anywhere from 150 to 300 amps. Either way, car manufactures had to start and refine starter motors.
As automotive technology matured, car starters saw incremental but vital improvements. During the 1930s, the integration of solenoids allowed for more reliable engagement between the starter motor and the engine’s flywheel. These early solenoid starter systems began to push the boundaries of technology. As starters evolved they became smaller and stronger. By the 1980s, the one-piece starter incorporated the solenoid with the motor and allowed a more seamless functionality.
In the past 30 years, the physical starter design has not changed much unless the car is a hybrid. Hybrid cars use a signal system instead of a generator or a starter. These systems can be called combined motor generators. Once a hybrid is turned on the car usually runs on the electric motor (hybrid system) until it reaches a certain speed and then the combined motor generator will start the combustion engine. This same system can use the weight and speed of the car to generate power (regenerative braking).
From the beginning, hand cranks were used but were hazardous. Today car starters have evolved to meet the changing needs of drivers and the environment. As we move toward a future dominated by electric and autonomous vehicles, the car starter continues to be a critical component in shaping automotive innovation of the future.
