Starting

The series of mechanical and electrical processes and technology that initially rotate an internal combustion engine vehicle's engine to start the combustion cycle.

Starting

Overview

Starting (始動, ignition/starting) is the process in an internal combustion engine vehicle of forcibly rotating a stopped engine using external power so that the fuel combustion cycle can sustain itself. The key is to rotate the crankshaft using human power or an electric motor so that the four strokes of compression, ignition, explosion, and exhaust occur continuously; in modern times, it is implemented by an electrical and electronic system combining a battery, starter motor, and electronic control unit (ECU). Recently, with the spread of electric vehicles and hybrids, the very concept of 'starting' is being redefined.

Key details

Basic principle of starting

An internal combustion engine mixes fuel and air, compresses the mixture, and then ignites it to obtain explosive force. When stopped, this cycle does not continue on its own, so the initial rotational force must be supplied from outside. This process is called cranking, and if cranking is successful, the engine enters self-sustaining idle operation. In other words, starting can be defined as 'the task of using external energy to switch the engine into a self-sustaining operating state.'

History of starting devices

Early automobiles were started by a person manually turning a crank handle. This method carried a high risk of injury from rotational kickback and was difficult for women, the elderly, and the infirm to use. In 1912, Cadillac adopted the first electric starter motor, making starting possible with the push of a button, which became a decisive opportunity for the popularization of automobiles.

Composition of modern starting systems

The starting system of a modern vehicle largely consists of the following elements.

  • Battery: The energy source that supplies a momentary current of hundreds of amperes to the starter motor.
  • Starter motor: Rotates the flywheel or torque converter to turn the crankshaft.
  • Ignition system: In a gasoline engine, a spark plug ignites the air-fuel mixture; recently, individual coil-on-plug (COP) systems have become mainstream.
  • Fuel injection device: Injects fuel from the cranking stage to achieve the proper air-fuel ratio during starting.
  • ECU (electronic control unit): Controls ignition timing and injection amount in real time based on signals from the crank angle sensor, camshaft sensor, coolant temperature sensor, etc.

Differences between diesel and gasoline

Gasoline engines use spark ignition (SI) and require a separate ignition device. Diesel engines, by contrast, use compression ignition (CI), in which the fuel self-ignites solely from the heat of compression. Because diesel has poor startability at low winter temperatures, a glow plug (preheating plug) is used to preheat the combustion chamber.

Main causes of starting failure

There are various causes for an engine not starting or being slow to start.

1. Battery discharge: The most common cause, and it surges in cold winter weather.

2. Starter motor failure: A faulty solenoid or worn brushes weaken cranking.

3. Fuel system problems: Faulty fuel pump, clogged injectors, clogged fuel filter, etc.

4. Ignition system problems: Worn spark plugs, faulty ignition coils.

5. Sensor errors: If the crank angle sensor is abnormal, the ECU cannot calculate the ignition timing.

Latest trends

As of 2024–2025, starting technology is changing in the following directions.

  • Standardization of smart keys and push-button starting: Starting without a physical key, using a smartphone or card key, has become common. In addition, starting via biometric authentication (fingerprint or face recognition) is being applied to some premium models.
  • Conceptual changes due to electrification: Electric vehicles use a 'power on' procedure that supplies battery power to the motor instead of an engine, and because there is almost no noise or vibration, the felt experience of starting has disappeared. Hybrids automatically switch between engine starting and electric motor drive depending on the situation.
  • 48V mild hybrids: As 48V systems that assist conventional 12V systems spread, ISG (Idle Stop & Go), which automatically turns the engine off and on while stopped, and integrated starter generators (ISG/BISG) have become common.
  • OTA updates and diagnostics: Starting-related ECU logic is updated wirelessly (OTA), and services that remotely analyze diagnostic trouble codes (DTCs) and recommend preventive maintenance are increasing.
  • Response to extreme environments: Battery preheating systems and thermal management technology to solve the low-temperature startability and battery performance degradation problems of electric vehicles are major research topics.

In this way, starting is evolving from a simple mechanical procedure into a comprehensive system combining battery management, electronic control, and software.

Related topics

  • [[internal combustion engine]]
  • [[battery]]
  • [[electric vehicle]]
  • [[starter motor]]
  • [[spark plug]]
  • [[hybrid vehicle]]
  • [[automotive maintenance]]