The Start / Strop Push Button
TECH TALK By Cha Ratnatunga
The Start / Strop Push Button
In the early cars , the starter motors required heavy currents to operate , so the only option was to mount a heavy large foot operated started button on the floor . The electric solenoid relay enabled the starter switch to operate on smaller currents . This made it possible to have a smaller starter button on the dash .
The procedure to start a car meant that the ignition switch had to be turned on with a key and before hitting the started switch . The ignition activated the solenoid , electrical system and provided current for the starter motor via through the starter button .
The engine starting procedure still remained a two stage process ( turning the ignition on and pressing the started button ). Car manufactures decided to combine the process by doing away with the starter button and having it all in one key operated switch . This key switch turned on the ignition in the first position and activated the starter in the second position . Turning the ignition switch key in the other direction switched the engine off .
Over the years , this procedure continued with security incorporated into the ignition system . What we know today as an engine immobiliser . The main component of the switch is a barrel with a key slot to activate the whole system . The driver has to insert the key into the slot in barrel to start the engine . Some more advanced systems like in the SAAB ’ s 2003-2011 ) had an electric circuit in the key that communicated constantly with the ignition and security components . However , the driver still has to insert and turn a key .
Many cars today have and engine start / stop button with ‘ Keyless Entry ’. The driver has the key fob in a pocket or bag and can simply get in , push the starter button and drive away . The need for an ignition key barrel has been eliminated . This feature is generally provided in the higher end model variants . The key fob communicates an electronic security code with the cars computer and unlocks the starter button . The driver presses the start / stop button and the car activates the ignition and engages the starter all in one go . More than convenience , the starter button is set up to provide a secure way to control authorised access to the vehicle . So , the start / stop button in a modern cars is designed for a very different purpose as compared to the older cars with starter buttons . When using vehicles with start / stop buttons it is important to note the following ;
• The key fob must be kept in securely with the driver . ( Most vehicles have a warning alert if the key fob is out of proximity from the vehicle )
• The engine can only be started / stopped when the gear selector is in ‘ Park ’ position and foot brake pedal is depressed .
• In an emergency situation , if the engine has to be stopped while the vehicle is moving , pressing the start / stop button 3 times with 30 seconds ( may vary with car manufactures ) will stop the engine . This will affect the directional control and braking of the vehicle .
The engine start / stop button will be a standard feature in vehicles of the future . It has its origins from older cars and inspired to some extent by race cars . The next stage in evolution might be finger print recognition or biometrics , but the starter button will do for now !
References 1 . Push Button Start https :// mycardoeswhat . org / safety-features / push-button-start /
2 . What happens if push the START / STOP button while driving ? http :// www . mycarforum . com / topic / 2704029-what-happens-if-push-the-startstop-button-while-driving /
56 Vol 34 No . 5 - June-July 2017