starter Start Stop, Affects the Starter?

[David]

Start Stop, Affects the Starter?

So I have also wondered this and another web site actually got an answer. More info available at Green Car Report but to quote their story, the end result of what happens with the starter system on new auto's is as follows:

What follows is his explanation of those technologies.

(1) The gear ratio from the starter-drive pinion to the flywheel ring gear is optimized to make the starter's motor turn more slowly. This can be done without materially changing the design of the transmission or flywheel at all on existing designs.

Crucially, this reduces starter-motor speed (in RPM), since 90 percent of starter-motor brush wear occurs not during cranking, but during the coast-down after the start has finished. If a higher-torque motor can spin more slowly, its coast-down time is shorter, increasing its longevity.

 

Pushbutton start

(2) The composition of the carbon and copper brushes on a start-stop motor differs from its traditional counterparts to increase longevity without accelerating the wear on the commutator.

(3) Rather than rely on oil-impregnated bushings for the rotating assemblies, start-stop starters mostly use needle bearings.

 

(4) The solenoid on start-stop starters decouples the mechanical action of engaging the drive pinion into the flywheel from the electrical action of stopping and starting the motor.

This allows for a dedicated design to turn power on and off to the motor, optimizing contact design and wear, against contacts that have to be integrated as part of a spring-loaded plunger.

This also reduces the electrical load requires to turn the engine, so that there is enough current available for accessories/lighting to operate during the start event.

(5) Finally, start-stop motors are integrated with other technologies that identify when each cylinder of the engine will reach top-dead center.

That lets the fuel injectors pulse and fire during the middle of a complete rotation of the crank, against having to wait for a complete revolution that lets the first cylinder reach that position to start the fuel-spark timing sequence.

So their story also has an explanation about the RAM start/stop system and a link to their story on the Cadillac using ultracapacitors in their auto start/stop system. Very cool tech.

[daves87rs]

Good stuff there!

[David]

On 4/8/2017 at 9:56 PM, daves87rs said:

Good stuff there!

Thank you, I too thought it was good info. Bet most do not really understand what has changed from the 80's when they first played with this tech.