I’ve always wondered this, my Mercedes c280 idles at 750 rpm and my BMW 2002 idles at 1000 rpm
Our mercedes also idles at something like that but every other car we had idled at abot 1100 rpm, diesel or petrol
Its just determined by whichever rpm the maker wants it at. Stock my jeep idled at 500 but I tuned it to run idle at 750
Diesel?
There is a thing called an idle air control valve in a petrol engine which is like a small throttle which bypass the normal throttle. It’s often ecu controlled. In civics the idle is at 1,5k when the engine is cold, and around 800 when warm.
It’s called “torque reserve” it’s basicly the torque you need for everything like, steering pump, alternator, A/C, moving camshaft, and every little electric components ;)
So, basically the lower rpm it is, the smaller amount of energy is needed to get them running, is it true? Btw you have fancy beard
The idle of a car will be a speed that the engine can happily run at without struggling or using too much fuel. This can vary on a lot of factors, one example is if en engine has a heavy flywheel it can idle at a lower speed because the flywheel inertia keeps the engine turning over, another is that a car with very extreme cams will require a higher than normal idle because at lower speeds it will be very lumpy and unpleasant.
I’ll also mention that engines idle at a higher speed when they’re cold to help get the engine into it’s optimum operating temperature faster, although this higher idle will normally only last for a few seconds or until you start driving. On a petrol car this is controlled by the aptly named idle control valve, which itself can either be controlled by the ECU or a thermostat. On cars with electronic throttles there is no need for an idle control valve as the ecu can directly control how open the throttle plate is when your foot is off the accelerator. On diesel engines the ECU will just simulate a small amount of accelerator input, naturally raising the idle.
On my car the factory idle was 750 rpm. I’ve had this increased to 980 as it’s a much stronger idle speed and the amount of extra fuel used is negligible. When it’s cold it will idle at around 1400 rpm.
But what about older engines, designed in the 70s? My fathers merc has an om616 diesel which idles the same anytime, not changing the rpm whatsoever
I dont know. My 2.0 megane idles at 750rpm while my 1.4 megane idles at 900, and my moms freelander 1 wins it with idling only on 400rpm.. I think it depends on number of cylinders and their position
My Kia idles all the way down at around 500rpm. When I’m stopped I always think it’s gonna stall. I actually tend to turn my AC on just so the revs will sit a little higher so I can hear my exhaust note better haha
My Taurus just idles at 800 rpm. Starts at 1000 when cold.
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I’ve always wondered this, my Mercedes c280 idles at 750 rpm and my BMW 2002 idles at 1000 rpm
Our mercedes also idles at something like that but every other car we had idled at abot 1100 rpm, diesel or petrol
Its just determined by whichever rpm the maker wants it at. Stock my jeep idled at 500 but I tuned it to run idle at 750
Diesel?
There is a thing called an idle air control valve in a petrol engine which is like a small throttle which bypass the normal throttle. It’s often ecu controlled. In civics the idle is at 1,5k when the engine is cold, and around 800 when warm.
It’s called “torque reserve” it’s basicly the torque you need for everything like, steering pump, alternator, A/C, moving camshaft, and every little electric components ;)
So, basically the lower rpm it is, the smaller amount of energy is needed to get them running, is it true? Btw you have fancy beard
The idle of a car will be a speed that the engine can happily run at without struggling or using too much fuel. This can vary on a lot of factors, one example is if en engine has a heavy flywheel it can idle at a lower speed because the flywheel inertia keeps the engine turning over, another is that a car with very extreme cams will require a higher than normal idle because at lower speeds it will be very lumpy and unpleasant.
I’ll also mention that engines idle at a higher speed when they’re cold to help get the engine into it’s optimum operating temperature faster, although this higher idle will normally only last for a few seconds or until you start driving. On a petrol car this is controlled by the aptly named idle control valve, which itself can either be controlled by the ECU or a thermostat. On cars with electronic throttles there is no need for an idle control valve as the ecu can directly control how open the throttle plate is when your foot is off the accelerator. On diesel engines the ECU will just simulate a small amount of accelerator input, naturally raising the idle.
On my car the factory idle was 750 rpm. I’ve had this increased to 980 as it’s a much stronger idle speed and the amount of extra fuel used is negligible. When it’s cold it will idle at around 1400 rpm.
But what about older engines, designed in the 70s? My fathers merc has an om616 diesel which idles the same anytime, not changing the rpm whatsoever
I dont know. My 2.0 megane idles at 750rpm while my 1.4 megane idles at 900, and my moms freelander 1 wins it with idling only on 400rpm.. I think it depends on number of cylinders and their position
My Kia idles all the way down at around 500rpm. When I’m stopped I always think it’s gonna stall. I actually tend to turn my AC on just so the revs will sit a little higher so I can hear my exhaust note better haha
My Taurus just idles at 800 rpm. Starts at 1000 when cold.