held down and the vehicle in gear. (Engine is on in both cases).
2006-08-02 05:53:04 · 13 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Virtually unmeasurable difference however, possibly "gear in neutral". Why? Gear in neutral engine turns gearbox input shaft and must overcome the resistance of two bearings and some oil and air drag - but very small compared to engine internal friction. Clutch pedal in eliminates the input shaft losses but adds resistance of the clutch release bearing which is heavily loaded with clutch in. It all depends on whether the friction of the clutch release bearing is more or less than the sum of gearbox bearing and oil drag. Also for clutch in, it doesnt matter, for fuel consumption purposes, whether a gear is engaged or not. Since nothing is turning in the gearbox, it doesn't matter.
More importantly however, clutch in will wear out the clutch release bearing more rapidly and this item costs a significant amount to replace. Also, if clutch in, in gear, there is a safety issue if your foot slips off the clutch.
Best practice - "gear in neutral"
2006-08-02 19:57:10 · answer #1 · answered by Peter T 2 · 0⤊ 0⤋
I would expect that the engine is running with the same fuel consumption in both cases because the engine will be turning nearly the same inertial mass at the same rate at the same temperature with the same airflow and the same internal friction in both cases.
However, in reality you are unlikely to keep the clutch pedal fully pressed down during the duration of the light, thus causing some slight increase in fuel efficiency by being in neutral. If there is clutch wear as many have mentioned, then I would expect that there is resistance to the engine rotation.
2006-08-02 06:02:04 · answer #2 · answered by Automation Wizard 6 · 0⤊ 0⤋
No real difference.
1) In neutral, the idling engine has to rotate the clutch and input gears.
2) In gear, but clutch in, the engine only rotates the flywheel, but there is the potential for very minor wear on the clutch plate if it floats.
A vast majority of the fuel required to idle while stopped is just to overcome the internal friction of the engine and keep it running. An automatic in gear while idling does take more fuel than when in neutral.
2006-08-02 06:00:41 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Makes no difference. Main point is the rpm. If that is the same rate in both cases the consumtion is also the same. For an (most) engine Neutral and clutched pedal are the same effect.
2006-08-02 05:56:30 · answer #4 · answered by Puppy Zwolle 7 · 0⤊ 0⤋
When the clutch is pressed down, your car is in neutral, so it should make no difference. However, you shouldn't hold the clutch down because it will wear out your clutch more quickly.
2006-08-02 05:59:54 · answer #5 · answered by neerdowel 3 · 0⤊ 0⤋
When you are in neutral it is the same (in rpm) as when your foot is on the clutch. So there should be no difference.
2006-08-02 05:57:20 · answer #6 · answered by Oblivia 5 · 0⤊ 0⤋
I know holding down your clutch will burn out the clutch quicker
2006-08-02 05:57:16 · answer #7 · answered by WhiteHat 6 · 0⤊ 0⤋
2) uses more gas, except in a hybrid.
2006-08-02 05:56:58 · answer #8 · answered by Anonymous · 0⤊ 0⤋
the engine is still at idle and working as hard no matter what you do.
2006-08-02 05:57:31 · answer #9 · answered by Dagblastit 4 · 0⤊ 0⤋
I think they are both the same.
2006-08-02 05:57:23 · answer #10 · answered by ? 4 · 0⤊ 0⤋