Grille Unblock to aid Regenerative braking.

[bestclimb]

This would not be regenerating anything. Some aero friction replaces brake friction. Aerodynamic braking is really only needed if you need more braking than traction allows.

[H-Man]

My prizm will drop the needle fast if I run the heater at all, otherwise the needle lives within a tenth of a radian of the halfway point on the gauge.

[Tesla]

Originally Posted by H-Man

My prizm will drop the needle fast if I run the heater at all, otherwise the needle lives within a tenth of a radian of the halfway point on the gauge.

I assume you are talking about the OEM gauge, the first thing you need to understand is that the OEM gauges are designed to stay in one place until the S#it is just about to hit the fan.

Back in the good old days, (Frank Lee sounds like he was there) vehicle temp gauges did actually indicate engine coolant temps, but then in the late 70's, possibly when more women were driving and they are more fastidious than men, mechanics found they were getting too many complaints about temperature fluctuations, so rather than educating drivers the manufacturers designed gauges with a flat spot in the operating range, so the gauge rises quickly from cold to warm, then virtually stands still from warm to hot, then starts moving again just before the system overheats. Not really a good idea, but it gives the drivers that warm fuzzy feeling.

If you ask anyone with an aftermarket gauge they will tell you there is a normal operating range of around 10-15°C, there is no way that any engine sits at the same temp continuously unless it is running on flat ground at the same speed all the time.

[Tesla]

Originally Posted by bestclimb

This would not be regenerating anything. Some aero friction replaces brake friction. Aerodynamic braking is really only needed if you need more braking than traction allows.

Lets take your analysis a little further:
.....Some aero friction replaces brake friction, the aero friction results in more cooling through the radiator, upon acceleration with grille fully closed results in lower aero drag, lower aerodrag results in lower fuel consumption.

So we have kinetic energy converted into a temperature differential which can be used to delay the use of further energy to cool the engine for a short period of time.

Isn't that a form of regenerative braking?
Does it have to be converted to electricity, compressed air, spinning flywheel, hydrogen to be defined as regenerative?

[wmjinman]

Originally Posted by bestclimb

This would not be regenerating anything. Some aero friction replaces brake friction. Aerodynamic braking is really only needed if you need more braking than traction allows.

That's kinda what I was thinking - not really regenerative braking so much, but more "braking assist".

Although I do love the idea of aerodynamic braking to save wear on the brake pads. Some of the hills we encounter here in the Sierras are so steep you either have to brake or come down them at 80 or 90 mph - even when revving the piss out of the engine because you've already downshifted.

I can't think of any "neat & streamlined" way to do it, but I still keep thinking some sort of a "deployable wind turbine" hooked to an alternator might actually do regenerative braking coming down these long, steep grades. Too "Wylie E. Coyote", I'm afraid, though.

[AndrzejM]

If you're breaking with DFCO your engine temp will drop anyway, especially when it's a downhill situation. I could notice that during my trips through Romanian mountains, where you can downhill for few miles. Engine temp was droping significantly without any help from blocked grille.

[brucepick]

Tesla wrote:
"Isn't that a form of regenerative braking?
Does it have to be converted to electricity, compressed air, spinning flywheel, hydrogen to be defined as regenerative?"

I'd think you would have to capture the energy somewhere to say its regenerative.

My grill block is adjustable but I need to get out of the car to change it. With a 55 mile highway commute, I try to avoid stopping. I monitor engine temp via ScanGauge.

For me, the game is to block as much air as possible (to reduce both aero drag AND heat loss from engine), WITHOUT letting engine temp go out of range. That happens if there is too much grill block for the conditions.

Aside from avoiding overheating, the last thing I want is to cool the engine below the approx 190 deg F it normally runs at. And I indefinitely don't want increased grill block when putting more load on the engine. If anything, it might need reduced block at such times.

[NeilBlanchard]

No, increasing drag will only add to the energy used to move the car - if you coast then higher drag means the car slows more, meaning there is less potential for regenerative braking; not more.