Grill blocking in mild winter temps

I've heard it said that the inverter should always be cool enough to put your hand on. Real world I've seen people post that they've had it up to 110 or a little past. Like others have said though, you really want to keep the inverter as cool as it is practical to do so.

 

Here's the XGauge for "Inverter Coolant Temp" in F:

TXD: 07E22175
RXF: 046105750000
RXD: 4808
MTH: 00090005FFD8
NAME: ICF

I guess the best thing to do is note the temperature before blocking the upper grill in all kinds of traffic conditions. This way you will have a base line.

 

2000 miles with grill blocking - Results | PriusChat

I was seeing about a 4 mpg increase by blocking the lower 75%. Some of this maybe from more worn tires (1-2 mpg), but the other values would be from blocking. It helped a great deal.

 

For what it is worth, I inadvertenly left my 50% lower grill block on the car when it was 90+ degrees outside on a road trip from Pleasanton to Shingle Springs (100+ miles). The engine temp did not go above 195F. I've pretty much run 50% blocking all summer long. My engine temp is usually 190F and the inverter is +20F above the outside air temperatures.

Likely you won't hurt a thing if you add a modest amount of grill blocking now, but no worries if you wait.

 

I know Toyota can't do everything at once to improve fuel economy, but the Prius is just crying for thermostatically controlled grill shutters.

 

I can't believe the leader in hybrids hasn't done that yet...

 

I've seen my Water Temperature range between 190F to 197F. I think folks (Ken?) that it should stay below 208F or something around that value.

Inverter temps are usually +20F above ambient temperatures. I've run my car blocked (50% lower and 0% upper) and unblocked and have not seen a difference in the Inverter temperature differential between the outside air temp and the inverter temp. People who work with electronics generally agree that cooler is better.

 

I wouldn't be surprised if we saw it on the 4th Gen.

That...along with camera side mirrors!

 

I don't know if there is a "safe" range. I would say that if you block your grill and you see your inverter get much past +20F from ambient, then I would consider removing some of the grill block to ensure the inverter gets all the cooling it can get.

My understanding is that the upper grills (in our Gen III cars) are in the same area as the inverter. If you block the lower grill, likely you won't see much of an increase in the inverter temperature compared to an unblocked grill. If you block the top grill (partially) monitor the inverter temp. If it doesn't go much past +20F, then you should be OK. If you grill block the upper grill (100%) and the inverter temp stays within +20F ambient air temp, you should be fine. If it goes up to +25F or higher (just picking a number here), consider removing some of the upper grill block to get it back to the +20F range.

Does that make sense?

 

I think the +20 rule of thumb is pretty good during warm and mild temps but I think we will see the inverter be +30 or even +40 at times in really cold weather.

 

Good Point, I don't know the winter values for the inverter, I only have Spring, Summer and (now) Fall data. I've not done a winter with grill blocking and monitoring inverter temps.

 

If 20F+ over ambient is OK for inverter coolant in 80F weather, wouldn't 40+F be OK for 60F ambient or lower?

Running that close to the edge would require closer monitoring but other than that what problems would there be?

Would there be any measurable benefit over running 20F+ at low ambient temps?

 

My understanding of electronics is that cooler = better, with better = longer life. If I was running my car in winter weather and the outside temperature was 35F and my inverter was 55F, I'd say that is fine, but if I 100% grill blocked and my inverter was running at 80F, I'd be a bit concerned. Yes, 80F is cooler than what it normally runs at in the summer time (typically around 90F+) but I would like to limit the stress conditons that I can control. I can't control the warm summer weather, but I can control my grill blocking impact in the winter.

 

I think that echoes what I've read in other places that essentially you want to keep the inverter as cool as possible.

 

I know this is a newbie question that might be answered elsewhere, but I couldn't find anything related to it: Grill blocking won't affect outside air coming through the vents, will it?

 

It shouldn't. All grill blocking is doing is reducing the amount of air flowing into the engine bay. I think the the vents take air in from underneath the windshield wipers.