VladSoare

Hello,

How does the heating system of the 300h work? Is it electrical, or coolant-based? Or maybe a combination of both? Does it blow warm air through the vents immediately after starting, or do you have to wait until the gasoline engine warms up?
How long does it usually take in winter until it gets comfortably warm inside? How does it compare to a regular gas-powered car in this respect?

Thank you.

4482

I've had my 300h for about a year now and it appears that the heater operates like any gas powered car. The 300h engine senses if heat may be needed and starts the engine automatically to generate heat. It appears the engine is designed to ALWAYS maintain a minimum temperature. Of course it's a coolant based heating system.
I also have the electrically heated seats.

VladSoare

I see.
How do you find the time it takes for the engine to warm up, compared to gas powered cars? Considering that the engine works at low revs and only does half the job (the rest being done by the electric motor), does it reach its normal working temperature in winter conditions as quickly as a regular gas engine?

On the other hand, you're right about the seats. With heated seats and heated steering wheel, engine warm-up doesn't seem to be so critical anymore.

4482

It appears to me to take about the same amount of time to warm up as the gas powered cars I've had. Like my RX's I've had in the past it appears the blower does not start blowing warm air until a minimum temperature is reached. No sense in blowing cold air on you !
All in all the 300h heater operates the very same way as any other gas powered car and warms up at about the same speed.

Writing about this reminds me of the rear engine VW Beatles I had back in the 1970's and 80's !
Now they really had heat problems ! Hi Hi

VladSoare

Thank you.

VladSoare

On the same note, how about the air conditioning? Is the compressor electrical? Or is it driven by the thermal engine, like in any other car? Does the gas engine need to be running to get cool air?

TeaAholic1

I'm not sure how you can measure that. Normal cars don't turn off when it's warmed up - it just keeps running under the half-way mark on the temperature gauge.

The NX engine warms up quite quickly... The temperature is just around 1/4 when the engine is switched off again on cold startup. Takes I would think 2 minutes.

The air con compressor is electrically driven. The air conditioning can be used while the engine is stopped. It's very nice! But you can hear the compressor. With the air con off and the fans switched off, the car is literally silent. It's very eerie.

4482

Who said it was measured? After driving cars for almost 60 years in a cold climate I think I can pretty much judge what about normal is before getting heat in an auto.

Being I'm driving my first hybrid I found I get heat at about the same waiting time as in a convential engine. The engine in the hybrid keeps the heater liquid at a certain temperature after warm up for instant heat as needed and never really cools down as long as the car is on and even at an idle. The gas engine turns on and off to keep a constant minimum temperature.

It's a great system!

TeaAholic1

What I meant was, what do you mean by "warmed up"? To me, it's when the temperature gets to the halfway mark, around 98C, that's when I think it's okay to floor the car if you need to.

4482

O.K. To me warmed up would be when you first start to get warm air from the vents. Of course as the engine runs longer it gets even warmer.
As far as what point you can floor it I would guess it's gets down to a matter of opinion and outside temperature.

mcomer

All Lexus Hybrids since 2010 have exhaust heat recovery in the form of a coolant jacket
around the hottest parts of the exhaust manifold. It heats the antifreeze right away and
you get heat and defrost very quickly after a cold start. It allows the engine to shut off
earlier for better MPG's but as an added benefit it warms up very quickly.

To the OP's question, the Auto feature of our HVAC delays the fan from ramping up to
speed until there is suitable heat to be supplied. There are additional electric grids in
the dash to provide occupant heat before the IC engine gets warm enough.

As Hybrids have abundant electricity most Lexus Hybrids also have electric wiper blade
bed heaters. Think of them like rear window defroster wires but concentrated at the windshield
base to quickly release the frozen blades from the glass.

4482

Very good information !
Thank you