Electric resistance heat before engine heat?


#1

So first of all my apologies for my ignorance as I am not a true engineer of any type, though I know a little about a lot! Ok my question is, wouldn’t it be possible for car manufacturers to add electric resistance heating as a precursor to standard engine coolant heat? Of course then it would be thermostatically controlled to shut off as soon as the heater core starts getting hot fluid. But then would standard alternators be able to handle the load? How cool (I didn’t plan that pun, btw) would that be to be able to get heat delivered out of the vents almost instantly on a cold day? Just a thought…


#2

Most automotive alternators have a maximum output <1,000 watts and that output requires the engine running at 3,000+ rpm so a 1,500 watt hair drier is beyond the capacity of the cars alternator and it is unhealthy for a cold engine to be run at high rpm. A block heater seems to be the best answer to a quick, warm getaway on a cold morning.

Gosh I’m glad I live in the south.


#3

Yup. But if its cold enough to need an electric auxiliary heater, who’d want to put more stress on the battery?

If a manufacturer decided to add an electric heater, the designers would simply add a more robust alternator. Vehicles now that are designed to operate auxiliary stuff (like cop cars) already have heavier duty alternators.

Adding draw to the electrical system would reduce gas mileage a bit, and with manufacturers trying hard to squeeze every last fraction of a MPG out of cars to meet ever-more-stringent fed requirements, I wouldn’t expect a system like this to be added any time soon. As more current is drawn through the alternator’s windings by more load, it takes more gas to move the armature magnetic fields through the stator fields to create the more electricity. There are no free rides. In short, more load on the battery means more load on the crankshaft, and more load on the crankshaft means more gas used.


#5

The coolant supplies ‘free’ heat, it would go out the radiator anyway. And there’s a huge amount available. Why spend money on an electric heater?


#6

The OP is saying they’d like heat immediately after starting the engine, rather than waiting for the engine to warm up. Electric heating seems possible to do. I don’t see why not the manufactures couldn’t install a little electrical heater for that situation. They’d have to size it to make sure the battery and alternator could handle the load is all. It might make more sense for quick heat to just heat the seats electrically, rather than trying to heat the entire cabin. Heating just the seats would be pretty effective for quick comfort I think.


#7

Lexus has been using “glow plugs” to heat the coolant during cold operation;

"The A/C ECU and ECM operate two glow plugs in engine coolant to reduce the
period of increased fuel consumption due to a cold engine, and to improve
heater performance."


#8

My father in law was from Saskachewan and grew up on a wheat farm. His family owned a Studebaker and in the winter the cooling system was filled each time it was driven and drained when parked for more than a few hours. The SOP was that when returning home the drains on the block and radiator were openened and the car car driven as deeply as possible into a snow bank. Then when needed a chimney pipe filled with hot coals was placed under the oil pan to warm the oil and hot water was poured into the radiator. Then the car was pushed out of the snow and the engine was had cranked, then hot bricks from the fireplace were scattered on the floor for people to rest their feet on and off they went. Those were the “good ole days.”


#9

Yeah, electric seat heaters make sense. Heating the cabin would take a lot of watts, so anything that wouldn’t put a big load on the charging system would be pretty useless.


#10

Corvairs had an optional gasoline heater because, being air cooled like the VWs the passenger heat from the engine was meager. The trouble with it was, the car got 30 mog, so did the heater . Result 15 mpg.

It was not a new idea with the Corvair, My father in law had a 37 Ford V8 60 with a gasoline heater that glowed red. The gas line going to it also dripped gasoline on the floor. Safety? We don’t need no stinking safety!

Seriously, it is memories like this that make me impatient with those that see doom and danger around every corner. Remember we are all going to die anyway so what is the point of letting some alarmist spoil your fun.


#11

I mentioned it some years ago but I remember back in high school, a classmate was commenting on the new Ford that his folks bought. It had an electric heater in it so you got instant heat. He was on a farm out in the country so heat in the winter right away was a nice thing. Near as I can remember it was a 1964 model or maybe a 65. I don’t think it lasted very long and maybe was an expensive option but at least it had been tried 50 years ago.


#12

Sounds like me talking to my kids…“Hey, cut that out. Someone might get hurt or have fun!”


#13

My wife’s diesel BMW X5 has this feature.


#14

Given the huge electrical drain already on most new cars with all the goodies you use at cold startup - lights, electric rear defrost, heater fan, radio, wipers, heated seats, plug in your phone or iPod, ect - you can’t package an alternator big enough to run electric heat as well. Years ago Cadillac and Lincoln offered electrically heated windshields with a thin layer of gold as a “see-thru” conductor on their top models. They drew 50 amps (and nullified radar detectors!) so the cars would seriously over stress the batteries. The car wouldn’t charge the batteries at leass than 45 mph or so. Similar issues with a certain generation of BMW 7 series that needed battery replacement every 18 months because they had too much electrical load, not enough alternator and too small a battery compartment.

And the electrical energy is not free! BIG alternators take BIG horsepower to drive them. A 200 amp alternator would take roughly 5 HP to drive the thing. (200 amps x 13.5 volts / 746 watt/HP / 0.7 efficiency)

Add another 100 amps for a 1350 watt heater and another 2.5 HP goes out the tailpipe!


#15

Yup, but for those that are willing to pay for them they already exist. Personally, I don’t want to pay for what I consider a luxury. As long as people like me opt not to get heated seats, regular seats will, thankfully, continue to be offered. I hope.


#16

+1
Heat the occupant, not the air. I have heated leather seats in two vehicles. They come up to temp very quickly and provide instant relief. Like standing by a fire, as long as one side is warm, you can tolerate just about anything. Having a warm back and tush on those cold mornings is very luxurious…


#17

For those like my wife who has back problems Heated Seats are really nice.


#18

They already have those systems in all-electric cars, because of course they don’t use engine coolant and therefore don’t have any way of using a standard heater core.

But electric cars have mammoth battery banks that can handle the load. Most of them also now have smartphone apps that you can use to turn the heater on 15 minutes before you drive it so that it’s nice and warm when you get in it, and so that the major heating portion is done while still connected to shore power.

Rapid-heating seats are the better answer for gas cars.


#19

Yeah, those of us like @Whitey and I don’t really NEED seat heaters so much… :wink: Floridians don’t buy them very often so regular seats should be around a while.


#20

You have the opposite problem, you could use air conditioned seats! :slight_smile:
I’ve never seen them but thought I heard about some high end cars that have cooling and heating. Now that is the high life, temperature regulated seats…


#21

Thanks for the informative and illustrative replies. I think that grounds out that idea!