[Ben]

I’m curious to know how much gas is used when the ICE is needed to charge the battery (either because of heat demands or a depleted battery following manual charge).
I am getting extremely good mileage and it seems like the ICE is almost never exclusively powering the vehicle - but it’s often not on full EV as it’s still cold here and needed to warm the engine…

not Sure how to quantify it… but the engine must use very little gas when it’s powering the battery and then the battery is driving the vehicle?
At first I thought the vehicle goes to straight gas when the battery depleted but that’s obviously not the case either.

 

[Jay]

Part of the problem with internal combustion engines is that they are most efficient at or near their rated load. At low loads they are very inefficient. The other part of the problem is that the force needed to accelerate your car is an exponential function. It takes a lot of power to accelerate and we like to accelerate quickly, so the tendency is to put big engines in our cars for better acceleration but operate them very inefficiently by only using a small fraction of the power most of the time. A hybrid improves efficiency in this scenario by putting a heavier load on the engine in low-power situations by charging the battery and mechanically powering the car simultaneously. When the battery can no longer accept charge, we shut the engine off and use the excess stored power. We also conserve some kinetic energy with regenerative braking.

It's more efficient to power the car mechanically with the ICE than it is to use the ICE to run a generator, charge a battery, then use the battery to power the car via an electric motor. Otherwise all our cars would be simple series hybrids instead of the much more complex parallel hybrids we now have. Nevertheless, we gain efficiency with an HEV by putting extra load on the ICE in low-load conditions, storing the extra and then using the stored energy under high-load conditions to aid the ICE or shutting the ICE off entirely in low-load conditions.

 

[Ben]

Part of the problem with internal combustion engines is that they are most efficient at or near their rated load. At low loads they are very inefficient. The other part of the problem is that the force needed to accelerate your car is an exponential function. It takes a lot of power to accelerate and we like to accelerate quickly, so the tendency is to put big engines in our cars for better acceleration but operate them very inefficiently by only using a small fraction of the power most of the time. A hybrid improves efficiency in this scenario by putting a heavier load on the engine in low-power situations by charging the battery and mechanically powering the car simultaneously. When the battery can no longer accept charge, we shut the engine off and use the excess stored power. We also conserve some kinetic energy with regenerative braking.

It's more efficient to power the car mechanically with the ICE than it is to use the ICE to run a generator, charge a battery, then use the battery to power the car via an electric motor. Otherwise all our cars would be simple series hybrids instead of the much more complex parallel hybrids we now have. Nevertheless, we gain efficiency with an HEV by putting extra load on the ICE in low-load conditions, storing the extra and then using the stored energy under high-load conditions to aid the ICE or shutting the ICE off entirely in low-load conditions.

I appreciate the detailed reply but I’m not sure I see the answer to my question in there as it was a bit technical. Essentially, you’re saying the ICE uses very little gas for the charging battery portion of its function? Sorry - I’m very uninformed on this stuff.

 

[mungo544]

Just about anytime the ICE is running, the battery is being charged if it is a full hybrid(not plug in) whether it is to power the vehicle or to supply heat. In cold weather the ICE will come on to provide heat, when otherwise it would be shut down. That is why economy goes down in cold weather. You can test this sometimes by turning off the heat while the engine is idling. If the ICE is running it may shut down the instant you turn the heat off and vice versa. I don't believe the ICE will ever run purely to charge the battery while the car is moving. Most of the ICE power goes to move the car. Think of the starter/ generator as the belt driven alternator in a regular ICE car when it is moving . Most of the ICE power is going to the wheels, not the starter/generator. If I had to guess I would say no more than 10 to 20 percent of the ICE power goes to charging the battery when the car is moving depending on the speed of the vehicle. If the ICE starts while the ICE is stopped (generally only on startup) the car is only idling so it won't be using too much fuel.

 

[Ben]

Just about anytime the ICE is running the battery is being charged if it is a full hybrid, (not plug in). I don't believe the ICE will ever run purely to charge the battery while the car is moving. Most of the ICE power goes to move the car. Think of the starter/ generator as the belt driven alternator in a regular ICE car when it is moving . Most of the ICE power is going to the wheels, not the starter/generator. If I had to guess I would say no more than 10 to 20 percent of the ICE power goes to charging the battery when the car is moving depending on the speed of the vehicle. If the ICE starts while the ICE is stopped (generally only on startup) the car is only idling so it won't be using too much fuel.

So essentially when ICE is being used you’re saying it’s only saving you 10-20% of what a non hybrid would be using for fuel? That seems low to me, no? On the energy flow chart it’s showing that the ICE is powering the battery and not the wheels… it shows wheels coming from the motor and being fed from the battery and ICE… whereas on very cold days it’s exclusively ICE… so I would suspect when ICE is just powering the battery it’s a big savings…

 

[mungo544]

As I said, that is just a guess. It may be higher. I just looked at the power of the ICE (around 200 hp) vs the power of the electric motor (around 60 hp). Another way you could look at it would be to compare fuel economy of the ICE Tucson, (less than 30) to the hybrid, (just under 40) or approximately 30+-% increase in fuel economy. Some of that increase comes from the regenerative braking and charge boost from downhill coasting.

 

[Ben]

As I said, that is just a guess. It may be higher. I just looked at the power of the ICE (around 200 hp) vs the power of the electric motor (around 60 hp). Another way you could look at it would be to compare fuel economy of the ICE Tucson, (less than 30) to the hybrid, (just under 40) or approximately 30+-% increase in fuel economy. Some of that increase comes from the regenerative braking and charge boost from downhill coasting.

did a test today…

Drove 15 KM total. When I started, gas range was 299 KM and Battery was 49 KM.

when I arrived at my destination, gas range was 296 and battery was 35.

so - thats roughly 85% on battery power.

the interesting part is, the EV mode only was on for maybe 2 KM total. The rest showed ICE power to the battery but not the wheels.

this suggests to me (answering my own questions I guess) that the ICE is using only 15% gas even when on but not in full EV mode.

the L/100 KM was 2.5. It’s -5 here this morning and I warmed the vehicle while plugged in for about 5 mins.

That’s absolutely incredible mileage.

 

[mungo544]

If you read my posts, I made sure I mentioned that I was not talking about the plug in vehicle.

 

[Ben]

If you read my posts, I made sure I mentioned that I was not talking about the plug in vehicle.

Didn’t see that. Nonetheless, it wasn’t a knock, just reporting back. Thanks for taking the time.

 

[mungo544]

Those really are great numbers for fuel efficiency. You showed us some very interesting information. Thanks.