[nilak (OP)]

This is going to be less convenient for the owner but if by reducing emissions of the car it becomes eligible for lower taxes, it may be a preferred way to go.
The idea is to make all electrical accessories of the car run on battery supply only. These components include: lights, wipers, electric power steering , power windows, water pump(if electric), fuel pump, injectors, ignition, on board computers, blower and others.
The easiest way is to remove the alternator and install a shorter belt. Some cars have electric water pumps and you can remove the belt and pulleys as well but you will lose the A/C. This will reduce the front weight by about 10kg.
Next step is  installing a battery module. A typical car may require about 400W of power to operate the components so with a 5kWh module you can run the car around 10h time. After that you will have to recharge the battery.
A 5kWh battery can take 60x30x8 cm3 volume and weigh 25kg.
3 li-ion cells operate between 10.5-12.3V, which will probably be enough voltage to power run the car. If the battery can provide enough current (many can do) for the starter the 12V battery can be removed otherwise the low voltage may damage it. Some Pb-Acid batteries can withstand deep discharge but 10.5 is a bit tool low.  A super capacitor bank can be also installed to increase burst current for startup but it will also increase the self discharge rate.
The 3s module will need a BMS and wires directly to the high power terminals. Some cars have the 12 battery in the boot so the high capacity battery can be installed there easily. A battery monitor will also be needed.
Then this will need a charging method. The simplest way is to install a charge connector and work with a portable charger which you can leave it home when doing short trips. With a 12V/100A 1200W charger you can charge the battery in about 5h.
One liter of gasoline contains about 8.9kWh energy. With an engine that has 30% efficiency you get 2.67kWh per liter. The 400W power needs 0.15l per hour but the conversion rate through the alternator is further reduced so it should be about 0.2l/h of fuel saving. With an average speed of a busy city for example 20kph or less can be the average speed so that means 1l/100km economy from say 18l/100km to 17 which is over 5% economy.

[CliffordK]

Keep in mind that some of the older diesel engines will run fine without any electricity.

But, virtually all gasoline engines as well as even diesel engines from the last 30 years will require some kind of electricity to run, from electric injectors to electronic ignition to the "ECU".

So if you run out of juice, not only do your headlights and taillights go out, but you are dead beside the road.

A related option might be to fit Thermoelectric generators onto the exhaust, perhaps a CAT heat shield, or even the auto cooling system.

[nilak (OP)]

In the bellow article they say replacing the alternator with a thermoelectric generator can increase the economy by up to 4% compared to my calculation example of 5%. While a 12h electric autonomy may be ok, a peltier generator may be an alternative even without requiring an additional battery.

[Bored chemist]

But, virtually all gasoline engines as well as even diesel engines from the last 30 years will require some kind of electricity to run, from electric injectors to electronic ignition to the "ECU".

True, but I think the OP's point is that if you buy this electricity from the grid it will be much "greener" than using a car engine to produce it.

It's obviously an inconvenience but that's a different matter.

So if you run out of juice, not only do your headlights and taillights go out, but you are dead beside the road.

That's true regardless of how you charge the battery.

[alancalverd]

Only if you have one of those ridiculous modern cars with loads of electrical stuff to go wrong. Diesel engines with mechanical injectors will run until the fuel runs out, and most small aero engines have dual magneto ignition so the battery is only used for starting - or you can swing the prop - and it will fly with completely dead avionics, no lights, and half the ignition system. Come to think of it, my lawnmower has a magneto too.

Not sure what our friend is doing with 400W of electrical load: about 20W of LED lighting will dazzle everyone around, and only a deaf teenager needs more than 5W of music power.

The biggest non-motive power drain is aircon.

[Bored chemist]

Only if you have one of those ridiculous modern cars with loads of electrical stuff to go wrong.

I.e. if you are in the majority.

[howardellis]

The amount of air load of cars and motorcycles has a great influence on the greenhouse effect.

[nilak (OP)]

The amount of air load of cars and motorcycles has a great influence on the greenhouse effect.

but not while they are going downhill

[Petrochemicals]

Electrically speaking you could surely do away with the alternator and use the regenerative breaking, if it can actually propel a car using it I would think there is enough power.

The biggest saving you could make is the engine braking, I think it has something to do with the selected gear of the car and the drive chain at the rpm not being in sync with the normal tick over speed of an idle engine, some sort of destructive interference, the alternator does not have a great effect.

[nilak (OP)]

Regenerative braking works with a powerful alternator and li-ion or similar battery because a normal 12V agm 80Ah has a charging current of about 25A. So it needs 3.2h of regenerative braking which is ridiculous. I have that on my car and I don’t think it does anything. On my previous car the system used to keep the battery always too low and in the winter you could n’t use the rear defrost because of extra current needed to charge the battery (bellow a certain state of charge it charges continuously). So to work a 5kW electric starter/generator may work, it would charge a 80Ah in 12min at maximum power which is ok. This electricity is better than using the grid like in my op example because it’s something that otherwise it would be lost, but it’s harder to implement and costs more. In addition it needs data from the car, and a custom made generator, and controller.

[Petrochemicals]

Electrically speaking you could surely do away with the alternator and use the regenerative breaking, if it can actually propel a car using it I would think there is enough power.

The biggest saving you could make is the engine braking, I think it has something to do with the selected gear of the car and the drive chain at the rpm not being in sync with the normal tick over speed of an idle engine, some sort of destructive interference, the alternator does not have a great effect.

I have completed a test of engine breaking loss. I have a vw polo 2010 1.2 litre petrol, no air con, nor does the car have auto off when stationary. I did 2 tests in largely similar weather conditions and traffic level conditions and area.

First test I depressed the clutch when not applying power, this disengaged the engine drive chain. I did not drive any differently other than clutch depression. I achieved 48mpg

Second test I drove as per usual achieving 43mpg

This is 11% more efficient. I believe that the car only needs power 1/3rd of the time, so with  cutting the engine when not in use could also save a considerable amount of fuel. Plus the alternator does not need to run continuously.

[nilak (OP)]

When you need to reduce speed with a rate of engine braking or faster because you can’t anticipate everything it is certainly better to use engine braking. The benefit is shown immediately on the board computer, the instant fuel flow is zero but in this situation if you press the clutch pedal and use the brake the engine will idle and take like 0.7-1.2l/hour so grater than zero.
On the other hand if you are at 800m and 130kph and approach an exit with 60kph limit, you can anticipate and press the clutch or set it to neutral then wait until you slow down to 60 right before the exit. This way the fuel consumption per distance will for most cars (there may be exceptions idk) minimum. My car has a coast function so it sets to neutral when coasting then if you slightly press the brake it engages transmission.
For regen you need a powerful generator and a large capacity with high rate of charge/discharge. Casual braking energy regen (not mild hybrids) use agm batteries that can be charged faster but they don’t charge fast enough and don’t tolerate that well low/med state of charge either the result being the function has marginal benefit and more disadvantages - battery stays quite low and if you let the car sit for a long time it will drain much quicker
The elimination of alternator/ puleys, may save weight on the front axis and a bit better fuel econ  , more space in engine bay (acces for maintenance) It could be an alternative for sports cars if the owner likes the advantages

[evan_au]

Tomorrow I am planning to test-drive a car with regenerative braking. I wonder how smoothly it can transition between modes?

[Petrochemicals]

When you need to reduce speed with a rate of engine braking or faster because you can’t anticipate everything it is certainly better to use engine braking.

Engine  breaking is the drag from the engaged drive chain. Brakes are better if you need to reduce speed.
 

To be honest, I did not find that actual breaking for road obstacles was the major source of energy loss, it was the gradient breaking, a car approaching an obstacle at 20 mph, which is what most drivers approach obstacles at, has less than half the energy than a car approaching an obstacle at 30mph, a car will quickly drop to 20 mph without the drive chain engaged due to the wind and road friction. You spend a lot of energy getting to the top of a hill but waste it all going down the other side. There are a lot of hills in the Midlands, unlike in Holland where it is known for its flat nature. Going at 60+ mph requires constant energy input due to the wind resistance.

Tomorrow I am planning to test-drive a car with regenerative braking. I wonder how smoothly it can transition between modes?

Intresting to know Evan.

Edit:

Anglia is also known for being flat, maybe  a University over that way could run a programme.

[nilak (OP)]

“Engine  breaking is the drag from the engaged drive chain. Brakes are better if you need to reduce speed. “
The discussion is not about what has more stopping power.
I mean letting the car in a gear versus coasting in neutral, if you need to reduce speed faster than the coasting in neutral(or clutch pedal pressed) does, then letting the car in gear is more fuel efficient because it cuts off the fuel.

[Petrochemicals]

“Engine  breaking is the drag from the engaged drive chain. Brakes are better if you need to reduce speed. “
The discussion is not about what has more stopping power.

but you did

When you need to reduce speed with a rate of engine braking or faster because you can’t anticipate everything it is certainly better to use engine braking.

I mean letting the car in a gear versus coasting in neutral, if you need to reduce speed faster than the coasting in neutral(or clutch pedal pressed) does, then letting the car in gear is more fuel efficient because it cuts off the fuel.

no the car does not cut fuel. Reducing speed nas no real effect on efficiency.
Edit
Intentionally breaking has no effect of the propulsion efficiency unless you measure that portion too

[Zer0]

Re: Concept for reducing emissions of an ICE car

How bout replacing the ICE car with an EE car?

Ps - Maintenance & upkeep costing.
✌️

EDIT - Sorry nilak
You specifically mentioned ICE Cars.
Hence my response stands Invalid.

Welcome to TNS!
🙂
TC!