Horsepower Robbing

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Soldato
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Just got this off another forum I visit. Looks clever but can it really make that much of a difference?
 
Pretty much true, a few details glossed over and some of the claims might be slightly exaggerated in terms of power loss from a standard alternator. Much easier to implement than a regenerative braking system which then powers electric motors to drive the wheels but still provides a benefit.

Seems like an easy win to me and kudos to Mazda for figuring it out first.

Edit:

acemastr said:
Looks very clever, I do wonder why no one has bothered to look into the alternator as it isn't very efficient
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They aren't that bad, on a race bike removing the alternator normally only gives you 1-2hp at most. Car alternators are far beefier to run all the fancy luxury gizmos but I don't think you'd be looking at more than a 4-5hp loss tops.
 
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Neat idea, but a fairly complex solution to a problem that dosen't really need solving.

When driving along normally with no lights on etc the current draw is maybe 20A, so ~300w, or 0.4hp :p

Even factoring in the inefficiencies in the alternator your still talking tiny losses.
 
Minstadave said:
No it's just an alternator that works only when decelerating, meaning it doesn't sap power all the time.
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kers doesnt sap power all the time and this is the same thing.

Kinetic Energy Recovery System
accept kers is designed to give extra horse power with the electricity rather than power the cars systems

I like how that video claims mazda invented it
 
Minstadave said:
No it's just an alternator that works only when decelerating, meaning it doesn't sap power all the time.
Click to expand...

It still is KERS though, it's taking kinetic energy and putting it to use. Granted it's not then dumped back through a motor back to the rear wheels, but it's still kinetic energy recovery.

It's essentially a very mild hybrid system, I assume it acts as a normal alternator when the capacity is dry and you've been driving on a flat road at a steady speed for more than 5 minutes.
 
A cap isn't going to store much energy. It's also going to dissipated that energy very fast. So the cars systems will still rely on the battery which in turn relies on the alternator.

If you're on a motorway, when are you going to brake?

If you're driving at night, your lights would dim if you didn't have a alternator running.

Caps are designed for storing power used for smoothing rails, not supplying them for long periods of time.

Now imagine your cap is about to drop lower then the voltage trigger off your airbag system and someone pulls out..

Could go on but basically, the concept has too many flaws imo.
 
AshD93 said:
A cap isn't going to store much energy. It's also going to dissipated that energy very fast. So the cars systems will still rely on the battery which in turn relies on the alternator.

If you're on a motorway, when are you going to brake?

If you're driving at night, your lights would dim if you didn't have a alternator running.

Caps are designed for storing power used for smoothing rails, not supplying them for long periods of time.

Now imagine your cap is about to drop lower then the voltage trigger off your airbag system and someone pulls out..

Could go on but basically, the concept has too many flaws imo.
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^^ this
 
acemastr said:
Looks very clever, I do wonder why no one has bothered to look into the alternator as it isn't very efficient
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They are coming but expensive at the moment, limited success with 24v so suppliers are developing 48v systems. belt integrated starter motors that start the engine aswell.

The Valeo iStars offers assist aswell so it's termed a micro hybrid. This system isn't, it's just a more intelligent and capable electricity generation system to manage electric load. It's not KERS as such, else all cars would have it... It's converting kinetic to electrical with no way of turning the electricity back into the kinetic energy hence not 'recovery'. Mazda also have a clever way of restarting the car in start stop aswell.

The cap is a load buffer for the 12V system, once full it will bleed its energy into the main battery through a DCDC at a rate far more appropriate for the battery chemistry. It's a power management exercise, nothing to do with energy. Nothing stopping a constant load on the system going straight to the battery either through the DCDC or it might be a variable voltage alternator anyway.

The cost of all this is why the decent stuff will be on premium cars first.
 
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BMW and Audi have been running a similar system for 2+ years.

My 1 Series has brake/coast regeneration which boosts the alternator voltage to power electric devices, and thus reducing the strain on the engine.
I get around 25 miles extra distance from this system per 500 miles of travelling. It's one of the contributing factors towards my 62.3 MPG on a recent trip. [Petrol]
 
arknor said:
kers doesnt sap power all the time and this is the same thing.

Kinetic Energy Recovery System
accept kers is designed to give extra horse power with the electricity rather than power the cars systems

I like how that video claims mazda invented it
Click to expand...

Regnerative braking as a concept is donkeys years old. KERS is just a half arsed version of it with a whole bunch of artificial limitations added in for good measure.

I'd much rather manufacturers focussed on proper regenerative braking rather than trying to copy KERS.
 
I don't really understand what you are talking about. Could you try to present what your point is in a more structured manner, as the above looks like gobbledygook to me. :)
 
DaveyD said:
It still is KERS though, it's taking kinetic energy and putting it to use. Granted it's not then dumped back through a motor back to the rear wheels, but it's still kinetic energy recovery.

It's essentially a very mild hybrid system, I assume it acts as a normal alternator when the capacity is dry and you've been driving on a flat road at a steady speed for more than 5 minutes.
Click to expand...

By that logic any car with an alternator has KERS.

This is simply an alternator that only works when braking, with a cap to smooth out the charging of the battery.
 
kaiowas said:
Regnerative braking as a concept is donkeys years old. KERS is just a half arsed version of it with a whole bunch of artificial limitations added in for good measure.

I'd much rather manufacturers focussed on proper regenerative braking rather than trying to copy KERS.
Click to expand...

What would you say is proper regenerative brakin as opposed to how it's done in F1?
 
Minstadave said:
By that logic any car with an alternator has KERS.

This is simply an alternator that only works when braking, with a cap to smooth out the charging of the battery.
Click to expand...

I'm referring to KERS being using any of the energy that would normally be wasted during braking to charge a battery.

Of course any moving part could argue that you're doing some form recovery to turn it in to something useful, but this principle is still the same.
 
another small step in acheieving better mpg figures,


they say only 5% which by itself is nothing but when you take 2/3 of these innovations and start fitting them to mainstream cars Its going to start having massive effects on fuel consumption. i'd imagine this sort of tech will get more love among hauliers and large fleet operators where a 5% increase in fleet mpg could equal millions of pounds
 
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