Citroen C3 alternator/starter as motor?

[bearing]

Some of Citroen's C3 cars doesn't have a normal starter motor, instead they got a combined starter/alternator. This improves city fuel economy by using the alternator mostly during braking, and allowing the engine to stop at red lights.

Maybe this alternator can be used as motor in a small motorcycle or electric bicycle?
I know the alternator idea isn't new. I've seen other thread about using alternators. However, I think this specific alternator is better than the overage.

The motor/alternator seems to be built like a standard car alternator with a claw rotor needing a separate field voltage. Valeo (the manufacturer) states 2.5kW @ 14V here. That figure may be continuous because the text also says electronics can deliver 600 A during cranking.

Valeo states 82% effiency in alternator mode (10 points more than conventional alternators according to Valeo). They don't say at which current, and if that figure includes losses in the rectifier. It can deliver 180 A. 180A * 14V = 2.5kW, so that is probably where the motor power statement came from. 82% is low, but that efficiency is probably at only 14-15V. If the motor can be used at higher voltages the efficiency will be better. The ratings actually seem close to those of the great high performance DC motors produced by Agni motors. Peak efficiency of the 119-series is 82% @ 12V. Peak efficiency of the 95-series is 86% @ 12V.

I wonder how many rpms this motor spins per volt, and how fast it can spin before breaking apart. If it can handle the same voltages as the Agni 95-series it should be able to produce about the same power and effiency; 26kW, 92% efficient @ 72V, 400A. In the picture below we see that the alternator pulley is small compared to the engine pulley. It looks like the reduction is 3:1 or higher. If the engine revs 6000 rpm the alternator sustains 18000 rpm in that case.

Agni's are light for their power, about 10 kg (22 lbs) I think. I don't know the weight of this motor.

The motor should also be quite cheap, at least when bought used. Salvation yards in Sweden sell it for about 1200 SEK which is about 150 USD. The Agni's are 5-10 times that price i think. EDIT: the alternators I found are probably not Valeo StARS, just normal Valeo alternators.

I've been trying to figure out the model number without luck. The pictures below may help if someone wants to make a try.

The interesting parts of the link above:

Operating principle

The starter alternator is driven by a belt that can also be used to drive other accessories, such as the air conditioning compressor, the water pump or the power steering. A reversible tensioner allows power to be transmitted in both directions, depending on whethern the StARS starter alternator is working as a starter or a generator. The system features a battery based on technology that accepts high numbers of charge/discharge cycles. The battery is also fitted with a sensor that enables the system to inhibit the Stop-Start function if the charge level is too low or to restart the engine if the charge level drops below a critical threshold.

Details of the StARS starter alternator

The StARS starter alternator is a synchronous machine with a claw rotor. It is air-cooled and uses a three-phase current that is transformed to 12 V DC voltage by a separate electronic transformer. In starter mode, the electronic transformer delivers three currents with a 120° phase shift in relation to the data from the machine’s three position sensors. It is capable of delivering a 600 A current generating enough torque to drive the internal combustion engine immediately and at higher revs than a conventional starter. The machine can start the engine in less than 0.4 seconds, before immediately switching to alternator mode. In this configuration, the electronic transformer uses MOSFET field effect transistor technology to rectify the three phases. This is one of the reasons behind the outstanding 82% efficiency of the StARS starter alternator, which is a full 10 points higher than the best conventional alternators on the market. The machine delivers a current of up to 180 A.

The benefits of the StARS starter alternator
Advantages for the automaker
The StARS starter alternator significantly reduces fuel consumption and CO2 emissions with minimal investment.
At 2.5 kW at 14 V, the starter power is high.
Electrical efficiency is greater than that of a conventional alternator.

 

[gogo]

Cheap is good and if you could use discarded (free) car batteries, that would be of value for the frugal. Chargers with reconditioning modes are widely available now for stretching the useful life of lead acid batteries.

Are these starter/alternators available from the salvage yards yet?

 

[bearing]

I think the alternators I found were not Valeo StARS, just normal Valeo alternators. Will look more into it.

Valeo StARS has been available as an accessory for Citroens from 2004 or 2005. In the future it will be standard.

Seems other manufacturers like Peugeot, BMW, Mercedes and Opel are also starting to use Valeo StARS (also known as "Start & Stop") from 2008 or earlier.

More Pictures:

 

[12p3phPMDC]

too bad it isn't a 42 volt system yet.

 

[dnmun]

it can probably be hacked up to 44V for 36V nominal. or maybe higher. the automatic tension for the belt depending on drive is kinda neat too. not sure how long they will take the heat though.

 

[12p3phPMDC]

The whole assembly is nicely integrated. It may be that
the system is already capable of 42V. I used to keep closer tabs on it,
but there is a trend to up the voltage in automotive to lower copper costs and
what not. But, I haven't seen a car with a 42V system yet. The three phase drive (assuming)
and inverter assembly looks really nice. I think that the trend in automotive edrive systems
is moving in this direction for alot of the motors in a car, i.e. starters, alternators,
AC compressors, traction motors, power steering by wire, throttle by wire, fans, etc..

exciting times!

 

[dnmun]

i think the trick with this hack would be getting access tot he code in the controller and working from there, or being able to change the PIC even. using a known solution for the motor drive and control.

first thing is to get one and then see how hot it gets under load and how much power it has. it may end up too much hassle for the output. but there could end up being a whole class of electrathons out of this.

 

[12p3phPMDC]

Voltage issues are typically inherent to the hardware i.e. fet ratings, cap ratings, feedback voltage dividers (sensorless).

 

[dnmun]

FETs and caps can be swapped, but it has a huge heat sink on the back side, that's good. eventually someone will get one and we can see how much power it will take.