Next Ferrari Super Car and KERS

Can a gauge be created to accommodate?

 

Very interesting, thank you for the insight. Regards-e

 

I'm really interested to see what Ferrari comes up with as well.

Remember that you're storing energy, not power. Power is energy/time ... if you drain that stored energy quickly, you'll get higher power ... but for a shorter period of time.

The interesting design parameter (among many others, of course) is : how much energy will you store? Every extra bit of extra energy storage adds the potential for more power, but also adds weight ... so there's an optimization here. The optimum is not, most likely, zero energy stored with zero weight ... but neither is the optimum to be found with massive amounts of energy & weight.

Can't wait to see what Maranello comes up with

 

i get that

My comment is more directed at a street car, let's say, with no sanctioning-imposed weight limit. Sometimes, we hear a comment like : "KERS is a waste, because it adds weight." To which i'd respond : "Really? Wouldn't you add ten pounds if it gave you a hundred horsepower?"

Yes, we all know that KERS weighs more than 10 pounds. My point is that you can't just look at the weight alone, and conclude that KERS is a waste ... that same thinking would lead you to decline the 100hp for 10lb offer

It will be interesting to see how Ferrari optimizes this energy/weight problem. My guess is that they'll be looking to store just enough energy (balanced against the weight penalty) to post some blistering laptimes on a few of the more popular tracks ... even though it's a street car, i think they'll be looking for laptime metrics more so than top-speed (or even zero->sixty), for example.

 

Have you seen car body of Enzo successor? One guy from Italy who is famous car spotter claims that he already saw it at Ferrari factory.

 

The tradeoff depends on the power/weight ratio of the car (usually), so if you're improving the ratio significantly, it's probably worth adding the weight. In the case of Jim's car, at 2850lbs with 500hp? - you'd need to be adding at least 1hp for every 5.5lbs (and probably more like 1hp for 4lbs), otherwise you will trade off reduced acceleration for more top end speed while also reducing handling prowess. In your example, if you could add 3hp for that 10lb weight gain, it'd probably be worth it, let alone 100hp.

 

So, we can envision a manettino for KERS. One setting probably full Auto - uses their default map for charging and discharges as much as possible during WOT. Other settings give PtP functionality on the discharge side, with perhaps a few different maps on charging (including brake charge only). Also, possibly a setting or two for Auto-discharge, but with more conservative maps than the full-dump-at-WOT mode. I have trouble envisioning a Push-to-Charge level of control.

As for me, I like to save one boost for the run to the finish line, and use the other two whenever the gal in the passenger seat yells "Hit it!". Maybe they can have a setting for that.

 

I'm still curious to if actually using KERS will be an automatic (controlled by the ECU) or manual (controlled by the driver) process on a streetcar.

 

A few interesting properties of DC electric motors may help illustrate how nicely they complement an internal combustion engine.

A DC electric motor has two input quantities of interest : voltage, and current.

A DC electric motor has two output quantities of interest : speed, and torque.

To first order, assuming no parasitic losses (not a bad assumption, electric motors tend to be pretty efficient), it so happens that : output speed is proportional to input voltage, and output torque is proportional to input current.

Finally, there's a classic torque vs speed relationship that's quite accurate for almost all DC electric motors : a straight-line relationship, with negative slope :

T = Ts - (Ts/wn)*w

T = Torque, w = speed (angular)
Ts = stall torque, wn = no-load speed

Power Calculations:

You can calculate the input power by multiplying voltage*current, or the output power by multiplying speed*torque. Either way, you'll find a classic "parabola" in the power vs voltage (on the input side) or power vs speed (on the output side) relationship, with a maximum power value at 0.5*wn.

Conclusions:

DC electric motors tend to generate maximum torque at zero speed, and they tend to generate maximum power at one-half their usable speed. In contrast, internal combustion engines tend to generate maximum torque somewhere near half of their usable speed (although the curve tends to be broad and flat-ish), and maximum power near their full usable speed. That's why this "pairing" of technologies tend to complement each other rather nicely.

 

My head hurts. Jeff I would be happy to discuss this topic with you over a glass of red wine & dinner at one of our favorite restaurants in Laguna Beach. Trouble is, I'm not sure I would have ANY meaningful input, besides complimenting the chef

 

if you're buyn' ... i'm there

 

I am, anytime, well overdue!

 

didn't mean to derail, rather just elaborate on the torque benefit of electric motor assist.

DC motor gives max torque at zero rpm, and max power at half its usable speed. In a sense, the torque & power benefits of an electric motor are "shifted" down the rpm range, compared to their internal combustion counterparts. One reason why the combo tends to work well.

 

now that's interesting!

We tend to immediately think of zero-rpm max-torque from an electric motor as nothing but goodness ... hadn't even thought of the stress to the rotating assemblies, "punching" them with max torque from a standstill.

maybe ya wanna delete this stuff to keep it from the competition!!

 

I have a suggestion, maybe it would be a good idea to make an added automatic control for low consumption. in this mode a processor will charge discharge to help fuel consumption instead of performance. For safty car periods, or when you just need to go an extra lap....

 

The future of rock 'n roll - show 'em who's boss next Saturday.