Expertize si testari auto

https://chargedevs.com/newswire/schaefflers-multimode-dedicated-hybrid-transmission-enters-volume-production-with-up-to-145-kw/?utm_source=ChargedEVs.com+Email+Newsletter+Opt-in&utm_campaign=2e34715445-Daily+Headlines+RSS+Email+Campaign&utm_medium=email&utm_term=0_6c05923d39-2e34715445-344200881

Schaeffler's MultiMode dedicated hybrid transmission enters volume production with up to 145 kW Schaeffler launches MultiMode dedicated hybrid transmission with up to 145 kW, entering volume production for European and Asian automakers.

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Richard Ruth is one of the OGs of EDR analysis. He's written lots of papers on them, and looked at more of their data than perhaps anyone I know. When he says something about EDRs, I try to listen. He offered two comments on my post a while back about the term "Maximum SDM Recorded Velocity Change (mph)" which may appear on some older reports. I'm reposting them here, as many folks don't follow the comment section, and the information is worth noting. EDR reports may look like plain language, but there's often more to it under the surface. Thanks for the pointers, Rick! Peace. -W

1. Side airbags started in 1999-ish but the side satellite sensors in the B and C pillars were running at 4K, the data could not be streamed at that rate to the central control modules, the decision to deploy had to made at the satellites and all the ACM knew was if it was told to deploy. There was no lateral sensor in the ACM because it was not used in the decision process in those days.

2. When GM Gen 2 (99-04ish) said "Max Delta V" yes it did mean "Max Longitudinal Delta V" and that was because ONLY longitudinal Delta V was recorded, there was no lateral Delta V recorded. But 𝗚𝗠 𝗚𝗲𝗻 𝟯 (𝟮𝟬𝟬𝟱-𝟮𝟬𝟬𝟵𝗶𝘀𝗵) is the EXCEPTION - the System Status still had "Max Delta V" with no identification, but it had both X and Y Delta V sensors and the Data Limitations defined Max Delta V as "the square root of x-squared plus y-squared", meaning the total Delta V. After that the labels were clear in the System Status.

https://www.facebook.com/share/18a9i6Zd64/

Recently, a comment was made to the effect that aero forces will affect the "double the speed, double the distance" stop relationship notion. That is not wrong, but let's think about that for a bit...Today' first step is "How do we calculate the aerodynamic drag on a body moving thru the air? The equation is pretty simple:
Fdrag = 0.5* rho * v² *Cd*A
where
rho is the density of the fluid you're moving through, commonly taken to be about 0.0765 slugs/ft³ ( 1.22 kg/m³ ) at sea level;
v is velocity in ft/s or m/s
Cd is the drag coefficient, pretty commonly in the 0.3 range for modern sedans
A is the frontal area punching a hole in the air

So, for a speed of 65mph (95.3 ft/s, ) and a typical car with frontal area of about 23 square feet (2.1 m²) we get:
F = 0.0765slugs/ft³ * 95.3² ft²/s² * 0.30 * 23ft² =2,396 Slugs*ft/s²

Man those units are goofy. I think I have the conversions all correct. If I'm wrong, I figure someone will check me on it, but getting the same answer in English and SI units gives me hope. What we really want is how many pounds of force the wind is applying, so divide by 32.17 to get Drag Force = 74.5 lb. If our car weighs 3,800 lb, then the aero forces will slow it by (74 lb / 3800 lb) = 0.02g. Compared to actual brake application of 0.2g for gentle slowing and 0.7g or more for hard braking, the aero forces are pretty small. They do increase as the square of the speed, though, so they build quickly. If you're working wrecks on the Autobahn at 125mph, aero probably does become a player...but it can be simply baked into your coefficient by conducting actual coasting and braking tests at comparable speeds.

One set of force-while-coasting-down test data is shown for a larger vehicle at higher speed, after releasing the throttle. The paper that test came from is in the Reference library, titled "2013 Fuel_Efficiency_by_Coasting_in_the_Vehicle aero drag example".

Peace. -W

EDIT: As an aside, I would love to find a copy of George Bonnett's IPTM treatise on the topic. It is out of print now, but it was titled "THE AIRBORNE DRAG FACTOR - Flying at Zero Altitude". Anyone got a copy?