PHEV maximum speed you have seen

[gwatpe]

While on my recent holiday, I was able to legally check my PHEV's top speed on a level road with no wind assist.

Speedo registered 175kph, but sadly only 170 on the GPS.

have others recorded a similar speed limiting. BTW the pedal still had more to go, but the PHEV would not go faster.

 

[jaapv]

Yes, it is the official specification. The reason is to stay within max revs of the ICE.
It is rather nice the way it accelerates up to the limit, isn't it?

 

[user 816]

Yup, mine won't do more than 105 mph on GPS.

 

[simonrh]

On closed roads - 108MPH indicated and it hit an electronic "wall", was pulling well up to that point

 

[asdf1087]

I used a hill to accelerate to top speed and this exacerbated the effect of the speed limiting. Speed limited to 170km/h GPS (175 km/h indicated). It was still pulling and accelerating well and then noticeable limiting/deceleration was felt (briefly registered 171km/h and then limited to maintain 170km/h).

Some interesting things at this speed:
1) Strange noises heard from front left (intermittent); but loud enough to hear on the dashcam when replayed
2) Regen braking did not work (only had 1/4 battery) until a more sensible speed was reached (way too much current being generated at that speed).

 

[anko]

Re. regen not working: the amount of current generated does not simply depend on speed. To an extend it is (within limits) controlled by the phev's brain. Otherwise, there could not be different B0 values.

As a matter of fact, the B levels are programmed to aim at a specific decellaration: B5 aims at a decellaration of -0.11 G or -1 m/s2. Reasons for not being able to achieve this decellaration can be the limit to the braking force the E-motors can produce or a limit to the amount of power the battery is willing to absorb. Especially when the battery is partially charged.

But it can also be the at her way around. Could it be that, at high speed, natural decellaration caused by air resistance, is more than what the selected B level was programmed for? In that case, you would expect no regen to take place. Until you also hit the break pedal.

 

[asdf1087]

Re. regen not working: the amount of current generated does not simply depend on speed. To an extend it is (within limits) controlled by the phev's brain. Otherwise, there could not be different B0 values.

There was no deflection into the Charge zone on the dash gauge. At 170km/h, B5 did absolutely nothing, no doubt the motors would be able to generate power at that speed but the control system and battery have certain limitations and the brain's seemed to say no way.

 

[anko]

But, when you lift the throttle at 170 kph, how much will the car decelerate just because of the aerodynamic drag? I believe that for an object that is not to much aerodynamically optimized, in free fall the aerodynamic drag conquers gravity at 220 kph or so. It simply will not fall faster. So, at 220 kph the natural deceleration is approx 10 m/s2. I

If the natural deceleration for our car at 170 kph is more than 1 m/s2, then the e-motors will not try to slow you down even more, as they are programmed to slow you down with 1 m/s2.

Edit: Did you by any chance also monitor the power dial when you hit the brakes at 170 kph in B5 mode? Did it regen then? That would confirm my assessment. If it didn't, it would indeed mean the the E-motors are not willing to regen at that speed.

 

[asdf1087]

If the natural deceleration for our car at 170 kph is more than 1 m/s2, then the e-motors will not try to slow you down even more, as they are programmed to slow you down with 1 m/s2.

Edit: Did you by any chance also monitor the power dial when you hit the brakes at 170 kph in B5 mode? Did it regen then? That would confirm my assessment. If it didn't, it would indeed mean the the E-motors are not willing to regen at that speed.

Your 1 m/s2 deceleration theory has some flaws. You can be on B5 and the car can still accelerate - ie going down a steep hill. Furthermore, it is possible to achieve a 1m/s2 deceleration by coasting at speed up a hill to achieve 1 m/s2 deceleration (whatever gradient that works out to be). According to your 1m/s2 deceleration theory, it would make no difference if you're in D or B5 because the vehicle is achieving the 1m/s2 deceleration. That is simply not the case in practice.

I tested my Subaru Forester 2.5L na in the same spot and didn't actually have to press the brakes to take the next easing left corner (same top speed) due to the aerodynamic AND ICE resistance (the PHEVs extra weight also would have had something to do with this). It therefore came as a surprise to me that I was going to have to use brakes to wash excess speed off. I don't recall if the Charge deflected under braking but even if it did, I only commenced braking at about ~130km/h (which is not crazy fast).

The only real way to know is to try a 170km/h to 0 km/h stop with brakes...

 

[anko]

Your 1 m/s2 deceleration theory has some flaws. You can be on B5 and the car can still accelerate - ie going down a steep hill.

As I wrote earlier:

Reasons for not being able to achieve this decellaration can be the limit to the braking force the E-motors can produce or a limit to the amount of power the battery is willing to absorb.

Furthermore, it is possible to achieve a 1m/s2 deceleration by coasting at speed up a hill to achieve 1 m/s2 deceleration (whatever gradient that works out to be). According to your 1m/s2 deceleration theory, it would make no difference if you're in D or B5 because the vehicle is achieving the 1m/s2 deceleration. That is simply not the case in practice.

I think it requires a 10% gradient or such, to achieve 1 m/s deceleration (ignoring air resistance). I don't think I would be able to feel the difference between D and B5 when driving up a 10% gradient.

I tested my Subaru Forester 2.5L na in the same spot and didn't actually have to press the brakes to take the next easing left corner (same top speed) due to the aerodynamic AND ICE resistance (the PHEVs extra weight also would have had something to do with this). It therefore came as a surprise to me that I was going to have to use brakes to wash excess speed off. I don't recall if the Charge deflected under braking but even if it did, ...

So, all you know was you pressed the brake pedal. Whether you actually used the brakes remains unclear. Keep in mind, pressing the brake pedal will initially only increase the amount of regen and only when you press harder apply the brakes themselves. Provided more stopping power is available in the E-motors.

I don't recall if the Charge deflected under braking but even if it did, I only commenced braking at about ~130km/h (which is not crazy fast).

Do you mean to say that up to 130 km/h, there was no regen as long as you didn't press the brake pedal?

The only real way to know is to try a 170km/h to 0 km/h stop with brakes...

I have it for 143 km/h You can see regen start immediately when the throttle is lifted at 143 km/h.

 

[gwatpe]

I have to agree that when I drove at the maximum speed and took my foot off the gas, that the car slowed with regen, at B2. Obviously wind resistance played some part as well. I had no need to use the brake, as there were no other cars on the road either way. Can't do it for long as the battery gauge goes down pretty quickly.

BTW the unlimited section of road is being extended another 90 or so km. Will test some more next time. Maybe back to the old days with unlimited speed outside of the towns from SA to Darwin.

 

[Ozukus]

Slightly off topic here as it actually relates to a Tesla, and not a PHEV, however is relative to speed, and thought a few would be interested in the information.

Was in Brighton on the weekend only to find the Brighton Speed Trials were running and there was a Tesla entered.

For the non-professional drivers class the Tesla came 31st achieving 106.5mph in 12.15 seconds over the quarter mile.

The key thing though was that there was a timing for 64 feet, assume it's the distance to achieve maximum tranction.

The Tesla did this in 1.92 seconds, and was only beaten by a worked Ford Sierra Cosworth XR 4x4 at 1.89. Even the fastest car on the day could only achieve this distance in 2.0 seconds.

Just shows the torque advantage of an electric engine.