HDC Speed

Just tried out the Hill Decent Control on my 2004 td4 and I needed a change of underware

The hill is steep in places with a firm loose surface, pic enclosed. I normally do it in my v8 series in low box, 2nd gear, with no problems at all. Following the handbook instructions, Hdc engaged and clutch, brake and accelerator were left untouched. The freelander descended at over 10mph and every time the hdc tried to slow it locked the front wheels causing a slide. As there are some deep ruts control is essential especially in the FL, half way down it was out of control so i reverted to stopping and controlling the decent manually.

Is it just my hdc that seems to be designed for Kamikaze pilots or does anyone elses simulated a plumiting brick

Paul

HDC.............. Hiroshima Driving Centre....... to be honnest its really so the people who can't drive offroad don't die instantly when they see a hill, same with terrain response its for the people who can't drive (like an auto gearbox)

Daft question, which gear were you in, and was the HDC light flashing, or solid?

First gear and the greenlight should be solid. If you're front brakes are locking I find myself thinking here, you got a 4x4 Hippo there or is it in Mondo mode?

Summat wrong there

mine took me down a very steep ice covered hill at 5mph in the winter
I was able to steer around the abandoned cars strewn all over the hill

very impressive bit of kit

was a bit un-nerving the 1st time, but after that mine seems to perform really well. never thought that it was out of control.

Hiya, 1st gear as per manual and green light solid and "no alarms" Thing is this hill is strewn with deep ruts so you need to be at less than walking pace as it is steeper than 45 degrees in places and any faster you can not negotiate past them.

The surface is loose stones and mud (dry at the mo) so unless you give it a gentle brake the wheels will lock and slide.

Reading further on the "early", 2004 is that early ? HDC I have found that the hdc keeps the speed at what ever throttle position you have. So on my 800 revs tick over in 1st, no throttle, on the flat, my FL does 10 mph so that is why my HDC is keeping the speed at 10 MPH. BUT>>> If the hdc detects a locked wheel it ACCELERATES to get it out of a slide it then brakes again, this time at a faster speed and slides then accelerates and so on and so on.........which is exactly what its doing!! Wikipedia says that "its set speed was too high for a controlled descent in difficult conditions" and I agree, dam shame, probably OK on terrain where you don't actually need it, if it did not,and I quote the handbook "Automatically accelerate the vehicle to maintain directional stability" it would not get itself into bother on harsh terrain, I wonder if there is a software update for the eprom !?!

Cheers

Have a look at this video of my Hippo using HDC on snow on a 15 degrees slope earlier this year. You can hear the ABS activate as the HDC controls/reduces the speed when I take my foot off.

[nomedia="http://www.youtube.com/watch?v=7fnCwA179hE"]YouTube - Freelander 1 v6 Hill Descent Control demo down hill on snow[/nomedia]

Certainly don't have this problem in my 1998 L-series or 2002 TD4. Must be about 4-5 mph at most, slightly faster than walking pace.

Cheers

Blippie

Hippo said:

Have a look at this video of my Hippo using HDC on snow on a 15 degrees slope earlier this year. You can hear the ABS activate as the HDC controls/reduces the speed when I take my foot off.

YouTube - Freelander 1 v6 Hill Descent Control demo down hill on snow

Click to expand...

I see you have a mini flatbed on standby just in case! Good idea!

Harleydee said:

Reading further on the "early", 2004 is that early ? HDC I have found that the hdc keeps the speed at what ever throttle position you have. So on my 800 revs tick over in 1st, no throttle, on the flat, my FL does 10 mph so that is why my HDC is keeping the speed at 10 MPH. BUT>>> If the hdc detects a locked wheel it ACCELERATES to get it out of a slide it then brakes again, this time at a faster speed and slides then accelerates and so on and so on.........which is exactly what its doing!! Wikipedia says that "its set speed was too high for a controlled descent in difficult conditions" and I agree, dam shame, probably OK on terrain where you don't actually need it, if it did not,and I quote the handbook "Automatically accelerate the vehicle to maintain directional stability" it would not get itself into bother on harsh terrain, I wonder if there is a software update for the eprom !?!

Cheers

Click to expand...

not sure your HDC was working, rather your vehicle was just using engine braking. If HDC was working, you should here solenoid block "clicking" (quite loudly) as the various wheels are braked. The wikepedia definition seems incorrect.

HDC detects individual rotation speeds of each of the wheels. If one is turning slower than the others, it must be slipping, then it releases the brake force to that wheel only (exactly like ABS, but at a higher speed threshold). Conversly, if one or more is turning faster than the set speed, it applies the brake to that wheel(s). All happening hundreds of times a second.

It does not affect the throttle settings in any way