usersteve:
Exactly it has its uses but I wouldnt fully trust it. like I said i would rather drive it myself then leave it to its own devices
Agree with you there.
ACC has it`s uses, but anyone blindly trusting it, and not knowing how it works could be in for a rude awakening.
I did use ACC on a descent, behind a slower vehicle, to see how it worked. After a few hundred metres of using service brakes in a high gear, I decided it was a bad idea.
The hill descent does use gears and the engine brake, in a much better way, but anyone using ACC to hold off from a slower vehicle will wear and possibly overheat service brakes excessively.
Long time since I passed my test, but how relevant is the current test? How much knowledge does a student driver have about different braking systems and auto braking/speed control systems?
I passed my test in Dec (class 2) and Feb (class 1).if it wasn’t for my instructor telling me the different braking systems and when to use them I wouldn’t have known. He even said some instructors don’t teach it. Certainly nothing came up in the test.
usersteve:
Exactly it has its uses but I wouldnt fully trust it. like I said i would rather drive it myself then leave it to its own devices
Agree with you there.
ACC has it`s uses, but anyone blindly trusting it, and not knowing how it works could be in for a rude awakening.
I did use ACC on a descent, behind a slower vehicle, to see how it worked. After a few hundred metres of using service brakes in a high gear, I decided it was a bad idea.
The hill descent does use gears and the engine brake, in a much better way, but anyone using ACC to hold off from a slower vehicle will wear and possibly overheat service brakes excessively.
Long time since I passed my test, but how relevant is the current test? How much knowledge does a student driver have about different braking systems and auto braking/speed control systems?
I passed my test in Dec (class 2) and Feb (class 1).if it wasn’t for my instructor telling me the different braking systems and when to use them I wouldn’t have known. He even said some instructors don’t teach it. Certainly nothing came up in the test.
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Its good that your instructor gave you some "heads up" on it. You can see that different systems will behave differently out on the road. And a pass is only really an OK to go out and continue learning by yourself, just not being accompanied. Every time we get in a different truck we should be aware of possible differences. On a flat motorway or grinding along in slow traffic there may be no issues, but on steep twisty hills there may be problems for the unaware. But is the current test too weak? Or would a comprehensive test take too long anyway? Not too many mountain passes in Norfolk I spose, and asking about every possible event would take forever.
The DAFs have to use the service brakes down hills to hold speed because the exhaust brake is about as effective as opening the door and sticking your foot on the ground to slow down. Even if you manually drop it from 12th into 2nd gear to send the revs off the end of the dial it just makes a lot of noise and not a lot else. Now if you tried that in the old mk1 FHs with the 3 stage exhaust brake you’d be picking up bits of your face from the windscreen .
The DAF eco thing picks you up for all sort of stupid reasons, eg. it’ll wreck your score and scream at you if you dare to tap the brake to cancel to CC as you’re about to slow down on a slip exit instead of manually cancelling it on the stalk. It comes up with “WARNING : ANTICIPATE BRAKING” or some BS like that and knocks your score down . Also unless you pull away from junctions slower that a tortoise it’ll hold your score under 60% if you’re pulling any kind of weight. I think even if you accelerated so slowly that it took you an hour to reach 56mph from a standstill it’d still deem you to be driving uneconomically and mark you down.
In short it’s a load of BS and in real world tests a good experienced driver would easily beat the mpg of how the computer wants you to drive.
Rob K:
The DAFs have to use the service brakes down hills to hold speed because the exhaust brake is about as effective as opening the door and sticking your foot on the ground to slow down. Even if you manually drop it from 12th into 2nd gear to send the revs off the end of the dial it just makes a lot of noise and not a lot else. Now if you tried that in the old mk1 FHs with the 3 stage exhaust brake you’d be picking up bits of your face from the windscreen .
The DAF eco thing picks you up for all sort of stupid reasons, eg. it’ll wreck your score and scream at you if you dare to tap the brake to cancel to CC as you’re about to slow down on a slip exit instead of manually cancelling it on the stalk. It comes up with “WARNING : ANTICIPATE BRAKING” or some BS like that and knocks your score down . Also unless you pull away from junctions slower that a tortoise it’ll hold your score under 60% if you’re pulling any kind of weight. I think even if you accelerated so slowly that it took you an hour to reach 56mph from a standstill it’d still deem you to be driving uneconomically and mark you down.
In short it’s a load of BS and in real world tests a good experienced driver would easily beat the mpg of how the computer wants you to drive.
All exhaust brakes are crap including volvs, penny to apound the one you are talking about is in fact an engine brake, which is a totally different thing.
Just a small aside away from the original posters idea. My DAF tells me off for braking too hard with a message which kinda reads " Gentler braking prolongs brake pad life" (something like that).
I’ve now got into my head the response " Yeah, it also kills the small child I was braking to avoid" every time like an ear wiggy worm…
Reset my eco driving thingee from 54% the other day, drive exactly the same but can’t get it above 37%. Go figure…
From what I gather running up to a junction, it wants you off the power and rolling for as long as possible, then on the exhaust brake, finally using the foot brake at the last moment to stop from a crawl.
The Newer DAF’s we have appear to be easier to achieve a good score. The Scania’s we have are even easier and seem to reward you for braking using the auto exhaust brake or not. Both systems seem to work differently which leaves me wondering what’s right or wrong?[/img]
Rob K:
The DAFs have to use the service brakes down hills to hold speed because the exhaust brake is about as effective as opening the door and sticking your foot on the ground to slow down. Even if you manually drop it from 12th into 2nd gear to send the revs off the end of the dial it just makes a lot of noise and not a lot else. Now if you tried that in the old mk1 FHs with the 3 stage exhaust brake you’d be picking up bits of your face from the windscreen .
The DAF eco thing picks you up for all sort of stupid reasons, eg. it’ll wreck your score and scream at you if you dare to tap the brake to cancel to CC as you’re about to slow down on a slip exit instead of manually cancelling it on the stalk. It comes up with “WARNING : ANTICIPATE BRAKING” or some BS like that and knocks your score down . Also unless you pull away from junctions slower that a tortoise it’ll hold your score under 60% if you’re pulling any kind of weight. I think even if you accelerated so slowly that it took you an hour to reach 56mph from a standstill it’d still deem you to be driving uneconomically and mark you down.
In short it’s a load of BS and in real world tests a good experienced driver would easily beat the mpg of how the computer wants you to drive.
All exhaust brakes are crap including volvs, penny to apound the one you are talking about is in fact an engine brake, which is a totally different thing.
On my current DAF it has the DAF engine brake, better than just an exhaust brake, but nowhere near as good as the intarder on my previous truck.
Using the intarder at higher speeds, when it`s most effective, then using the exhauster in lower gears as the vehicle slows means that the service brakes stay cooler and have much less wear, than otherwise. Using the combination of different braking systems with the gearbox meant a fully freighted truck could be controlled on pretty hilly roads without “grilling the girling”.
Driving the A75 through the Massif Central was a pleasure with a properly equipped truck.
Will_161:
From what I gather running up to a junction, it wants you off the power and rolling for as long as possible, then on the exhaust brake, finally using the foot brake at the last moment to stop from a crawl.
That’s the proper way to drive a lorry going down through the gears utilising the best engine braking (auxilliary braking engaged) possible, Daf didn’t come up with it via some computer generated model, lorry drivers worthy of the name have been doing this for ever.
I understood that modern Dafs and Mercs have Jake Brakes fitted, not as effective as in some older installations ie in ■■■■■■■■ because the engines are smaller in capacity.
Happy to be corrected if they arn’t Jake brakes.
I average about 68 . All a big con. Gives you tips hints how to save fuel. Fair enough we all need to do our bit to save the planet.
But my old daf did more mpg compared to this one with the eco score.
So it uses more fuel than older models then tells you how to save it.
Will_161:
From what I gather running up to a junction, it wants you off the power and rolling for as long as possible, then on the exhaust brake, finally using the foot brake at the last moment to stop from a crawl.
That’s the proper way to drive a lorry going down through the gears utilising the best engine braking (auxilliary braking engaged) possible, Daf didn’t come up with it via some computer generated model, lorry drivers worthy of the name have been doing this for ever.
I understood that modern Dafs and Mercs have Jake Brakes fitted, not as effective as in some older installations ie in ■■■■■■■■ because the engines are smaller in capacity.
Happy to be corrected if they arn’t Jake brakes.
For those not familiar with the idea of the system:
When not using the engine to power the vehicle, no fuel is being injected into the engine. The wheels continue to turn the engine over. With conventional diesel designs the engine ■■■■■ air into the cylinder, it is compressed then released after the “power stroke”, so the energy used to compress the air is returned during the power or expansion stroke.
With a Jake Brake the engine ■■■■■ in air as before, but the exhaust valves are opened at peak compression, thus releasing the compressed air. (This is the point fuel is normally injected and power produced, with all valves closed).The Jake releases the air, compressed by the engine, so it doesnt get to expand and return its energy back to the crankshaft. It is taking energy from the system.
An exhaust brake is basically a flap blocking off the exhaust near the manifold,that prevents the compressed air leaving the cylinder easily when the exhaust valves open (at the normal time) so some of the air stays in the cylinder and makes the engine act as a compressor again, but not as effectively, as with an engine brake.
Thanks Franglais.
The Jake takes a lot of explaining and getting your head around, very clever design.
I had one on a 14 litre ■■■■■■■ in the early 80’s, even though it only worked on 4 cylinders at the time (the work around for the extra 2 cyls hadn’t yet been designed) the retardation was amazing, and it encouraged a whole different approach to driving, you took a great pleasure and some foolish pride in almost never having to use the main brakes.
Something i have tried to pursue since and one cannot stress the safety aspect enough of utilising such systems as much as possible, leaving those all important main service brakes cool for those thankfully rare moments they are really needed.
The only engine brake i’ve used since that came close to ■■■■■■ effort was the 3 stage brake on a Volvo FM.
Have requested a retarder (, won’t be a Jake but a system over and above the standard exhauster) on the next vehicle, currently on order, whether it arrives so equipped is another thing entirely
Bit of a farce really all these eco scores. If you don’t drive around on the redline, aren’t the King of the late brakers, don’t throw your load around, don’t corner like Lewis Hamilton and have a degree of mechanical sympathy then imo you’re halfway there to being a decent driver and these so called scores are a crock of ■■■. Like any system designed by man they can be massaged to make you look like the worlds greatest driver when in reality you’re no better or worse than the next man. Below is a pic of the new gen Scania I had on demo, it took me a couple of days to figure out what the computer wanted and then gave it to it. Did I earn more money for the Co whilst doing this? I doubt it, same as I probably didn’t cost less to them to do the job.
Maoster, you could have got the ''over the hill ‘’ score up to top rankings (bit of rhyming slang) by allowing the terrain linked cruise control to do its thing.
However doing so allows the speed to drop by up to 5mph as the vehicles crests a rise, which means you end up causing havoc in the endless convoys of lorries, most of which haven’t got that crock of ■■■ system yet and assume you’re being an idiot who can’t maintain a steady speed.
I take no bloody notice of these gold stars, didn’t we get gold stars in primary school as i recall , cos i never look at the score and have switched all driving advisories off too.
The system wants you to cause a slowing up of everyone around you, and if you comply the inevitable line of lorries that then pulls out to overtake you (can’t blame them nothing more annoying than some pillock who drops from 53 to 48mph 400yds before the crest) means you’ll be braking to prevent the heffelump race half way down the next bank leading to more fuel being wasted to build back up to speed.
In theory if you did as the vehicle wants, you’d get slower and slower till eventually bloody tractors would be overtaking you then milk floats if we still had any.
I wouldn’t mind (and where i work no pointy shoed bugger’s in the least interested in these score things…yet) but it’s just one more one size fits all load of ■■■■■■■■, most of us interested in beating the computer driven vehicle’s fuel economy, and yes we can and do, already lift off before the crest and allow gravity to do its thing, but a lorry driver judges the traffic situation and doesn’t just cut power inconveniencing everyone else every single time.
Juddian:
I wouldn’t mind (and where i work no pointy shoed bugger’s in the least interested in these score things…yet)
Briefly had a job last year…where they were interested.
Bearing in mind I was on percentage…I got a phone call off the"driver trainer"to tell me my fleet score was down…and that I would have to come back to the yard for an assessment.
I told him to stick the job up his arse,and that I would be finishing Friday.
I then ripped into him about the stupid fkrs in the office,sending me to jobs where they knew full well there were long delays…and I was earning no money…and did he really expect me to spend another day earning ■■■■ all,on assessment.
He hung up.
Cue…loads of arse licking texts/phone calls off the tm.
Made no difference though.i left on the Friday after another day of earning ■■■■ all because they were sending lorries into ferrybridge power station,when they knew one of the incinerators was broke.
Firm I worked at previously(hourly pay) paid a monthly bonus for the top 3 drivers.
I was never out of the top 3.
I work for money…not pats on the head
To be fair…who gives a ■■■■…i drive as best as i can, i stay in the green…never in the red, and i look at the fuel and temp gauges…and the speedo…thats about it…the engine should look after me, and it should be efficient on its own…as most are auto…not a lot to do is there…if i am bottom of the list…on a chart they choose to stick on a wall for everyone to see…thats theyre choice…never was any good at maths anyway.
Sadly Juddian ,the engine brake is not standard on DAF and has to be specced…What I have noticed on this thread there are 2 type of drivers People like yourself ,who understand the vehicle you drive and how to use the systems supplied ie intarder ,engine brake ,exhaust brake etc ,and how to drive properly and economically ,and realise these eco scores are not 100% perfect…Obviously all manufacturers will tell you they are …
Then we have the next driver criticises the truck no end everything is crap etc etc ,but basically does not know how to drive professionally ,in a rush harsh braking ,then foot to the floor when accelerating ,and won’t accept they are crap as they have been driving since I was born ( I’m in my 50s lol ) They don’t realise that as the trucks have changed so the have to change how they drive …Apart from reliability of all makes driving one of todays trucks is a breeze ,Obviously the score will be relevant to all the crap people fit on the cab to the type of trailer /load and terrain ,I bet people who putter about flat Norfolk have great scores …On a plus at least AEBS on vehicles has put an end to light bars on the grill
Sadly Juddian ,the engine brake is not standard on DAF and has to be specced…What I have noticed on this thread there are 2 type of drivers People like yourself ,who understand the vehicle you drive and how to use the systems supplied ie intarder ,engine brake ,exhaust brake etc ,and how to drive properly and economically ,and realise these eco scores are not 100% perfect…Obviously all manufacturers will tell you they are …
Then we have the next driver criticises the truck no end everything is crap etc etc ,but basically does not know how to drive professionally ,in a rush harsh braking ,then foot to the floor when accelerating ,and won’t accept they are crap as they have been driving since I was born ( I’m in my 50s lol ) They don’t realise that as the trucks have changed so the have to change how they drive …Apart from reliability of all makes driving one of todays trucks is a breeze ,Obviously the score will be relevant to all the crap people fit on the cab to the type of trailer /load and terrain ,I bet people who putter about flat Norfolk have great scores …On a plus at least AEBS on vehicles has put an end to light bars on the grill
.
. Also unless you pull away from junctions slower that a tortoise it’ll hold your score under 60% if you’re pulling any kind of weight. I think even if you accelerated so slowly that it took you an hour to reach 56mph from a standstill it’d still deem you to be driving uneconomically and mark you down.
‘’ score up to top rankings (bit of rhyming slang) by allowing the terrain linked cruise control to do its thing.