A query about truck noise.OT.

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john.whiting
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A query about truck noise.OT.

Postby john.whiting » Thu Jul 05, 2018 5:11 am

I am interested to know if big trucks in Britain or the EU have compression release "braking"........commony called "Jake Brakes" on some older trucks..Trucks here have had it for 50 years,and the system is capable of being altered to make really loud noises,imagine a 650 twin with no mufflers ,that kind of noise...Needless to say a small idiot fringe do just that.......But I was under the impression the system had never been used in GB,or Europe.

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Re: A query about truck noise.OT.

Postby Bob.Murphy » Thu Jul 05, 2018 2:16 pm

I have seen that system on American trucks on TV ("American Truckers" / "Ice Road Truckers"-type programmes) but never in the UK.

Am I right in thinking that it pumps compressed air into the motor on the compression stroke (whilst on the over-run) to increase engine braking ??

From "Outback Truckers" I see you guys Down Under are using the American 'Bonneted Control' Mac, Peterbilt, GMC, Northern Star, Kenworth trucks so presumably the system comes as standard.

Almost exclusively 'Forward Control' trucks in the UK - Volvo, Merc, Renault, Iveco, Ford and so on.

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Re: A query about truck noise.OT.

Postby john.whiting » Thu Jul 05, 2018 11:10 pm

Hello,Bob,......what about excessive noise?.......like 120dB ,if you are standing on the roadside.........Im starting a legal action against the Transport and Main Roads Dept,to provide a noise barrier in front of my house...They claim it will cost $80-100,000,and are refusing.....Theoetically ,the noise is illegal,but very hard to police.......especially when the transport inspectors spend half the day in coffee and fast food shops..............The devices simply lift exhaust valves at TDC compression stroke......hence the machinegun noises........and mufflers with some of the baffling removed to increase the noise.

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Re: A query about truck noise.OT.

Postby Bob.Murphy » Thu Jul 05, 2018 11:36 pm

John,

Do you have a "No Jake Brake" sign on your road already ??

See the attached:

http://bestride.com/news/safety-and-recalls/what-do-no-jake-brake-signs-mean-and-why-are-they-posted

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Re: A query about truck noise.OT.

Postby Bob.Murphy » Thu Jul 05, 2018 11:56 pm

Interestingly, the 'Jacobs Manufacturing Co.' considers the "No Jake" signs to be an illegal infringement of their Registered Name !

http://www.todayifoundout.com/index.php/2011/10/how-jake-brakes-work/

I didn't find the explanation particularly clear. It seems that the motor, on over-run, sucks in air as normal and compresses it - creating a drag on the transmission, so far so normal. Then that compressed air is released into the exhaust system via the "Jake Valve".

The piston then descends on the (non) power stroke, presumably creating a partial vacuum above it, unless it lifts the valves off their seats.

The exhaust stroke then does nothing - apart from possibly letting some expelled air back into the vacuum.

The inlet stroke re-fills the cylinder with air and the cycle is repeated.

The only difference being that the (non) power stroke no longer has heated compressed air in it to provide some push.

Interesting, I thought there was more to it than that.

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Re: A query about truck noise.OT.

Postby nevhunter » Fri Jul 06, 2018 12:27 am

If the air is compressed in the cylinders and nothing done it works like a spring except for small losses. You get most of the energy back. The decompressor acts as a very effective brake on early bikes, although it makes the engine easy to turn at very low speeds. Diesel engine braking is extremely noisy and fairly hard on the transmissions, due to the loads. If you used EGR (electro regenerative) you could recover it as trains and trams do (and HYbrid cars, vans). Nev

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Re: A query about truck noise.OT.

Postby john.whiting » Fri Jul 06, 2018 1:36 am

Very hard on the ears,and the patience too,when every five minutes one of these turkeys in a 30 year old Kenworth shatters the peace and quiet.....well as much peace and quiet as you can have with around 5000 cars and trucks a day going past..And the Transport fob off complaints to the police,or the council,despite the Transport being responsible for inspection of trucks.

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Re: A query about truck noise.OT.

Postby Vincent.vanGinneke » Tue Jul 10, 2018 12:10 pm

Never heard of this over here in Europe, I am amazed that it is o.k. to use it.
Are mountains & hills so much steeper in da United States then in Europe ?
I imagine that you could even trigger moutainslides with it .

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Re: A query about truck noise.OT.

Postby nevhunter » Tue Jul 10, 2018 12:27 pm

It gets your attention when one uses it right alongside you. There's absolutely no warning. It's off or on. Nev

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Re: A query about truck noise.OT.

Postby roger.fellows » Thu Jul 12, 2018 10:28 pm

I was deafened the other day I think by a safety valve release from a coach. Quite violent about 6 feet away.


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