Engine braking - OK or not OK?

[roxburd]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

 

[SpeedyDux]

I hired a VW iD3 which, despite me expecting to hate it, I actually enjoyed. I quickly adapted to one pedal mode. Even throwing it down some back country roads, one pedal mode provided enough braking to have a bit of fun. It was the most useful in town though. It quickly becomes natural and more convenient that two-foot-coast mode, and it's probably saving a bit more energy too. My annoyance was that the iD3 only slowed to a creep speed. So I still needed to move my foot over to stop at lights and junctions, which just felt a bit awkward and unnecessary, like they were pretending it was an ICE automatic? I'm not sure if there's a technical or safety reason for this choice? As you said, some manufacturers have their cars come to a complete stop in one pedal mode.

Did the regen braking also turn on the brake lights to warn the car behind? Or, do the brake lights need slight pressure on the brake pedal?

 

[L' Hobo]

My recollection was that on dry tarmac, four locked wheels gave the shortest stopping distance, although maybe with less control.

That was in a Mini. Those were the days.

No your wrong, a brick house or 32ton artic provided the shortest stopping distance!

 

[bladerunner]

ABS is rubbish in really icy conditions - although you may continue in a straight line.
I've twice braked on a steep icy bridge to have the care brrrrrrrr happily along without losing speed - (without incident).
Some bikers had fun coming down the Wrynose pass ahead of me. It was so wrinkled from rain that their ABS cut in all the time and they were taking the hairpins at interesting speeds.

The first thing they tell you to do on a motorcycle off road course is to switch off the ABS.

 

[Yorick]

The first thing they tell you to do on a motorcycle off road course is to switch off the ABS.

I'd hate ABS on my dirt bike.
Coming down the volcanoes we just lock the back wheel and dab the front brake.
Keeps the descent steady.

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[gilbaro]

My recollection was that on dry tarmac, four locked wheels gave the shortest stopping distance, although maybe with less control.

That was in a Mini. Those were the days.

We did a lot of testing of this in the late nineties.
Shortest stopping distance will come at the threshold of grip just before lock up or ABS activation with the wheels straight.
If the wheels are turned even slightly lock up will occur sooner or ABS will activate sooner whichever is appropriate.
Mr average driver, who only concentrates 25% of the time, will generally stand on the brakes and ABS will allow a degree of steering in this case.
In practice no effort is made to avoid the collision and we generally hit what we are looking at. If we do manage to stop then the danger shifts behind us!

 

[pappajohn]

When i was learning to drive the instructor insisted it was gears to slow, brakes to stop.
Today its the opposite.... leave it in whatever gear until you have to use the clutch then brake to stop, when stopped engage 1st gear ready to move off.
I couldnt believe what i was hearing from my daughter when taking lessons.

 

[L' Hobo]

When i was learning to drive the instructor insisted it was gears to slow, brakes to stop.
Today its the opposite.... leave it in whatever gear until you have to use the clutch then brake to stop, when stopped engage 1st gear ready to move off.
I couldnt believe what i was hearing from my daughter when taking lessons.

I still believe in the old saying, 'right gear, right position' what happens now if something suddenly happens and you need power to escape it?
Anticipation for any situation is what my Sargent Instructor taught me!

 

[dunnah01]

Every robotised manual I've owned have used engine braking by default so manufacturers seem to think it's necessary

 

[BeeHappy]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

HGV and coaches etc, large heavy vehicles rely a lot on engine braking, to the extent that they commonly have an additional system to increase and regulate engine braking, an exhaust brake or as the yanks would call it Jake brake. On long decents there would be so much energy to dissipate that using just the brakes would hammer them so hard they would be liable to catch fire, fade or just wear out quickly. A motorhome is not in the same category in terms of weight obviously, but I certainly don’t worry about using what engine braking is available and going a bit easier on the brake discs and pads.

On a motorbike incidentally, I remember the IAM saying of brakes to slow and gears to go, but I took it a bit more aligned with town riding, slow speed, although becomes quite aligned with track riding, where a slipperclutch reduces engine braking as there is so little weight on the back tyre it’ll just skip and lock up when your braking hard. On track the saying goes, if you’re not either on the brakes or on the gas, you’re losing time. Out on the open road on sweeping bends is still just drop a gear and roll off for smoother riding.

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[Clive Mott]

My Mrs did the IAM course in her van and passed. It is correct what has been reported but it is based on "Brakes are cheeper to replace than gearboxes." Many HGVs have methods of increasing engine braking, Exhaust brakes where the exhaust is shrunk so the engine acts as a compresdor, or a Telmer Retarder which is an electric generator driven off tge oropshaft with the output energy disipated in a load of resistors.. One thing is clear, if you are comming down a mountain then you do not want to be reliant on just brakes. Always slow down and go through the gears until whatever engine braking you have is sufficient to stop you running away.
Stay safe, The gearbox is cheaper to replace than you.

 

[Don Campbell]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

After I saw a large Winnebago crash out of control with failed brakes on a steep twisty descent in the US, I started using engine braking a lot more!

 

[Captain Birdseye]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

We have a final ducato based motorhome with an automatic gearbox. Going downhill the box changes down of its own volition if I am off the throttle. I assume that it's programmed to do that.
Comments anyone?

 

[Pausim]

We have a final ducato based motorhome with an automatic gearbox. Going downhill the box changes down of its own volition if I am off the throttle. I assume that it's programmed to do that.
Comments anyone?

Sounds like it is doing exactly what it is supposed to do.

 

[Orion]

We have a final ducato based motorhome with an automatic gearbox. Going downhill the box changes down of its own volition if I am off the throttle. I assume that it's programmed to do that.
Comments anyone?

Yes, I’ve found it very good in that respect.

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[stewartwebr]

I know it’s slightly different in terms of the initial subject, but the engine brake on my Atego Motorhome is very affective but takes a bit of getting used too. On pressing the brake the engine brake automatically applies the engine brake which you hear as the engine revs increases and vehicle starts to slow. As the revs drop in that gear the system drops the gear but at this point the vehicle does tend to lurch if you are not on the footbrake until such time as the engine brake kicks in again and so the process goes on unit the vehicle stops. It’s a bit of a game working between the engine braking and you using the foot brake to keep the momentum down until the engine brake kicks in again, takes a bit of getting used too. It is excellent when declining a steep hill, it keeps a constant speed, a bit loud but very effective. The 3 stage engine brake is standard on models above 9.5t but can be upgraded from standard 235kW to 295Kw of brake power which we have.

Engine brake.​

The three-stage brake system offers up to 235 kW of brake power, which comes as standard on vehicles with a permissible gross vehicle weight of 9.5 t or over. This reduces wear on the service brake while enhancing safety and control of the vehicle.

 

[Stoosal]

Using engine compression to slow a vehicle on descents by selecting a lower gear is a recognised way of assisting control of a vehicle in addition to use of brakes and assists in reducing brake fade, stops vehicle continuing to accelerate etc. Reading the road ahead and using deceleration on approach to a corner to reach the appropriate speed then selecting the correct gear is also correct. What is not recommended during advanced driver training is approaching a roundabout and then going down gears sequentially (6 to 5 to 4 to 3 to 2 etc) as a way of slowing the vehicle. Use the brakes to reach the correct speed then select the correct gear ie in 6th gear, brake speed down to 20mph then select 2nd gear.

 

[L' Hobo]

I know it’s slightly different in terms of the initial subject, but the engine brake on my Atego Motorhome is very affective but takes a bit of getting used too. On pressing the brake the engine brake automatically applies the engine brake which you hear as the engine revs increases and vehicle starts to slow. As the revs drop in that gear the system drops the gear but at this point the vehicle does tend to lurch if you are not on the footbrake until such time as the engine brake kicks in again and so the process goes on unit the vehicle stops. It’s a bit of a game working between the engine braking and you using the foot brake to keep the momentum down until the engine brake kicks in again, takes a bit of getting used too. It is excellent when declining a steep hill, it keeps a constant speed, a bit loud but very effective. The 3 stage engine brake is standard on models above 9.5t but can be upgraded from standard 235kW to 295Kw of brake power which we have.

Engine brake.​

The three-stage brake system offers up to 235 kW of brake power, which comes as standard on vehicles with a permissible gross vehicle weight of 9.5 t or over. This reduces wear on the service brake while enhancing safety and control of the vehicle.

I think what you are describing there is not the Jake brake but the Telma retarder.
We used to have them on the coaches with a lever near the steering wheel so one could use more or less depending on the severity of the hill.
I found them invaluable when doing the Ski trips as the wheels never locked up because the retardation was achieved by the use of electromagnetics on a disc fitted to the prop shaft.

I might be wrong?

 

[iwanttoretire]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

We are in Norway at the moment. The brakes would be toast without engine braking

 

[SpeedyDux]

This thread reminds me why I wish Fiat would offer a hybrid drivetrain Ducato. The sales cut-off date of 2035 for ICE and hybrids probably acts as a major disincentive for Stellantis to invest in such a system.

A fully hybrid drivetrain uses the generator to recharge the HV battery when descending a hill in regen mode, reducing the need for brakes. The bonus is that the KERS will improve diesel mpg by up to 30% compared with a non-hybrid ICE.

Whether retardation is achieved by using the engine as an air pump or using disc brakes the result is the same - wasted kinetic (or potential) energy by turning energy into heat, and consequentially increased diesel fuel consumption.

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[Apacheman]

Perhaps Police driving needs different techniques from motorhome driving.

Some interesting and differing comments in this thread. A retired cop, finishing my 30 years as a driver trainer I saw many changes in driver trainer approach. Throughout the early 80s when I did my initial and advanced courses there was a strict instructed ‘Roadcraft’ regime where everything had to be done in sequence, only one braking manoeuvre and only one gear change. By the time I retired the system had become much more flexible so that you could constantly revisit any aspect of it and instruction had gone out of the window in preference to experiential learning.
On steep hills common sense dictates engine braking. A lower gear will help control the speed and reduce the amount of braking, especially over longer declines such as Porlock Hill. The faster you go the harder it is to stop.
On the approach to hazards such as red lights or roundabouts, going down through several gears one at a time for engine braking is not necessary and not fuel efficient. Modern braking systems can easily cope with these events without overheating or fading.

 

[PaulW2]

This thread reminds me why I wish Fiat would offer a hybrid drivetrain Ducato. The sales cut-off date of 2035 for ICE and hybrids probably acts as a major disincentive for Stellantis to invest in such a system.

A fully hybrid drivetrain uses the generator to recharge the HV battery when descending a hill in regen mode, reducing the need for brakes. The bonus is that the KERS will improve diesel mpg by up to 30% compared with a non-hybrid ICE.

Whether retardation is achieved by using the engine as an air pump or using disc brakes the result is the same - wasted kinetic (or potential) energy by turning energy into heat, and consequentially increased diesel fuel consumption.

Do you see them achieving the 2035 date? Seems like a stretch to me.

But of course research and investment in ICE and hybrid drivetrains is hardly likely with this regulatory change looming.

 

[cmj01]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

I would love to know what's best too as I overheated transmission this summer on a hot day in the mountains. I think stopping periodically for things to cool down / running in neutral whilst stationary is probably the right thing to do.

 

[elwyn horton]

When I was a student in the 80’s one guy tried engine braking by chucking the car in reverse, he wrote it off and nearly killed himself. It was his Dads car!
He said well that’s what they do on planes.

 

[PaulW2]

I would love to know what's best too as I overheated transmission this summer on a hot day in the mountains. I think stopping periodically for things to cool down / running in neutral whilst stationary is probably the right thing to do.

How did you know?

In my previous van with the Iveco Agile Auto box it would very easily have panic attacks and claim that the clutch was overheated.

In my current manual 6-speed I'm not aware that it even has the means to tell me that any part of the transmission is overheated?

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[Jerrywh]

Bikes are ridden very differently to how cars and vans are driven though.

On a bike, I brake as little as possible. <snip>

You are not alone
I didn't even realise bikes had braking capability, only accelerators.

On the van however, (auto 6cyl 3l diesel), I use engine braking seldom and sparingly because I am terrified of expensive damage to engine or gearbox. Alpine passes, yes but not otherwise.

 

[gus-lopez]

Did the regen braking also turn on the brake lights to warn the car behind?

It does

We have a final ducato based motorhome with an automatic gearbox. Going downhill the box changes down of its own volition if I am off the throttle. I assume that it's programmed to do that.
Comments anyone?

so did my Kia Carnuval mpv & that was 2003

 

[SpeedyDux]

Do you see them achieving the 2035 date? Seems like a stretch to me.

But of course research and investment in ICE and hybrid drivetrains is hardly likely with this regulatory change looming.

The technology for hybrid drivetrains is quite mature, having been developed for at least 15 years.

Stellantis is putting hybrid cars and small vans on the market already. Some mild and some true hybrids. Along with BEVs. Why not bigger vans?

My opinion FWIW is that the next gen Ducato will be a full BEV because that is cheaper to manufacture than a hybrid 4.2 tonne van.

 

[Pausim]

When I was a student in the 80’s one guy tried engine braking by chucking the car in reverse, he wrote it off and nearly killed himself. It was his Dads car!
He said well that’s what they do on planes.

I managed something similar when a novice driver the first time I drove on snow and ice. I had a Morris Minor with a loose stick in the middle called a gear lever, in practice it was more like the arm of a one armed bandit because what it selected was mostly chance. As I approached a roundabout reasonably slowly I locked up all 4 wheels but remembered that using the engine to slow down was a more gentle option. In my haste to avoid hitting the car in front of me I managed to inadvertently select reverse. The gearbox did not object because the wheels were not turning. I then blipped the engine and lifted the clutch. The result was the car spun through 180 degrees and slid sideways into a service road in front of some shops. It came to rest very neatly parked alongside the kerb facing back towards the slip road entrance. I felt very embarrassed and looked sheepishly at the car that had been following me, they were clapping. No damage done I drove on concentrating on my driving rather than on the delightful young woman I was driving to visit.

 

[Bazzagas]

Bikes are ridden very differently to how cars and vans are driven though.

On a bike, I brake as little as possible. Preferring to watch ahead and adjust speed, road position and being in the right gear. There is generally a decent degree of natural braking when rolling off the throttle. This does vary though. Depending on the design of the engine.

My current bike has the boxer engine which has loads of engine breaking. So brakes hardly touched.

A previous one though, ZZR1400, had little and used to “over run” had to ride that very differently.

Back to the van though, again make sure it’s in the right gear for the road. But as has been said, on steep declines the road signs state to use low gear so I usually do. Stops the van sort of getting away from you too.
The brakes are used more often though on other roads. With a little gentle engine braking.

Thats called " sensible driving " Graham...

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[PaulW2]

The technology for hybrid drivetrains is quite mature, having been developed for at least 15 years.

Stellantis is putting hybrid cars and small vans on the market already. Some mild and some true hybrids. Along with BEVs. Why not bigger vans?

My opinion FWIW is that the next gen Ducato will be a full BEV because that is cheaper to manufacture than a hybrid 4.2 tonne van.

I would guess that would knock them out of the motorhome conversion market.