Lack Of Engine Braking

[Geriatric]

The petrol engine seems to have little or no engine braking. Changing down a couple of gears at a roundabout only seems to increase the revs. Is this normal and if so why does this engine have so little braking? I have to use the brakes more than on many other cars.

[ihpj]

Never noticed this myself; admittedly I haven't been looking that closely - but even in our MMT I haven't found this to be a real issue. You've got me pondering now!

[AygoIronman]

The petrol engine seems to have little or no engine braking. Changing down a couple of gears at a roundabout only seems to increase the revs. Is this normal and if so why does this engine have so little braking? I have to use the brakes more than on many other cars.

No idea what your talking about. You need to be more specific. Engines dont "brake". You disengage the engine by using the clutch. The "brakes" stop the car, NOT the engine.

[daf-fy]

the term 'engine braking' refers to when a car is in gear and you lift off the throttle the car will not (on a level surface) speed up, in fact it will slow down due to the resistance of the engine being turned over without any throttle input.

ie the engine is in effect 'braking' the car unlike say if you put your foot on the clutch or put into neutral then it would 'free-wheel' and take far longer to slow down without using the brakes!

hope this helps

[geezbeez]

Its high geared with a light relatively low friction engine so theres a little sense there, but then the car's also very light so that swings things the other way.

I havent noticed this at all , maybe if your comparing with a van like a Berlingo or something? A Ford transit or say an old style Mini which were very low geared you might think this.

Try driving a big oldfashioned 3 or 4 speed auto to know what not a lot of engine braking is like!

[AygoIronman]

the term 'engine braking' refers to when a car is in gear and you lift off the throttle the car will not (on a level surface) speed up, in fact it will slow down due to the resistance of the engine being turned over without any throttle input.

ie the engine is in effect 'braking' the car unlike say if you put your foot on the clutch or put into neutral then it would 'free-wheel' and take far longer to slow down without using the brakes!

hope this helps

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

[geezbeez]

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

That'll be engine braking then! Even has its own wikipedia page!

You can argue the toss over whether its gramatically correct but that s what its called.

I mean the front wish bones on my Aygo dont come from a chicken! and I never made a wish on them. You can bet if I did make a wish it wouldn't come true and the Toyota warantee would not cover it!!!!

[AYGOgummy]

The petrol engine seems to have little or no engine braking. Changing down a couple of gears at a roundabout only seems to increase the revs. Is this normal and if so why does this engine have so little braking? I have to use the brakes more than on many other cars.

No idea what your talking about. You need to be more specific. Engines dont "brake". You disengage the engine by using the clutch. The "brakes" stop the car, NOT the engine.

Of course there's such a thing as engine braking!!! It's when you take your foot off the accelerator and the car slows down, before you need to use the brakes. There should then be less revs and this should slow the car down. I thought everyone knew about engine braking :P

Geriatric, changing down gears will increase the revs, but as long as the car isn't speeding up, I should think it's fine :)

[DONFRAMAC]

The petrol engine seems to have little or no engine braking. Changing down a couple of gears at a roundabout only seems to increase the revs. Is this normal and if so why does this engine have so little braking? I have to use the brakes more than on many other cars.

My own car, a 16 valve Fiesta 1.25, is very revvy, but has little or no engine-braking, despite a high compression ratio.

The 2009 model Aygo family have revised pedal-box switches, to cut fuel-injection when doing gear-changes;-- switches on clutch and accelerator pedals, to improve MPG and lowers emissions to 106 grams from original 109, aided by thinner engine and gear oil. (also noise reduction measures on an engine pulley, and anti-drumming panels in the body, and exhaust improved.)

The above mentioned cut in fuelling may well give more engine braking in current cars.

Your car is known to be hard on brakes, with soft disks and abrasive pads.

[arbs]

'brakes for slow, engine for go' etc...

probably got all kinds of low resistance bearings etc for efficiency - can't say i've noticed it!

[megagem]

In the days when brakes didn't slow vehicles down much, it was standard practice to change down the gears to slow a vehicle down - especially in lorries and buses. My dad learnt to drive this way in the Air Force during WW2 and passed it on to me.

It works brilliantly in icy weather, when using brakes can be suicidal.

On steep hills, signs always used to say "Engage low gear" or something similar - the engine would then keep the speed down on the descent.

Compared with my Honda Jazz, my Aygo seems far less effective at slowing down using the gears, but with modern computerised engine management so much depends on how the system has been configured.

Richard

[TetsuoEightyThree]

No engine braking my a$$... I accidentally went from 5th to 2nd today, found out ALLLLLLLLLL about how much engine braking it had there!

[ricardo1000]

Engne brake with Aygo no problem just hit the "engine brake button" also called the AIR CON, with the AIR CON switched on and the blower on full I don't even need to use the brakes on a 1 in 6 bank where everyone else is busy hitting theirs. It's amazing how much torque the AIR CON places on the toy engine, I always turn the air con off going up hill "TURBO" function too

[acetip]

the term 'engine braking' refers to when a car is in gear and you lift off the throttle the car will not (on a level surface) speed up, in fact it will slow down due to the resistance of the engine being turned over without any throttle input.

ie the engine is in effect 'braking' the car unlike say if you put your foot on the clutch or put into neutral then it would 'free-wheel' and take far longer to slow down without using the brakes!

hope this helps

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

in the days when i took my driving test ( long,long ago ) part of the test was to slow the car/van/lorry down

through the gears when approaching traffic lights, junctions etc using the ENGINE BRAKING as it is called.

when i took the lorry test you had keep the road speed constant when going down a hiil by using the correct lower gear.

a petrol engine used to have better ENGINE BRAKING than diesel before the electronic management systems came in.

you could save a bit of fuel once upon a time by slipping your gearbox into nuetral and coasting along for a bit

but once again ecu came in have spoilt that a bit.

[Pugboxter]

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

You'd be better off not replying when you so quite clearly have no idea what you're talking about

[acetip]

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

You'd be better off not replying when you so quite clearly have no idea what you're talking about

i second that,well said.

[PumpkinSteve]

Engne brake with Aygo no problem just hit the "engine brake button" also called the AIR CON, with the AIR CON switched on and the blower on full I don't even need to use the brakes on a 1 in 6 bank where everyone else is busy hitting theirs. It's amazing how much torque the AIR CON places on the toy engine, I always turn the air con off going up hill "TURBO" function too

Haha, exactly right. On my first drive home after buying the Aygo I made the mistake of switching the air con on when going up a hill, being passed by horse & carts...even just carts by themselves

[piezo]

Mine brakes down when engaging a lower gear, but it's not very impressive. I'm using the brakes a lot, but they're still fine. I hope.

[Essex Toura]

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

You'd be better off not replying when you so quite clearly have no idea what you're talking about

Classic I like it, I find that I get same engine breaking on mine but you need to drive smoothly to take advantage of it, about 20 secs to go from 30 to 20, lol

[AygoIronman]

Ah, yes. I know whay you mean, but the term "engine braking" is NOT the correct term. All you are doing is going down the gear ratios to slow the car down. Hope this helps back. lol

You'd be better off not replying when you so quite clearly have no idea what you're talking about

Oh!? I d like to hear your explanation!

[Red Yaris 54]

I think this has gone far enough!

Please try to play nicely on the forums!................Or the topic is toast!

[Raistlin]

Petrol

The term engine braking usually refers to the braking effect caused by throttle position induced vacuum in petrol engines.

While some of the braking force is due to friction in the drive train, this is negligible compared to the effect from vacuum.

When the throttle is lifted less air is allowed to pass through the intake manifold, and the engine works against this vacuum.

It is the deceleration of the engine against this vacuum which provides the braking effect.

Diesel

Diesel engines do not maintain a throttle vacuum as they do not have an intake throttle.

The fuel itself is the throttle, and thus diesel engines are not subject to the same engine braking effects as gasoline engines are.

However, there are several other mechanisms which diesel engines use that could also technically fall under the term engine braking:

An engine retarder/engine brake

A compression release brake which is used mainly in large diesel trucks. It works by opening the exhaust valves at the top of the compression stroke, releasing the compressed air in pop then immediately closing the valves to create an extreme vacuum in the cylinder and providing immense amounts of braking force.

A 565 hp (421 kW) diesel engine can produce up to 600 hp (450 kW) of braking power.

This works by causing a restriction in the exhaust much like the intake throttle causes in a gasoline engine. Nearly all of these brakes are butterfly valves mounted downstream of the turbocharger.

A mechanism related to the exhaust brake is back-pressure from a turbocharger.

In turbo diesels with variable-vane turbos, the vanes will close when the accelerator is released which creates a back pressure braking effect similar to an exhaust brake.

[Cyker]

Hahaha!! I wrote most of that Wikipedia article!!

(Previously the article had engine braking confused with jake-braking, which I've only ever seen (Well, HEARD :o ) on large american artic's!)

I will say that compared to larger engines, you probably won't feel the engine braking as much, especially if you're in the higher end of the rev range.

Does the Aygo have a fuel cutoff when the throttle is closed? If it doesn't, that may be why the feeling of engine braking isn't as high.

My Yaris (supposedly) doesn't inject any fuel if it's above 1000rpm and I take my foot off the accelerator, but because it's diesel I tend to use the aircon trick to slow down too

[Raistlin]

Hahaha!! I wrote most of that Wikipedia article!!

(Previously the article had engine braking confused with jake-braking, which I've only ever seen (Well, HEARD ) on large american artic's!)

I will say that compared to larger engines, you probably won't feel the engine braking as much, especially if you're in the higher end of the rev range.

Does the Aygo have a fuel cutoff when the throttle is closed? If it doesn't, that may be why the feeling of engine braking isn't as high.

My Yaris (supposedly) doesn't inject any fuel if it's above 1000rpm and I take my foot off the accelerator, but because it's diesel I tend to use the aircon trick to slow down too

A damn fine piece of work and only posted to stop the bickering :D

[Jan&tone]

As an observer for the Institute of Advanced Motorists, I was taught and pass on the following:-

Brakes are for stopping, gears are for going!

Ie, use the brakes to slow you down and change to the lower gear just before you go again. brakes are cheaper than clutches!!!