Do lorry engines shut off fuel to some cylinders on motorway?

[startinghandle]

Do lorry engines shut off fuel to some cylinders when traveling on motorway or have I been told complete ballox??

 

[TechWise]

My old car certainly did, so I see no reason why that wouldn't have been extended to larger engines.

 

[JMTHORNLEY]

It was an idea banded about for a while but trouble is in the UK we have such varying topography that it’s not ideal. I drive a 460 HP motor and there’s very few times I’d be happy for it to shut a few cylinders down

 

[Flatlander]

im In the flattest area you could drive in and pulling a load is still needing every horse to do it’s share. Between wind and suction behind the truck and physically rolling the tires with a load on there are next to no time I’d like to see a few cylinders go out of commission. Also the lost exhaust gases going o the turbo would cut its boost pressure killing off the remaining cylinders.

 

[Courier]

Do lorry engines shut off fuel to some cylinders when traveling on motorway or have I been told complete ballox??

Son of driver who drives vans for us is Hgv driver and was telling his dad the the Cruise Control on his unit has sessions of increasing speed then a short while un fuelled - Improves the MPG apparently (Don;t think it was April 1st )

 

[Timbo]

Son of driver who drives vans for us is Hgv driver and was telling his dad the the Cruise Control on his unit has sessions of increasing speed then a short while un fuelled - Improves the MPG apparently (Don;t think it was April 1st )

He tells the truth actually.

 

[Henarar]

Do lorry engines shut off fuel to some cylinders when traveling on motorway or have I been told complete ballox??

shuts it off to all of them downhill

 

[Andrew]

Scania eco cruise will put the gearbox in neutral before the crest of the hill, so you top the hill 3-4mph slower than the cruise is set, then pick up speed as you coast downhill. If you pick up to much speed it puts it back in gear so you get some engine braking.

 

[grass man]

Scania eco cruise will put the gearbox in neutral before the crest of the hill, so you top the hill 3-4mph slower than the cruise is set, then pick up speed as you coast downhill. If you pick up to much speed it puts it back in gear so you get some engine braking.

How will it know its before the crest of the hill? Is it Gps linked?

 

[Andrew]

How will it know its before the crest of the hill? Is it Gps linked?

Yes

 

[ACEngineering]

Seems another pointless emissions thing imo! Just like the smart alternators.

If your off throttle coasting down hill the engine is in overrun and governor has shut the fuel off anyway if common rail the ECU would shut the injectors off.

Most stuff wont even record a MPG when overrunning down hill, both current van and the old one just went blank on the MPG display.

 

[Robt]

Seems another pointless emissions thing imo! Just like the smart alternators.

If your off throttle coasting down hill the engine is in overrun and governor has shut the fuel off anyway if common rail the ECU would shut the injectors off.

Most stuff wont even record a MPG when overrunning down hill, both current van and the old one just went blank on the MPG display.

Not quite, it’s all about smooth driving. By using GPS it takes driver error out of situation. How can driver think to shut off throttle while going down hill all while eating a pot noodle, picking his nose, using his phone, hoovering his curtains, and gawping at the legs of the lady in lane 3

 

[Steevo]

Not quite, it’s all about smooth driving. By using GPS it takes driver error out of situation. How can driver think to shut off throttle while going down hill all while eating a pot noodle, picking his nose, using his phone, hoovering his curtains, and gawping at the legs of the lady in lane 3

......and to think they say that men can't multitask!

 

[Wellpark]

You could pull the lever on the pump of the old 5 cylinder Gardner to shut of the supply to individual pots to save fuel . Not sure you could reach from the seat though

 

[Al R]

You could pull the lever on the pump of the old 5 cylinder Gardner to shut of the supply to individual pots to save fuel . Not sure you could reach from the seat though

Starting them on a cold morning you could warm a Gardner up a few at a time could you not?

 

[fendtfiasco]

Think a Cadilac V8 saloon shut off some cylinders to save fuel , talking back in early nineties from memory.

Guessing with the latest ecu's and engine management wouldn't be much of an advantage or saving to be made.

Some cars satnav and cruise control are linked perhaps Merc S class so similar to the Scania system.

 

[Norfolk Olly]

One of my motorbikes goes from a V4 to a Vtwin when going through town or plodding about in traffic. Apparently to reduce heat and noise

 

[kiwi pom]

Seems another pointless emissions thing imo! Just like the smart alternators.

If your off throttle coasting down hill the engine is in overrun and governor has shut the fuel off anyway if common rail the ECU would shut the injectors off.

Most stuff wont even record a MPG when overrunning down hill, both current van and the old one just went blank on the MPG display.

Yes I always thought that if you coast in gear the fuel was shut off but if you coast in neutral the engine has to use fuel to keep it idling.
Might be wrong though.

 

[Steevo]

One of my motorbikes goes from a V4 to a Vtwin when going through town or plodding about in traffic. Apparently to reduce heat and noise

Got a feeling a car on Top Gear/Grand Tour did similar too.

(yes I know I’m so helpful giving such specifics! )

 

[Wellpark]

Starting them on a cold morning you could warm a Gardner up a few at a time could you not?

I think you could, my experience of that engine was limited and not in a lorry and I was the pup then