Thread: Expediting diesel engine warm up period

Originally Posted by B92 8NW

Would there be any gains to be had by fitting a butterfly or another type of restrictor into the intake of say a 300Tdi to allow it to warm up more quickly?

It seems logical given that most diesels are running such a high air fuel ratio at idle that they hardly begin to warm up until you start driving at moderate speed.

Any thoughts?

I would think it unlikely, a full charge of air when compressed is actually going to be hotter than a part charge. More succesful is to rev the engine a few times without overdoing it, the combustion and turbo action will get things hot quicker. I tried this on a Rodeo 3.0TDi to demonsrate to the owner on how to get it moving in the morning. On them cold fuelling is severely cut back to stop smoke emission, so they have no power at all until a bit warmer.

If you wanted to mess around fitting an exhaust brake it may be a better option.
Our Canter crew cab has a "warm up" button on the dash.It simply engages the exhaust brake whilst idleing.Once operating temp is reached it cuts off and can no longer be activated.
It would be easy enough to get the exhaust brake fittings to fit and work,they are in the pipe away from the manifold.
You would also then have an exhaust brake,not that they are hugely effective on light trucks.
Andrew

Originally Posted by B92 8NW

Would there be any gains to be had by fitting a butterfly or another type of restrictor into the intake of say a 300Tdi to allow it to warm up more quickly?

It seems logical given that most diesels are running such a high air fuel ratio at idle that they hardly begin to warm up until you start driving at moderate speed.

Any thoughts?

At low load or idling, certainly. My nissan work car has this feature.
It's got a warm up switch which raises the idle speed, closes an intake butterfly and would have used more EGR too, but the EGR doesn't work any longer.

As LandyAndy said, exhaust brakes work too. I keep thinking about fitting one for warm up but haven't got around to it. Some Isuzu bighorns (Holden Jackaroos to you) have such a valve fitted, might be worth checking the wreckers.

Can't really see a reason for it,start your engine and let it idle for a minute and then don't use an open throttle for the first few K's and go from there.Very few engines ''wear out'',most meet their end by overheating or crash's or in the case of LC's and Patrols the vehicle rusts out. Pat

Thanks Andy/Dougal, I was thinking exactly along the lines of a "warm up button". I'll keep a look out at the wreckers. So I'd be looking for 4JG2/4JX1 engines?

Originally Posted by PAT303

Can't really see a reason for it,start your engine and let it idle for a minute and then don't use an open throttle for the first few K's and go from there.Very few engines ''wear out'',most meet their end by overheating or crash's or in the case of LC's and Patrols the vehicle rusts out. Pat

True, but it's not so much the wear I was concerned about. Sure, idling for a minute allows the oil pressure to come up and circulate to everywhere, it's the sluggishness/baulkiness for the first few kilometres until the combustion temperature increases that'd be good to reduce.

Originally Posted by PAT303

Can't really see a reason for it,start your engine and let it idle for a minute and then don't use an open throttle for the first few K's and go from there.Very few engines ''wear out'',most meet their end by overheating or crash's or in the case of LC's and Patrols the vehicle rusts out. Pat

In warmer parts of Australia I can understand why you'd never need such a system. But there are two situations where I want one.
The first is being stuck in traffic in a frosty morning. No engine load to warm it up can be a long time before the heater works.
The second is leaving a skifield. Could be -10 and you've got up to 15km of downhill driving before the engine sees any load and can warm up.

Originally Posted by Dougal

In warmer parts of Australia I can understand why you'd never need such a system. But there are two situations where I want one.
The first is being stuck in traffic in a frosty morning. No engine load to warm it up can be a long time before the heater works.
The second is leaving a skifield. Could be -10 and you've got up to 15km of downhill driving before the engine sees any load and can warm up.

I'm not in an Alpine area but I have about 10 km downhill each morning. Even with the engine at operating temperature the EGTs fall to about 90 degrees.

Originally Posted by B92 8NW

I'm not in an Alpine area but I have about 10 km downhill each morning. Even with the engine at operating temperature the EGTs fall to about 90 degrees.

My EGT gauge doesn't go below 100C. 130C is a cold idle, when using engine braking for such a long time downhill it doesn't read anything. I don't know if my fuel pump will completely shut off in overrun or not, but there's no usable heat coming out.