You *could* argue, but it may be playing with words, that the device which governs the rate of flow of fuel through the injector (ie the dose for each injection) is "throttling" (controlling, restricting) its flow.
But unlike a petrol engine, nothing is restricting the rate of flow of air - a cylinder always gets a full charge of air, irrespective of the amount of fuel that is injected into it. Petrol engines with a carburettor, in contrast, got a volume of fuel and air mixture that varied according to the position of the butterfly throttle: the proportion of fuel:air was fixed (excluding the special case when the engine was started on a richer mixture) and only the amount of fuel+air varied.
OK, so you could (mis)use the term throttle to refer to the fuel control device.
Now he's already explained that he has distinguished a fuel cut-off from the throttle (look up!). So he plainly does not mean the fuel flow control. In a diesel (except model aircraft types!) there is only the fuel flow control.
That is not always strictly true. I know the old Ford 2.5DI had a flap that allowed for exhaust gas recirculation at low 'accelerator' positions by throttling clean air.
I'm pretty sure others used a 'strangler' to provide a vacuum for servo assist too.
When someone uses the term 'throttle' on a diesel, its pretty obvious what they mean. There isn't really a well used common alternative word to represent the rightmost pedal apart from 'accelerator'.
The type that are rated for use in situations where there's any possibility of a flammable gas leak I'd imagine by now, like on an oil or gas rig for example (assuming lessons have been learned of course).
Normally, diesel engines have no need of an intake throttle, they suck a full charge of air and control the heat input energy by metering the amount of fuel injected on each power stroke unlike a petrol/gasoline engine which throttles both air and fuel supply, rendering their part throttle efficiency a piss poor second to that of the almighty diesel.
My old Fordson Major had one (butterfly in the intake manifold, I never did understand why.
Yes that's my understanding, the volumetric efficiency is always 100% (subject to losses in the inlet system) so the same volume of air is compressed, is then heated up from the fuel injection and expands doing work. As there is a direct relation between the expansion ratio and power conversion it is better than the throttled SI engine which not only starts with a lower compression ratio, to prevent detonation, but restricts the volume of air:fuel at lower throttle openings so the effective compression is less.
The drawback is that as the fuel injection and subsequent slower burn out takes place while the piston is descending the effective expansion of the end of the burn is less than at the beginning, also in order to burn the fuel the amount of fuel and air is always weaker than stoichiometric, so the charge expands from a lower temperature than the SI engine which burns essentially instantaneously from a high temperature and constant volume.
This is why we are seeing SI engines being developed with stratified charge and variable compression ratios.
Given DERV has 10% more energy per litre the part throttle performance gap is probably closing, I get about 65mpg from my 1.6 diesel and my mate manages 55mpg from his 1.4 hybrid.
Anyway we still don't know what causes the OPs engine to kick back when hot, could it be wear causing lubrication oil to be in the cylinder?
Could it be that the engine is turning too slowly, so there is insufficient turning moment in the flywheel to take the piston over the "hump" of compressing the air before combustion.
I wish I could get 65 mpg from a 1.6 diesel. My Peugeot 308 has averaged about 55 mpg in the 150,000 miles since I've had it (no noticeable worsening as the car has got older) and my wife's Honda CR-V averages about 42 mpg - admittedly from a less aerodynamic body, and 4 WD, even if the back wheels are not normally driven, will incur some losses.
yes it could easily be something as simple as that. On older hand start diesels there would be a valve lifter that pushed the exhaust valve of its seat so you could get the engine spinning over until it had enough inertia and then drop the lifter.
On a slightly related note; Paul the proprietor of Internal Fire museum in west Wales would demonstrate starting a semi-diesel by rotating it the wrong way so it bounced against the air fuel mixture and fired before TDC and thence ran the right way as the initial explosion imparted enough momentum to carry it over the next compression stroke.
I seldom drive in traffic and that includes a fair bit of 70mph driving.
For the last seven years of my working life I commuted 45 miles along the M25-M23 in an old pug 206 1.4 diesel van which I handed bag with 305k miles on the clock. As I administered the company fuel cards I logged my usage and others', I consistently returned 70+mpg, the other manager with a slightly newer 206 who had a 70 mile journey and ended up at 260k miles when the engine blew managed about 43mpg.
I need to look hard at it but what seemed to me to be happening was the starter motor took the engine past one compression, it fired and the resultant increase in speed disengages the starter. If (as sometimes appears to happen) the starter stays engaged and continues to push the motor round then it starts OK.
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