For those of us of a certain age, Yanmar and all diesel engines were controlled by a cable that was attached to a throttle pedal or throttle lever. When you moved this the cable moved a throttle lever on the side of the fuel injection pump which increased or decreased the engine revs. Sounds simple doesn’t it? Actually it is a little bit more complicated than that as most people presume that this movement moved the rack in the pump which gave it more or less fuel. This actually isn’t true, there is no direct connection between the Yanmar throttle lever and the Yanmar injection pump, they both in turn are connected to the governor. A governor is effectively a set of weights spinning round which by the cunning use of centrifugal force is always trying to turn the fuel off, as the weights spin faster they apply more force to a moving collar which then pulls the rack towards the no fuel position. When you press the throttle, the lever on the side of the Yanmar pump which is connected to the centrifugal weights by a spring counteracts the centrifugal force and allows the rack to move to give the Yanmar engine more fuel and hence the revs are increased. Basically everything is in balance, the more you move the throttle pedal the more the spring applies more pressure and counteracts the governor.
Now this basic system has been around on all diesels engines let alone Yanmar engines for years. The Yanmar TNE used it as did the Yanmar TNV engines, but as soon as we decided to go all dolphin friendly and save the planet from diesel emissions this system simply wasn’t accurate. We all remember revving diesel engines up and a cloud of black smoke coming out the exhaust. Well this was unburnt diesel and had all manner of nasty particulates in it which, when breathed in, was the equivalent of smoking 40 Woodbines all at once.
So, the next stage in the evolution of Yanmar TNV engine control was the electronic engine. You still had a mechanical fuel injection pump but the governor that was bolted on the back of it was removed and a new housing fitted with an electronic actuator on it which was directly attached to the rack. You now had a Yanmar TNV ECU which controlled the revs, when you moved the throttle pedal, which was electronic, it sent a signal to the Yanmar ECU which in turn sent a signal to the actuator that moved the rack which in turn revved the engine up. There was a speed sensor on the pump which told the Yanmar ECU what the revs were which then allowed it to maintain the selected revs via the actuator and also a Yanmar exhaust gas re-circulation valve which, controlled by the Yanmar ECU, sent a portion of the exhaust gas back through the inlet manifold to be burnt again in the combustion process. The dolphins loved it. No more black smoke when you revved the engine up or when the engine came under load quickly and when you breathed the exhaust fumes in we were down to 10 Woodbines at once.
Then the dolphins got used to it and the Yanmar technology wasn’t so revolutionary so they complained again. Out went the mechanical fuel injection pump with its mechanical injector ‘cracking off’ at a certain pressure and in came the Yanmar TNV common rail system, nothing to do with British Rail I might add. You now had a high-pressure pump supplying fuel at an incredible pressure (29,000 PSI) to a ‘common rail’ which had injector pipes coming from it to individual electronic injectors, You still had a Yanmar ECU controlling everything but this time it was telling the injectors when to ‘crack off’ at exactly the right time for ideal combustion, often up to 5 times in one injection cycle. A myriad of sensors all over the engine supplied information to the Yanmar ECU which monitored and controlled the fuel supply to achieve the most efficient combustion process in the Yanmar engine. On the exhaust side was a DPF filter which was basically a big ceramic filter which the gases passed through, trapping the particulate matters in the ceramic. The Yanmar ECU monitored the inlet gas pressure and the outlet gas pressure on this DPF and when it realised the ceramic filter was becoming blocked it injected fuel into the filter which burnt the particulate matter and reduced them to gas which was expelled with the other exhaust gases. We’re now down to 5 Woodbines at once which is good, the price of an engine however is probably twice as much now which is bad. Somebody has to pay for all the technology though!!!
‘Wow’ I hear you say, those dolphins sure were lucky. However, they were satisfied for a bit and then they complained again. What more could we possibly do you might say……………………..AdBlue was the answer. AdBlue is the posh word for it, what it actually is is sheep’s piss, or Urea, and distilled water. This is injected into the exhaust system and converts the Nitrogen Oxides into harmless Nitrogen and Oxygen. You can tell a bit of construction equipment with an owner that is as tight as a ducks arse that has an AdBlue system on the engine. They’re the ones who have strapped a sheep to the side of the excavator which pisses directly into the AdBlue tank!!!!! Only joking, the price of lamb these days means its cheaper to buy AdBlue but you wait till there’s a glut of lamb on the market and the price comes down.
Now we’re down to 1 Woodbine and all that effort and development work that Yanmar have done you’d think those bloody dolphins would be satisfied, how more dolphin friendly can we get?
Well now, all along it appears that the dolphins have been working with the Chinese who just happen to own 95% of the world’s lithium, a key component in batteries. We’ve now got to go electric to be dolphin friendly!!! Call me a cynic but are we missing something here. What the dolphins refuse to acknowledge along with all the tree huggers and, dare I say it, a large portion of our population is that to produce electricity we generally have to burn something to make it, whether it be wood pellets, gas or that stuff that kills you quicker than a bit of black smoke coming out of an exhaust, nuclear fuel.
Funnily enough the biggest air polluters on the planet by a country mile is………………China.
How dumb are we in the west? Answers on a postcard to PES.
