Er..only from a woefully low figure that a straight timed fast revving engine has.
VVT allows a 'racing' engine to perate efficiently when not 'racing' It doesn't overall do anything that tuning the engine more modestlly would allow in the first place, other than develop more power without spitting unburbnt fuel out the exhaust at lower RPM.
Not necessarily either. If you can increae peak peressures and combustion temperatures you can actually gain efficiency. However thats not the way they are set up on road cars.
Well, here was goo reason not to have the countries whole energy supplies at the mercy of a bunch of guys whose sole interest was working less and earning more.
Sadly she got one lot, but the next lot have taken the reins.
That's one of the problems.. too many engineers trying to solve the problem when the real problem has not been identified. To save a significant amount of energy requires someone to beat the owners into buying smaller cars.. not in marketing men designing hybrids.
A real saving in energy could be made by removing the speed control from the driver and letting a properly programmed computer do the job. This is only a year or two away if someone gets serious about it.
Don't be stupid. It wasn't Thatcher that turned a pay dispute into a political fight. It was the miners union that vowed to topple the elected government by any means at its disposal.
Thatcher did what she was elected to do.. make sure that citizens were protected from the powerful minority. To do this they changed the rules to get gas and oil into the generating system so that the miners could never try again.
If the miners had stuck to pay/conditions then we would probably be burning coal now.. but their leaders choose suicide for them.
Incidentally the clean coal research was mainly to allow us to burn cheap imported coal and not the stuff that is still in the ground.
True. We have lost the plot. 200hp / 150mph / 4x4 when for most people, most of the time a Nissan Micra would do the same *job* (but not massage their egos). I know I know, 'big powereful cars are safer' etc etc but like all the 4x4's stuck in the snowbound traffic .. ok as long as everyone has got one.
True. But I suppose *someone* has to buy then to get some real world testing done? Did I hear the 'Smart car' has ceased production? Another marketing failure or just no good / too expensive? Or was it that we *still* aren't ready for a very compact runabout?
And the steering control. How many million tonns of pollution are created by thousands of vehicles stuck in 'tailbacks' caused by 'accidents' when (in most probability) those accidents were a function of poor / inconsiderate driving?
Even making certain things an offence .. like driving whilst on a mobile phone, driving the wrong side of a keep left sign, driving without wearing a seat belt, parking in a dissabled bay, speeding, driving a defective vehicle, parking on a crossing, jumping red lights, littering and undertaking to name a few .. I see the same people doing ALL those things daily? What part of the rules *do* apply to them? The only reason they (more often) get away with it is because the majority of us don't do it?
As mentioned, a big part of protecting the planet will come with new technologies but we can probably do better *now* by saving not squandering... why do so many people have to be forced to do what's right for the survival of them and their offspring?
It took millions of years to make and we squander it in just 200 years ....?
Basically the nonsense of us tying ourselves in knots over Kyoto when China and Merika et al make our global contributions absolutely insignificant. 10% of sod all is sod all.
Isn't that the idea? You get the benefit of a powerful engine when you need that power, but still have tractability in the form of decent low rev torque and better efficiency. Have you ever driven essentially the same engine with and without variable valve timing? I have, and it's a revelation.
Err, if you're happy with an engine that has a poor power output then fair enough. But variable timing gives you the choice - it's up to you whether you use the extra performance at high revs.
Then what is their point in this discussion about road cars? Unless you're suggesting hybrids will appear in racing cars?
No, you have totally failed to grasp the concept, but then again I didn't explicitly mention it! In an historical UK electricity system context i.e everything installed pre 1990, gas turbines used gas oil, the total installed capacity of this type in the UK would have been around 2000MW, distributed around most of the large generating stations both coal, oil and nuclear, together with dedicated sites where the security of supply requirements would not be met without them. Most of these would hardly ever run (the last long term running would have been in the early 1970's and only then for peak demand in exceptional circumstances as the cost of generation was VERY high)
Combined cycle gas fired power stations which first appeared in the UK around 1992 are NOT the same thing, they cannot be "spun up in a few seconds" These CCGT's now comprise around 40% of UK generating capacity, they are fuelled with natural gas powering a "gas turbine" and use heat recovery techniques from the gas turbine exhaust gas to heat water and thus also drive a low pressure steam turbine. Some of them also supply process heat (steam and/or water) to industrial premises co-located with the power station.
Now down to the rapidity of loading:
If the unit has been on load in the last few hours with the expectation of a short term return to generation you might possibly expect an increase from first firing to full load in around an hour. If it has been considerably longer than 4-6 hours then look at 2-3 hours from first firing to full load.
In limited circumstances more rapid loading in around 15 minutes on the gas turbine part of the station is theoretically possible, this practice however *very* seriously reduces the operational life of turbine components and thus forms no part of any UK operators regime, nor is any assumption on this basis made in declaring or despatching generation.
A few comments on that report:
1) on page 50, the sites deemed as having declared capacities as of
1st April 1990 such as
Cowes Letchworth Lister Drive Norwich Ocker Hill Watford
....are noted as being CCGT's. That is absolutely incorrect, they are pure gas turbines (open cycle) they should really have been designated "GT" or "OCGT" in the report. These sites could run up to full load in a very short period of time typically 2 minutes to synchronisation and up to around 5 minutes for full load, but almost all of them have long since shut down. There are other ones remaining which are not detailed at all in that report located at power stations with declared black start capability, or where they are required for other reasons such as at all the nuclear stations where it is desirable to keep some forced reactor cooling flow after shutdown.
2) it was produced 7.5 years ago and while a lot of the information may still be current a lot of it isn't, for instance while a few of the sites listed with consent have since been built, many ran out of time and lost consent (5 years after initial grant) and at least one not even mentioned on that report has subsequently been built (in slightly questionable circumstances it has to be said!)
Not sure where that idea came from, the whole basis of the program was to enable the use of high sulphur coal commonly found IN the UK! They sited the large scale test facility where it was for precisely that reason!
Even during the darkest days of the strike essential maintenance and safety checks in accordance with the relevant legislation were always carried out - semi-continuous pumping in some areas is essential and nothing I have seen reported at the time or since would suggest that pits were deliberately flooded or pumping stopped before the final closure date, and even then recovery of equipment in some cases went on for months. In fact I vaguely recall some NUM staff actually going underground to deal with either a fire or a flood during the strike - totally sanctioned by the union (and despite that I believe they were never paid by the NCB)
Being relatively local to the Selby coalfield and having watched all the billboards in the area proclaiming "British Coal - one hundred years of energy!" or similar wording I was amazed to see the mines on this coalfield shutdown. Hopefully McGregors ideas of leaving it in the ground until conditions were right mean that we have a source of UKenergy after others are depleted
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.