TOO GOOD TO MISS?
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Wouldn't it be nice to be able to look into the future? To bet on next year's World Cup, buy into the next Microsoft—or just to know if its going to rain next week...Mere fantasy, of course, but just occasionally you get a glimpse at tomorrow CM has seen the shape of things to come (perhaps), and it comes from Detroit.
Detroit Diesel is a name that should be familiar. For decades the company produced two-stroke diesels the 53, 71 and 92-Series, each number corresponding to their capacity in cubic inches per cylinder, They were notable for developing a high output for their weight but they've long disappeared from the UK, at least in roadgoing vehicles (Detroit is still a name to be reckoned with in the marine, construction and power-generating sectors).
Cummins has become the most successful US truck engine supplier but, like Caterpillar, Detroit Diesel is planning to make a comeback. Or, to be precise, another comeback.
CM last tested Detroit's Series 60 engine in 1995, powering a Foden tractor operated by Railfreight Distribution. It worked well—it was the first Euro-2 tractor we tested that delivered over 8mpg round our Scottish route—but Foden never took up the option of fitting the Detroit engine in production.
Where one Sandbach firm fears to tread, another is tempted to try, without rushing in: ERF has co-operated with Detroit Diesel's Northampton-based UK operation to put the latest version of the Series 60 into an EC tractive unit. It's strictly a development vehicle rather than the finished production article, and ERE hasn't yet decided whether to offer Detroit engines in Britain. But it does give us a taste of what we could he offered—a look into a possible future,
• PRODUCT PROFILE The Series 60, first shown 10 years ago, breaks with Detroit Diesel tradition in that its number has nothing to do with its cylinder capacity. Instead it's part of a range that IP'
includes the Series 30, 40 and 50. The ERF's (entirely provisional) designation is the EC127, reflecting the 12.7-litre capacity of this Series 60; a longer-stroke variant of the 11.1litre engine we tested in the Foden.
But the biggest change from the previous version is electronic rather than mechanical. This ERF has DDEC III engine management (Detroit Diesel Electronic Control), rather than the Foden's earlier DDEC IL With software developed in the UK, DDEC III is an advanced system which manages the engine and its ancillaries, and provides information via the ProDriver system. ProDriver is a display in the cab (rather like Cummins' RoadRelay) which offers real-time and historical data, from cruise control setting and engine temperature to gear usage and the next oil change mileage. It can all be downloaded to a laptop computer or printed off.
Comparisons with Cummins' Celect system are inevitable. Like Celect, DDEC controls the torque curve, and it too can be reprogrammed—up to four power ratings can be stored in the ECM (Electronic Control Module). The Series 60 is available with a bewildering variety of power and torque curves, spanning the range from 300hp to 500hp and 1,1501bft to 1,6501bft, with rated power corresponding to either 1,800rpm or 2,100rpm. The range brochure (covering USlegal models) lists no less than 52 combinations of power and torque.
Not all the trickery is electronic however: the overhead-cam, four-valve engine includes features such as cylinder liners with cooling channels built in, and super-tough ceramic (silicon nitride) cam-follower rollers on the injector rocker.
This particular Euro-2 example is rated at 370hp (276kW) and 1,4501b1t (1,966Nm)—but it's not as simple as that, as 370hp is the rated output at 1,800rpm, well beyond the laserstraight plateau of maximum torque that stretches from 1,200 to 1,500rpm. Claimed torque drops off in a steep, straight line to just 1,080Ibft (1,464Nm) at 1,800rpm. And back at 1,500rpm the engine puts out a genuine 414hp. Confused? We don't blame you.
This is not just a test of an engine: the chas sis it's in is pretty important too, as is the way it has been installed. Putting the Series 60 into the EC was not as difficult as it might have been, because ERF already has experience of fitting it in Sandbach-built Western Star Commanders bound for Australia.
The EC chassis is very much a known quantity; we last tested it only last month. That was the Cummins Mll-powered EC11.38, rated at 380hp and a clear benchmark for the EC127. Fresh from ERF's "Fuel Duel" campaign, and beautifully fettled for peak efficiency, it managed an all-time record average round (Ms Scottish route of 8.47mpg. That's a tough target by any standard: could the Detroit prove a worthy dueller?
CM's Scottish route is designed to give repeatable results, and it usually does, but you can't legislate for the weather or the traffic. Whereas last month's run in the EC11 was largely clear of bad weather or congestion, the
EC127's journey was dogged by both. Edinburgh's city centre was gridlockedwell, it was the height of the Edinburgh Festival—while on the third day (including the tough A68 section and long motorway runs) heavy rain was forcing the engine to work hard. So the results are not perfectly comparable.
But even so, and with a fractionally taller trailer than the ECU's, the Detroit-powered ERF managed a more than creditable 8.03mpg overall—well within the normal range for 380-400hp Euro-2 tractors. And bear in mind that this was not a production vehicle.
-40 After making allowances for the Edinburgh traffic the EC127 also put in a similar average speed to the EC11 and it. dispatched most of the hill climbs a little faster, reflecting the Series 60's peak torque of around 100lbft more than the smaller-displacement Cummins Ml I.
The final element of the productivity equation is payload. At the same 3.80m wheelbase, the steel-sprung EC127 tares out at 7,320kg, providing a payload with a seven-tonne trailer) of 23,680kg. That's 340kg less than the EC11, but well in line with other modern tractive units. Detail changes may alter the kerbweight if it reaches production.
What can't yet be known is how expensive the Series 60 will be, or how much it will cost to maintain. But the engine is available at up to 470hp with exactly the same mechanicals, so a relatively lightly stressed version like this one should be reliable and long-lived. DDEC is being developed to include an oil analysis function, so there is also the promise of extremely long service intervals.
Existing features include engine protection, which reduces power or shuts down the engine if it detects a problem such as overheating or loss of oil pressure, and "Optimised Idle". No, this doesn't ensure that the driver takes his breaks (though DDEC might well be able to organise that...) but is a feature which starts and stops the engine while at rest to ensure that battery voltage, engine temperature and cab temperature are within set limits.
Detroit argues that this cuts the damage that excessive idling (which generates sulphuric acid, attacking the oil) can do to the engine.
Having recently driven an M11-powered truck, which had a high take-off torque for throttle-free starts, it came as a surprise that this engine needed the accelerator to get going. But once on the move it becomes clear that the Series 60 is a superbly responsive engine. It belies its large capacity by revving freely and smoothly (noticeably more so than the Cummins unit) and this will be enough to sell it to many owner-drivers.
But using all those revs is not the most efficient way to operate the Detroit. The engine requires a measured driving style to keep it in the 1,200-1,500rpm area of maximum torque. Beyond 1,500rpm the drop-off in torque is so dramatic that it can take you by surprise, so early upshifts are the order of the day. Conversely, when approaching a steep uphill grade it can be frustrating to take a downshift too early as you'll find yourself at high revs but relatively low torque.
Like the Fuel Duel vehicle, this ERF has ZF's 16-speed synchromesh gearbox (despite the Eaton-badged gearlever) and a Rockwell 3.91:1 rear axle. The shift is not especially smooth or precise, but then our test truck had only covered 23,000km.
Still, once the driveline had warmed up we felt confident enough to shift up happily even on the gruelling Black Hill.
One benefit of electronically controlled engines is cruise control. The EC127 has a similar system to the ECll's with dashboard rocker switches controlling the main func tions. Useful features include speed adjustment, in one-mile-per-hour increments, and automatic resumption of the set speed after accelerating for a hill. One measure of the system is that on the first day, spent mostly on the 3,16, the truck was in cruise control 70% of the time, according to the ProDriver record.
It also spent 78% of its time in top gear, not having to split down for Shap or any of the other big grades. In fact, despite being geared for 67mph at 1,800rpm, it felt like it could have taken a taller final drive ratio-particularly as 56mph equated to just over 1,500rpm, which is beyond the torque plateau. On the other hand, a slightly shorter (numerically higher) rear axle would have made top gear more useful on A-roads.
Test-track performance was good, with the EC127 polishing off the 0-80km/h sprint in just 49.6sec, 6.1sec faster than the EC11.38.
The service brakes are the EC's standard all-drum setup, which is progressive and reasonably powerful, while a useful improvement is the Series 60's three-stage Jake Brake (the M11 has a two-stage control). This can be combined with cruise control, to come in progressively as the speed climbs.
The engine will safely rev to at least 2,100rpm so it's possible to get powerful retardation from the Jake if you choose your gear correctly, and braking can be adjusted with the relatively fine three-stage control. Our only grouse was that we'd prefer a stalk-controlled unit: those near-identical rocker switches in a row can become confusing.
The ProDriver display above the windscreen (a four-line fluorescent screen) could be a bit distracting but you'd probably get used to it. The system could be more reliable though: for a while we lost all fuel usage information, necessitating a number of complicated restarts and adjustments.
In the past couple of years we've been impressed by ERF's composite-panelled EC cab. Access is easy, there's plenty of room and stowage, and build quality are up with the best. The driving position is nicely adjustable (though a seat belt would have been useful) and visibility is fine.
One aspect of the Detroit's installation was irritating, however. The massive Horton radiator fan, controlled by an air clutch connected to the ECM, cut in just as we were changing down on a steep hill, making an enormous noise and convincing us that mechanical mayhem was about to take place.
Apparently a digitally controlled variablespeed fan is under development in the USwe can't wait.
For a development "hack", the EC127 is a very well-sorted machine. It returned fine fuel results in less-than-perfect conditions; its performance is excellent, belying its 370hp rating, and it was very driveable.
This is no doubt good news for Detroit Diesel but it must put ERF in a quandary. In the European market the company is committed to Cummins power-and, on the basis of past performance, tightly so. If it were to introduce Detroit Diesel as an alternative, it might puzzle its customers. On the other hand, some argue that the customer is always right, and that more choice can only be good.
CM would like to see the EC127 on the market. It's a pleasure to drive, it offers a host of interesting features, and it would certainly keep the other engine manufacturers on their toes. The future should be interesting.