Are new vehicles below legal standards
Page 39
Page 40
If you've noticed an error in this article please click here to report it so we can fix it.
They are operating at above 92 dBA maximum, says Mr Denniss, who also blames manufacturers for too little practical testing
by Paul Brockington
VEHICLE manufacturers were strongly criticized for their failure to test adequately new vehicles by Mr R. Denniss, group fleet engineer of Bass Charrington, at the Institute of --Road Transport Engineers' National Conference in Solihull on Saturday during the technical session.
In an earlier paper Mr Walter Manning, chief engineer, truck engineering, Ford Motor Co, reviewed commercial vehicle chassis design, production and testing with particular reference to product acceptance specifications. And Mr P. W. H. Hackman, executive engineer, chassis and transmission, engineering, truck operations, Ford, reviewed power transmissions and axles and gave details of the company's recently introduced range of allsynchrom esh gearboxes.
Mr R. Duncalfe, chairman of the Conference, chaired the technical session and Friday's tneeting of traffic area Goods Vehicle Maintenance Advisory Committees.
In the conclusion of his paper Mr Denniss declared: "It is quite clear to the writer as the result of the tests undertaken over the past 12 months that manufacturers do not do sufficient practical testing of vehicles due, possibly to lack of time and the massive weight of new legislation being thrown into the melting pot every few months. More alarming is the fact that vehicles coming off the assembly line at this moment do not appear to meet the existing current legislation in respect of noise, smoke and in some cases brakes.
"However, what concerns the writer more than this is the condition of the vehicles coming out of the workshops of British factories. In one case. no less than 37 quite major defects were noted On a newly delivered vehicle and even on the more expensive vehicles it is not uncommon to find a pageful of defects."
Earlier, Mr Denniss outlined how
evaluation had been made of new retail 10-ton-gross delivery vehicles and of heavy tninking vehicles of 32-ton, 38-ton and 44-ton gvw which included specification and loading cheeks and tests on the road with the vehicle carrying a full load, carrying'a 50 per cent load and running empty. This was followed by brake testing on a roller tester (unless the vehicle had been returned to the maker to rectify faults) and the results were compared with deceleration rates measured on the straight at the Motor Industry Research Association proving ' ground using a chalk-pellet gun. The vehicle was then tested on the Dunlop skid pan at Fradley, and in the case of an artic it was -driven with and without the load-sensing valves in operation.
Jack-knifing tendencies of an artic were compared with those of an outfit hauled by a tractive unit equipped with a Dunlop Maxaret Mk 2 anti-locking system. After the vehicle had been brake tested, brake drums were removed for check of heat crazing, which is a current problem of the group.
The next test comprised wheel-power checks on a chassis dynamometer which in some cases was also used to measure transmission losses. It was then possible to compare installed flywheel horsepower with the rated horsepower, which, said Mr Denniss, often differed widely; the test proved that the efficiencies of certain two-speed axles were "quite appalling".
Acceleration tests were subsequently performed on the level at MIRA which were followed by tests of gradientability and of turning circles, particular note being made of the swing-out and cut-in of articulated vehicles. The author noted that joining MIRA had been the group's most successful venture in the evaluation programme.
The results of vehicle noise checks with a Bruel KJAR 2207 meter were described by the author as "a real eye-opener". Assuming that the meter was accurate, the tests showed that new vehicles were operating at above the maximum allowable noise level of a noise level of above 89 dBA.
Smoke meter
The impossibility of finding a smoke meter that was "acceptable to everybody" was mentioned by the author when dealing with smoke levels. He also spoke of the advisability of modifying the exhaust system to diffuse the exhaust under the vehicle instead of discharging it at the side. If there was any doubt regarding the smoke level of a new vehicle it was sent to MIRA for a report.
In a comment on vehicle stability, Mr Denniss described the ride and handling course at MIRA as "absolutely first-class" for determining the feel of a vehicle. It either felt right or it did not. While to date, group drivers had not succeeded in overturning a vehicle it was child's play to lift the inner wheels of the rear bogie of a 40ft semi-trailer even with a relatively low load. Stability was checked with loads of varying heights and in various positions. Loads were made up of I-ton weights. In some cases stability was greatly improved by fitting shock absorbers and anti-roll bars.
In assessing the value of using a five-speed direct-top close-ratio gearbox for delivery vehicles compared with a wide-ratio overdrive box, the author said that close ratios provided far quicker gear changes and improved acceleration and gradientability by some 20 per cent, the only disadvantage being that in practice overrun braking was reduced with a consequent reduction in brake lining life. A Dynair fan increased the output available by 4 bhp measured at the road wheels and greatly reduced cab noise for 95 per cent of the vehicle's running time.
Specification checks of delivery vehicles included loading the vehicle with 1-ton concrete test weights to simulate "every conceivable load configuration" and to ensure that there was ample axle capacity to cater for all types of service including differential loading and unloading. A Polaroid camera was used to record load positions and weight checks were made with Hawker Siddeley 10-ton scales. Weigh bridges were found to be suspect. The scales were located in a concreted trench and care taklen to locate the wheels centrally on them.
European standards • Dealing with current Ford trends in design and development, Mr Manning referred to the company's decision to base planning on product acceptance specifications that are known at Ford as "European General Product Acceptance Specifications (EGPASs)". These provided minimum requirements for acceptable vehicles and vehicle systems in terms of overall performance, driving effort, appearance, durability, reliability and other qualities that ' were necessary to the attainment of a design level consistent with product acceptability in Europe with due regard to the legal requirements of all the territories. Geographical coverage extended from Scandinavia to Southern Italy and from Eire to Russia.
European standards included those of major competitors as well as Ford's. Standards were continually tnoving.upwards and the movement was more rapid in Europe than in other major areas. Programmes were changed accordingly.
Ford was confident that any vehicle or component scheduled for production would meet 1, European operators' standards; 2, European current and future legislation; 3, European service standards; 4, European appearance standards; 5, European depreciation rates. All the commercial vehicle development of Ford Europe was undertaken at the Dunton Research and Engineering Centre or was controlled by the Centre. Set routes in Europe were used for durability testing and included cold-weather testing in Finland and hot-weather testing in Southern Italy.
Designers' analyses of component requirements were "backed-up" by computer programming. There would be opportunities for raising acceptance standards during the coming decade and Ford was confident that, with the aid of EGPASs, it would be possible to avoid the mistake of improving one vehicle type at the expense of another. Ford intended to raise the level of its products to the highest in Europe.
European competitors had been lifting acceptance standards more rapidly than local competitors in recent years and their costs appeared reasonable. Suspension systems were now designed with interior noise in mind as well as ride and handling. Ford handling depended on the position of the suspension relative to the vehicle load as well as the type of springing used. For general-purpose vehicles, further improvement of leaf springs could be expected.
Full support by all UK manufacturers would be given to DoE legislation to control smoke, power-to-weight and vehicle noise levels provided that timing was realistic and objectives were feasible. Overall performance, said the author, should ultimately be "set out against acceleration times through the gears". The trend towards legislation that specified minimum speeds on specific gradients was evident.
A curve produced by computer programming enabled predictions to be made of the adjustments to engine power and to transmission characteristics that were required to optimize overall vehicle performance with respect to driver acceptance, fuel consumption, noise and so on. The most important chassis acceptance level was, perhaps, vehicle stability under all known operating conditions.
Road surface safety It was noted by the author that the condition of road surfaces was as important to vehicle safety as sophisticated braking systems. The most acceptable answer to the jack-knifing problem could well be found in improved road surfaces and the application of known load-apportioning techniques. Future acceptance levels would have to include lane-change stability at high speeds and course diversions at low speeds. Suspension components would have to be designed to provide characteristics that optimized vehicle handling, ranging from tyre-wall stability to platform frequencies.
In conclusion, Mr Manning said that field information was the most valuable type of information because it related to "competitive cost of ownership". And this was the basic ingredient of a successful test and development programme.
After describing the investigations and tests that inspired the development of the recently announced Ford range of all-synchromesh four-, sixand eight-speed gearboxes (CM. April 30) and outlining their main features, Mr Hackman said that tests of the gearboxes had included operations over many thousands of miles on pave and rough road surfaces and in low ambient temperatures.
He predicted a future demand for all-synchromesh transmissions because they reduced driver fatigue and improved the durability of the gears by reducing engagement shock loading. In the case of a 28-ton-gross articulated outfit, the eight-speed box appeared to be the best compromise because it provided for good use of engine rpm and only four shifts were required to attain 17 mph.
Before opening the discussion on Mr Denniss's paper, Mr Duncalfe described it as "very excellent, earthy and like a dose of salts". And Dr Noel Penny, managing director of British Leyland Gas Turbines Division, who was co-opted on to the panel for the discussion, referred to the paper as "down-to-earth and like a breath of spring".
In reply to a question Dr Penny said that it would be some time before all the weaknesses of the 350 bhp (plus) gas turbine had been eradicated and that many hundreds of thousands of miles would have to be covered on test. Later, it would be possible to concentrate on smaller units.
The turbine had a lot of power, it could flog and it could "fairly readily" meet noise requirements. And there was no doubt that exhaust emission would be acceptable. Reliability was the most important requirement. Performance was second on the list and cost was third. Cost was a "tough nut".
In a comment on lubricating oils, Mr Denniss said that all the engines of the 2800 vehicles in his fleet operated on the same grade of engine oil and the same grade of lubricant (90EP) was used for transmissions. The engines did not include turbo-charged units.
Referring to durability levels of Ford trucks, during the discussion on Mr Manning's paper, the author said that these were based on the mileage run before it was necessary to "break the cylinder head gasket".
The rated mileage was 100,000. In service, the mileage varied according to operating conditions. A standard vehicle could be expected to cover 150,000 miles on normal service while a premium vehicle should cover 250,000. Engaged on continuous high-load motorway work mileage levels might be reduced by around 30 per cent .. . .
Taking part in the discussion on Mr Hackman's paper, Mr Manning reminded delegates that automatic transmission have an unsuccessful history of 40/50 years. They were a must for the future, said Mr Manning. But when? Ford was working on a type of automatic that gave "maximum driver control". When the successful automatic was produced it would not be in its existing form.
Replying to a delegate who suggested that gradient ability would be a better yardstick than bhp/ton on which to base performance, Mr Manning said that the complications of basing the legal requirement on gradientability would be so great as to be unimaginable.
A national conference of Area Maintenance Advisory Committees will be incorporated in the IRTE National Conference in 1972. This was approved during a session of the chairman, secretaries and committee members of area committees at which the chief speakers were Mr R. R. Jackson, chairman of the South Wales Licensing Committee, and Mr R. J. E. Dawson, assistant secretary Roads Transport Goods Division, DoE.
After forecasting a change in the work of the committee, Mr Jackson said that, in future, it would probably 'concentrate on spare parts shortage, vehicle design and type approval. Commenting on a question from the floor, Mr Duncalfe said that a vehicle could cover an enormous mileage in the first three years of its life. In his opinion vehicles should be tested every year.
There, was general approval of another speaker's suggestion that the DoE should take over the testing of commercial vehicles of up to 3f tons gross. Mr Dawson said that the Department was studying accident statistics and would consider taking action in the light of these studies.
Agreeing with the claim that,the standard of maintenance of Continental vehicles was far below the UK standard, Mr Jackson said that it would "also be necessary to level up the Construction and Use Regulations". Mr Dawson pointed out that the Department was seeking powers to enforce laws against foreign vehicles and in a later comment on unlicensed vehicles he said that a computerized licensing system would make it more difficult to evade excise licensing.