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Tractor-trailer ride on a chassis dynamometer
1 I0
ABSTRACTS weighing less than 6.t)00 Ib could tra',el w i t h o u t difficulty on all con~,,iida:ed :',~uskcz areas but h a d var,,ing degrees of difficulty on floating mats. Hea~ier vehicles ~vei,-'hinz up to 33.000 Ib could ~raveI on s o m e consolidated m u s k e g areas but r',,~ ,~n ;~iher-ii M a x i m u m dravvbar pulls with the M 2 9 C Weasel w'ere approximate[,. ')-" >er cen~ t~: vehicle weight on c o n s o l i d a t e d m u s k e g a n d a p p r o x i m a t e l y 73 per ceni f,~r (he i-irst few passes on floating m a t m u s k e g . C o n e index values in the v a r i o u s m u s k e e surface co~er f o r m u l a s varied widely being influenced principally by the q m m t i t y o f - ~ a t e r present. T h e data obtained did n o t reveal even a general relation between m u s k e g
111.
J. C. Vaverek. T r a c t o r - t r a i l e r
ride on a chassis d y n a m o m e t e r . 5.A.L'. Paper, A , t o m o t .
Epzgng. Congr.. J a n u a r y 10--14, 1966.6 pp. T r a c t o r - t r a i l e r ride can be studied by m e a n s of a large chassis d } n a m o m e t e r ; an e x a m p l e s h o w s h o w such a d y n a m o m e t e r has served to clarify trailer-pitch dynamics. T h e d y n a m o m e t e r plant, h o u s e d in a single building, can handle a full-size, fully-loaded tractor-trailer c o m b i n a t i o n . Five d r u m s of 40 in. d i a m e t e r can be arranged to accomm o d a t e a n y w h e e l - b a s e or c o m b i n a t i o n of axles, and each can s u p p o r t an axle g r o u n d load of 24,000 lb. T w o 200 h . p . d . c , m o t o r s with infinitely variable speed-control a n d installed in the pit can be positioned to drive a n y c o m b i n a t i o n of drums. Speed-control is very accurate. In the tractor-trailer c o m b i n a t i o n , poor ride attributed to excessive cab pitching in the speed range of 40--45 m.p.h, on relatively s m o o t h roads led to drivers refusing to operate the e q u i p m e n t . T h e t a n d e m - a x l e tractor m e a s u r e d 90 in. f r o m b u m p e r to back of cab and h a d r u b b e r - i n - s h e a r s u s p e n s i o n . Loaded gross c o m b i n a t i o n weight, 73,090 lb. and Diesel e n g i n e of 195 h.p. dictated a cruising speed of 40-45 m.p.h., drivers thus being forced to o p e r a t e at the speed of objectionable cab pitching. T h e tank trailer, 37 ft long. and because of its size the d o m i n a n t vibrating body was s u s p e n d e d on four. single-leaf, tapered s p r i n g s c o n v e n t i o n a l l y m o u n t e d . T e s t i n g on the d y n a m o m e t e r and on the road c o n f i r m e d that the drivers" c o m p l a i n t s were fully justified. A change f r o m 1 0 " 0 0 × 2 0 bias fabric ply tyres to I 0 - 0 0 × 2 0 radial wire ply t,vres lowered the cTitica[ speed by a b o u t 2 m.p.h, at a tyre pressure of 90 lb/in, z and reduced pitching a m p l i t u d e by half. Additional a d v a n t a g e s were easier puIling of the trailer a n d higher top speed. O t h e r modifications tried included c h a n g e s in trailer s u s p e n s i o n and tractor s u s p e n s i o n . It is c o n c l u d e d that, while trailer pitching c a n n o t be eliminated, its frequency can be shifted to a l e s s used portion o["the vehicle-speed range. [M.1.R.A.]
112.
H. L. yon H o e n e . Variable v o l u m e h y d r a u l i c motors. 5.A.E. Paper, ,4utotttot. Et~g,tzg.
Congr., J a n u a r y 10-14, 1966. 14 pp. H y d r a u l i c m o t o r s have low inertia, small size, low weight a n d adaptability to various control s y s t e m s - - - t h e f o u r - w a y directional valve is usual. T h e y are used with gearr e d u c t i o n m e c h a n i s m s to p o w e r rotary devices and, unlike hydraulic cylinders, can operate_where c o n t i n u o u s m o t i o n or long travel is required. In application, drain oil a n d shock pressures cause p r o b l e m s , V a r i a b l e - d i s p l a c e m e n t m o t o r s ft,nction at small disp l a c e m e n t to provide the h i g h - s p e e d characteristics of a small m o t o r and at a larger d i s p l a c e m e n t to provide high torque; characteristics, operation, p e r f o r m a n c e a n d control m e t h o d s are described. U s e d with h y d r o s t a t i c t r a n s m i s s i o n , they extend the speed range at c o n s t a n t h.p. [M.I.R.A.]
113.
F. J. Wallace, E. J. W r i g h t a n d J. S. C a m p b e l l . F u t u r e d e v e l o p m e n t of free piston gasifier t u r b i n e c o m b i n a t i o n s for vehicle traction. 5.A.E. Paper, Auro,~ot. bzgt~,,. Cotzgr,, J a n u a r y 10-14, 1966. 13 pp. T h e g a s - g e n e r a t o r cycle is c o m p a r e d with that of t u r b o - c h a r g e d and c o m p o u n d engines. At 5:1 t u r b i n e - p r e s s u r e ratio, the overall thermal efficiency of the g a s - g e n e r a t o r / t u r b i n e c o m b i n a t i o n is 3 9 2 per cent. T h e d i m e n s i o n s a n d p e r f o r m a n c e are described of a• existing gasifier, a robust, o u t w a r d - c o m p r e s s i n g m a c h i n e having two injectors, a jerk fuel p u m p a n d internal b o u n c e cylinders a n d pistons. Projected d e v e l o p m e n t s include (I) a larger unit d e v e l o p i n g 200 gas h.p. a n d (2) m u l t i - c y l i n d e r a r r a n g e m e n t s . F o r vehicle traction, a g a s i f i e r / t w o - s t a g e , i n w a r d - r a d i a l - f l o w - t u r b i n e is p r o p o s e d with r e d u c t i o n g e a r b o x a n d either three-speed g e a r b o x or torque converter; an overall torque ratio of 10: I is possible. [M.I.R.A.]
ABSTRACTS weighing less than 6.t)00 Ib could tra',el w i t h o u t difficulty on all con~,,iida:ed :',~uskcz areas but h a d var,,ing degrees of difficulty on floating mats. Hea~ier vehicles ~vei,-'hinz up to 33.000 Ib could ~raveI on s o m e consolidated m u s k e g areas but r',,~ ,~n ;~iher-ii M a x i m u m dravvbar pulls with the M 2 9 C Weasel w'ere approximate[,. ')-" >er cen~ t~: vehicle weight on c o n s o l i d a t e d m u s k e g a n d a p p r o x i m a t e l y 73 per ceni f,~r (he i-irst few passes on floating m a t m u s k e g . C o n e index values in the v a r i o u s m u s k e e surface co~er f o r m u l a s varied widely being influenced principally by the q m m t i t y o f - ~ a t e r present. T h e data obtained did n o t reveal even a general relation between m u s k e g
111.
J. C. Vaverek. T r a c t o r - t r a i l e r
ride on a chassis d y n a m o m e t e r . 5.A.L'. Paper, A , t o m o t .
Epzgng. Congr.. J a n u a r y 10--14, 1966.6 pp. T r a c t o r - t r a i l e r ride can be studied by m e a n s of a large chassis d } n a m o m e t e r ; an e x a m p l e s h o w s h o w such a d y n a m o m e t e r has served to clarify trailer-pitch dynamics. T h e d y n a m o m e t e r plant, h o u s e d in a single building, can handle a full-size, fully-loaded tractor-trailer c o m b i n a t i o n . Five d r u m s of 40 in. d i a m e t e r can be arranged to accomm o d a t e a n y w h e e l - b a s e or c o m b i n a t i o n of axles, and each can s u p p o r t an axle g r o u n d load of 24,000 lb. T w o 200 h . p . d . c , m o t o r s with infinitely variable speed-control a n d installed in the pit can be positioned to drive a n y c o m b i n a t i o n of drums. Speed-control is very accurate. In the tractor-trailer c o m b i n a t i o n , poor ride attributed to excessive cab pitching in the speed range of 40--45 m.p.h, on relatively s m o o t h roads led to drivers refusing to operate the e q u i p m e n t . T h e t a n d e m - a x l e tractor m e a s u r e d 90 in. f r o m b u m p e r to back of cab and h a d r u b b e r - i n - s h e a r s u s p e n s i o n . Loaded gross c o m b i n a t i o n weight, 73,090 lb. and Diesel e n g i n e of 195 h.p. dictated a cruising speed of 40-45 m.p.h., drivers thus being forced to o p e r a t e at the speed of objectionable cab pitching. T h e tank trailer, 37 ft long. and because of its size the d o m i n a n t vibrating body was s u s p e n d e d on four. single-leaf, tapered s p r i n g s c o n v e n t i o n a l l y m o u n t e d . T e s t i n g on the d y n a m o m e t e r and on the road c o n f i r m e d that the drivers" c o m p l a i n t s were fully justified. A change f r o m 1 0 " 0 0 × 2 0 bias fabric ply tyres to I 0 - 0 0 × 2 0 radial wire ply t,vres lowered the cTitica[ speed by a b o u t 2 m.p.h, at a tyre pressure of 90 lb/in, z and reduced pitching a m p l i t u d e by half. Additional a d v a n t a g e s were easier puIling of the trailer a n d higher top speed. O t h e r modifications tried included c h a n g e s in trailer s u s p e n s i o n and tractor s u s p e n s i o n . It is c o n c l u d e d that, while trailer pitching c a n n o t be eliminated, its frequency can be shifted to a l e s s used portion o["the vehicle-speed range. [M.1.R.A.]
112.
H. L. yon H o e n e . Variable v o l u m e h y d r a u l i c motors. 5.A.E. Paper, ,4utotttot. Et~g,tzg.
Congr., J a n u a r y 10-14, 1966. 14 pp. H y d r a u l i c m o t o r s have low inertia, small size, low weight a n d adaptability to various control s y s t e m s - - - t h e f o u r - w a y directional valve is usual. T h e y are used with gearr e d u c t i o n m e c h a n i s m s to p o w e r rotary devices and, unlike hydraulic cylinders, can operate_where c o n t i n u o u s m o t i o n or long travel is required. In application, drain oil a n d shock pressures cause p r o b l e m s , V a r i a b l e - d i s p l a c e m e n t m o t o r s ft,nction at small disp l a c e m e n t to provide the h i g h - s p e e d characteristics of a small m o t o r and at a larger d i s p l a c e m e n t to provide high torque; characteristics, operation, p e r f o r m a n c e a n d control m e t h o d s are described. U s e d with h y d r o s t a t i c t r a n s m i s s i o n , they extend the speed range at c o n s t a n t h.p. [M.I.R.A.]
113.
F. J. Wallace, E. J. W r i g h t a n d J. S. C a m p b e l l . F u t u r e d e v e l o p m e n t of free piston gasifier t u r b i n e c o m b i n a t i o n s for vehicle traction. 5.A.E. Paper, Auro,~ot. bzgt~,,. Cotzgr,, J a n u a r y 10-14, 1966. 13 pp. T h e g a s - g e n e r a t o r cycle is c o m p a r e d with that of t u r b o - c h a r g e d and c o m p o u n d engines. At 5:1 t u r b i n e - p r e s s u r e ratio, the overall thermal efficiency of the g a s - g e n e r a t o r / t u r b i n e c o m b i n a t i o n is 3 9 2 per cent. T h e d i m e n s i o n s a n d p e r f o r m a n c e are described of a• existing gasifier, a robust, o u t w a r d - c o m p r e s s i n g m a c h i n e having two injectors, a jerk fuel p u m p a n d internal b o u n c e cylinders a n d pistons. Projected d e v e l o p m e n t s include (I) a larger unit d e v e l o p i n g 200 gas h.p. a n d (2) m u l t i - c y l i n d e r a r r a n g e m e n t s . F o r vehicle traction, a g a s i f i e r / t w o - s t a g e , i n w a r d - r a d i a l - f l o w - t u r b i n e is p r o p o s e d with r e d u c t i o n g e a r b o x a n d either three-speed g e a r b o x or torque converter; an overall torque ratio of 10: I is possible. [M.I.R.A.]