Society of Automotive Engineers of Japan, Inc. 240 Landmarks Top JSAE HOME
240 Landmarks of Japanese Automotive Technology
left image
240 Landmarks TopBuses > Minsei Air Suspension Bus
 Minsei Air Suspension Bus
image
This was the first Japanese air suspension bus to be put on the market. It supported the load of the body on air springs instead of the conventional steel leaf springs, suspending the axles from the body by means of radius rods, so that even on rough roads, it achieved the same good ride comfort as a passenger car, regardless of the load condition. A trailing beam suspension was used for the front axle, which successfully reduced the effective spring constant. During the development stage, Minsei conducted research jointly with a railroad research institute, and in manufacturing the body, relied on the cooperation of Fuji Heavy Industries. With the cooperation of makers of functional parts such as air bellows, leveling valves, and dampers, an air suspension bus was completed that was entirely made in Japan. Thereafter, three other makers of large vehicles followed suit, and within two years, all four companies had brought air suspension vehicles to the market that rapidly gained acceptance for use as highway buses. This is a famous vehicle that should be remembered as the catalyst for revolutionary progress in the ride comfort of buses.
dot
Storage location:NISSAN DIESEL MOTOR CO., LTD. (1-1, Ageo-shi, Saitama-ken 362-8523)
dot
Year manufactured:1957
dot
Manufacturer:Minsei Diesel Industries, Ltd.
dot
Classification:Literature
dot
Current status:In storage: open to the public
dot
Vehicle name / Manufacture
Vehicle name:Minsei Condor (Air Suspension)
dot
Model name:RF91
dot
Company name:Minsei Diesel Industries, Ltd. (current Nissan Diesel Motor Co., Ltd.)
dot
Year manufactured:1957
dot
Designed by:Minsei Diesel
dot
Collaboration:Fuji Jidosha Kogyo Co., Ltd.
dot
Vehicle type/usage:Large route bus and sightseeing bus
dot
Location of actual vehicle/replica:None
dot
Model / Weight
Style:Box type bus
dot
Number of doors:Middle: 1 + emergency exit: 1
dot
Passenger capacity:Seat: 41 + standing capacity: 25 + other: 2
dot
Vehicle weight:7970 kg
dot
Points of interest, topicality:Japan's first air suspension bus
dot
Body / Size
Structure:Stressed skin construction Riveted steel sheets
dot
Bumpers:Stamped steel sheets
dot
Step:1 step (step height: approx. 400 mm)
dot
Overall length:9660 mm
dot
Overall width:2450 mm
dot
Overall height:2970 mm
dot
Tire size:9.00-20-14PR
dot
Features:Load was applied on air bellows instead of conventional steel springs, and double-acting cylinder dampers were combined with the springs.
dot
Body / Axle / Driving / Others
Frame:None
dot
Front axle:Forged I beam reverse Elliott type, trailing beam type, 2 Φ240 bellows
dot
Rear axle:Cast steel banjo axle tube full floating type, parallel 4 link type, 4 Φ240 bellows
dot
Wheelbase:5000 mm
dot
Front tread x rear tread:1915×1760 mm
dot
Vehicle height adjustment:Leveling valves: 1 for front, 2 for rear
dot
Steering:Worm and roller type
dot
Dampers:Hydraulic cylinder double-acting type for front and rear
dot
Stabilizer:Torsion bar type (rear axle)
dot
Driving stability devices:None
dot
Features:Vehicle height was kept constant by the leveling valves, achieving good ride comfort similar to passenger cars in loaded and unloaded states.
dot
Engine / Size / Power
Cooling/cylinder arrangement:Water-cooled/inline 4-cylinder, model: UD4
dot
Valve train:Overhead valve exhaust, port intake type
dot
Bore x stroke:110×130 mm
dot
Displacement:4.941 L
dot
Max. power/r.p.m.:150 ps/2000 rpm
dot
Fuel tank capacity:130 L
dot
Fetures:UD type 2-cycle direct injection engine, overhead valve exhaust, port intake uniflow-scavenging type high performance engine with specific output of 30.4 ps/L.
dot
Hybrid
Hybrid system type:None
dot
Drive-train
Transmission:4 forward speeds and 1 reverse speed, constant-mesh type 70 deg. turning device
dot
Drive system:RR engine lateral
dot
Performance
Mode fuel efficiency:-
dot
Reference materials:Minsei Giho, No. 20, pp. 1-7, Shigeru Miyakawa, "Ea Suspension RF91 Ni Tsuite", Aug. 1957;
Journal of Society of Automotive Engineers of Japan, Vol. 51, No. 6, pp. 72-77, Yutaka Hayashi, "Development of an air suspension bus", Jun. 1997
dot
240 Landmarks TopBuses > Minsei Air Suspension Bus page top
COPYRIGHT (C) SOCIETY OF AUTOMOTIVE ENGINEERS OF JAPAN, INC. ALL RIGHTS RESERVED.