240 Landmarks Top ＞ Buses ＞ Minsei Air Suspension Bus 　Minsei Air Suspension Bus 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. Storage location : NISSAN DIESEL MOTOR CO., LTD. (1-1, Ageo-shi, Saitama-ken 362-8523) Year manufactured : 1957 Manufacturer : Minsei Diesel Industries, Ltd. Classification : Literature Current status : In storage: open to the public Vehicle name / Manufacture Vehicle name : Minsei Condor (Air Suspension) Model name : RF91 Company name : Minsei Diesel Industries, Ltd. (current Nissan Diesel Motor Co., Ltd.) Year manufactured : 1957 Designed by : Minsei Diesel Collaboration : Fuji Jidosha Kogyo Co., Ltd. Vehicle type/usage : Large route bus and sightseeing bus Location of actual vehicle/replica : None Model / Weight Style : Box type bus Number of doors : Middle: 1 + emergency exit: 1 Passenger capacity : Seat: 41 + standing capacity: 25 + other: 2 Vehicle weight : 7970 kg Points of interest, topicality : Japan's first air suspension bus Body / Size Structure : Stressed skin construction Riveted steel sheets Bumpers : Stamped steel sheets Step : 1 step (step height: approx. 400 mm) Overall length : 9660 mm Overall width : 2450 mm Overall height : 2970 mm Tire size : 9.00-20-14PR Features : Load was applied on air bellows instead of conventional steel springs, and double-acting cylinder dampers were combined with the springs. Body / Axle / Driving / Others Frame : None Front axle : Forged I beam reverse Elliott type, trailing beam type, 2 Φ240 bellows Rear axle : Cast steel banjo axle tube full floating type, parallel 4 link type, 4 Φ240 bellows Wheelbase : 5000 mm Front tread x rear tread : 1915×1760 mm Vehicle height adjustment : Leveling valves: 1 for front, 2 for rear Steering : Worm and roller type Dampers : Hydraulic cylinder double-acting type for front and rear Stabilizer : Torsion bar type (rear axle) Driving stability devices : None Features : Vehicle height was kept constant by the leveling valves, achieving good ride comfort similar to passenger cars in loaded and unloaded states. Engine / Size / Power Cooling/cylinder arrangement : Water-cooled/inline 4-cylinder, model: UD4 Valve train : Overhead valve exhaust, port intake type Bore x stroke : 110×130 mm Displacement : 4.941 L Max. power/r.p.m. : 150 ps/2000 rpm Fuel tank capacity : 130 L 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. Hybrid Hybrid system type : None Drive-train Transmission : 4 forward speeds and 1 reverse speed, constant-mesh type 70 deg. turning device Drive system : RR engine lateral Performance Mode fuel efficiency : - 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 240 Landmarks Top ＞ Buses ＞ Minsei Air Suspension Bus