Mercedes-Benz O 321

Mercedes Benz
O 321 H coach with roof edge glazing
O 321 H.
Manufacturer	Daimler Benz
design type	Public bus, coach
Production period	12.1954-1970
axes	2
engine	Diesel engines: OM 321 , (5,103 cm 3 ) or OM 322, (5,675 cm 3 )
power	81-93 kW
length	9.23 m
width	2.5 m
height	2.9 m
Wheelbase	4180 mm
Turning circle	16 m
Seats	26 + driver's seat
Standing room	46
Perm. total weight	9300 kg
Previous model	O 3500
successor	O 302
Similar models	LAS-695

The Mercedes-Benz O 321 H is a bus with a rear engine of the brand Mercedes-Benz , which the Daimler-Benz AG of 6 December 1954 to 1970 in the Mercedes-Benz plant in Mannheim and in Brazil, Argentina and Greece 29,586 times produced a total of . Two thirds of the production falls on the plant in Mannheim, four units were built in Argentina, 116 in Greece and around 11,000 in Brazil. The O 321 H, which were not manufactured in Germany, were pre-produced as partial sets in Mannheim and then shipped for final assembly. It shares part of the drive technology with the L 321 .

variants

O 321 H as a city bus with folding doors

O 321 HL touring coach with roof edge glazing and hinged doors, after the first facelift: the front windows have been enlarged downwards

Driver's seat of the O 321 H as a coach

Mercedes-Benz Bus O 321 Drögmöller

The O 321 H is a bus primarily designed as a bus and coach . O was built 321 H 1954, 1956 also in the 1.5 m extended variant O 321 HL ( H eckmotor- L HS). In addition, Daimler-Benz also delivered the O 321 H to other bodybuilders without a body and only with a front wall. The equipment varied, so the O 321 H and O 321 HL were built both as touring and city buses. There were different variants for the doors: simple wing doors that could be opened and closed manually (flap doors) at the front and rear, compressed air-operated folding doors at the front and rear or double-wide in the middle, or combinations thereof. The O 321 H had 26 seats and 46 standing places as a city bus, and 46 seats as a coach; The longer version O 321 HL had 36 seats and 48 standing places on the city bus, and 45 seats on the intercity bus.

In 1957 the first facelift was carried out, in which the windshield was extended downwards, followed in 1961 by the second facelift in which the windshield was extended upwards. At the same time, the rear window was also made in one piece. The interior was adapted to the field of application of the bus. In the case of the coach in particular, the outside of the roof was glazed and luggage nets were attached in the interior. On the outside, the coaches were usually more decorated than city buses, different colored paintwork and chrome were often used for decoration (see pictures). The buses had inner folding doors, fewer decorations on the outside and a different layout in the interior, in favor of a higher number of passengers in city traffic, fewer seats were available so that more passengers could be transported standing. A destination display at the front was also available.

technology

The O 321 H is a two-axle high-floor bus in front-link design with a rear engine . It has space for nine or eleven rows of seats in the long version (O 321 HL). The body was welded to the floor pan and was self-supporting . Luggage compartments were possible under the passenger compartment. The two axles are rigid axles and are suspended at the rear from two semi-elliptical leaf springs each with an additional stabilizer, at the front there are coil springs with additional springs and telescopic shock absorbers installed as damping elements. The front axle has single tires, the rear axle double. The 8.25–20 eHD tires are mounted on steel tapered shoulder rims of 6.5–20. A Daimler-Benz recirculating ball steering system with undivided tie rod is used for steering ; the O 321 H was also available as a right-hand drive . Braking is done with a hydraulic brake system with compressed air support (brake servo), the O 321 H has drum brakes on all wheels.

The engine is installed lengthways in the rear. A diesel engine (at Daimler-Benz: O el- M otor) of the type OM 321 was installed as standard . The OM 322 was also available from 1962. Both engines are in-line six-cylinder prechamber engines that are technically very similar. They differ primarily in a changed bore / stroke ratio and thus different displacement sizes. The OM 321 has a displacement of 5,103 cm ³ and has an output of 110 DIN PS. The OM 322 has a displacement of 5,675 cm ³ and has an output of 126 DIN PS. The driving force is an engine of single-plate type Fichtel & Sachs H 32 BH and fully synchronized, a manually-switching five-speed transmission of the type Daimler-Benz G 32 transmitted to the rear axle. Depending on the design of the bus, the transmission ratio from the gearbox to the rear wheels is 5.72: 1 for intercity buses and touring buses or 6.83: 1 for city buses.

Technical specifications

Parameters	O 321 H (1958)	O 321 H (1961)	O 321 HL (1960)	O 321 HL (1962)
Dimensions and weights (mm / kg)
wheelbase	4180	4180	5550	5550
Front track	1905	1875	1875	1905
Rear track	1700	1745	1725	1745
Ground clearance	255	255	255	255
length	9230	9230	10600	10595
width	2500	2500	2500	2500
height	2900	2830	2830	2830
Front overhang	2310	2310	2310	2300
Rear overhang	2740	2740	2740	2745
Turning circle diameter	16000	16000	19600	19600
Empty weight	Depending on the structure	Depending on the structure	Depending on the structure	Depending on the structure
Maximum permissible total mass	9300	9300	10200	10750
engine
Engine designation	OM 321			OM 322
Engine type	Straight-six four-stroke - antechamber -Saug dieselmotor
Valve control	OHV valve control
Cooling system	Water cooling
Firing order	1-5-3-6-2-4
Dimensions	385 kg	400 kg	385 kg	410 kg
Compression ratio	21: 1	20.3: 1	20.8: 1	22.7: 1
Medium work pressure	7.35 bar			7.85 bar
Injection pressure	132.39 bar	127.5-137.3 bar	132.39 bar	127.5-137.3 bar
Bore × stroke	95 mm × 120 mm			97 mm × 128 mm
Displacement	5103 cm 3			5675 cm 3
rated capacity	110 DIN-PS / 81 kW (120 hp SAE gross) at 3000 min -1			126 DIN-PS / 93 kW (138 hp SAE gross) at 2800 min -1
maximum torque	30.5 kg · m / 299 N · m at 1600 min -1			36 kgf · m / 353 N · m at 1600 min -1
Further data
Fuel consumption according to DIN 70030	15.2 l / 100 km		16 l / 100 km	15.8 l / 100 km
Top speed	95 km / h	92.2 km / h	95 km / h	86.1 km / h
Gear ratios	1st gear: 8.02 2nd gear: 4.785 3rd gear: 2.736 4th gear: 1.663 5th gear: 1.00 reverse gear: 8.29			1st gear: 8.02 2nd gear: 4.769 3rd gear: 2.754 4th gear: 1.66 5th gear: 1.00 R gear: 8.29

Rear view of an O 321 H

Literature and Sources

• Association of the Automotive Industry : Daimler-Benz AG. Mannheim: Type O 321 H . Number 870. Frankfurt am Main. May 1958
• Association of the Automotive Industry : Daimler-Benz AG. Mannheim: Type O 321 H . Number 915. Frankfurt am Main. November 1961
• Association of the Automotive Industry : Daimler-Benz AG. Mannheim plant: Type O 321 HL . Number 990. Frankfurt am Main. November 1960
• Association of the Automotive Industry : Daimler-Benz AG. Mannheim plant: Type O 321 HL . Number 1075. Frankfurt am Main. November 1962
• Daimler-Benz-Global-Media: The omnibus world champion comes in the form of the O 321 H (October 2008)

Web links

Commons : Mercedes-Benz O 321  - Collection of Pictures, Videos and Audio Files