Easy changing MOM
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111 Volvo Bus has followed the trend towards micro-processorcontrolled gear changing systems with the launch of its Easy Gear Shift (EGS) system in the latest Mk1II BlOM coach chassis. The 1989 BlOM range also features new engines, improved ride and handling and a number of minor changes to the market-leading singleand double-deck coach chassis.
Alongside the existing 178kW and 201kW midmounted, six-cylinder turbocharged THD101GC and THD101GD engines currently fitted in the BlOM, Volvo has added a more torquey, chargecooled THD102KA diesel as an option on the GL chassis.
The previously mostpowerful THD101KC engine, however, has now been ousted by the latest 250kW THD102KD block which becomes standard on the twoaxle GLE chassis, as well as the tri-axle BlOMT.
Compared with its predecessor, the THD102KD offers 10% more power and 15% more torque. It also features articulated pistons like those of the recently revised Volvo F10 heavy truck engines.
As part of its new engine programme, Volvo Bus has de
veloped two "pro environmental engines" — the THD102KB and KF, rated at 210kW and 180kW respectively. They have been designed to meet forthcoming EEC reduced emission regulations which are due to come into effect in 1994.
Neither these engines, however, will be available initially, (at least during 1988) on right-hand-drive BlOM chasis.
All the new Volvo engines (including the THD102 1(D) feature an updated air-to-water charge-cooling system with two separate cooling circuits.
By far the most interesting aspect of the B 10M MkIII is its electro-pneumatic EGS package (revealed exclusively by Commercial Motor last week) which is optional on the BlOMGL coach chassis and comes as standard on GLE and BlOMT variants.
To select a gear the driver simply uses the gear lever as normal (the EGS stick has a conventional double-H pattern) while depressing the clutch. Switches built into the gear lever unit send a signal to a microprocessor control unit on the gearbox which activates a system of valves and compressed air cylinders that select the required ratio. Gear changing with EGS is as quick as with a conventional synchromesh gearbox, with mechanical linkage, but with considerably less physical effort needed from the driver.
On the latest BlOM the EGS system is used in conjunction with the all-new Volvo G7 seven-speed synchromesh gearbox — derived in turn from the R1000 range-change truck transmission.
The adoption of the EGS/G7 box has also enabled Volvo to offer a lighter gearbox-mounted Voith retarder as an option on the B 10M in addition to the Telma electro-magnetic unit.
Other changes to the BlOM chassis include a new front axle, compressor and alloy air tanks. In addition, wheelbases have been changed to six metres and 5.5m for 12m and llm bodies.
The first RIM chassis are now being built at Volvo Bus's assembly plant at Boras in Sweden and will shortly be supplied to UK bodybuilders.