Electronic brakes on trial
Page 25
If you've noticed an error in this article please click here to report it so we can fix it.
• Scania is about to begin "market acceptance tests" on its electronically controlled braking system (ELB), developed in conjunction with Bosch.
The trials will be conducted on articulated and drawbar outfits and will involve trailer manufacturers. According to Scania, "providing the market tests are successful ELB will become generally available during the midnineties".
ELB is a microprocessorbased system which incorporates anti-lock (ABS) and traction control (ASR) equipment. It can also be linked to the vehicle's electronic fuel injection system (the Swedish truck maker uses Bosch's EDC on its vehicles).
Instead of the normal pneumatically controlled braking arrangement, ELB works with electrical control signals. When the foot brake is pressed electronic signals pass to the computer which relays the message to the ELB electric/pneumatic valves close to each brake. These then apply the brakes "simultaneously and instantaneously".
Sensors on each wheel ensure that the desired amount of pressure is applied in each case.
When the driver releases the brake, more signals are sent to the valves to release the brakes.
Scania cites the consistency
of the ELB system as one of its key advantages; "There is no tendency for one brake to operate differently from another," says the company. "This means less risk of skidding or jack-knifing and more even brake wear." The speed of application and release is also a lot quicker then with a conventional full air braking system.
However, ELB-equipped vehicles will still be equipped with a pneumatically operated back-up system in case of an electrical failure.
A dashboard lamp tells the driver of any problems; flash codes and self-diagnostics are also built into the system.
Scania claims that the system will most benefit those operators running with trailers, "which should ideally be equipped with ELB. Part of the reason for the anticipated time before general introduction is that trailer manufacturers must be able to equip their products with complementary equipment," it adds. "Another reason is the awaited decision on a new ISO trailer connection standard."
Details of the ELB trials were released at last week's Hanover truck show where Scania also unveiled a new lifting mid-axle twin-steer which will appear in the UK before the end of the year together with the latest GR801 eight-speed gearbox. This will become standard on most nine-litre Scania models (see show report, pages 8-12).