LOUISVILLE, Ky. — The Caterpillar heavy-duty compression brake will be introduced as an option on the C15 during fall of this year.
Caterpillar officials made the announcement at the Mid-America Trucking Show. The brake is currently available as an option for the C11 and C13.
The system provides 25 per cent more braking power in the recommended operating range when compared to previous systems, said John Campbell, director of Caterpillar on-highway engine products.
“The optional Cat compression brake is integral to the engine and delivers increased braking power, along with lower operating costs, higher productivity, shorter trip times and better vehicle control,” said Campbell. The Cat compression braking system provides engine-braking torque by opening the exhaust valves during the compression stroke of the engine. Using a conventional master/slave brake actuation system, the retarder opens the cylinder’s exhaust valves to release compressed air.
The electronic control module (ECM) controls the actuator valves through a data link that supplies and receives information from vehicle subsystems, automatically activating and deactivating the system as needed.
Compression braking is available at all times, provided engine speed is greater than a preset minimum (typically 800 rpm), and the fuel command sensory signal is less than or equal to zero, so no fuel is supplied to the engine. The enhanced control provided by the Cat compression brake translates to numerous benefits for the driver, according to Campbell.
“The driver can slow vehicle speeds on down grades without using the service brakes, making brake fade much less likely. The brake also helps the driver slow the vehicle without using the service brake when adjusting to ever-changing traffic speeds on the highway,” he said.
Engines with ACERT technology provide increased displacement and higher airflow, allowing the driver to operate the engine at lower rpm ratings, Campbell explained. As a result, the new Cat engines feature more retarding capability at these lower engine speeds.
The system is engaged by the driver using a toggle switch located in the vehicle cab. The driver may use a second switch to select from three different operational modes-retarder low, retarder medium and retarder high. These braking levels correspond to the degree of braking effort that the engine can provide when compression braking operation is initiated.
The ECM can be programmed to operate the brake in three different modes: manual, coast and latch. The coast and latch modes require that the Cruise Enable Switch be on. In the manual mode, the brake system becomes active when the operator removes his foot from the accelerator. In the coast mode, the compression brake does not automatically activate until the operator applies the foot brake, and disengages as soon as the operator releases the foot brake. In the latch mode, compression braking operates as in the coast mode, except that it remains on when the operator releases the foot brake.
The Cat brake is compatible with anti-lock braking systems (ABS). Compression braking may be disabled by the ABS system if wheel slippage is detected. An “auto retarder in cruise” option allows the heavy duty brake to come on while cruise control is active to help prevent the vehicle from exceeding the cruise control set speed.
The Caterpillar compression brake provides 330 retarding horsepower for the C11 and 400 retarding horsepower for the C13. When the brake is incorporated on the C15 and the 625 hp “King of the Hill” engine, it will provide 600 retarding horsepower. A 725 horsepower option will be available for the C15 when the compression brake system is combined with the exclusive Caterpillar BrakeSaver.
More information is available at http://www.cattruckengines.com.
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