Closer integration with engine shows the way As the trend toward higher-horsepower engines continues, the need for engine brakes increases. There's also considerable return on investment since they extend the life of service brakes and reduce maintenance costs. Not to mention their growing popularity with drivers, which fleets cannot afford to ignore. In addition, the aerodynamic design of many new vehicles means less drag and thus an even greater need for extra braking power.
The latest engine brake from Pacbrake is the new P-80A for model-year 2001 DDC Series 60 12.7L and 14.0L engines. According to Pacbrake, the new unit features higher retarding power, easier servicing and reduced engine pressures. The biggest change over the P-80 is a modified adjusting screw with fewer moving parts for simpler adjustment, which in turn makes retarding power more consistent. For model-year 2000 DDC 12.7L and 14.0L units, the original P-80 engine brake must be purchased; retrofit kits will not be offered.
Jacobs Vehicle Systems, which makes retarders for Caterpillar, Cummins, DDC, International and Mack engines, has broadened its role to serve as an engine-overhead design consultant to engine makers. The first product to come out of this new collaborative format is the Cummins Intebrake, which is designed into ISX and Signature 600 engines. A dual overhead cam design gives it considerably more power. The unit, which takes up less room and weighs less, functions in cruise-control mode.
The Jacobs C Brake is optional on Cummins N14 Plus, ISM and ISL engine platforms. The development of a Jacobs C Brake for the ISL platform is particularly significant as it brings compression-brake options to the "smaller" heavy-duties.
New from TecBrake are units for Detroit Diesel's Series 60 DDEC II and III, as well as a housing assembly trade-in program that lets users buy new, discounted engine-brake housing assemblies as replacements for broken or worn-out units, regardless of maker.
Retarders for medium-duty engines are typically exhaust brakes, which work by restricting the flow of exhaust gases and thus increasing the backpressure inside the engine, and ultimately slowing the vehicle. Although they offer only about half the retarding power of engine brakes, they have an advantage in terms of weight, noise and cost.
Pacbrake makes exhaust brakes for a number of engine companies, including Caterpillar, Cummins, Detroit Diesel Corp. and International, in sizes ranging from light through heavy duty. Recent improvements to the product line include use of a salt-bath nitriding process during manufacturing to improve wear resistance, lubricity, fatigue strength and corrosion resistance. Pacbrake's most popular exhaust brakes will be treated this way by the end of the second quarter of 2001.
The most recent exhaust brake from Jacob is a turbo-mounted unit for Caterpillar medium-duty engines. This configuration makes installation easier; the unit itself cleaner; and enables it to be more responsive.
For off-road, severe-service applications, Caterpillar makes the Brakesaver hydraulic retarder, which works on the flywheel.
What does the future hold for engine retarders? In terms of product development, Jacobs says the emphasis will continue to move in the direction of retarders designed into the engine rather than bolted on. Cummins concurs, adding that the move to more integrated solutions is a path that's already been established with the development of the Intebrake. Changes here could involve even tighter integration into engine design and closer coupling with electronic controls.
Noise is an issue that isn't going away, as communities continue to ban engine brakes, perceiving them as the cause of excessive truck noise. But manufacturers say that engines are just about as loud in full acceleration as in engine braking mode. The culprit may actually be trucks without mufflers. Jacobs emphasizes the importance of educating the public since a ban on engine brakes could have a negative impact on public safety.
The trend toward closer integration of engine brakes and engines could provide a partial solution to the noise problem by making it possible to set minimum speeds for the use of engine brakes.
