The stricter emissions standards mandated by EPA are no doubt having their most dramatic impact on engine development. And such widespread changes to engines means that changes to engine brakes and exhaust brakes can't be far behind.
One emissions-related technology that affects exhaust brakes is exhaust-gas recirculation (EGR), which a number of engine makers are planning to use to meet the '02 standards. Pacbrake explains that if EGR is operational during idle on an engine using an exhaust brake that is turned on, the massive flow of exhaust to the intake will cause the engine to stall. To prevent this, EGR must be controlled so that it doesn't function during idle rpm. Since EPA requires that EGR function in all phases of engine operations, it's important that the agency grant an exception to vehicles using exhaust brakes.
EGR will not really affect engine brakes, Pacbrake points out, since they are programmed from the ECU to stop working at idle.
Common-rail fuel injection, which should enable engine makers to achieve the high injection pressures needed to meet '04 emissions levels, will mean changes for engine brakes as well. Currently in field-trial stage, this technology provides more room under the valve cover, which means the engine brake can be integrated into the engine, rather than bolted on. Pacbrake says that engine brakes being developed for this new engine configuration will have rocker-type controls and take up less space.
Common rail also frees up cam lobe for additional engine braking control. So in addition to being more powerful, engine brakes will also be smaller and lighter.
New turbocharging technology, such as VGT and VNT (variable geometry and variable nozzle turbocharging, respectively), will also affect engine braking. Pacbrake explains that by constricting exhaust flow out its back, the turbocharger could function as a type of high-pressure exhaust brake by itself or in conjunction with an engine brake. An example of this is the Cummins ISL, which has an engine brake and a VGT for better performance than a standard engine brake.
The use of alternatives to diesel fuel will also impact engine brakes. According to Pacbrake, at present there isn't any room for an engine brake in vehicles using fuels that are spark-ignited, such as LNG.
Changes taking place outside the lab are also affecting engine brakes. The most predominant is the trend to stronger business ties between vehicle OEMs and component suppliers.
Jacobs Vehicle Systems, for example, worked closely with Cummins to develop the industry's first integrated engine brake. Designed for Cummins' ISX engine platform, the Intebrake has 20-25% greater retarding power than conventional engine brakes, yet is smaller and about 80% lighter, according to Jacobs.
Now that Jacobs has signed a five-year supply and development agreement with Cummins, it seems likely that the integrated engine brake concept will be extended to other Cummins engine platforms as well. Jacobs is also working with other engine makers.
Since Jacobs sells its products exclusively to engine makers, users that want to retrofit a Jacobs engine brake must do so through the engine supplier.
Pacbrake holds some patents on integrated engine-braking designs and is also working with engine makers, although it does not yet have an integrated product in the field.
Jacobs also reports that new Cummins ISL engines now have its bolt-on C-brake as an option, and that retrofits will soon be available.
Focusing specifically on the heavy-duty aftermarket, TecBrake manufactures engine brakes for Caterpillar, Cummins, DDC and Mack engines. TecBrake products are traditional bolt-on models; the company is not working on integrated engine brakes at this time.
In terms of new products, TecBrake is pursuing development of engine brakes for Cat 3406E and Cummins M11 applications. Availability is slated for early 2002.
TecBrake offers a trade-in program where users can purchase new, warranted engine brake housing assemblies (including mounting parts) as replacements for broken or worn-out units, regardless of engine brake manufacturer, at a discount price.
Meanwhile, Pacbrake recently launched an all makes parts program. The first product is the P19654 Tune-up Kit, designed to fit the Jacobs 340, 340A/B for Cat 3406E, C15/16 engines. According to PacBrake, the kit contains all the consumable components needed to “freshen up” the engine brake.