Exhaust brake how does it work

The backpressure works against the engine as it pumps air out of the cylinders, helping to slow down the engine and therefore the vehicle. Some exhaust brakes are completely mechanical, while others communicate directly with the engine's PCM computer to provide precision on-demand braking. Exhaust brakes are great for controlling speeds when towing downhill or bringing heavy loads to a halt while saving the truck and trailer brakes by reducing use.

Presents a small restriction in the exhaust system - negligible for most trucks when the exhaust brake valve is in the open position. Decreases distance in which a truck and trailer can be stopped, particularly beneficial in an emergency situation. Besides, an exhaust brake cannot close the exhaust system completely for a number of other good reasons. If the exhaust is completely closed, the pressure in the exhaust system will continue to rise until either the exhaust system ruptures or engine damage occurs.

Consequently, an exhaust brake must vent some exhaust flow through the exhaust system to keep the peak system pressure below the danger point. The pressure at which the exhaust valves can be blown open depends on the valve spring seat pressure and size area of the valve head of the valves used.

This is a carefully engineered setting on all Banks Brake applications: a careful determination is made to produce maximum practical braking without causing engine damage. First, if creating backpressure in the exhaust system generates negative torque and engine braking, then any exhaust system restriction that prevents free exhaust flow during cruise conditions or full throttle operation actually detracts from power output and fuel economy in the same way.

Secondly, when closed, an exhaust brake stalls the turbine section of the turbocharger. The exhaust brake must open before the turbo can spool up again to provide boost on demand. The Banks Brake is engineered to open at speeds below 15 MPH, when very little exhaust braking is available anyway, to quicken turbo response when the driver again steps on the fuel pedal.

Only the Banks Brake has this computerized feature. This is just one of the functions of the CBC computerized brake controller. Here too, the Banks Brake, which is designed to actually enhance exhaust flow out of the turbine in the open position, improves both power and fuel economy, as well as supplemental braking when needed. Diesel engines do not use a throttle valve, as their operation is based on the regulation of fuel, rather than the regulation of air, as is the case with gasoline engines.

Without a supplemental braking option, the combination of heavy loads and lack of engine braking easily overwhelms wheel brakes. Diesel exhaust brakes often are the preferred choice as they provide stopping benefits, but without the very loud noise associated with compression brakes. An exception would be heavy duty vehicles under significant load. In cases like this, compression brakes would be preferred as they provide the greatest braking force.

So, how does an exhaust brake work? Essentially, it works by trapping engine pressure in the exhaust system, which in turn forces the engine to rotate slower backpressure. Normally, pistons travel upward in their cylinder bore to force spent exhaust gasses out of the engine via the exhaust valve.

When the exhaust brake is applied and the inline butterfly valve is partially closed, significant additional force is required to push the spent exhaust from the engine. As the engine slows, the vehicle decelerates.

In some exhaust brake systems, the vehicle computer controls their operation. In others, the driver can manually actuate the exhaust brake. With either system, the mechanism which closes the butterfly valve may be powered by hydraulic pressure, air pressure or rely on an electronically operated servo motor. Many diesel powered vehicles have supplemental braking systems, such as exhaust brakes. As a diesel technician , familiarity with their use and operation are important skills to have for your career.

The braking systems require occasional maintenance and some users report decreased effectiveness over time. Properly inspecting, diagnosing, repairing and maintaining exhaust brake systems are important skills to have and can take you far in this industry. One of these programs is the agricultural equipment technician training program , which was created with Fendt, part of the AGCO Corporation. In this week program, students who qualify learn the ins and outs of working on agricultural equipment.

They also earn valuable agricultural technician qualifications that can give them a competitive edge as they start their careers. To learn more, request information today. While times might seem uncertain, the demand for diesel techs remains.

He works as a Caterpillar field service tech by day. And he's an entrepreneur by night. This rate excludes graduates not available for employment because of continuing education, military service, health, incarceration, death or international student status.

The rate includes graduates who completed manufacturer-specific advanced training programs and those employed in positions that were obtained before or during their UTI education, where the primary job duties after graduation align with the educational and training objectives of the program. UTI is an educational institution and cannot guarantee employment or salary. Individual circumstances and wages depend on personal credentials and economic factors. Work experience, industry certifications, the location of the employer and their compensation programs affect wages.

Awards vary due to specific conditions, criteria and state. Bureau of Labor Statistics, Employment Projections , www. Job openings include openings due to growth and net replacements. Plus, you are saving the brake pads from being used — which means less maintenance.

During Jake braking, exhaust valves are opened prematurely during compression stroke to let the pressure out. In the typical combustion scenario, combustion occurs when the piston moves up AKA compression. During combustion, the explosion and exhaust gases create significant pressure that push the pistons down to move the vehicle.

On Jake brakes, exhaust valves are opened before the pistons complete their compression cycle move up. This means when combustion happens, the created pressure goes directly out of the cylinder into the exhaust system — resulting in less power to move the pistons. These brakes were patented by Clessie Cummins in and the first company to make them was Jacobs Vehicle systems.

And from this, they are known as the Jake Brake. The biggest drawback of this solution is the sound these brakes are creating. In many countries, they are prohibited for use in city limits and they are used mostly on the highway. If you are a truck driver and you haul a lot of things with your truck, an exhaust brake is a must in order to quickly and powerfully slow down your truck. Exhaust brakes can even ensure your safety when you require immediate halt. So, use your exhaust brake wisely and stay safe on the road!

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? This site is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.

Hit enter to search or ESC to close. By Ifandi S. May 30, Exhaust. No Comments. No direct contact on rods or pistons During exhaust brakes, there are no direct contacts being made to rods or pistons. Exhaust brakes are not used all the time Exhaust brakes are only used in certain scenarios where more braking power is required — think downhill scenarios where you are driving downhill with your fully loaded truck and there is a lot of traffic on the road.

Truck exhaust manifolds are made to be tough Exhaust manifolds are tough, they are made from special steel that can withstand a lot of heating-and-cooling cycles as well as the pressure.