Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Problem 103

An automobile engine will work test when the back pressure at the interface of the exhaust manifold and the engine block is minimized. Show how reduction of losses in the exhaust manifold. piping, and muffler will also reduce the back pressure. How could losses in the exhaust system be reduced? What primarily limits the minimization of exhaust system losses?

Short Answer

Expert verified
The reduction of losses in the exhaust manifold, piping, and muffler reduces back pressure in a car engine as it minimizes the resistance to the flow of exhaust gases. Losses can be reduced by using smoother, wider pipes, minimizing sharp bends, insulating exhaust pipes and regular maintenance to avoid carbon buildup. The minimization of exhaust system losses is however limited by physical imbalances that can be caused in the system and also by economic constraints regarding the design and maintenance of an optimal exhaust system.

Step by step solution

01

Understanding Back Pressure

Back pressure is the resistance or force opposing the desired flow of fluid in pipes. In terms of cars, back pressure is typically produced by the exhaust system (comprising the exhaust manifold, piping, and muffler), which is responsible for directing the exhaust gases from the engine out into the atmosphere. If losses (caused by friction and heat dissipation) in these sections are minimized, the resistance to the flow of exhaust gases decreases, thus reducing the back pressure.
02

Ways to Reduce Losses in the Exhaust System

Losses in the exhaust system can be reduced by using smoother and wider pipes, ensuring that there are no sharp bends or turns to slow down the flow of gases, and by using insulation around the exhaust pipes to prevent heat dissipation. Proper maintenance to remove carbon buildup in the exhaust pipes can also help reduce losses.
03

Limitations to the Minimization of Exhaust System Losses

The minimization of exhaust system losses is primarily limited by physical and economic factors. From a physical perspective, reducing too much backpressure can lead to an imbalance between the pressure in the exhaust system and the outside atmosphere, causing fresh air to enter the system (a phenomenon known as 'reversion'), which is detrimental to engine performance. Economically, it may be expensive to design and maintain an exhaust system that is capable of minimizing losses to the desired extent.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Calculate the kinetic energy correction factor for each of the following velocity profiles for a circular pipe: (a) \(u=u_{\max }\left(1-\frac{r}{R}\right)\) (b) \(u=u_{\max }\left(1-\frac{r^{2}}{R^{2}}\right)\) (c) \(u=u_{\max }\left(1-\frac{r}{R}\right)^{1 / 7}\)

For an automobile moving along a highway, descrite the control volume you would use to estimate the flowrate of air across the radiator. Explain how you would estimate the velocity of that air.

At cruise conditions, air flows into a jet engine at a steady rate of 65 lbm/s. Fuel enters the engine at a sieady rate of \(0.60 \mathrm{Ism} / \mathrm{s}\). The average velocity of the exhaust gases is 1500 ft/s relative to the engine. If the engine exhaust effective cross-sectional area is \(3.5 \mathrm{ft}^{2}\), estimate the density of the exhaust gases in \(\mathrm{lbm} / \mathrm{ft}^{3}\).

Molten plastic at a temperature of \(510^{\circ} \mathrm{F}\) is angered through an extruder barrel by a screw oscupying \(s\) of the tarrel's volume (Fig. \(P 5.16\) ). The extruder is \(16 \mathrm{ft}\) long and has an inner dianeter of 8 in. The barrel is connected to an adspter having a volume of \(0.48 \mathrm{ft}^{3} .\) The adapter is then connected to a die of equal volume. The plastic exiting the die is immediately rolled into sheets. The line is producing 4 -ft widths of material at a rate of \(30 \mathrm{ft} / \mathrm{min}\) and a gauge thickness of 187 mil. What is the axial velocity, \(V_{1},\) of the plastic in the barrel' Assume that the plastic density is constant as it solidifies from a liquid (in the extruder) into a solid sheet.

A hypodermic syringe (see Fig. \(P 5.30\) ) is used to apply a vaccine. If the plunger is moved forward at the steady rate of \(20 \mathrm{mm} / \mathrm{s}\) and if vaccine leaks past the plunger at 0.1 of the volume flowrate out the needle opening, calculate the average velocity of the needle exit flow. The inside diameters of the syringe ard the needle are \(20 \mathrm{mm}\) and \(0.7 \mathrm{mm}\)
See all solutions

Recommended explanations on Physics Textbooks

Circular Motion and Gravitation

Read Explanation

Electrostatics

Read Explanation

Astrophysics

Read Explanation

Modern Physics

Read Explanation

Force

Read Explanation

Fluids

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free