
Concept explainers
The CAFÉ standards under which vehicles are tested.

Explanation of Solution
CAFÉ stands for Corporate Average Fuel Economy standards. These were established in 1975 to build more fuel-efficient vehicles to increase the overall fuel efficiency of the vehicles. Under the CAFÉ standards, different models from different manufacturers of vehicles are tested for the number of miles they can be driven on a gallon of gas. Then the fuel efficiencies of these vehicles are averaged together. If the average fuel economy of a manufacturer falls below the usual requirement, then the manufacturer has to cover CAFÉ credits or may have to pay a penalty. For this the car makers have replaced many parts of the engine with new technology and techniques to attain higher fuel efficiency in addition to get increased power output. They replaced many manually operated systems with automatic or electronic system to get more fuel efficient vehicles and also get less emission from burning of fuel.
According to estimation, due to CAFÉ standards, the fuel economy will increase nearly to 54.5 mpg between the years 2017 and 2025.
Want to see more full solutions like this?
Chapter 4 Solutions
AUTOMOTIVE TECHNOLOGY TECH MANUAL
- . A gas turbine with air enters the compressor at 300 K, 1 bar, and exits from the turbine at 750 K, 1 bar. The thermal efficiency of the cycle is 40.1% and the back work ratio (BWR) is 0.4. Find the pressure ratio of the cycle. Assume variable specific heat.arrow_forwardA regenerative gas turbine power plant is shown in Fig. below. Air enters the compressor at 1 bar, 27°C with a mass flow rate of 0.562 kg/s and is compressed to 4 bar. The isentropic efficiency of the compressor is 80%, and the regenerator effectiveness is 90%. All the power developed by the high-pressure turbine is used to run the compressor. The low-pressure turbine provides the net power output. Each turbine has an isentropic efficiency of 87% and the temperature at the inlet to the highpressure turbine is 1200 K. Assume cold air properties, determine: a. The net power output, in kW. b. The thermal efficiency of the cycle.arrow_forwardFor tixed inlet state and exit pressure, use a cold-air standard analysis to show that the pressure ratio across the two compressor stages that gives nunimum work input is:=)) k/(k-1) when Ta Ti, where Ta is the temperature of the air entering the second stage compressor and Pi is the intercooler pressure. Put the suitable assumptionsarrow_forward
- Derive the equation below ah ap ax 12μ ax, +( ah ap ay 12μ ay Where P P (x, y) is the oil film pressure. 1..ah 2 axarrow_forwardCan you determine the eignevalues by hand?arrow_forwardMonthly exam 13 2021-2022 Power plant Time: 1.5 Hrs Q1. A The gas-turbine cycle shown in Fig. is used as an automotive engine. In the first turbine, the gas expands to pressure Ps, just low enough for this turbine to drive the compressor. The gas is then expanded through the second turbine connected to the drive wheels. The data for the engine are shown in the figure, and assume that all processes are ideal. Determine the intermediate pressure Ps, the net specific work output of the engine, and the mass flow rate through the engine. Find also the air temperature entering the burner T3 and the thermal efficiency of the engine. Exhaust Air intake Φ www Regenerator www Bumer Compressor Turbine Power turbine et 150 kW Wompressor P₁ = 100 kPa T₁ = 300 K PP₁ =60 P-100 kPa T₁ = 1600 K Q2. On the basis of a cold air-standard analysis, show that the thermal efficiency of an ideal regenerative gas turbine can be expressed as 77 = 1- where - () () гp is the compressor pressure ratio, and T₁ and…arrow_forward
- I need to find m in R = mD from the image given. Do you really need to know what R and D is to find R. I was thinking geometrically we can find a relationship between R and D. D = R*cos(30). Then R = mD becomes m = R/D = 1/cos(30) = 1.1547. Is that correct?arrow_forwardQ1] B/ (16 Marks) To produce a lightweight epoxy part to provide thermal insulation. The available material are hollow glass beads for which the outside diameter is 1.6 mm and the wall thickness is 0.04 mm. Determine the weight and number of beads that must be added to the epoxy to produce a 0.5 kg of composite with a density of 0.65 g/cm³. The density of the glass is 2.5 g/cm³ and that of the epoxy is 1.25 g/cm³.arrow_forwardBelow is a projection of the inertia ellipsoid in the b1-b2 plane (b1 and b2 are unit vectors). All points on the ellipsoid surface represent moments of inertia in various directions. The distance R is related to the distance D such that R = md. Determine m.arrow_forward
- Below is a projection of the inertia ellipsoid in the b1-b2 plane (b1 and b2 are unit vectors). All points on the ellipsoid surface represent moments of inertia in various directions. Determine I_aa ( moment of inertia) for direction n_a (this is a unit vector).arrow_forwardThe problems are generally based on the following model: A particular spacecraft can be represented as a single axisymmetric rigid body B. Let n₂ be inertially fixed unit vectors; then, 6, are parallel to central, principal axes. To make the mathematics simpler, introduce a frame C where n₂ = ĉ₁ = b; initially. 6₁ Assume a mass distribution such that J =₁₁• B* •b₁ = 450 kg - m² I = b² •Ï¾˜ • b₂ = b¸ •Ï¾* •b¸ = 200 kg - m² K J-I C³ =r₁₁ = r₁₁arrow_forwardThe problems are generally based on the following model: A particular spacecraft can be represented as a single axisymmetric rigid body B. Let n₂ be inertially fixed unit vectors; then, 6, are parallel to central, principal axes. To make the mathematics simpler, introduce a frame C where n₂ = ĉ₁ = b; initially. 6₁ Assume a mass distribution such that J =₁₁• B* •b₁ = 450 kg - m² I = b² •Ï¾˜ • b₂ = b¸ •Ï¾* •b¸ = 200 kg - m² K J-I C³ =r₁₁ = r₁₁arrow_forward
- Automotive Technology: A Systems Approach (MindTa...Mechanical EngineeringISBN:9781133612315Author:Jack Erjavec, Rob ThompsonPublisher:Cengage LearningElectrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage LearningRefrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning


