The Diesel cycle comprises the subsequent four processes_________________?
Show answer Hide answer
Answer: C. two isentropics, one constant volume and one constant pressure
Explanation
Diesel cycle features two adiabatic isentropic processes for compression and expansion phases. Heat addition occurs at constant pressure during fuel injection, followed by constant volume heat rejection. This specific sequence differentiates the ideal Diesel cycle from Otto and dual combustion cycles. Rudolf Diesel invented compression ignition engines that operate on this theoretical thermodynamic cycle. Fuel injection into high-temperature compressed air maintains constant pressure as combustion expands gases. Exhaust blowdown is typically modeled as a constant volume heat rejection process in cycle analysis.
Automotive engineering courses use the ideal Diesel cycle to evaluate heavy-duty compression ignition performance. Thermal efficiency calculations for diesel engines depend on compression ratio and cut-off ratio parameters. Comparing diesel and gasoline cycles helps engineers optimize fuel economy for different transportation sectors. Two isothermals and two isentropics define the theoretical Stirling or Carnot cycles, not the Diesel cycle. Two isentropics and two constant volume processes describe the ideal Otto cycle used in spark-ignition engines. Using two constant pressure processes does not match the standard cycle configurations taught in thermodynamics.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. An engine functions between 900°K and T2, while another operates between T2 and 400°K. For both to produce identical work, the value of T2 must be________________?
Show answer Hide answer
Answer: A. 650°K
Serial Carnot engines producing equal work output require a specific intermediate temperature calculation. Using harmonic mean temperature principles for equal work output yields 650 Kelvin. This balanced temperature dro...
Q2. For a thermodynamic process to achieve reversibility, the temperature variance between the hot body and the working substance ought to be___________________?
Show answer Hide answer
Answer: A. zero
Reversibility demands that systems remain infinitesimally close to thermodynamic equilibrium throughout every single operational stage. Finite temperature differences drive spontaneous heat transfer, which introduces irr...
Q3. Gas laws can be applied with the least error for which of the following substances_________________?
Show answer Hide answer
Answer: D. superheated steam
Superheated steam behaves most closely to an ideal gas, making gas laws applicable with minimal error. High temperatures and low pressures keep steam molecules far apart, reducing intermolecular forces. Deviations from i...
Q4. Carnot cycle efficiency attains maximum value for__________________?
Show answer Hide answer
Answer: A. reversible engine
Reversible engines operate without internal or external irreversibilities like friction or heat loss. The Carnot theorem proves that no engine can be more efficient than a reversible engine. Reversibility ensures maximum...
Q5. A perfect gas at 27°C undergoes constant pressure heating until its volume doubles, resulting in a final temperature of________________?
Show answer Hide answer
Answer: B. 327°C
Charles law states that volume is directly proportional to absolute temperature during constant pressure processes. Converting the initial temperature of 27 degrees Celsius to Kelvin gives a starting value of 300 Kelvin....
Q6. Given identical compression ratios and equal heat addition_________________?
Show answer Hide answer
Answer: A. Otto cycle is more efficient than Diesel cycle
For the same compression ratio and heat input, the Otto cycle is more efficient than the Diesel cycle. Heat addition in the Otto cycle occurs at constant volume rather than constant pressure. This thermodynamic differenc...