A 1.60-L gasoline engine with a compression ratio of 6.20...

A 1.60-L gasoline engine with a compression ratio of $6.20$ has a power output of $102 \mathrm{hp}$. Assuming that the engine operates in an idealized Otto cycle, find the energy absorbed and exhausted each second. Assume that the fuel-air mixture behaves like an ideal gas, with $\gamma=1.40$.

Key Concepts

Ideal Gas Behavior and Specific Heats

Assuming the fuel-air mixture behaves like an ideal gas simplifies the analysis of the Otto cycle. This involves using the ideal gas law and the concept of specific heats, particularly the ratio of specific heats (gamma), to model the adiabatic compression and expansion processes. The parameter gamma is essential for determining temperature and pressure variations during these processes.

Engine Power Conversion

Engine power output, often given in horsepower, is a measure of the work produced by the engine per unit time. In thermodynamic analyses, converting power into energy per second (using appropriate conversion factors) is crucial for quantifying the net energy absorbed (during the heat addition phase) and the energy rejected (during the exhaust phase) in each cycle of the engine. This conversion underpins the understanding of energy flow and efficiency in engine cycles.

Otto Cycle

The Otto cycle is an idealized thermodynamic cycle that models the functioning of a spark-ignition internal combustion engine. It consists of distinct processes that include adiabatic (no heat transfer) compression and expansion, and constant-volume heat addition and rejection. This cycle serves as a foundational concept in understanding engine efficiency and performance in gasoline engines.

Compression Ratio

The compression ratio is defined as the ratio of the maximum volume to the minimum volume in the engine cylinder during the cycle. It is a critical parameter that significantly influences the efficiency and work output of an engine. A higher compression ratio typically leads to a more efficient engine cycle due to higher thermal efficiency, although it must be balanced against the risk of engine knock.

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