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lattice (version 0.22-5)

H_ethanol: Engine exhaust fumes from burning ethanol

Description

Ethanol fuel was burned in a single-cylinder engine. For various settings of the engine compression and equivalence ratio, the emissions of nitrogen oxides were recorded.

Usage

ethanol

Arguments

Format

A data frame with 88 observations on the following 3 variables.

NOx

Concentration of nitrogen oxides (NO and NO2) in micrograms/J.

C

Compression ratio of the engine.

E

Equivalence ratio--a measure of the richness of the air and ethanol fuel mixture.

Author

Documentation contributed by Kevin Wright.

References

Cleveland, William S. (1993) Visualizing Data. Hobart Press, Summit, New Jersey.

Examples

Run this code
## Constructing panel functions on the fly
EE <- equal.count(ethanol$E, number=9, overlap=1/4)
xyplot(NOx ~ C | EE, data = ethanol,
       prepanel = function(x, y) prepanel.loess(x, y, span = 1),
       xlab = "Compression ratio", ylab = "NOx (micrograms/J)",
       panel = function(x, y) {
           panel.grid(h=-1, v= 2)
           panel.xyplot(x, y, grid = FALSE)
           panel.loess(x, y, span = 1)
       },
       aspect = "xy")

# Wireframe loess surface fit.  See Figure 4.61 from Cleveland.
require(stats)
with(ethanol, {
  eth.lo <- loess(NOx ~ C * E, span = 1/3, parametric = "C", 
                  drop.square = "C", family="symmetric")
  eth.marginal <- list(C = seq(min(C), max(C), length.out = 25), 
                       E = seq(min(E), max(E), length.out = 25))
  eth.grid <- expand.grid(eth.marginal)
  eth.fit <- predict(eth.lo, eth.grid)
  wireframe(eth.fit ~ eth.grid$C * eth.grid$E,
            shade=TRUE,
	    screen = list(z = 40, x = -60, y=0),
	    distance = .1,
	    xlab = "C", ylab = "E", zlab = "NOx")
})

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