Measurements from a single-cylinder automobile test engine burning ethanol,
exhibiting two homogeneous regimes when the equivalence ratio is regressed on
nitrous-oxide concentration – the engine example of Wu & Yao (2016, Fig. 5).
Derived from the public-domain ethanol data redistributed in the lattice
package (Brinkman 1981).
Format
A data frame with 88 rows and 3 columns:
- equivalence
equivalence ratio: richness of the air/ethanol mix (response).
- nox
concentration of nitrous oxide (NO and NO2) in the exhaust, normalized by engine work (predictor).
- compression
compression ratio of the engine.
Source
Brinkman, N. D. (1981). Ethanol fuel – a single-cylinder engine study
of efficiency and exhaust emissions. SAE Transactions 90, 1410–1427.
Redistributed via the lattice package ethanol dataset.
Examples
fit <- mixqr(equivalence ~ nox, data = engine, tau = 0.5, m = 2)
summary(fit)
#> Mixture of quantile regressions (mixqr) -- summary
#> engine: ald tau = 0.5 m = 2 n = 88
#>
#> Component 1 (pi = 0.5081):
#> Estimate
#> (Intercept) 1.243
#> nox -0.083
#>
#> Component 2 (pi = 0.4919):
#> Estimate
#> (Intercept) 0.557
#> nox 0.091
#> Responsibility overlap (0 = separated, 1 = overlapping): 0.129
#>
#> logLik = 113.995 (ALD working likelihood) AIC = -213.99 BIC = -196.65