Investigation on formaldehyde generation characteristics and influencing factors of PODE/methanol dual-fuel combustion mode.

Polyoxymethylene dimethyl ether (PODE) and methanol are important low-carbon substitutable fuels for reducing carbon emissions in internal combustion engines. In the research, the impacts of methanol ratio, injection timing, and intake temperature on HCHO generation and emission were investigated using both engine tests and numerical simulations. Results suggest that an increase in methanol ratio suppresses auto-ignition tendency of PODE, leading to the increase of ignition delay period, pressure peak, and heat release rate peak inside the cylinder. The decrease in in-cylinder combustion temperature contributes to an increase in HCHO emission due to partial oxidation of methanol in the cylinder and exhaust pipe. While the injection timing is gradually postponed from -10 °CA ATDC to 2 °CA ATDC, in-cylinder high-temperature area decreases, the quantity of unburned methanol increases, but part of HCHO is converted to HCO due to H radical influence, resulting in 72% increased HCHO emission. With the increment of intake temperature, the oxidation and decomposition of in-cylinder methanol accelerate, leading to an improvement in combustion stability, more uniform temperature distribution, and a decrease in unburned methanol, which results in lower HCHO emission. When the intake temperature is rose from 30 to 60 °C, HCHO emission decreases by 11.2%.

[Development of one corn ear and verification the three laws of inheritance].

A new corn was developed as a lab material to verify the three Laws of Inheritance on only one F2 ear with correct segregation ratios of kernel traits. In order to investigate the three Inheritance Laws simultaneously with one ear, the sweet endosperm (Sn1), kernel color (C1) and the glutinous endosperm (Wx) were chosen as the original phenotypes. Gene Sn1sn1 is located on chromosome four, genes C(1c1) and Wxwx are located on chromosome nine. After several generations of continuous self-pollination and test crossing, direct crossing and back crossing, with strict selections, the homozygous parents were obtained. With different combinations of homozygous parents, different hybrids were developed. The segregation ratios of each phenotype on the same F2 ear are compared to the theoretical segregation ratios according to the corn gene exchange and gamete types and quantities produced through meiosis. The results showed three ratios of 3:1, two ratios of 9:3:3:1, and one ratio of linkage and exchange, with all the chi-square values smaller than the permitted ones. This means that only one ear of this new hybrid corn can be used as a new teaching aid to examine and verify the three Laws of Inheritance.