An experimental investigation on the cold-start idle condition of an electrically heated catalytic converter on a four-stroke engine has been carried out. The preheated temperature of the catalytic converter and the level of CO emission of the catalyst were studied, and other measured quantities included the exhaust gas temperatures at the mid-section and at the outlet of the catalytic converter and the concentration of CO. The preheated temperatures of the catalytic converter were varied from raw temperature (non-preheating) to 100, 140 and 180 °C. The levels of CO emissions were set at 1.0, 1.5 and 2.0 per cent. The catalyst was tested with and without heat-storing material around the heater. The experimental results revealed that the catalytic converter with a preheated temperature of 180 °C triggered an early catalytic reaction. A high-level CO setting has the same effect, with the optimum value at approximately 2.0 per cent.

Another method of applying the dynamic tribo-electrification mechanisms in a gas flow sensor was studied experimentally in this paper. The gas used was nitrogen (N 2 ) and the tribo-electrification mechanisms were from the incompatible pair (Pb/Fe) and the partially compatible pair (Cu/Fe) in dry severe wear condition. Generally, flow sensors using the dynamic tribo-electrification mechanisms will be sensitive for material pairs with high thermal eletromotive force, low specific heat, and thermal conductivity. For the incompatible pairs, results from this study revealed that the method was adequate for measuring small flowrate and only a small amount of masses was transferred from the soft metals to the iron, forming a very thin layer with a friction coefficient of less than 0.3. Moreover, variations of the tribo-electrification and friction coefficient with sliding time appeared to be very stable, indicate that the effect of N 2 flowrate on tribo-electrification was significant. This effect of N 2 flowrate and the average interface temperature rise were particularly pronounced at a N 2 flowrate of less than 100 l/min. Finally, a model to represent the tribo-electrification mechanisms of various soft metals sliding on iron in N 2 gas flow was proposed.