Abstract: A solid particle counting system for measuring solid particle number concentrations from engine or vehicle exhausts in real-time includes an evaporation unit, a diluter arrangement, and a particle counter. The diluter arrangement mixes the dilution gas with the gases from the evaporation unit at a dilution ratio, and the diluter arrangement includes a flow meter located upstream of the evaporation unit for measuring the flow of gases into the evaporation unit which, in turn, flow into the diluter arrangement.

Abstract: A penetration and removal efficiency calibration unit for a volatile particle remover in a solid particle counting system provides an accurate and efficient approach to calibration. The calibration unit includes an aerosol inlet, a flow meter downstream of the aerosol inlet, and a mixer. The flow meter receives the aerosol flow from the aerosol inlet and provides an output flow to the mixer. The mixer receives the output flow from the flow meter and also has a dilution gas inlet. The mixer provides a mixer output flow for reception by the volatile particle remover or particle counter. A first flow controller controls flow into the dilution gas inlet. The calibration unit also includes a bypass inlet. A second flow controller controls flow into the bypass inlet, and a control loop controls the bypass flow such that the aerosol flow tracks a reference value.

Abstract: A solid particle counting system for measuring solid particle number concentrations from engine or vehicle exhausts in real-time includes an evaporation unit, a diluter arrangement, and a particle counter. The diluter arrangement mixes the dilution gas with the gases from the evaporation unit at a dilution ratio, and the diluter arrangement includes a flow meter located upstream of the evaporation unit for measuring the flow of gases into the evaporation unit which, in turn, flow into the diluter arrangement.

Abstract: A solid particle counting system for measuring solid particle number concentrations from engine or vehicle exhausts in real-time includes a flow splitter having an inlet, a sample outlet, and a by-pass outlet arranged such that a main flow enters the inlet and changes direction to exit the by-pass outlet. A sample flow from the main flow exits the sample outlet. The flow splitter further includes a guiding element arranged such that particles at a sampling location upstream of the main flow direction change are guided to the sample outlet.

Abstract: A solid particle counting system for measuring solid particle number concentrations from engine or vehicle exhausts in real-time includes a diluter arrangement, a particle counter, and a flow splitter. The diluter arrangement mixes the dilution gas with flowing sample gases. The flow splitter receives the output flow from the diluter arrangement, provides a portion of this flow to the particle counter, and provides a by-pass flow that is received by a vacuum pump. A second flow route to the particle counter includes a valve arranged such that opening the valve during the starting of the vacuum pump reduces a pressure pulse at the particle counter caused by the starting of the vacuum pump, thereby avoiding work fluid backflow from the particle counter prior to the vacuum pump stabilizing.