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Although hydrogen ICE engines have existed in one sort or another for many years, the testing of fuel consumption by way of exhaust emissions is not yet a proven method. The current consumption method for gasoline- and diesel-fueled vehicles is called the Carbon-Balance method, and it works by testing the vehicle exhaust for all carbon-containing components. Through conservation of mass, the carbon that comes out as exhaust must have gone in as fuel. Just like the Carbon-Balance method for gas and diesel engines, the new Hydrogen-Balance equation works on the principle that what goes into the engine must come out as exhaust components. This allows for fuel consumption measurements without direct contact with the fuel. This means increased accuracy and simplicity. This new method requires some modifications to the testing procedures and CVS (Constant Volume Sampling) system.

New Federal and California Regulations present some new challenges for emission testing as low emission variability and different test cell environments through SFTP. One approach to achieve these challenges could be replacing the human driver by a robot driving system. To make a great step forward in the improvement of such robot systems, the German automotive technology research association (FAT) initialized an investigation program in cooperation with three different suppliers. The work was done and reported by the Department of Internal Combustion Engines at the Darmstadt University of Technology. This report summarizes the comparison of the driving style of the human driver to three automatic driving systems from those major manufacturers and some basic optimization work.

This paper reports on the development and testing of a compact and mobile CVS system for the measurement of particulate matter emissions of diesel passenger cars. It consists of the same components as a conventional CVS system but needs much less space. Reducing the size of the CVS system was achieved by the optimization of the turbulent flow in the dilution tunnel by the use of an optimized mixing chamber, in which the engine exhaust gas is diluted with filtered ambient air. The measures taken to improve the turbulence in the dilution tunnel lead to the same effect as a tunnel with dimensions according to the legislative regulations. All the components of the mobile CVS system are arranged in a very compact design, so that the new system has a size of only about (1.70 x 0.80 x 2.10) m. Due to the mobility which is possible with such a design, the new system can be quickly adapted to different engine and vehicle test cells for passenger cars.

A laser mass spectrometer (LAMS) for simultaneous detection of NO, NO2, NH3 and other components (N2O, CO, O2, H2O, aromatics) in the exhaust of combustion engines is presented. Its temporal resolution is in the 10 ms range. Comparison with non-dispersive IR, flame ionisation detection and chemical luminescence detection have been performed. Emissions of Otto and Diesel engines have been studied at different velocities, load and three sampling positions: in front of a catalytic pre-converter, in front and after the main catalytic converter. Finally, NO, CO, H2O, toluene and O2 were detected within the cylinder in dependence on the crank angle with a time resolution in the 10 ms range.

The variety of increasingly complex powertrains including Plug-In Hybrid Electric Vehicles (PHEVs) is associated with a number of challenges to measure exhaust gas emissions: Although the conventional constant volume sampling (CVS) and exhaust gas measurement systems remain a high precision emission measurement concept new questions occur that need to be answered, such as mass transport, catalyst cooling during ICE-off and emission measurement accuracy. Mass transport of exhaust emissions from the transfer tube into the dilution tunnel during engine-off complicates phase assignment. This includes the investigation of the physical processes that are diffusion on basis of concentration differences, extraction due to the CVS underpressure and convection because of density diversities. Catalyst cooling will be investigated using a temperature sensor positioned at the oxy catalyst of a Diesel-PHEV.