Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
1999-07-23
2001-10-23
Wolfe, Willis R. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C073S023310, C073S118040
Reexamination Certificate
active
06308130
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of vehicle emissions measuring systems and, more particularly, to an improved on-board mass emissions measuring system.
BACKGROUND ART
Motor vehicle emissions are the leading source of air pollution in most metropolitan areas, causing health, ecological and economical damage. As a result, considerable effort and resources are currently devoted to various emission reduction strategies, such as emission inspection programs, reformulated or alternative fuels, stricter standards for new vehicles, mass transit, improved engine control and catalyst technologies, and upgrade and repair of existing vehicles. However, in order to evaluate the impact of these reduction strategies, it is necessary to measure and collect accurate real-world emission measurements over the life of a vehicle.
Presently, the vast majority of emission tests are performed in a specialized laboratory, where the vehicle is driven on a dynamo meter according to a prescribed driving cycle, such as I/M 240 or FTP for light and medium duty vehicles and CBD for heavy duty vehicles.
This approach has several significant disadvantages: (1) the driving cycles do not adequately represent real-world driving conditions, which vary and are often unknown; (2) vehicles can be optimized for low emissions during the driving cycle, but do not operate optimally in actual use; (3) the testing equipment is bulky and expensive; (4) there are significant costs associated with testing the vehicle, such as vehicle (and/or mobile laboratory) mileage, vehicle downtime, and the test itself, especially on heavy-duty vehicles; (5) individual vehicles engines have unique characteristics which effect emissions, and (6) only a relatively small number of vehicles can be tested.
The first two disadvantages can be eliminated by using a testing system mounted on the vehicle. However, the use of an on-board system is presently limited to repair grade gas analyzers that provide only a rough estimate of mass emissions for repair purposes and a relatively small number of dedicated instrumented vehicles.
For example, it is known that an on-board testing system mounted on a dedicated instrumented vehicle was disclosed by Sierra Research. This system uses a repair-grade four-gas non-dispersive infra-red (NDIR) analyzer to measure exhaust gas concentrations and several sensors mounted on the engine to determine intake air flow. From these measurements, exhaust mass flow and mass emissions can be computed.
A simpler system, using repair grade NDIR analyzer concentration data only, has been developed at the University of Denver to predict I/M 240 mass emissions. Using this system, the average ratio of pollutant to fuel consumed is calculated from the concentration data. The amount of fuel consumed is then estimated from the length of the trip and fuel economy. While this method is successful in predicting whether a vehicle will pass or fail an I/M 240 test, and has been incorporated into newer repair grade analyzers, it is not sufficiently accurate in measuring actual mass emissions, since it does not properly account for emissions during extreme (high or low) exhaust flow. Also, errors in estimating fuel consumption results in the same relative error in mass emission readings.
Accordingly, a system which allows for the testing of individual vehicles during daily operation is necessary to eliminate many of the shortfalls found in the existing systems. One such system was previously disclosed by the inventor. The system employs a five-gas analyzer drawing undiluted exhaust from the tailpipe and calculates mass exhaust flow from engine operating data obtained via a diagnostic link to the computer controlled engine. However, this system can only be employed on engines which include a computerized engine control unit. This greatly limits the number and type of vehicles from which emission measurements may be taken.
Hence, it would be useful to provide a portable mass emissions measuring system which could measure accurate real-world vehicle emissions on a large variety of vehicles without displacing the vehicle from service.
DISCLOSURE OF THE INVENTION
With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for the purposes of illustration and not by way of limitation, the present invention provides an improved mass emissions measuring system (
15
) for an internal combustion engine (
17
), comprising an exhaust analyzer (
16
), at least one sensor (
18
,
22
or
29
) which may be temporarily attached to the engine for sensing parameters of the engine, and a processor (
19
) programmed to collect and manipulate data from the analyzer and the sensor, whereby the mass emissions of the engine may be calculated.
The system may further comprise a display (
20
) for displaying the mass emissions of the engine. The system may also include an engine-control interface (
21
). The sensor may be capable of sensing engine RPM, engine oil temperature, or intake manifold pressure. The exhaust analyzer may be capable of measuring concentrations of the engine exhaust constituents, particulates, aerosols, and gases in the engine emissions. The system may be adapted for use on-board a moving vehicle. The present invention also discloses a portable mass emissions measuring system for an internal combustion engine comprising an exhaust analyzer (
16
), a trace-gas injector (
23
), and a processor (
19
) programmed to collect and manipulate data from the analyzer and the injector, whereby the mass emissions of the engine may be calculated.
The present invention also discloses a method for determining the emission flow rate of an internal combustion engine, comprising the steps of providing an internal combustion engine having an exhaust, providing an exhaust analyzer having a sampling point downstream from the engine, operating the engine, injecting a trace-gas upstream from the sampling point of the exhaust analyzer at a controlled flow rate, measuring concentrations of the trace-gas with the exhaust analyzer, and calculating the emissions flow rate of the engine based on the known trace-gas injection flow rates and measured trace-gas concentrations.
Accordingly, the general object of the present invention is to provide an improved mass emissions measuring system which is adapted to be used to determine real-world vehicle emissions.
Another object is to provide an improved system for determining vehicle emissions which is portable.
Another object is to provide an improved system which is adapted for use on a wide variety of vehicles.
Another object is to provide an improved system which may be used on a vehicle without permanent modification to the vehicle
Another object is to provide an improved emission measuring system which can be installed for use in a vehicle in a very short period of time.
Another object is to provide an improved mass emissions measuring system which may be used without displacing a vehicle from service.
Another object is to provide an improved emissions measuring system which allows for use with a large number of vehicles.
Another object is to provide an improved emissions measuring system which may be used on vehicles which do not have an engine electronic control unit.
REFERENCES:
patent: 5099437 (1992-03-01), Weber
patent: 6062092 (2000-05-01), Weaver
patent: 6148656 (2000-11-01), Breton
patent: 6151952 (2000-11-01), Mathews et al.
Michal Vojtisek-Lom and James T. Cobb, Jr., Vehicle Mass Emissions Measurement Using Portable 5-gas Exhaust Analyzer and Engine Computer Data, presented at Emission Inventory: Planning for the Future Conference, Research Triangle Park, North Carolina, Oct. 28-30, 1997.
Michal Vojtisek-Lom and James T. Cobb, Jr., On-road Light-duty Vehicle Emission Measurements Using a Novel Inexpensive On-board Portable System; presented at the Eighth CRC On-road Vehicle Emissions Workshop, San Diego, California, Apr. 20-22, 1998.
Michal Vojtisek-Lom and James T. Cobb, Jr., Measurement, Variance and Reductio
Clean Air Technologies International, Inc.
Phillips, Lytle, Hitchcock, Blaine & Huber LLP
Wolfe Willis R.
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