Method and apparatus for quickly evaluating engine exhaust gas emissions
First Claim
1. The method of evaluating engine gas emissions to determine therefrom whether they exceed prescribed permissible air pollution values for CO and HC for different prescribed test modes and whether there is a need for adjustment and/or repair of the engine to reduce air pollution, comprising:
- withdrawing a sample of exhaust gas from the exhaust gas system of the engine;
operating the engine according to a first test mode at a first predetermined high cruise speed of about 1700 to 2200 r.p.m. and under a first predetermined load of about 35 to 60% of the engine'"'"'s maximum torque capability and at which an emission-related malfunction of the engine is likely to occur;
measuring the value of CO and HC in the gas sample at said first predetermined speed and load;
operating the engine according to a second test mode at a second predetermined but different low cruise speed of about 1250 to 1500 r.p.m. and under a second predetermined but different load of about 3.5 to 12% of the engine'"'"'s maximum torque capability and at which an emission-related malfunction of the engine is likely to occur;
measuring the value of the CO and HC in the gas sample at said different speed and load;
operating the engine according to a third test mode at idle speed, and measuring the value of the CO and HC in the gas sample at said idle speed; and
comparing said measured values of CO and HC with the prescribed permissible values of CO and HC for said first, second and third test modes, respectively, to determine which, if any, test values are excessive and thereby indicate the occurrence of a malfunction during a particular mode of engine operation.
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Abstract
Modal test method and apparatus is described for use in automotive engine plants, vehicle inspection stations, diagnostic centers, etc., for quickly, accurately and repeatably measuring the principal air contaminants; i.e., carbon monoxide (CO) and hydrocarbons (HC) in engine exhaust gas emissions. Quantitive measurement of oxides of nitrogen (NOx) and oxygen (O2) may also be measured if desired. While O2 is not an air contaminant, a measure of its concentration in the exhaust gas has diagnostic value. The engines are tested at prescribed modes of operation (usually three; high cruise, low cruise and idle) at which emission-related engine malfunctions, if they exist, are most likely to be exposed. CO and HC (NOx and O2 if desired) evaluations are made at each test mode and may be recorded on a "report card." The measured test values of the air contaminants are compared at each test mode with prescribed permissible values either automatically or manually. For example, the measured values may be recorded on a report card which includes the permissible values. An excessive value of the measured air contaminants for any prescribed mode indicates an emission-related malfunction and warrants rejection. Adjustment or repair to correct malfunctions is facilitated by providing "truth chart" having a reject pattern matching that on the report card and a written statement of the probable defects and the recommended repair guidelines to enable a mechanic to quickly correct the malfunction.
40 Citations
128 Claims
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1. The method of evaluating engine gas emissions to determine therefrom whether they exceed prescribed permissible air pollution values for CO and HC for different prescribed test modes and whether there is a need for adjustment and/or repair of the engine to reduce air pollution, comprising:
- withdrawing a sample of exhaust gas from the exhaust gas system of the engine;
operating the engine according to a first test mode at a first predetermined high cruise speed of about 1700 to 2200 r.p.m. and under a first predetermined load of about 35 to 60% of the engine'"'"'s maximum torque capability and at which an emission-related malfunction of the engine is likely to occur;
measuring the value of CO and HC in the gas sample at said first predetermined speed and load;
operating the engine according to a second test mode at a second predetermined but different low cruise speed of about 1250 to 1500 r.p.m. and under a second predetermined but different load of about 3.5 to 12% of the engine'"'"'s maximum torque capability and at which an emission-related malfunction of the engine is likely to occur;
measuring the value of the CO and HC in the gas sample at said different speed and load;
operating the engine according to a third test mode at idle speed, and measuring the value of the CO and HC in the gas sample at said idle speed; and
comparing said measured values of CO and HC with the prescribed permissible values of CO and HC for said first, second and third test modes, respectively, to determine which, if any, test values are excessive and thereby indicate the occurrence of a malfunction during a particular mode of engine operation.
- withdrawing a sample of exhaust gas from the exhaust gas system of the engine;
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2. The method of evaluating the exhaust gas emissions of an engine in an automotive vehicle to ascertain whether there is need for adjustment and/or repair to reduce air pollution, comprising:
- withdrawing a sample of exhaust gas from the exhaust system of the vehicle;
operating the engine at test KEY MODES corresponding to high cruise, low cruise, and idle, respectively, and in that order;
measuring the value of CO and HC in the exhaust gas sample during each of said test modes;
printing the measured value of the CO and HC for high cruise, low cruise and idle, respectively, in red on a report card having preprinted thereon permissible air pollution values for the high cruise, low cruise and idle test modes of operation, respectively, if the measured value exceeds the corresponding permissible air pollution values of CO and HC preprinted on the report card; and
comparing said measured values of CO and HC with the corresponding prescribed permissible air pollution values for the respective test modes to determine the occurrence of an emission-related malfunction in engine operation at one or more of said test modes, if any.
- withdrawing a sample of exhaust gas from the exhaust system of the vehicle;
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3. The method of evaluating the exhaust gas emissions of an engine in an automotive vehicle to ascertain whether there is need for adjustment and/or repair to reduce air pollution, comprising:
- withdrawing a sample of exhaust gas from the exhaust system of the vehicle;
operating the engine at test KEY MODES corresponding to high cruise, low cruise, and idle, respectively, and in that order;
measuring the value of CO and HC in the exhaust gas sample during each of said test modes;
printing the measured value of the CO and HC for high cruise, low cruise and idle test modes of operation, respectively, on a report card having preprinted thereon permissible air pollution values for high cruise, low cruise and idle test modes of operation, respectively, on said report card, but delaying printing of the measured values of CO and HC on the report card for a prescribed period of time after the start of exhaust gas sampling to enable the values to stabilize before the respective values are printed on the report card; and
comparing said measured values of CO and HC with the corresponding prescribed permissible air pollution values for the respective test modes to determine the occurrence of an emission-related malfunction in engine operation at one or more of said test modes, if any. - View Dependent Claims (4, 5, 6, 7)
- withdrawing a sample of exhaust gas from the exhaust system of the vehicle;
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8. The method of quickly testing an internal combustion engine mounted in an automotive vehicle to ascertain whether there is a need for adjustment or repair to reduce air pollution, comprising:
- positioning the vehicle on a chassis dynamometer with its driven wheels engaged with the rolls of the dynamometer, and wherein one of said rolls is connected with a power absorption unit that automatically applies load on the engine that varies substantially in accordance with changes in the cube of the speed of said one roll, comprising;
withdrawing a sample of exhaust gas from the exhaust system of the vehicle;
operating the engine for a short time interval according to a first KEY MODE wherein a first predetermined load corresponding to a given weight class vehicle is applied to the engine while operating at a first predetermined speed and at which first load and speed, emission-related engine malfunctions are likely to occur;
measuring the value of the CO and HC content of the exhaust gas sample while the engine is operating at said first predetermined load and speed;
operating the engine for another short time interval according to a second KEY MODE wherein a second but different predetermined load corresponding to said given weight class vehicle is applied to the engine while operating at a second but different speed and at which second load and speed emission-related engine malfunctions are likely to occur;
measuring the value of the CO and HC content of the exhaust gas sample while the engine is operating at said second predetermined load and speed;
operating the engine for still another short time interval according to a third KEY MODE wherein the engine is operated at its normal idle speed;
measuring the value of the CO and HC content of the exhaust gas sample at said idle speed; and
comparing said measured values of CO and HC content at said three KEY MODES with prescribed permissible air pollution values for said respective modes to determine whether the measured values exceed said permissible values in any of said test modes and thus reveal malfunctions in the operation of the engine, if any. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
- positioning the vehicle on a chassis dynamometer with its driven wheels engaged with the rolls of the dynamometer, and wherein one of said rolls is connected with a power absorption unit that automatically applies load on the engine that varies substantially in accordance with changes in the cube of the speed of said one roll, comprising;
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16. In an apparatus for evaluating the exhaust emission of an internal combustion engine to detect emission-related malfunctions, the combination which comprises:
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a power absorption unit adapted to be driven by said engine for providing a selectable load to the engine for any given engine speed, an exhaust gas analyzer adapted to be coupled to the engine exhaust for providing a quantative measurement of at least one gas present in the exhaust emissions, load signal generating means for generating a load signal proportional to the load applied to the engine, comparing means coupled to the exhaust gas analyzer and responsive to the load signal for comparing the measured value of said gas with an acceptable value when the engine load falls within a preset range, and output signal generating means coupled to the comparing means for generating an output signal when the measured value of said gas remains below or exceeds said acceptable value. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. In an apparatus for evaluating the exhaust gas emissions of an internal combustion engine mounted in a vehicle chassis at a plurality of prescribed test modes of engine operation with each test mode representing a different engine load, at which malfunctions are likely to be exposed, the combination which comprises:
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a chassis dynamometer having at least one roll to be engaged by the driven wheels of the vehicle, the chassis dynamometer including a power absorption unit connected to the roll to provide a selectable load to the engine, a load signal generator coupled to the dynamometer for providing a measured load signal proportional to the power absorbed by the absorption unit, load comparing means coupled to the load signal generator for comparing the measured load signal with load signals corresponding to a pre-established range for each test mode and for generating a load enabling signal when the absorbed power falls within each of said pre-established load ranges, an exhaust gas analyzer adapted to be coupled to the engine exhaust for providing a quantative measurement of at least two gases present in the exhaust, first gas emission comparing means coupled to the exhaust gas analyzer and responsive to the load enabling signal for comparing the measured values of one of said gases with acceptable values at each of said test modes, second gas emission comparing means coupled to the exhaust gas analyzer and responsive to the load enabling signal for comparing the measured values of said other gas with acceptable values at each of said test modes, and output signal generating means coupled to the first and second gas emission comparing means for providing a separate pass or fail signal for each gas at each of the test modes when the measured value of the gas remains below or exceeds said acceptable values. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88)
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89. In an apparatus for evaluating the exhaust gas emissions of an internal combustion engine mounted in a wheeled vehicle chassis to ascertain whether the emissions are within acceptable air pollution values for CO and HC at different prescribed test modes of engine loading, the combination which comprises:
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a chassis dynamometer having at least one roll to be engaged by the driven wheels of the vehicle, the dynamometer including a power absorption unit connected to the roll to provide a selectable load to the engine; an exhaust gas analyzer adapted to be coupled to the engine exhaust for providing CO and HC signals, each of said CO and HC signals being representative of the quantitive measurement of the CO and HC content in the exhaust emissions; gas signal stabilizing means responsive to the CO and HC signals for producing stabilized CO and HC signals when said signals have remained within a preset range for a given time interval. - View Dependent Claims (90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107)
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108. In an apparatus for evaluating the exhaust gas emissions of an internal combustion engine mounted in wheeled vehicle to ascertain whether the emissions are within acceptable air pollution values for at least two gases at a plurality of different prescribed test modes of engine operation and whether there is need for adjustment or repair of the vehicle to reduce such emissions, the combination which comprises:
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a chassis dynamometer having at least one roll to be engaged by the driven wheels of the vehicle, the dynamometer including a power absorption unit connected to the roll to provide a separate predetermined load to the engine at each test mode; a speed signal generator coupled to the dynamometer for generating a speed signal representative of the vehicle wheel speed; speed comparing means having a measured signal input coupled to the speed signal generator, a reference speed range input, and an output, the speed comparing means being arranged to compare the speed signal with a reference speed range signal and to produce a speed enabling signal in the output when the speed signal remains within the reference speed range for a preset time; an exhaust gas analyzer adapted to be coupled to the engine exhaust for providing at least first and second measured gas signals, each of the first and second measured gas signals being representative of the quantitive measurement of the first and second gases in the exhaust emissions; gas stabilizing means responsive to the first and second measured gas signals for producing stabilized first and second gas signals when the respective measured gas signals have remained within a preset range of values for a given time interval; first gas comparing means having a measured first gas input coupled to the first gas stabilizing means, a first gas reference input, and an output, the first gas comparing means being responsive to the speed enabling signal and arranged to compare the stabilized first gas signal with a first gas reference signal applied to the reference input thereof, and to produce a first gas pass or fail signal when the stabilized first gas signal falls below or exceeds the first gas reference signal; second gas comparing means having a measured second gas input coupled to the second gas stabilizing means, a second gas reference input, and an output, the second gas comparing means being responsive to the speed enabling signal and arranged to compare the stabilized second gas signal with a second gas reference signal applied to the reference input thereof, and to produce a second gas pass or fail signal when the stabilized second gas signal falls below or exceeds the second gas reference signal; and automatic control means for sequentially applying preselected speed reference range signals to the speed reference input of the speed comparing means and preselected first and second gas reference signals to the reference inputs of the first and second gas comparing means to sequentially test the engine at each prescribed test mode of operation. - View Dependent Claims (109, 110, 111, 112, 113, 114)
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115. In an apparatus for evaluating the exhaust gas emissions of an internal combustion engine mounted in wheeled vehicle to ascertain whether the emissions are within acceptable air pollution values for at least one gas at a plurality of different prescribed test modes of engine operation, the combination which comprises:
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a chassis dynamometer having at least one roll to be engaged by the driven wheels of the vehicle, the dynamometer including a power absorption unit connected to the roll to provide a selected load to the engine during at least one test mode; a load signal generator coupled to the dynamometer for generating a load signal representative of the load applied to the vehicle; load comparing means having a measured load input coupled to the load signal generator, a reference load range input, and an output, the load comparing means being arranged to compare measured load signal with a reference load range signal applied to the reference input and to produce a load enabling signal in the output when the measured load signal remains within the reference load range for a preset time; an exhaust gas analyzer adapted to be coupled to the engine exhaust for providing at least one measured gas signal representative of the quantitive measurement of said one gas in the exhaust emissions; gas stabilizing means responsive to the measured gas signal for producing a stabilized gas signal when the measured gas signal has remained within a preset range of values for a given time interval; gas comparing means having a measured gas input coupled to the gas stabilizing means, a gas reference input, and an output, the gas comparing means being responsive to the load enabling signal and arranged to compare the stabilized gas signal with a gas reference signal applied to the reference input thereof, and to produce a gas pass or fail signal when the stabilized gas signal falls below or exceeds the gas reference signal; automatic control means for applying a different gas reference signal to the reference input of the gas comparing means during each of at least two test modes and to apply a selected load reference range signal to the reference input of the load comparing means during one of said test modes to sequentially test the engine at prescribed test modes of operations. - View Dependent Claims (116, 117, 118, 119, 120, 121, 122)
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123. The method of evaluating the operability of a TSAD NOx control device installed on a motor vehicle comprising:
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operating the engine at a selected load greater than idle; measuring the value of NOx in the exhaust at said selected engine load with the transmission gear in the highest and next lower gear; and comparing said measured values of NOx to determine whether the value of NOx in the lower gear has decreased below a preset fraction of the value of NOx in the highest gear.
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124. The method of evaluating the operability of a SAD NOx control device installed on a motor vehicle having ignition timing regulating means connected to the engine vacuum source by a vacuum line comprising:
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operating the engine at a selected load greater than idle; measuring the value of NOx in the exhaust with the SAD control device connected and disconnected at said selected engine load; measuring the rate of vacuum rise in the vacuum line normally connected to the regulating means; comparing the measured values of NOx with the SAD control device connected and disconnected to determine whether the value of NOx with the SAD control device disconnected exceeds a preset fraction of the measured value of NOx with the SAD control device connected; and comparing the rate of vacuum rise with a preset limit.
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125. The method of evaluating the operability of an EGR NOx control device installed in a motor vehicle, comprising:
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operating the engine at a selected load above idle; measuring the value of NOx in the exhaust with the ERG control device connected and disconnected at said selected load; and comparing the measured values of NOx to determine whether the value of NOx with the EGR control device disconnected has increased a preset percentage above the value of NOx with the EGR control device connected.
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126. The method of evaluating the operability of an SSAD NOx control device installed on a motor vehicle, the SSAD control device including an ignition timing regulating means connected to the engine vacuum source by a vacuum line, comprising:
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operating the engine at a selected load above idle; measuring the speed of the vehicle; monitoring the presence or absence of vacuum in said vacuum line when the vehicle speed has reached a first preset limit to determine whether the SSAD control device is operative at said speed; increasing the vehicle speed until a vacuum is present in said vacuum line or until a second preset speed is reached; measuring the value of NOx in the vehicle exhaust at a vehicle speed when vacuum is first detected in said vacuum line with the SSAD control device operative and inoperative; and comparing the measured values of NOx with the SSAD control device operative and inoperative to determine whether the value of NOx decreased a preset percentage after the SSAD control device was rendered operative.
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127. The method of evaluating the integrity of the exhaust system of a motor vehicle, comprising:
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operating the engine of the motor vehicle; measuring the value of CO in the vehicle exhaust; comparing the measured value of CO with a preset limit to determine whether the engine is operating richer or leaner than stoichiometric; pressurizing the exhaust system when the measured value of O2 exceeds the respective first or second preset limits; and comparing the measured values of O2 before and after pressurization of the exhaust system to determine whether the value of O2 after pressurization has decreased by a predetermined percentage from the value of O2 before pressurization to thereby ascertain whether air is leaking into the exhaust system when the system is not pressurized. - View Dependent Claims (128)
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Specification