System for controlling exhaust emissions produced by an internal combustion engine
First Claim
1. System for controlling exhaust emissions produced by an internal combustion engine, the system comprising:
- an engine speed sensor sensing a rotational speed of an internal combustion engine and producing a speed signal corresponding thereto;
means for determining an altitude of said engine and producing an altitude value corresponding thereto;
means for determining an ambient temperature external to said engine and producing a temperature value corresponding thereto;
means for determining an output torque produced by said engine and producing a torque value corresponding thereto; and
a control computer determining a maximum allowable emission level as a function of said speed signal, said altitude value, said temperature value and said torque value, said computer controlling an air handling system of said engine as a function of said maximum allowable emission level such that exhaust emissions produced by said engine are limited to said maximum allowable emission level.
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Accused Products
Abstract
A system for controlling exhaust emissions produced by an internal combustion engine includes an engine controller having an emission manager configured to produce a base emission level cap command, corresponding to a maximum allowable emission level of the engine, as a function of at least altitude and ambient temperature. The emission manager may also include one or more auxiliary emission control devices (AECDs), and the emission manager is further operable in such cases to determine a maximum allowable emission level associated with each active AECD. A final emission level cap command is determined as a function of the base emission level cap command and the maximum allowable emission level associated with each active AECD. The emission manager is further operable to produce a protection state data structure that includes information relating to the operational status of each AECD.
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Citations
15 Claims
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1. System for controlling exhaust emissions produced by an internal combustion engine, the system comprising:
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an engine speed sensor sensing a rotational speed of an internal combustion engine and producing a speed signal corresponding thereto;
means for determining an altitude of said engine and producing an altitude value corresponding thereto;
means for determining an ambient temperature external to said engine and producing a temperature value corresponding thereto;
means for determining an output torque produced by said engine and producing a torque value corresponding thereto; and
a control computer determining a maximum allowable emission level as a function of said speed signal, said altitude value, said temperature value and said torque value, said computer controlling an air handling system of said engine as a function of said maximum allowable emission level such that exhaust emissions produced by said engine are limited to said maximum allowable emission level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
means for determining a first engine operating parameter different from said rotational speed of said engine, said altitude of said engine, said ambient temperature external to said engine and said output torque produced by said engine, and producing a first operating parameter value corresponding thereto; and
a first auxiliary emission control device (AECD) producing a first auxiliary emission level as a function of at least one of any of said engine speed signal, said altitude value, said temperature value, said torque value and said first operating parameter value;
wherein said control computer is operable to determine said maximum allowable emission level as a function of said engine speed signal, said altitude value, said temperature value, said torque value and said first auxiliary emission level.
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3. The system of claim 2 wherein said control computer is operable to determine a reference emission level as a function of said engine speed signal, said altitude value, said temperature value and said torque value, said control computer determining said maximum allowable emission level as a maximum of said reference emission level and said first auxiliary emission level.
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4. The system of claim 3 wherein said control computer includes:
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means responsive to said altitude value and said temperature value for determining an emission level cap value;
means responsive to said engine speed signal and said torque value for determining a ratio value; and
means for determining said reference emission level as a product of said emission level cap value and said ratio value.
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5. The system of claim 1 further including:
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a plurality of means for determining a corresponding plurality of engine operating parameters each different from said rotational speed of said engine, said altitude of said engine, said ambient temperature external to said engine and said output torque produced by said engine, and producing a plurality of operating parameter values corresponding thereto; and
a number of auxiliary emission control devices (AECDs) producing a corresponding number of independent auxiliary emission levels each as a function of at least one of any of said engine speed signal, said altitude value, said temperature value, said torque value and said plurality of operating parameter values;
wherein said control computer is operable to determine a reference emission level as a function of said engine speed signal, said altitude value, said temperature value and said torque value, said control computer determining said maximum allowable emission level as a maximum of said reference emission level and said number of auxiliary emission levels.
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6. The system of claim 5 further including an engine compression brake coupled to said engine;
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wherein said means for determining an output torque of said engine includes;
means for determining a retarding torque produced by said engine; and
means for producing said retarding torque as said torque value when said engine compression brake is operational and for producing a commanded engine output torque value as said torque value when said engine compression brake is not operational.
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7. The system of claim 6 wherein said means for determining an output torque of said engine further includes:
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means responsive to said engine speed signal for determining a first resistance torque attributable to operation of a cooling fan driven by said engine; and
means for producing a motor torque value by subtracting said first resistance torque from said torque value, said motor torque value corresponding to one of said plurality of operating parameter values.
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8. The system of claim 7 wherein said means for determining an output torque of said engine further includes means responsive to said engine speed signal for determining a second resistance torque attributable to operation of at least one accessory driven by said engine;
and wherein said means for producing a motor torque value is operable to produce said motor torque value by subtracting a sum of said first and second resistance torques from said torque value.
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9. The system of claim 6 wherein said control computer includes:
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means responsive to said altitude value and said temperature value for determining an emission level cap value;
means responsive to said engine speed signal and said torque value for determining a ratio value; and
means for determining said reference emission level as a product of said emission level cap value and said ratio value.
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10. The system of claim 5 further including a memory coupled to said control computer;
and wherein said control computer is operable to determine an enable value as a function of said engine speed signal and said torque value, said control computer storing in said memory a rolling average of said maximum allowable emission level over a predefined time interval when said enable value is active.
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11. The system of claim 10 wherein said control computer is operable to produce an active enable value when said engine speed signal is greater than an engine speed threshold and said torque value is greater than a torque threshold, said control computer otherwise producing an inactive enable value.
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12. The system of claim 11 further including means for determining an NOx value indicative of NOx content of exhaust gas produced by said engine;
and wherein said control computer is operable to store in said memory a rolling average of said NOx value over said predefined time interval when said enable value is active.
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13. The system of claim 1 wherein said control computer includes:
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means responsive to said altitude value and said temperature value for determining an emission level cap value;
means responsive to said engine speed signal and said torque value for determining a ratio value; and
means for determining said maximum allowable emission level as a product of said emission level cap value and said ratio value.
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14. A method of controlling exhaust emissions produced by an internal combustion engine, the method comprising:
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determining a rotational speed of an internal combustion engine;
determining an altitude of said engine;
determining an ambient temperature external to said engine;
determining an output torque produced by said engine;
determining a maximum allowable emission level as a function of said rotational speed, said altitude, said ambient temperature and said output torque; and
controlling an air handling system of said engine as a function of said maximum allowable emission level such that exhaust emissions produced by said engine are limited to said maximum allowable emission level. - View Dependent Claims (15)
determining a plurality of operating parameters each corresponding to a different operating condition of said engine and each different from said rotational speed, said altitude, said ambient temperature and said output torque; and
determining a number of auxiliary emission levels each corresponding to a different auxiliary emission control device (AECD) and each as a function of at least one of any of said rotational speed, said altitude, said ambient temperature, said output torque and said plurality of operating parameters;
and wherein the step of determining a maximum allowable emission level includes determining a reference emission level as a function of said rotational speed, said altitude, said ambient temperature and said output torque, and determining said maximum allowable emission level as a maximum one of said reference emission level and said number of auxiliary emission levels.
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Specification