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Method and apparatus for quickly evaluating engine exhaust gas emissions

  • US 3,998,095 A
  • Filed: 07/28/1975
  • Issued: 12/21/1976
  • Est. Priority Date: 11/15/1972
  • Status: Expired due to Term
First Claim
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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.

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