Method of and apparatus for analyzing exhaust gases of motor vehicles

• US 5,105,651 A
• Filed: 07/17/1990
• Issued: 04/21/1992
• Est. Priority Date: 07/18/1989
• Status: Expired due to Fees

• Current Assignee: Gutmann Messtechnik AG (Forvia SE)
• Original Assignee: Gutmann Messtechnik AG (Forvia SE)
• Inventors: Gutmann, Kurt
• Primary Examiner(s): MYRACLE, JERRY
• Application Number:
  US07/554,297
• Time in Patent Office: 644 Days
• Field of Search: 73/23.2, 73/23.31, 73/23.23, 73/117.3, 73/118.1, 73/23.31, 422/98
• US Class Current: 73/23.31
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 2550/02 Catalytic activity of catalytic converters
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: G01M 15/104 using oxygen or lambda-sensors testing catalytic converters F01N3/18, F01N11/007
• CPC Class Codes: G01M 17/007 Wheeled or endless-tracked vehicles G01M17/08 takes precedence
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Exhaust gases of a motor vehicle wherein the exhaust pipe contains a three-way catalytic converter downstream of a lambda sensor are sampled by a standard HC and CO detector downstream of the converter and the corresponding signals are transmitted to a computer which stores reference signals denoting the desired parameters of exhaust gases in a particular vehicle. The computer further receives signals from the lambda sensor, either directly or by way of a separate memory. The latter can be installed in and can be transported by the motor vehicle to memorize signals from the sensor while the vehicle is in motion. The computer compares signals from the memory and signals from the detector with stored reference signals. The testing can be carried out in several stages. For example, a complete test can include a first stage while the engine is still cold and the computer receives signals from the detector, a second stage while the vehicle is in motion and transports the computer and/or the memory, and thereafter a third stage while the engine is hot and the computer receives signals from the detector.

Claims

1. A method of evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust gases pass through an adjustable three-way catalytic converter which is installed downstream of a lambda sensor, comprising the steps of memorizing for a period of at least 2 minutes, particularly for a period of 2-4 minutes, first signals which are transmitted by the sensor while the vehicle is in motion;

sampling the exhaust gases in the exhaust pipe downstream of the catalytic converter and generating second signals denoting the parameters of exhaust gases;

storing reference signals denoting the desired parameters of exhaust gases; and

comparing the stored reference signals with said first signals and said second signals.

2. A method of evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust gases pass through an adjustable three-way catalytic converter which is installed downstream of a lambda sensor, comprising the step of memorizing first signals which are transmitted by the sensor during at least one stage of operation of the vehicle;

sampling the exhaust gases in the exhaust pipe downstream of the catalytic converter and generating second signals denoting the parameters of exhaust gases;

storing reference signals denoting the desired parameters of exhaust gases; and

comparing the stored reference signals with said first signals and said second signals, said sampling step including ascertaining the CO and HC contents of exhaust gases downstream of the catalytic converter and transmitting the corresponding second signals to a computer which stores the reference signals, said comparing step following said step of transmitting said second signals.

3. The method of claim 2 further comprising the step of displaying information denoting the differences between the stored reference signals and the first and/or second signals when such differences are ascertained in the course of said comparing step.

4. A method of evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust gases pass through an adjustable three-way catalytic converter which is installed downstream of a lambda sensor, comprising the steps of memorizing first signals which are transmitted by the sensor during at least one stage of operation of the vehicle;

sampling the exhaust gases in the exhaust pipe downstream of the catalytic converter and generating second signals denoting the parameters of exhaust gases;

storing reference signals denoting the desired parameters of exhaust gases, said storing step including storing the reference signals in a computer which receives first signals from the sensor and second signals after elapse of first and second intervals following starting of a cold engine;

measuring said first and second intervals;

transmitting to the computer additional signals denoting the measured intervals; and

processing the additional signals together with said first and second signals, including comparing the stored reference signals with said first signals and said second signals.

5. A method of evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust gases pass through an adjustable three-way catalytic converter which is installed downstream of a lambda sensor, comprising the steps of memorizing first signals which are transmitted by the sensor during at least one stage of operation of the vehicle, said at least one stage involving idling the engine at approximately 1000 RPM;

sampling the exhaust gases in the exhaust pipe downstream of the catalytic converter and generating second signals denoting the parameters of exhaust gases;

storing reference signals denoting the desired parameters of exhaust gases;

comparing the stored reference signals with said first signals and said second signals;

memorizing, sampling and comparing while the engine is operated under no-load conditions at approximately 3000 RPM; and

utilizing the results of said comparing steps for determination of the efficiency of the catalytic converter.

6. Apparatus for evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust pipe contains an adjustable three-way catalytic converter downstream of a lambda sensor which transmits first signals, comprising a portable memory having input means for first signals;

means for sampling exhaust gases downstream of the catalytic converter and for transmitting second signals denoting predetermined parameters of exhaust gases, said portable memory being designed to be installed in or to be carried by the motor vehicle during sampling of exhaust gases; and

means for storing reference signals denoting the desired parameters of exhaust gases, said storing means having input means for said first and second signals and being operative to compare said reference signals with said first and second signals.

7. The apparatus of claim 6, wherein said storing means comprises a stationary computer and further comprising means for separably connecting said at least one output with the respective input means of said computer.

8. The apparatus of claim 6, further comprising means for establishing a direct electrical connection between said storing means and said sampling means.

9. Apparatus for evaluating and analyzing exhaust gases issuing from the exhaust pipe of a motor vehicle wherein the exhaust pipe contains an adjustable three-way catalytic converter downstream of a lambda sensor which transmits first signals, comprising a memory having input means for first signals;

means for sampling exhaust gases downstream of the catalytic converter and for transmitting second signals denoting predetermined parameters of exhaust gases; and

means for storing reference signals denoting the desired parameters of exhaust gases, said storing means having input means for said first and second signals and being operative to compare said reference signals with said first and second signals, said memory forming part of said storing means and said storing means comprising a portable computer which is designed to be installed in or to be carried by the motor vehicle during evaluation of exhaust gases.