Acute angle pressure sensor probe and method

1. A sensor probe located upstream of an exhaust particulate filter and disposed in exhaust gas having carbon particles, the sensor probe comprising:

a probe tip having an exhaust gas inlet opening and a probe centerline;

a pressure tube fluidly connecting the probe tip with a pressure sensor;

wherein a pipe having a pipe centerline is disposable around the probe tip such that said probe tip protrudes into the pipe;

said pipe configured to channel exhaust gases such that said carbon particles included in the exhaust gas have a momentum vector at said exhaust gas inlet opening that is parallel to said pipe centerline;

wherein the pipe centerline and the probe centerline form an acute angle when the pipe is disposed around the probe tip; and

wherein the probe tip points in a downstream direction of the pipe when the pipe is disposed around the probe tip, such that the probe tip is pointed away from the direction of carbon particles traveling along the momentum vector toward the exhaust particulate filter to reduce entry of carbon particles into said exhaust gas inlet opening.

2. The sensor probe of claim 1 , wherein the acute angle is between 30 degrees and 75 degrees.

3. The sensor probe of claim 1 , wherein the pipe is disposed upstream of a diesel engine particulate filter.

4. The sensor probe of claim 1 , wherein the pressure sensor is connected to an electronic engine controller.

5. A sensor system for an internal combustion engine, comprising:

an exhaust pipe having a pipe centerline, an upstream end, and a downstream end;

a differential pressure sensor, having a first probe and a second probe disposed on the exhaust pipe;

a diesel particulate filter disposed in the exhaust pipe between the first probe and the second probe;

wherein the first probe has a first probe tip having a first exhaust gas inlet opening and a first centerline;

wherein the first probe tip is disposed in the exhaust pipe at a first location close to the upstream end of the exhaust pipe;

wherein said exhaust pipe at said first location is configured to channel exhaust gases such that carbon particles included in the exhaust gas have a momentum vector at said first exhaust gas inlet opening that is parallel to said pipe centerline;

wherein the first centerline forms an acute angle with the pipe centerline of the exhaust pipe such that the first tip faces the downstream end of the exhaust pipe, such that the first probe tip is pointed away from the direction of carbon particles traveling along the momentum vector toward the exhaust particulate filter to reduce entry of carbon particles into said first exhaust gas inlet opening.

6. The sensor system of claim 5 ,

wherein the second probe has a second probe tip having a second centerline and a second exhaust gas opening;

wherein the second tip is disposed close to the downstream end of the exhaust pipe at a second location;

wherein the second tip centerline forms an acute angle with the centerline of the exhaust pipe such that the second tip points toward the downstream end of the exhaust pipe, such that the second probe tip is pointed away from the momentum direction of any carbon particles traveling away from the exhaust particulate filter at said second exhaust gas opening to reduce entry of carbon particles into said second exhaust gas opening.

7. The sensor system of claim 5 , wherein the differential pressure sensor includes at least two diaphragms.

8. The sensor system of claim 5 , further comprising an electronic engine controller connected to the differential pressure sensor.