Exhaust gas recirculation system module with integral vacuum

A system module is provided for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine. The module includes a body (12) including a passageway (41) between an exhaust gas inlet (32) and an exhaust gas outlet (34). An orifice (36) constricts the flow of exhaust gases proximate the exhaust gas outlet. A differential pressure sensor (38) is constructed and arranged to sense differential pressure across the orifice. A manifold absolute pressure sensor (42) is constructed and arranged to sense vacuum pressure associated with the exhaust gas outlet. A first hose (40) is coupled with the body and provides the differential pressure sensor with vacuum pressure on a first side of the orifice. A second hose (44) is coupled with the body and provides the manifold pressure sensor with vacuum pressure. The first and second hoses are integral with the system module.

FIELD OF THE INVENTION

This invention relates to vehicle Exhaust Gas Recirculation (EGR) valves and an EGR System Module (ESM) that includes an EGR valve and, more particularly, to an ESM that eliminates the need for external vacuum supply lines and vacuum connections.

BACKGROUND OF THE INVENTION

The ESM is a vacuum actuated EGR system that obtains engine vacuum from a dedicated vacuum harness linking the intake manifold vacuum port to a vacuum supply port on the ESM. Conventional vacuum driven applications obtain source vacuum from the intake manifold pick-of-port and link to a device through conventional vacuum harness technology. Two connections to the intake vacuum port are required with the conventional configuration, one dedicated line for manifold absolute pressure (MAP) and one for an EGR vacuum regulator (EVR).

The conventional ESM system has field issues including vacuum harness damage, connection integrity, part robustness, system cost and ease of assembly. These issue are influencing ESM customers to investigate/source competing electric/solenoid driven EGR systems that do not require vacuum to operate.

Thus, there is a need to provide a robust and cost-effective ESM.

SUMMARY OF THE INVENTION

An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is obtained by providing a system module for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine. The module includes a body including a passageway between an exhaust gas inlet and an exhaust gas outlet. An orifice constricts the flow of exhaust gases proximate the exhaust gas outlet. A differential pressure sensor is constructed and arranged to sense differential pressure across the orifice. A manifold absolute pressure sensor is constructed and arranged to sense vacuum pressure associated with the exhaust gas outlet. A first hose is coupled with the body and provides the differential pressure sensor with vacuum pressure on a first side of the orifice. A second hose is coupled with the body and provides the manifold pressure sensor with vacuum pressure. The first and second hoses are integral with the system module.

In accordance with another aspect of the invention, a system module for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine includes a body having a passageway between an exhaust gas inlet and an exhaust gas outlet. First means are provided for sensing differential pressure across an orifice associated with the body. Second means are provided for sensing manifold absolute pressure associated with the exhaust gas outlet. Means, directly coupled with the body, provide the first means with vacuum pressure on a first side of the orifice. Means, directly coupled with the body, provide the second means with vacuum pressure.

In accordance with yet another aspect of the invention, a method is provided for supplying a differential pressure sensor and a manifold absolute pressure sensor of an exhaust gas recirculation system module with vacuum pressure. The method provides a differential pressure sensor and a manifold absolute pressure sensor of an exhaust gas recirculation system module. The differential pressure sensor is supplied with vacuum pressure with a first hose. The manifold absolute pressure sensor is supplied with vacuum pressure with a dedicated second hose. The first and second hoses are integral with the system module.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Referring toFIG. 1, an ESM, generally indicated at10, comprises an EGR valve body12, a fluid-pressure-operated actuator24, an electric-operated vacuum regulator (EVR) valve26, and a sensor structure28that provides an electric signal related to the magnitude of sensed vacuum. The EVR valve26and the sensor structure28are in fluid communication via connection30. The construction, operation, and interrelationship of these features are more particularly described in U.S. Pat. No. 6,502,564 B1, the content of which is hereby incorporated by reference into this specification.

Examples of EVR valves that may be used are disclosed in commonly assigned U.S. Pat. No. 5,448,981 to Cook et al. and U.S. Pat. No. 5,967,172 to Cook, which are incorporated herein in their entirety by reference.

The EGR valve body12includes an exhaust gas inlet32, which is adapted to be connected to an exhaust gas supply (not shown), and an exhaust gas outlet34, which is adapted to be connected to an intake manifold (not shown). A conventional valve35in passageway41regulates the flow of exhaust gas from the inlet32to the outlet34. A gasket orifice36is preferably located at the exhaust gas outlet34to develop a pressure differential on either side of the gasket orifice36and to provide a seal for the connection to the EGR valve body12. Specifically, the gasket orifice36can be formed as a thin gasket that seals the EGR valve body12onto the intake manifold (not shown). The gasket orifice36can be made of stainless steel, which provides dimensional stability at high temperatures. Of course, other materials exhibiting similar properties can be used.

The sensor structure28includes a Differential Pressure (DP) sensor38that measures the pressures on either side of the gasket orifice36. An internal passage of end39of hose40extends within a passage41the EGR valve body12and provides the DP sensor38with the pressure signal from the upstream side, i.e., exhaust manifold side, of the gasket orifice36. Thus, end39is coupled directly with the valve body12and the end43of hose40is associated with the sensor structure28(FIG. 3). The hose40is considered to be integral with the system module10. The DP sensor38can be connected directly to the intake manifold (not shown) on the downstream side of the gasket orifice36. The DP sensor60continually computes a differential pressure value on either side of the gasket orifice36and provides this data to an ECU (not shown), which uses this data to compute an EVR control signal.

In the embodiment, the DP sensor28and the EVR valve26share hose40that provides a source of vacuum. The DP output is not used when the solenoid of the EVR valve26is in an un-energized state where the max flow condition occurs, thus, it has no effect on the DP output. As the energy of the solenoid of the EVR valve26is increased, flow through this hose40is reduced and any offset detected can be compensated through sensor electronics, thus providing a transparent replacement for a conventional product.

With reference toFIG. 3, the sensor structure28of the ESM10also includes a manifold absolute pressure (MAP) sensor42to measure the intake vacuum (pressure at outlet34). In the embodiment, the MAP sensor42requires a dedicated vacuum source from a dead headed hose44to provide an accurate pressure reading without corruption. One end46of the hose44is associated with the sensor structure28and thus sensor42and the other end48of the hose44is directly connected with the pick-off port on the EGR valve body12.

Thus, since the hose44is integral to the ESM10, the need for external vacuum supply lines and vacuum connections is eliminated. Furthermore, the integral hose44reduces customer system costs through the elimination of the vacuum harness, assembly plant installation and production test/certification costs. The configuration of the ESM10provides a self-contained vacuum EGR system module with only one electrical connection required to operate, which is similar to conventional electric/solenoid driven EGR systems.