BACKGROUND AND SUMMARY OF THE INVENTION

The invention concerns an interior ventilation system for a motor vehicle for measuring ambient air and internal air of the vehicle.

A system and a method for the control of odors and/or harmful substances in the interior of the vehicle are known from DE 102 54 496 A1. The system described in this document has some sensors for detecting harmful substances in the interior of the vehicle and in the surroundings of a vehicle.

Such interior ventilation systems are relatively expensive, including owing to the number of sensors required.

It is the object of the invention to provide an interior ventilation system for detecting harmful substances that can be provided less expensively.

This and other objects are achieved with an interior ventilation system according to embodiments of the invention.

According to an exemplary embodiment of the invention, an interior ventilation system for a motor vehicle is provided with an air measurement chamber, into which ambient (outdoor) air of the motor vehicle is delivered via an external air feed line and internal air of the motor vehicle is delivered via an internal air feed line, air quality sensors for measuring a harmful substance content in air located in the air measurement chamber, and a measurement air control device that is adapted to supply the air measurement chamber selectively with ambient air and internal air.

All air quality sensors that are disposed in the air measurement chamber are disposed to be accessible both to the ambient air and to the internal air. This means that owing to the arrangement within a related, bounded spatial volume, each individual air quality sensor that is disposed in the air measurement chamber is accessible both to the ambient air and to the internal air. The exemplary embodiment has the advantage that combined sensors, for example in the form of a combined air quality sensor module, can be purchased less expensively than purchasing all air quality sensors individually. Further, only a single installation space is required and thus only a single ground connection, a single current connection and a single cable loom connection or bus connection, which reduces the cost of assembly. The exemplary embodiment enables all relevant air quality values to be measured centrally.

According to a further exemplary embodiment of the invention, the interior ventilation system includes a PM sensor for measuring a fine dust content in the ambient air, a NOxsensor for measuring a NOxcontent in the ambient air, and a CO sensor for measuring a CO content in the ambient air. The most important air quality values in the ambient air are thereby covered.

According to a further exemplary embodiment of the invention, the interior ventilation system is further provided with an air guidance device that, depending on the setting, takes air for the ventilation of the internal space of the motor vehicle at least predominantly from the surroundings of a vehicle or the interior of the vehicle or stops ventilation of the internal space, and a control device that controls the air guidance device depending on the measurement results of the air quality sensors.

According to a further exemplary embodiment of the invention, the air quality sensors include a CO2sensor for measuring a CO2content in the internal air, and the control device is adapted, on exceeding a limit value for the CO2content, to control the air guidance device so that the air for the ventilation of the internal space is at least predominantly taken from outside of the vehicle. This has the advantage that in air conditioning systems that use CO2as the coolant, the CO2sensor can be used as a safety-relevant sensor that can detect a leak in the coolant circuit. Further, an excessive CO2content in the internal air could result in driver fatigue. This could be avoided by detection and delivering fresh air.

According to a further exemplary embodiment of the invention, the control device is adapted, on exceeding at least one limit value for the fine dust content, NOxcontent or CO content, to control the air guidance device so that the air for the ventilation of the internal space is at least predominantly taken from the interior of the vehicle or an air feed is inhibited if the limit value for the CO2content is exceeded or a screen detector signals a fogged windshield. Thus, safety-relevant aspects are prioritized during ventilation of the internal space.

According to a further exemplary embodiment of the invention, the air measurement chamber is embodied in a housing to which the air quality sensors are attached, wherein the housing has a single interface for connecting to a vehicle bus. This reduces the costs of assembly and cabling.

According to a further exemplary embodiment, the measurement air control device only switches the air quality sensors that are provided for measuring the ambient air to be active if the air measurement chamber is supplied with ambient air, and only switches the air quality sensors that are provided for measuring the internal air to be active if the air measurement chamber is supplied with internal air. Thus, the sensors are only activated when required, which can save energy.

According to a further exemplary embodiment of the invention, the measurement air control device is adapted for controlling air flow control elements that selectively feed air via the external air feed line or the internal air feed line, wherein the air flow control elements include a fan, a pump and/or vacuum generation device.

According to a further exemplary embodiment of the invention, the air quality sensors include a VOC sensor for measuring a content of volatile hydrocarbons in the internal air, and the control device is adapted, on exceeding a limit value for the VOC content, to control the air guidance device so that the air for the ventilation of the internal space is at least predominantly taken from outside of the vehicle.

Moreover, the invention provides a motor vehicle with an interior ventilation system according to any one of the above exemplary embodiments.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

