VENTILATION SYSTEM

Abstract

The present invention relates to a ventilation system 24 for a land vehicle 10. The ventilation system 24 comprises an inlet duct 26 for allowing exterior air to enter a cabin of the vehicle. The inlet duct 26 has a source port 38 located at an exterior of the vehicle 10 and the inlet duct 26 also has an exhaust port 40 located within a cabin of the vehicle 10. The ventilation system 24 has an outlet duct 28 for allowing interior air to exit the cabin of the vehicle 10. The outlet duct 28 has a source port 44 located within the cabin of the vehicle 10 and the outlet duct 28 also has an exhaust port 46 located at an exterior of the vehicle. The ventilation system 24 has an air propulsion element to cause selectively an airflow between the cabin interior and the vehicle exterior; wherein the source port 38 of the inlet duct 26 and the exhaust port 46 of the outlet duct 28 are collocated in a zone of substantially equivalent dynamic pressure, in-use.

Claims

1. A ventilation system for a land vehicle, the ventilation system comprising: an inlet duct for allowing exterior air to enter a cabin of the vehicle, the inlet duct having a source port located at an exterior of the vehicle and the inlet duct also having an exhaust port located within the cabin of the vehicle; an outlet duct for allowing interior air to exit the cabin of the vehicle, the outlet duct having a source port located within the cabin of the vehicle and the outlet duct also having an exhaust port located at an exterior of the vehicle; and an air propulsion element arranged to selectively cause an airflow between the cabin interior and the vehicle exterior, wherein the inlet duct and the outlet duct share a common structural interface to divide the inlet duct from the outlet duct, and wherein the inlet duct and outlet duct are arranged one inside the other; and wherein the source port of the inlet duct and the exhaust port of the outlet duct are collocated in a zone of substantially equivalent dynamic pressure, in-use.

2. (canceled)

3. The ventilation system of claim 1, wherein the common structural interface comprises a heat exchange feature.

4. The ventilation system of claim 3, wherein the heat exchange feature comprises one or more of the following: fins, ribs, pins, dimples and grooves.

5. The ventilation system of claim 1, wherein the inlet duct and the outlet duct comprise concentrically arranged pipes.

6. The ventilation system of claim 1, wherein the inlet duct and the outlet duct are formed as eccentrically arranged pipes.

7. The ventilation system of claim 1, wherein the outlet duct forms an interior pipe and the inlet duct forms an exterior pipe.

8. The ventilation system of claim 1, wherein the air propulsion element comprises a variable speed fan.

9. The ventilation system of claim 1, wherein the inlet and outlet ducts are continuous, door-less, ducts arranged aside from the air propulsion element.

10. The ventilation system of claim 1, further comprising at least one interior environment parameter sensor arranged to monitor an environment parameter within the cabin interior.

11. The ventilation system of claim 10, further comprising a control module arranged to configure the air propulsion element to induce a flow of air between the vehicle exterior and the cabin interior based upon a level of the environment parameter measured within the cabin, wherein the flow of air is being arranged to maintain the level of the environment parameter within the cabin to within a predefined limit.

12. The ventilation system of claim 11, further comprising at least one complimentary exterior environment parameter sensor at the vehicle exterior to monitor the same environment parameter as monitored by the at least one interior environment parameter sensor.

13. The ventilation system of claim 12, wherein the control module is arranged to configure the air propulsion element to induce an air flow between the vehicle exterior and the cabin interior based upon a level of the environment parameter at the exterior of the vehicle.

14. The ventilation system of claim 10, wherein the environment parameter is CO.sub.2.

15. The ventilation system of claim 10, wherein the environment parameter is humidity.

16. A land vehicle defining a vehicle exterior having a plurality of dynamic pressure zones in-use, the vehicle comprising a cabin defining a vehicle interior, and wherein the vehicle comprises the ventilation system of claim 1.

17-18. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0041] FIG. 1 shows a schematic of a ventilation system according to an embodiment of the present invention;

[0042] FIG. 2 shows a cross sectional view of an inlet and outlet duct shown in FIG. 1; and

[0043] FIG. 3 shows a land vehicle according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0044] With reference to FIG. 1 and FIG. 3, a vehicle 10 includes a body supporting a plurality of doors and windows (not shown). The vehicle defines a vehicle exterior 12 and a cabin interior 14 since the body of the vehicle is substantially hermetically sealed unless the doors and/or windows are open. When the vehicle 10 is stationary, the exterior of the vehicle 12 is at a substantially constant pressure. This of course is subject to factors such as local wind speeds and temperature variations around the vehicle 10. However, to all intents and purposes the pressure around the vehicle exterior 12 is substantially constant.

[0045] During motion of the vehicle 10, pressure variations exist around an exterior surface of the vehicle 10. These changes in pressure are due to dynamic effects. For instance, local air velocities around the exterior surface of a vehicle 10 change due to differences in shape and contours thereof. An increase in local velocity can result in a decrease in local pressure. A decrease in velocity can result in an increase in local pressure. Other effects such as ram-air also have an impact on the pressure at the exterior surface of vehicle 10, again causing local changes and variations in pressure.

[0046] Broadly speaking, the vehicle can be imagined as having a plurality of dynamic pressure zones where the pressure across a particular zone is substantially constant. The pressure across the front of the vehicle 10 is substantially constant and at a higher pressure than experienced at the rear of the vehicle 10, which is also a zone of substantially constant dynamic pressure. In addition, a top side of the vehicle 10 may have substantially constant pressure thereacross, which would be at a different pressure to an underside of the vehicle 10. In this way, the vehicle exterior 12 can be imagined as having a front pressure zone 16, a rear pressure zone 18, an upper pressure zone 20, and a lower pressure zone 22. As described above, these zones 16-22 may experience different dynamic pressures to one another during motion of the vehicle.

[0047] The vehicle 10 includes a ventilation system 24. The ventilation system 24 includes an inlet duct 26, an outlet duct 28, an air propulsion element 30, an interior environment parameter sensor 32, an exterior environment parameter sensor 34, and a control module 36.

[0048] The inlet duct 26 is a pipe. The inlet duct 26 includes a source port 38, and an exhaust port 40. The source port 38 and the exhaust port 40 are formed from pipe ends. The source port 38 is located in the front pressure zone 16. The exhaust port 40 of the inlet duct 26 is located within the cabin interior 14. The inlet duct 26 allows exterior air 42 to enter the cabin interior 14.

[0049] The outlet duct 28 is formed from an elbow pipe. One elongated section of the pipe is concentrically arranged with the pipe forming the inlet duct 26. In this way, the outlet duct 28 forms an interior pipe and the in inlet duct 26 forms an exterior pipe. The pipes may be arranged in different ways such as an eccentric arrangement for flow distribution reasons, if desired. However, for the concentric arrangement, a transverse section of the elbow pipe protrudes through a passage provided at a wall of the inlet duct 26. The transverse portion of the pipe terminates at a source port 44 located within the cabin interior 14. The other section of the pipe terminates at an exhaust port 46 located in the front pressure zone 16 at the vehicle exterior 12. The source port 44 and the exhaust port 46 are formed as pipe ends.

[0050] The source port 38 of the inlet duct 26 and the exhaust port 46 of the outlet duct 28 are thus collocated in a zone of substantially equivalent dynamic pressure, namely the front dynamic pressure zone 16. These ports may be collocated at the front zone 16 as opposed to the rear zone 18 since the vehicle 10 has an engine exhaust (not shown) located at the rear of the vehicle 10. This should minimise the risk of engine pollutants entering the cabin interior 14. Alternatively, in the case of an electric vehicle the ports may be collocated at either the front 16 or rear 18 pressure zone.

[0051] With reference to FIG. 2, a cross sectional view of the concentrically arranged inlet and outlet duct, 26 and 28 respectively, is shown. Arranged across a common structural interface, which joins the inlet and outlet duct, are one or more heat exchange features, in the form of fins 54. The fins 54 increase the surface area of the common structural interface in order to conduct a larger amount of thermal energy from one air flow to the other.

[0052] With further reference to FIG. 1, the air propulsion element 30 comprises a variable speed fan 50. The fan 50 is located within the inlet duct 26. The fan 50 is arranged to draw exterior air 42 in to the cabin interior 14. Alternatively the variable speed fan 50 may be arranged to push interior air 48 from the cabin interior 14, to the exterior of the vehicle 12; and/or be located within the outlet duct.

[0053] The fan 50 is the only obstruction within the inlet and outlet ducts 26, 28, since each duct 26, 28 is door-less. The fan 50 is driven by a motor 52. The revolutions per minute (RPM) of the motor 52 is controlled by the control module 36. A high motor speed results in a high rotational speed of the fan 50. A low motor speed results in a low rotational speed of the fan 50. Fan speed is proportional to the flow of air being induced in to the cabin interior 14 from the vehicle exterior 12.

[0054] The interior environment parameter sensor 32 is arranged to monitor an environment parameter within the cabin interior 14. The environment parameter is a parameter of the air 14. The parameters of particular interest are CO2 and humidity. The interior environment parameter sensor 32 can thus either be a CO2 sensor, a humidity sensor, or a combination of the two.

[0055] The CO.sub.2 sensor is a non-dispersive infrared (NDIR) sensor. The NDIR sensor is a spectroscopic sensor. The spectroscopic sensor detects CO.sub.2 in a gaseous environment, in this case the cabin interior 14, by the characteristic absorption of the gas (cabin air 48) which the NDIR sensor acts upon.

[0056] The humidity sensor is a hygrometer. The hygrometer measures moisture content of the cabin air 48 indirectly by monitoring temperature of the dew point. An alternative hygrometer can be implemented which monitors changes in electrical capacitance or resistance in order to measure humidity differences. The exterior environment parameter sensor 34 is a complementary environment parameter sensor in that it may measure the same environment parameter as the interior environment parameter sensor 32. The exterior environment parameter sensor is located at the vehicle exterior 12. It is advantageous to use the same type of sensor for measuring each respective environment parameter, for instance, the CO.sub.2 sensors at the interior and exterior of the vehicle are both NDIR sensors.

[0057] The interior and exterior environment parameter sensors 32, 34 are both connected to the control module 36. The control module 36 is provided as electronic data stored on a memory component of a computer of the vehicle 10. The memory component is a non-volatile memory component. The computer also includes a processor arranged to execute the electronic data of the control module 36, in use. Output of the control module 36 configures the motor 52 to control the speed of the fan 50.

[0058] The control module 36 includes a look-up table, which associates sensed environment parameter levels with rotational fan speeds. In this way, a sensed environment parameter level at the cabin interior 14 may be associated to a rotational speed of the fan 50 to induce a predetermined flow of air from the cabin exterior 12 to the cabin interior 14. In this way, the control module 36 is arranged to configure the fan 50 to induce an air flow between the vehicle exterior 12 and the cabin interior 14 based upon the environment parameter measured within the cabin. In addition, the control module 36 uses the reading from the exterior parameter sensor 34 in the same way such that the rotational speed of the fan 50 is a function of the environment parameter sensed both at the vehicle interior 14 and the vehicle exterior 16.

[0059] The level of each environment parameter within the cabin interior 14 is arranged to be kept within a predefined limit, and in certain cases within predefined limits. For CO.sub.2 these predefined limits are between about 500 ppm and about 1500 ppm CO.sub.2. For humidity levels, the predefined limits are between about 20% and about 40%.

[0060] In operation, the vehicle 10 moves through the exterior air 42 during travel. Movement of the vehicle 10 creates the different pressure zones around the vehicle exterior 12. In particular, the front pressure zone 16 is created which is a zone of relatively high dynamic pressure. In addition, the rear pressure zone 18 is created which is a zone of relatively low dynamic pressure. Since the source port 38 of the inlet duct 26 and the exhaust port 46 of the outlet duct 28 are collocated in a zone of substantially equivalent dynamic pressure, there is minimal passive air flowing through the ventilation system 24. Interior air 48 is recirculated within the cabin interior 14 for air conditioning purposes. The CO.sub.2 sensor and/or the humidity sensor 32 continuously measure the CO.sub.2 and humidity levels within the cabin interior 14. Provided those levels are within the aforementioned predefined limits, as determined by the control module 36, the control module 36 causes no motion of the fan 50.

[0061] Since the cabin interior 14 is substantially hermetically sealed from the vehicle exterior 12, CO.sub.2 and humidity levels progressively increase over time as a result of the vehicle 10 being occupied by passengers. When these levels rise above the aforementioned predefined limits, the control module 36 configures the motor 52 to command the fan 50 to rotate at a particular rotational speed in order to provide flow of air from the vehicle exterior 12 to the vehicle interior 14. The flow of air provided by the fan 50 is proportional to the speed of rotation of the fan, thus as the control module 36 commands a change in the speed of the motor 52, the control module 36 controls the air flow into the interior 14 of the vehicle. The control module 36 may be arranged to command a sudden and significant change in the speed of the motor 52, for example a step-change from 20% to 80% fan speed, in order to effect a rapid adjustment to the environment of the vehicle cabin interior 14 at the expense of electrical load from the motor 52 and noise from the fan 50. This may be particularly useful if one or more environmental parameters of the vehicle interior 14 is/are significantly outside of predetermined limits. Additionally or alternatively, the control module 36 may adopt an approach to gradually adjust the fan speed, for example a more linear ramp-up or ramp-down, if one or more environmental parameters of the vehicle interior 14 is/are only slightly outside of predetermined limits, or if energy consumed by the fan motor 52 has a higher priority and/or if the vehicle occupants are particularly sensitive to the noise the motor 52 generates when operating at higher speeds.

[0062] Exterior air 42 flowing into the cabin interior 14 through the inlet duct 26 results in an equivalent volume of interior air 48 being exhausted out through the outlet duct 28 to the vehicle exterior 12. Provided the CO.sub.2 levels are higher within the cabin 14 than at the vehicle exterior 12, CO.sub.2 levels will reduce. The same is true of the humidity levels. When the CO.sub.2 and/or humidity levels revert back to within the predefined limits, as determined by the control module 36, the control module 36 configures the motor 52 to stop rotation of the fan 50.

[0063] Some environments, for example some major cities around the World, have relatively high levels of humidity and/or CO.sub.2. The complementary exterior sensor 34 measures the exterior air 42 in order to monitor these parameters. It may be the case that the exterior air 42 has non ideal levels of CO.sub.2 and/or humidity, as well as other pollutants. In this case, transferring exterior air 42 to the cabin interior 12 may be detrimental to the cabin environment and occupant comfort. Accordingly, in such circumstances the control module 36 may be configured to configure the motor 52 to keep the fan 50 stationary. The complementary exterior sensor 34 is thus connected to the control module 36 such that the control module 36 may configure the fan 50 to induce an air flow through the ventilation system 24 taking into account both the CO.sub.2 and/or humidity levels within the cabin interior 14 and the vehicle exterior 12.

[0064] In a further embodiment, the interior environment parameter sensor 32 is arranged to monitor an environment parameter within the cabin interior 14. The interior environment parameter sensor 32 can either be a CO.sub.2 sensor, a humidity sensor, or a combination of the two.

[0065] The exterior environment parameter sensor 34 comprises a complementary environment parameter sensor and a supplementary environmental parameter sensor.

[0066] The complementary environment parameter sensor measures the same environment parameter as the interior environment parameter sensor 32. The complementary environment parameter sensor can thus either be a CO.sub.2 sensor, a humidity sensor, or a combination of the two.

[0067] The supplementary environment parameter sensor measures an additional environmental parameter of the air, which is different to that measured by the interior environmental parameter sensor 32, such as carbon monoxide (CO) and/or nitrogen oxide (NOx). The supplementary environment parameter sensor can either be a CO sensor, a NOx sensor or a combination of the two.

[0068] The CO sensor is an electrochemical instant detection and response (IDR) sensor. The IDR measures the CO content of the air at the vehicle exterior 42 indirectly by monitoring changes in electrical resistance through an electrochemical solution.

[0069] The NOx sensor is a potentiometric sensor, which measures the potential difference between a working electrode and reference electrode. The working electrode's potential depends on the concentration of the NOx in the air of the vehicle exterior 42.

[0070] The complementary and supplementary exterior sensors measure the exterior air 42 in order to monitor the environment parameters. It may be the case that the exterior air 42 has non ideal levels of CO.sub.2 and/or humidity, as well as other pollutants. In this case, transferring exterior air 42 to the cabin interior 12 may be detrimental to the cabin environment and occupant comfort. Accordingly, the control module 36 would thus configure the motor 52 to keep the fan 50 stationary. The complementary and supplementary exterior sensors are thus connected to the control module 36 such that the control module 36 can configure the fan 50 to induce an air flow through the ventilation system 24 taking into account the CO.sub.2 and/or humidity levels within the cabin interior 14, as well as the CO.sub.2, humidity, CO and NOx levels at the vehicle exterior 12.

[0071] The control module 36 is arranged to configure the fan 50 to induce an air flow between the vehicle exterior 12 and the cabin interior 14 based upon the environment parameter measured within the cabin. In addition, the control module 36 uses the reading from the complementary and supplementary exterior parameter sensors such that the rotational speed of the fan 50 is a function of one environment parameter sensed at the vehicle interior 14 and the vehicle exterior 16, and a second environment parameter that is also sensed at the vehicle exterior 16.

[0072] In an alternative arrangement of the above described embodiments, the control system is arranged, when operating in a prescribed mode of operation, to continuously vary the fan speed, in order to maintain a constant environment parameter level of CO.sub.2 to a predefined set point such as, for example, 750 ppm. The prescribed mode of operation may be a default mode, a user-selected mode, or a mode automatically triggered based on user preferences, geographical location or time.

[0073] It will be appreciated by a person skilled in the art that the invention could be modified to take many alternative forms to that described herein, without departing from the scope of the appended claims.