Air conditioner for vehicle

Patent metadata

Field	Value
Publication number	US-9688118-B2
Application number	US-201113331272-A
Country	US
Kind code	B2
Filing date	Dec 20, 2011
Priority date	Dec 23, 2010
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

An air conditioner for a vehicle includes a casing, a cooling heat exchanger, a cooling temperature adjusting portion, a dew-point detector, a target temperature determining portion, and a cooling temperature control portion. The cooling heat exchanger is arranged in the casing to cool air to be blown into a vehicle compartment. The cooling temperature adjusting portion adjusts a cooling temperature of air cooled at the cooling heat exchanger such that the cooling temperature approaches a target cooling temperature of the cooling heat exchanger. The dew-point detector detects a dew-point temperature of air flowing to the cooling heat exchanger. The target temperature determining portion determines the target cooling temperature to be a first target temperature lower than the dew-point temperature by a standard degree, and temporarily to be a second target temperature lower than the first target temperature.

First claim

What is claimed is:

1. An air conditioner for a vehicle, comprising:
a casing defining an air passage through which air to be blown into a vehicle compartment passes;
a cooling heat exchanger arranged in the casing to cool air;
a cooling temperature adjusting portion configured to adjust a cooling temperature of air cooled at the cooling heat exchanger, the cooling temperature adjusting portion including a compressor;
a dew-point detector configured to detect a physical amount relevant to a dew-point temperature of air flowing to the cooling heat exchanger;
a target temperature determining portion configured to determine a target cooling temperature that is a target temperature of the cooling heat exchanger;
a cooling temperature control portion configured to control the cooling temperature adjusting portion so that the cooling temperature approaches the target cooling temperature;
a cooling temperature detector configured to detect a temperature of air immediately after flowing out of the cooling heat exchanger; and
a water-holding amount calculation portion configured to calculate a water-holding amount of an outer surface of the cooling heat exchanger based on an inlet humidity calculated from a detection value of the dew-point detector and an outlet humidity calculated from a detection value of the cooling temperature detector, wherein the water-holding amount calculation portion calculates the water-holding amount by accumulating over time a dehumidified amount that is calculated by subtracting the outlet humidity from the inlet humidity, wherein:
a standard water-holding amount is set to be larger than a largest evaporation amount of dew condensation water on the outer surface of the cooling heat exchanger, the largest evaporation amount being estimated depending on change in dew-point temperature of air flowing into the casing by an experiment or a simulation in advance;
the target temperature determining portion determines the target cooling temperature to be one of a first target temperature lower than the dew-point temperature by a standard temperature amount and a second target temperature lower than the first target temperature;
the target temperature determining portion switches the target cooling temperature between the first target temperature and the second target temperature based on one or more conditions;
the target temperature determining portion determines the target cooling temperature as the first target temperature when the water-holding amount is higher than the standard water-holding amount;
the target temperature determining portion determines the target cooling temperature as the second target temperature when the water-holding amount is lower than or equal to the standard water-holding amount; and
wherein the compressor rotation speed is determined based upon the determined target cooling temperature.

2. The air conditioner according to claim 1 , wherein the temperature determining portion determines the target cooling temperature to be the second target temperature at least one time, until a base time elapses after air conditioning of the vehicle compartment starts.

3. The air conditioner according to claim 1 , wherein the target temperature of the cooling heat exchanger is a target temperature of air blown across the cooling heat exchanger.

4. The air conditioner according to claim 1 , wherein the water-holding amount is an amount necessary for keeping an outer surface of the cooling heat exchanger in a moist state.

5. The air conditioner according to claim 1 , wherein the water-holding amount calculation portion calculates the water-holding amount by adding the dehumidified amount to a water-holding amount calculated by the water-holding amount calculation portion a previous time period.

6. The air conditioner according to claim 1 , wherein the water-holding amount calculation portion sets the water-holding amount to zero at a start of air conditioning.

7. The air conditioner according to claim 1 , wherein the water-holding amount calculation portion calculates the water-holding amount by using a previous water-holding amount that is a water-holding amount calculated by the water-holding amount calculation portion at a last stop of air conditioning.

8. The air conditioner according to claim 7 , wherein the water-holding amount calculation portion reduces the previous water-holding amount with time elapsing from the last stop of air conditioning to a restart of air conditioning.

9. The air conditioner according to claim 1 , wherein the second target temperature is set at a lowest degree in a temperature range where frost is not formed on the cooling heat exchanger.

10. The air conditioner according to claim 1 , wherein the target temperature determining portion determines the standard temperature difference between the dew-point temperature and the first target temperature to be a variable value determined based on a temperature and a humidity of air flowing into the cooling heat exchanger.

11. The air conditioner according to claim 1 , wherein the target temperature determining portion determines the standard temperature difference between the dew-point temperature and the first target temperature to be a variable value determined based on a number of occupants in the vehicle.

12. The air conditioner according to claim 11 , wherein the target temperature determining portion determines the standard temperature difference to increase in accordance with increase in the number of occupants in the vehicle.

Assignees

• Misumi Haruki
• Denso Corp

Inventors

• Misumi Haruki

Classifications

• B60H2001/3245

  of air · CPC title

• B60H3/0085 Primary

  Smell or pollution preventing arrangements (B60H3/0007, B60H3/0071, B60H3/02, B60H3/06 take precedence) · CPC title

• B60H1/3207

  for minimizing the humidity of the air · CPC title