JP2024033055A - Warming up method and device for vehicle internal combustion engine - Google Patents

Abstract

An object of the present invention is to effectively utilize waste heat from an inverter 21, etc. to warm up the area around the intake port of an internal combustion engine before starting the engine, and to notify a passenger in the event of a system abnormality. [Solution] A cooling system for a series hybrid vehicle includes a first cooling water circuit 1 that mainly cools a water jacket 11 of an internal combustion engine, and a second cooling water circuit that mainly cools an inverter 21, a driving motor generator 22, etc. It includes a water circuit 2 and a refrigeration cycle 3 that constitutes a vehicle interior air conditioner. The refrigeration cycle 3 thermally connects the first cooling water circuit 1 and the second cooling water circuit 2, and absorbs the heat of the cooling water in the second cooling water circuit 2 as heat of vaporization in the chiller 37. , the cooling water in the first cooling water circuit 1 is heated as condensation heat in the engine warm-up condenser 36 . The heated cooling water circulates through the intake port water jacket 16. The system is diagnosed based on the rise in cooling water temperature, etc., and a warning light 51 is turned on when an abnormality occurs. [Selection diagram] Figure 1

Description

The present invention relates to a technology for promoting warm-up before starting an internal combustion engine that drives a motor generator for power generation in, for example, a series hybrid vehicle.

When a so-called port-injection internal combustion engine is started in a cold state, the fuel injected from the fuel injection valve toward the intake port becomes a liquid film that adheres to the low-temperature intake port wall, and then continues through the intake valve. Since it flows into the combustion chamber, an increase in unburned HC and CO occurs. During such startup, the temperature of the catalyst provided in the exhaust system is low, so that sufficient exhaust purification performance by the catalyst cannot be obtained.

Patent Document 1 discloses a technique for warming up the engine in a hybrid vehicle by heating engine cooling water using a refrigeration cycle in a cabin air conditioner. Specifically, a warm-up coolant circuit is formed in parallel with the heater core, which is part of the engine coolant circuit, and the refrigeration cycle condenser is connected to the coolant in the warm-up coolant circuit and the refrigerant in the refrigeration cycle. It is configured to exchange heat between the In other words, the condenser is cooled not by outside air but by engine coolant. This causes the engine coolant to be warmed by the heat released from the condenser during operation of the refrigeration cycle.

Japanese Patent Application Publication No. 2009-180103

However, in the conventional configuration described above, the heat obtained from the outside air by the evaporator housed in the so-called air conditioner unit of the passenger compartment air conditioner is simply transferred to the engine cooling water, which is particularly inefficient under conditions such as low outside temperatures. It is not possible to promote warm-up properly. Furthermore, waste heat from drive mechanisms such as inverters and motor generators in hybrid vehicles cannot be effectively utilized.

Further, when the refrigeration cycle that constitutes the vehicle air conditioner is involved in the exhaust performance of the internal combustion engine, it is not preferable that the abnormality is left untreated.

The warming-up method of the present invention uses an electric compressor that constitutes a cabin air conditioner to connect a cooling water circuit in which cooling water flows around at least the intake port of an internal combustion engine, and a waste heat source separate from the internal combustion engine. The refrigeration cycle is thermally connected to the cooling water circuit, and when a warm-up request is made before starting the internal combustion engine, heat is transferred from the waste heat source to the cooling water circuit by the action of the refrigeration cycle, and
Diagnoses whether or not there is an abnormality in the refrigeration cycle, and lights up a warning light if an abnormality occurs.

In such a configuration, at least a portion of the waste heat emitted from the waste heat source such as an inverter is given to the cooling water of the cooling water circuit via the refrigeration cycle. This warms the area around the intake port. If there is an abnormality in the refrigeration cycle, the occupants are notified by lighting a warning light.

According to this invention, the area around the intake port of the internal combustion engine can be heated by effectively utilizing waste heat from an appropriate waste heat source, and deterioration of emissions due to the low temperature of the intake port can be suppressed. Since a warning light is turned on when an abnormality occurs, it is possible to prevent the vehicle from being driven repeatedly without being properly warmed up.

FIG. 1 is a cooling circuit diagram of an embodiment of the present invention.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram showing the overall configuration of a vehicle cooling system according to an embodiment. The vehicle of one embodiment is a series hybrid vehicle in which an internal combustion engine drives a motor generator for power generation to generate electricity, and the generated electric power drives a motor generator for driving. The internal combustion engine is, for example, a four-stroke cycle spark ignition internal combustion engine (so-called gasoline engine), and has a port injection type configuration in which fuel is injected from fuel injection valves provided at the intake ports of each cylinder toward the intake ports. It becomes.

The cooling device of one embodiment includes a first cooling water circuit 1 that cools an internal combustion engine by circulating cooling water, and a second cooling water circuit 2 that cools a traveling drive mechanism by circulating cooling water. It is roughly composed of three components: a refrigeration cycle 3 that constitutes a vehicle interior air conditioner. Note that in the present invention, "cooling water" broadly means a liquid phase refrigerant. As will be described later, in this embodiment, the object to be cooled by the second cooling water circuit 2 corresponds to the waste heat source.

The first cooling water circuit 1 basically has the same configuration as a general water-cooled cooling system for an internal combustion engine, and the main cooling objects are the water jacket 11 of the internal combustion engine (the water jacket 11a on the cylinder block side and the cylinder a radiator 12 that cools the high-temperature cooling water that has passed through the water jacket 11 by exchanging heat with the outside air; It is configured as a closed circuit including an electric water pump 13 that supplies water to the water. The radiator 12 is disposed at a position such as the front of the vehicle body where it can receive wind from the vehicle. Similar to a general water-cooled cooling system for an internal combustion engine, the cooling system includes a bypass passage 14 and a thermostatic valve 15 for allowing cooling water to bypass the radiator 12 when the water temperature is low. The thermostatic valve 15 may be of a type that mechanically responds to the temperature of the cooling water, or may be of a type that can electrically control its opening.

Further, in this embodiment, the water jacket around the intake port is independent as an intake port water jacket 16, and a circuit is created so that cooling water flows in parallel with the water jacket 11 between the electric water pump 13 and the radiator 12. It is configured. That is, it has a branch passage that passes through the intake port water jacket 16. A control valve 17 is provided on the outlet side of the water jacket 11 so that cooling water mainly circulates through the intake port water jacket 16 when the intake port is warmed up. When the control valve 17 is fully closed, the entire amount of cooling water discharged by the electric water pump 13 flows through the intake port water jacket 16.

The second cooling water circuit 2 cools several elements that need to be cooled in the drive mechanism of the hybrid vehicle, such as an inverter 21, a driving motor generator 22, and a power generation motor generator 23. , which performs cooling by circulating cooling water, and includes a second radiator 24 that exchanges heat between the cooling water circulating in the circuit and the outside air, and a second electric water pump 25 that circulates the cooling water. There is. It is desirable that the second radiator 24 be placed at a position where it can receive wind from the vehicle, such as at the front of the vehicle body. The cooling water flowing through the second cooling water circuit 2 is different from the cooling water flowing through the first cooling water circuit 1, that is, it is independent from the cooling water flowing through the first cooling water circuit 1. . Note that the cooling water flowing through the first cooling water circuit 1 and the cooling water flowing through the second cooling water circuit 2 may be different types of cooling water, that is, they may have different components from each other. May be used for.

Further, the temperature of the cooling water circulating in the second cooling water circuit 2 is relatively lower than the temperature of the cooling water circulating in the first cooling water circuit 1. For example, while the internal combustion engine is operating, the temperature of the cooling water in the first cooling water circuit 1 is maintained at about 70 to 90°C, whereas the temperature of the cooling water in the second cooling water circuit 2 is maintained at about 40 to 60°C. It is maintained at around ℃. However, such a relationship between the cooling water temperatures of the two cooling water circuits 1 and 2 is not essential in the present invention.

Note that although the diagram shows a configuration in which cooling water flows in series between the inverter 21, the driving motor generator 22, and the power generation motor generator 23, which are waste heat sources, each of them has a configuration in which the cooling water flows in parallel with each other. good. Further, like the first cooling water circuit 1, a bypass passage and a thermostatic valve (not shown) may be provided so that the cooling water bypasses the second radiator 24 when the water temperature is low.

The refrigeration cycle 3 includes an electric compressor 31 that compresses a refrigerant into a high-temperature, high-pressure gaseous refrigerant, and on the downstream side of the electric compressor 31, cools the high-temperature, high-pressure gaseous refrigerant by heat exchange with outside air and converts it into a liquid phase. A closed circuit including a condenser 32, an expansion valve 33 that reduces the pressure of the refrigerant liquefied by the condenser 32, and an evaporator 34 located downstream of the expansion valve 33 that vaporizes the liquid phase refrigerant through heat exchange with outside air. It is configured. The capacitor 32 is arranged, for example, in line with the radiator 12 at the front of the vehicle body. The evaporator 34 is housed in an air conditioner unit for generating conditioned air for the vehicle air conditioner. The outside air taken in by a blower (not shown) passes through the evaporator 34 and is cooled.

Further, between the discharge side of the electric compressor 31 and the capacitor 32, a vehicle interior heating capacitor 35 and an engine warming capacitor 36 are arranged in series. The vehicle interior heating capacitor 35 is housed in the air conditioner unit together with the evaporator 34 as an alternative to a general hot water type heater core for vehicle interior heating. Heats the conditioned air by exchanging heat. The proportion of the conditioned air that passes through the cabin heating condenser 35 is controlled by the opening degree of an air mix door (not shown). Note that in one embodiment, the conditioned air always passes through the evaporator 34 to perform cooling and dehumidification.

The engine warm-up capacitor 36 exchanges heat between the high-temperature, high-pressure gaseous refrigerant discharged from the electric compressor 31 and the cooling water of the first cooling water circuit 1 . That is, the cooling water in the first cooling water circuit 1 is heated by the heat of condensation when the gaseous refrigerant liquefies. In one embodiment, a cooling water passage is connected to an engine warm-up condenser 36 in the first cooling water circuit 1 at a position on the suction side of the electric water pump 13 and downstream of the thermostatic valve 15. .

In the illustrated example, the engine warm-up capacitor 36 is located downstream of the cabin heating capacitor 35 in the refrigeration cycle 3, but the engine warming capacitor 36 is located upstream of the cabin heating capacitor 35. The relationship may be such that Alternatively, the cabin heating capacitor 35 and the engine warming capacitor 36 may be arranged in parallel.

The refrigeration cycle 3 further includes a heat exchanger or chiller 37 arranged in parallel with the evaporator 34 . A chiller expansion valve 38 is provided at the inlet of the chiller 37. A refrigerant whose pressure has been reduced by the chiller expansion valve 38 passes through the chiller 37, and heat exchange is performed between this refrigerant and the cooling water of the second cooling water circuit 2. That is, in the chiller 37, similar to the evaporator 34, the refrigerant is vaporized, and the cooling water in the second cooling water circuit 2 is cooled by the heat of vaporization. In one embodiment, in the second cooling water circuit 2, a cooling water passage is connected to the chiller 37 at a position upstream of the second radiator 24 through which high-temperature cooling water flows after cooling objects to be cooled such as the inverter 21. ing. In addition, it is desirable to configure so that the heat exchange in the chiller 37 can be stopped by, for example, controlling the chiller expansion valve 38 to be fully open or fully closed.

In this way, the first cooling water circuit 1 and the second cooling water circuit 2 are configured independently so that the cooling water circulates separately, while the first cooling water circuit 1 and the second cooling water circuit 2 are configured to circulate the cooling water separately. By operating the refrigeration cycle 3, the heat of the cooling water in the second cooling water circuit 2 can be transferred to the cooling water in the first cooling water circuit 1.

The operations of the first cooling water circuit 1, the second cooling water circuit 2, and the refrigeration cycle 3 described above are controlled by the controller 41. Note that the controller 41 is actually configured to include a plurality of controllers such as an engine controller and an air conditioner controller. Further, a warning light 51 is connected to the controller 41 to notify the occupants in the event of an abnormality in the system. The warning light 51 is arranged, for example, on the instrument panel of the driver's seat.

In a series hybrid vehicle, the internal combustion engine is basically started when the SOC of the battery drops to a predetermined lower limit SOC value, and is stopped when the SOC recovers to a predetermined level. That is, the internal combustion engine drives the power generation motor generator in response to a power generation request to generate power.

Here, if the internal combustion engine is in a cold state and not warmed up and restarted, in order to warm up the area around the intake port, the internal combustion engine is warmed up by the transfer of heat via the refrigeration cycle 3 described above before starting (before the start of combustion operation). Control is exercised. That is, the electric compressor 31 is driven to operate the refrigeration cycle 3, and the chiller expansion valve 38 and the chiller 37 act to absorb the heat of the cooling water in the second cooling water circuit 2 into the refrigerant. Heat is then applied from the refrigerant in the refrigerant cycle 3 to the cooling water in the first cooling water circuit 1 via the engine warm-up condenser 36 . At this time, the control valve 17 of the first cooling water circuit 1 is closed as appropriate, and the cooling water that has become high temperature due to the heat from the refrigeration cycle 3 is sent to the intake port water jacket 16 by the action of the electric water pump 13. , warm up the area around the intake port. After passing through the intake port water jacket 16, the cooling water circulates through the bypass passage 14 and through the engine warm-up condenser 36 again.

By warming the area around the intake port before starting in this manner, the fuel properties become good from the initial stage of starting, and for example, transient increases in unburned HC and CO can be suppressed.

In the above embodiment, the waste heat from the inverter 21 and the like in the second cooling water circuit 2 is effectively utilized to promote warming up around the intake port, so that no other heating source is required. Moreover, compared to the conventional technology in which the temperature of the cooling water is increased by a refrigeration cycle using outside air as the heat source, the temperature of the heat source can be obtained relatively high, so that the cooling water can be heated efficiently.

Here, if the area around the intake port is not warmed up normally via the refrigeration cycle 3 as described above, the fuel properties may deteriorate and the emissions such as unburned HC may deteriorate. Therefore, in a preferred embodiment, an abnormality in the system is diagnosed as in the following several examples, and when an abnormality is determined, the warning light 51 is turned on.

In the first example, the coolant temperature in the first coolant circuit 1 is measured, and an abnormality is determined when the coolant temperature does not reach a threshold within a predetermined time from the start of warm-up via the refrigeration cycle 3. Then, the warning light 51 is turned on. The water temperature sensor for detecting the cooling water temperature is preferably placed, for example, in the intake port water jacket 16, but may be placed in another location such as the cylinder block water jacket 11a.

In the second example, the temperature of the cylinder head or cylinder block of the internal combustion engine is measured, and when the temperature does not reach the threshold within a predetermined time from the start of warm-up via the refrigeration cycle 3, it is determined that there is an abnormality. In this case, it is desirable to arrange the temperature sensor around the intake port, but it may be located at other locations such as a metal part of the cylinder head.

In the third example, the outlet pressure of the electric compressor 31 in the refrigeration cycle 3 is measured during warm-up via the refrigeration cycle 3, and an abnormality is detected when the outlet pressure does not reach the threshold within a predetermined time from the start of warm-up. It is determined that A pressure sensor (not shown) is provided at the outlet of the electric compressor 31.

In the fourth example, the outlet temperature of the electric compressor 31 in the refrigeration cycle 3 is measured during warm-up via the refrigeration cycle 3, and an abnormality is detected when the outlet temperature does not reach the threshold within a predetermined time from the start of warm-up. It is determined that A refrigerant temperature sensor (not shown) is provided at the outlet of the electric compressor 31.

In the fifth example, the cooling water temperature in the first cooling water circuit 1 is measured, and when the amount of change in the cooling water temperature during a predetermined period of time from the start of warm-up via the refrigeration cycle 3 does not reach a threshold value, Determined as abnormal. The water temperature sensor for detecting the cooling water temperature is preferably placed, for example, in the intake port water jacket 16, but may be placed in another location such as the cylinder block water jacket 11a.

In the sixth example, the temperature of the cylinder head or cylinder block of the internal combustion engine is measured, and an abnormality is determined when the amount of change in temperature during a predetermined period of time from the start of warm-up via the refrigeration cycle 3 does not reach a threshold value. do. In this case, it is desirable to arrange the temperature sensor around the intake port, but it may be located at other locations such as a metal part of the cylinder head.

In addition, it may be determined whether the refrigeration cycle 3 is operating sufficiently by an appropriate known method.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be applied to the first cooling water circuit 1, the second cooling water circuit 2, and the refrigeration cycle 3. The configuration can be changed as appropriate. For example, the intake port water jacket 16 may be configured to heat the area around the intake port as part of the water jacket 11b on the cylinder head side, instead of using a separate circuit. Furthermore, the present invention is applicable not only to the above-mentioned cooling system for series hybrid vehicles, but also to vehicles whose driving power source is an internal combustion engine, as long as the device is equipped with a suitable waste heat source separate from the internal combustion engine. can do.

1... First cooling water circuit 2... Second cooling water circuit 3... Refrigeration cycle 11... Water jacket 12... Radiator 13... Electric water pump 16... Intake port water jacket 21... Inverter 22... Traveling motor generator 23... Power generation Motor generator 24...Second radiator 25...Second electric water pump 31...Electric compressor 32...Capacitor 33...Expansion valve 34...Evaporator 35...Capacitor for cabin heating 36...Capacitor for engine warm-up 37...Chiller 38...For chiller Expansion valve 41...Controller 51...Warning light

Claims (8)

A cooling water circuit in which cooling water circulates around at least the intake port of the internal combustion engine and a waste heat source separate from the internal combustion engine are thermally connected through a refrigeration cycle using an electric compressor that constitutes a cabin air conditioner. When a warm-up request is made before starting the internal combustion engine, heat is transferred from the waste heat source to the cooling water circuit by the action of the refrigeration cycle, and
Diagnoses whether or not there is an abnormality in the refrigeration cycle mentioned above, and lights up a warning light in the event of an abnormality.
How to warm up a vehicle's internal combustion engine. measuring the cooling water temperature of the cooling water circuit, and determining that there is an abnormality when the cooling water temperature does not reach a threshold within a predetermined time from the start of warm-up through the refrigeration cycle;
A method for warming up an internal combustion engine of a vehicle according to claim 1. Measuring the temperature of the cylinder head or cylinder block of the internal combustion engine, and determining an abnormality when the temperature does not reach a threshold within a predetermined time from the start of warming up via the refrigeration cycle;
A method for warming up an internal combustion engine of a vehicle according to claim 1. During warm-up through the refrigeration cycle, the outlet pressure of the electric compressor in the refrigeration cycle is measured, and an abnormality is determined when the outlet pressure does not reach a threshold within a predetermined time from the start of warm-up.
A method for warming up an internal combustion engine of a vehicle according to claim 1. measuring the outlet temperature of the electric compressor in the refrigeration cycle during warm-up via the refrigeration cycle, and determining an abnormality when the outlet temperature does not reach a threshold within a predetermined time from the start of warm-up;
A method for warming up an internal combustion engine of a vehicle according to claim 1. measuring the cooling water temperature of the cooling water circuit, and determining that there is an abnormality when the amount of change in the cooling water temperature during a predetermined period of time from the start of warm-up through the refrigeration cycle does not reach a threshold;
A method for warming up an internal combustion engine of a vehicle according to claim 1. Measuring the temperature of the cylinder head or cylinder block of the internal combustion engine, and determining an abnormality when the amount of change in the temperature during a predetermined period of time from the start of warming up via the refrigeration cycle does not reach a threshold;
A method for warming up an internal combustion engine of a vehicle according to claim 1. a cooling water circuit in which cooling water flows around at least an intake port of an internal combustion engine;
A waste heat source separate from the internal combustion engine,
A refrigeration cycle using an electric compressor constituting a vehicle interior air conditioner, the refrigeration cycle thermally connecting the cooling water circuit and the waste heat source;
When a warm-up request is made before starting the internal combustion engine, the refrigeration cycle is operated to transfer heat from the waste heat source to the cooling water circuit, and the refrigeration cycle is diagnosed for any abnormality, and in the event of an abnormality, a warning light is activated. A controller that lights up;
A warm-up device for a vehicle's internal combustion engine.

Images