JP6202275B2 - Engine system with combustion heater - Google Patents

Description

  The present invention relates to a combustion heater-equipped engine system, and more particularly to a combustion heater-equipped engine system having a combustion heater that is attached to an engine and warms the engine by combustion heat.

  Conventionally, it is known to use a heater in order to quickly warm up an engine immediately after a cold start. For example, Patent Document 1 discloses that a combustion heater used as a heating device for a vehicle heating device is also used as an engine warm-up device. The combustion heater disclosed in Patent Document 1 vaporizes fuel supplied from a fuel tank by a wick or glow plug built in the combustion heater, and heats the engine coolant by burning the vaporized fuel. .

JP 2004-270658 A

  However, since the above-described combustion heater disclosed in Patent Document 1 uses liquid fuel supplied from a fuel tank, it is necessary to provide a vaporizer such as a wick or a glow plug in order to vaporize the liquid fuel. The structure of the type heater is complicated, leading to an increase in cost.

  The present invention has been made to solve the above-described problems of the prior art, and provides a combustion heater-equipped engine system capable of warming up the engine with a combustion heater having a simple structure. Objective.

In order to achieve the above object, an engine system with a combustion heater according to the present invention is a combustion heater-equipped engine system that includes a combustion heater that is attached to an engine and warms the engine by combustion heat. A fuel tank that stores fuel supplied to the fuel tank, a canister that adsorbs fuel vapor generated inside the fuel tank, a canister communication passage that connects the canister and the intake passage of the engine, a crank chamber and an intake passage of the engine, Connecting the crank chamber communication passage, the canister communication passage, and the combustion type heater, the fuel vapor supply passage for supplying fuel vapor from the canister communication passage to the combustion type heater, and / or the crank chamber communication passage and the combustion type Blow-by gas that connects the heater and supplies blow-by gas from the crankcase communication passage to the combustion heater A liquid fuel supply passage, a liquid fuel supply passage, a fuel vapor supply passage, and / or a blow-by gas supply passage for connecting the supply passage, the fuel tank, and the combustion heater to supply liquid fuel from the fuel tank to the combustion heater Switching means for switching the connection to the combustion heater, and whether or not the combustion heater is warmed up . If the combustion heater is not warmed up, the switching means switches the fuel vapor supply passage and / or Alternatively, when the blow-by gas supply passage is connected to the combustion heater and fuel vapor and / or blow-by gas is burned by the combustion heater and the combustion heater is warmed up, the liquid fuel supply passage is connected to the combustion heater by the switching means. And a heater control means for combusting liquid fuel with a combustion heater.
In the present invention configured as described above, when the combustion heater is not warmed up, the heater control means burns the already vaporized fuel vapor and / or blow-by gas with the combustion heater, and the combustion heater When the combustion heater is not warmed up, the liquid fuel is combusted by the combustion heater, so there is no need to use a vaporizer when the combustion heater is not warmed up. The liquid fuel can be vaporized and burned by the thermal energy of the combustion heater itself without using the vaporizer, and the combustion heater can be operated without using the vaporizer. That is, the engine can be warmed up by a combustion heater having a simple structure.

In the present invention, preferably, the engine system with a combustion heater includes a fuel vapor supply passage and a blow-by gas supply passage, and the switching means includes a liquid fuel supply passage, a fuel vapor supply passage, and a blow-by gas supply. When the combustion heater is not warmed up, the heater control means connects the fuel vapor supply passage and the blow-by gas supply passage to the combustion heater by the switching means when the combustion heater is not warmed up. Steam and blow-by gas are burned with a combustion heater.
In the present invention configured as described above, when the combustion heater is not warmed up, the heater control means burns the fuel vapor and blow-by gas with the combustion heater, so the combustion heater is not warmed up. In this case, the amount of vaporized fuel supplied to the combustion heater can be increased, and the combustion heater can be warmed up early. Therefore, the engine can be warmed up earlier.

In the present invention, preferably, the engine is subjected to compression self-ignition combustion, which is combustion by self-ignition of the air-fuel mixture in a predetermined first operation region, and has a higher load or higher rotation speed than the first operation region. A compression self-ignition gasoline engine configured to perform spark ignition combustion, which is forced combustion by spark ignition in two operating regions, and a combustion heater is attached to an engine block of the engine, The engine is warmed up by heating the flowing cooling water.
In the present invention configured as described above, in order to perform the operation by the compression auto-ignition combustion in the first operation region, the engine that has been cold-started is warmed up as early as possible so that the cylinder of the engine block In a compression self-ignition gasoline engine that is required to raise the wall temperature, the combustion heater is attached to the engine block, so the combustion heat generated by the combustion heater is efficiently used as cooling water flowing inside the engine block. Thus, the wall surface temperature of the cylinder of the engine block can be raised early, and the combustion mode in the first operation region can be shifted to compression self-ignition combustion at an early stage.

In the present invention, preferably, the engine system with a combustion heater further includes a combustion gas discharge passage that connects the combustion heater and the intake passage and discharges combustion gas generated by the combustion heater to the intake passage. .
In the present invention configured as above, the temperature of the intake air introduced into the cylinder rises due to the combustion gas generated by the combustion heater, so that the engine can be warmed up more efficiently. In addition, since the combustion gas generated by the combustion heater can be processed together with the exhaust of the engine itself, the necessary emission performance can be ensured without providing an exhaust treatment device dedicated to the combustion heater. The engine can be warmed up by a combustion heater having a simple structure.

  According to the engine system with a combustion heater according to the present invention, the engine can be warmed up by the combustion heater having a simple structure.

1 is a system configuration diagram of an engine system with a combustion heater according to an embodiment of the present invention. It is a diagram which shows the operation area | region where compression self-ignition combustion is performed, and the operation area | region where spark ignition combustion is performed in the engine by embodiment of this invention. It is a flowchart which shows operation | movement of the combustion type heater by embodiment of this invention.

Hereinafter, an engine system with a combustion heater according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the overall configuration of an engine system with a combustion heater according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a system configuration diagram of an engine system with a combustion heater according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a combustion heater-equipped engine system according to an embodiment of the present invention. As shown in FIG. 1, the combustion heater-equipped engine system 1 includes an engine 2 and a fuel tank 4 that stores fuel supplied to the engine 2.

The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine. In particular, in this embodiment, spark ignition (SI) combustion and premixed compression auto-ignition (HCCI) combustion are performed. It is the HCCI gasoline engine comprised as follows.
The engine 2 includes an engine block 8 having a cylinder 6 that takes out power by burning a mixture of fuel and intake air, a piston 10 that reciprocates in the cylinder 6, and a reciprocating motion of the piston 10 is converted into a rotational motion. A crank 12 and a crank chamber 14 for housing the crank 12 are provided. The engine 2 is connected to an intake passage 16 for introducing intake air into the cylinder 6 and an exhaust passage 18 for discharging exhaust generated in the cylinder 6 to the atmosphere.

  A crank chamber communication passage 20 that connects the crank chamber 14 and the intake passage 16 is connected between the crank chamber 14 and the intake passage 16 of the engine 2. The blow-by gas leaked into the crank chamber 14 from the gap between the piston 10 and the cylinder 6 of the engine 2 is introduced into the intake passage 16 of the engine 2 through the crank chamber communication passage 20 and burned in the cylinder 6 of the engine 2. .

  The engine block 8 is provided with an injector 22 for injecting fuel into the cylinder 6, and a fuel passage 24 for introducing the fuel sent from the fuel tank 4 to the injector 22 is connected to the injector 22. ing. Further, a cooling water passage (not shown) through which cooling water for cooling the engine 2 circulates is formed inside the engine block 8.

  A fuel passage 24 is connected to the fuel tank 4, and a fuel pump 26 that delivers fuel from the fuel tank 4 is provided. The fuel stored in the fuel tank 4 is sent out from the fuel tank 4 by the fuel pump 26 and introduced into the injector 22 of the engine 2 through the fuel passage 24.

Inside the fuel tank 4, there is a fuel vapor 30 in which the liquid fuel 28 is vaporized together with the liquid fuel 28 (gasoline in the present embodiment). In order to prevent the fuel vapor 30 from being released into the atmosphere, a canister 32 that adsorbs the fuel vapor 30 is provided.
Between the canister 32 and the fuel tank 4, a fuel vapor passage 34 that connects the canister 32 and the fuel tank 4 is connected. The fuel vapor 30 generated inside the fuel tank 4 It is guided to the canister 32 through 34 and is adsorbed by the canister 32.
Further, between the canister 32 and the intake passage 16, a canister communication passage 36 that connects the canister 32 and the intake passage 16 is connected. The fuel vapor 30 adsorbed by the canister 32 is separated from the canister 32 by the negative pressure of the intake passage 16 during operation of the engine 2, introduced into the intake passage 16 of the engine 2 through the canister communication passage 36, and Combusted in the cylinder 6.

  Further, a combustion heater 38 that warms up the engine 2 by combustion heat is attached to the engine block 8. Between the combustion type heater 38 and the canister communication path 36, a fuel vapor supply path 40 for connecting the combustion type heater 38 and the canister communication path 36 is connected. A part of the fuel vapor 30 passing through the canister communication passage 36 is supplied from the canister communication passage 36 to the combustion heater 38 through the fuel vapor supply passage 40. Further, a blow-by gas supply passage 42 for connecting the combustion heater 38 and the crank chamber communication passage 20 is connected between the combustion heater 38 and the crank chamber communication passage 20. A part of the blow-by gas passing through the crank chamber communication passage 20 is supplied from the crank chamber communication passage 20 to the combustion heater 38 through the blow-by gas supply passage 42. Further, a liquid fuel supply passage 44 that connects the combustion heater 38 and the fuel passage 24 is connected between the combustion heater 38 and the fuel passage 24. A part of the liquid fuel 28 passing through the fuel passage 24 is supplied from the fuel passage 24 through the liquid fuel supply passage 44 to the combustion heater 38.

  The fuel vapor supply passage 40 is provided with a control valve 46 that adjusts the flow rate of the fuel vapor 30 supplied to the combustion heater 38. The blow-by gas supply passage 42 is provided with a control valve 48 that adjusts the flow rate of blow-by gas supplied to the combustion heater 38. The liquid fuel supply passage 44 is provided with a control valve 50 that adjusts the flow rate of the liquid fuel 28 supplied to the combustion heater 38. These control valves 46, 48 and 50 function as switching means for switching the connection of the liquid fuel supply passage 44, the fuel vapor supply passage 40 and the blow-by gas supply passage 42 to the combustion heater 38.

  When the combustion heater 38 is operated, the fuel vapor 30, blow-by gas, or liquid fuel 28 is supplied to the combustion chamber (not shown) of the combustion heater 38, and is ignited and burned by an ignition device (not shown). The combustion heat is transmitted to the cooling water circulating inside the engine block 8, whereby the engine 2 is warmed up.

  Further, a combustion gas discharge passage 52 is connected between the combustion heater 38 and the intake passage 16. Combustion gas generated by combustion of the fuel vapor 30, blow-by gas, or liquid fuel 28 in the combustion heater 38 is introduced from the combustion heater 38 into the intake passage 16 through the combustion gas discharge passage 52.

  The combustion heater 38 is provided with a temperature sensor 54 for measuring the temperature of the combustion chamber wall of the combustion heater 38 and the temperature of the generated combustion gas. The value detected by the temperature sensor 54 is output to the ECU 56.

  The ECU 56 (heater control means) determines the opening and combustion type of the control valves 46, 48, 50 based on the detected value output from the temperature sensor 54 and various data such as a control map stored in the memory of the ECU 56. The ignition device of the heater 38 is controlled.

  Next, the operation of the combustion heater 38 according to the present invention will be described with reference to FIGS. FIG. 2 is a diagram showing an operation region where compression self-ignition combustion is performed and an operation region where spark ignition combustion is performed in the engine 2 according to the embodiment of the present invention, and FIG. 3 is a combustion according to the embodiment of the present invention. 6 is a flowchart showing the operation of the heater 38.

First, with reference to FIG. 2, an operation region in which compression self-ignition combustion is performed and an operation region in which spark ignition combustion is performed in the HCCI gasoline engine 2 according to the present embodiment will be described. In FIG. 2, the horizontal axis indicates the engine speed, and the vertical axis indicates the engine load. As shown in FIG. 2, the operation region (HCCI combustion region) in which compression self-ignition combustion is performed is lower in load than the operation region (SI combustion region) in which spark ignition combustion is performed (the load is L _{1 in} FIG. 2). or L less than ₂₎ and a low rotational speed (engine rotational speed in FIG. 2 is a driving region of R less than _1).
However, in a state where the engine 2 is not warmed up immediately after the cold start, the wall surface temperature of the cylinder 6 is low and the heat loss is large, so there is a possibility that ignition will not occur even if HCCI combustion is performed. Therefore, until the engine 2 is warmed up, even if the operation region of the engine 2 is in the HCCI combustion region, the operation by SI combustion must be performed, and the effects of improving fuel consumption and reducing NOx by HCCI combustion are obtained. I can't. Therefore, it is required that the engine 2 that has been cold-started is warmed up as early as possible to raise the wall surface temperature of the cylinder 6 so that the operation can be performed by HCCI combustion in the HCCI combustion region.

Next, the process of FIG. 3 is started when the ignition of the vehicle is turned on and the ECU 56 is powered on. As shown in FIG. 3, when the process is started, in step S1, the ECU 56 determines whether or not the engine 2 has been cold started. For example, the ECU 56 determines that the engine 2 has been cold started when the coolant temperature at the time of starting the engine 2 is less than 40 ° C.
As a result, when the engine 2 is not cold-started, for example, when the cooling water temperature is 40 ° C. or higher when the engine 2 is started and the engine 2 is already warmed up, the combustion heater 38 warms up the engine 2. Since it is not necessary to perform the machine, the ECU 56 ends the process.

  On the other hand, when the engine 2 is cold-started, the process proceeds to step S2, and the ECU 56 determines whether or not the combustion heater 38 is not warmed up. For example, the ECU 56 determines that the combustion heater 38 is not warmed up when the wall surface temperature of the combustion chamber of the combustion heater 38 detected by the temperature sensor 54 is less than 250 ° C.

  As a result, when the combustion heater 38 is not warmed up, the process proceeds to step S3, where the ECU 56 opens the control valves 46, 48 of the fuel vapor supply passage 40 and the blowby gas supply passage 42, and these fuel vapor supply passages 40 are opened. The blow-by gas supply passage 42 is connected to the combustion heater 38, and the control valve 50 of the liquid fuel supply passage 44 is closed. Thereby, a part of the fuel vapor 30 passing through the canister communication passage 36 is supplied from the canister communication passage 36 through the fuel vapor supply passage 40 to the combustion heater 38 and a part of blow-by gas passing through the crank chamber communication passage 20. Is supplied from the crank chamber communication passage 20 to the combustion heater 38 through the blow-by gas supply passage 42. That is, already vaporized fuel is supplied to the combustion heater 38.

Next, in step S4, the ECU 56 operates the combustion heater 38 by burning the fuel vapor 30 and blow-by gas supplied to the combustion heater 38 in step S3. For example, the ECU 56 operates the ignition device to ignite the fuel vapor 30 and blow-by gas supplied to the combustion heater 38.
Since the fuel vapor 30 and blow-by gas supplied to the combustion heater 38 in step S3 are already vaporized, it is not necessary to use a fuel vaporizer, and ignition is performed when the ignition device is operated.
The combustion heat generated by the combustion of the fuel vapor 30 and the blow-by gas supplied to the combustion heater 38 is transmitted to the cooling water circulating inside the engine block 8, so that the engine 2 is warmed up. The The combustion gas generated by the combustion of the fuel vapor 30 and the blow-by gas is introduced from the combustion heater 38 into the intake passage 16 through the combustion gas discharge passage 52.

  In step S2, if the combustion heater 38 is not warmed up (ie, warmed up), the process proceeds to step S5, where the ECU 56 controls the control valves 46, 48 of the fuel vapor supply passage 40 and blow-by gas supply passage 42. And the control valve 50 of the liquid fuel supply passage 44 is opened, and the liquid fuel supply passage 44 is connected to the combustion heater 38. Thereby, a part of the liquid fuel 28 passing through the fuel passage 24 is supplied from the fuel passage 24 to the combustion heater 38 through the liquid fuel supply passage 44.

Next, in step S6, the ECU 56 operates the combustion heater 38 by burning the liquid fuel 28 supplied to the combustion heater 38 in step S5. In this case, since the combustion heater 38 is warmed up (the combustion chamber is sufficiently hot), the liquid fuel 28 supplied to the combustion heater 38 is vaporized and ignited without using a vaporizer. It ignites spontaneously without operating the device.
Then, the combustion heat generated by the combustion of the liquid fuel 28 supplied to the combustion heater 38 is transmitted to the cooling water circulating inside the engine block 8, whereby the engine 2 is warmed up. The combustion gas generated by the combustion of the liquid fuel 28 is introduced into the intake passage 16 from the combustion heater 38 through the combustion gas discharge passage 52.

  After step S4 or S6, the process proceeds to step S7, where the ECU 56 determines whether the warm-up of the engine 2 has been completed. For example, the ECU 56 determines that the warm-up of the engine 2 has been completed when the temperature of the cooling water of the engine 2 becomes 50 ° C. or higher. Alternatively, when a predetermined time has elapsed after the engine 2 is started, it is determined that the warm-up of the engine 2 has been completed.

  As a result, when the warm-up of the engine 2 is not completed, the process returns to step S2. Thereafter, the processes of steps S2 to S5 are repeated until the warm-up of the engine 2 is completed.

  On the other hand, when warming up of the engine 2 is completed in step S7, the process proceeds to step S8, and the ECU 56 stops the operation of the combustion heater 38. Specifically, the ECU 56 closes the control valves 46, 48, and 50 of the fuel vapor supply passage 40, the blow-by gas supply passage 42, and the liquid fuel supply passage 44 to stop the combustion in the combustion heater 38. After step S8, the ECU 56 ends the process.

Next, further modifications of the embodiment of the present invention will be described.
First, in the above-described embodiment, it has been described that the control valves 46, 48, and 50 are provided in the fuel vapor supply passage 40, the blow-by gas supply passage 42, and the liquid fuel supply passage 44, respectively. A switching valve that switches connection of the supply passage 44, the fuel vapor supply passage 40, and the blow-by gas supply passage 42 to the combustion heater 38 may be provided inside the combustion heater 38.

  In the above-described embodiment, when the combustion heater 38 is not warmed up, the fuel vapor supply passage 40 and the blow-by gas supply passage 42 are connected to the combustion heater 38 so that the fuel vapor 30 and the blow-by gas are supplied to the combustion heater. However, one of the fuel vapor supply passage 40 or the blow-by gas supply passage 42 is connected to the combustion heater 38, and one of the fuel vapor 30 or the blow-by gas is burned by the combustion heater 38. Also good. In this case, since the amount of fuel vapor 30 that can be used is larger than that of blow-by gas, it is preferable to connect the fuel vapor supply passage 40 to the combustion heater 38 and burn the fuel vapor 30 with the combustion heater 38.

  Next, the operation and effect of the above-described embodiment of the present invention and the engine system 1 with the combustion heater according to the modification of the embodiment of the present invention will be described.

  First, when the combustion heater 38 is not warmed up, the ECU 56 burns the vaporized fuel vapor 30 and / or blow-by gas with the combustion heater 38, and the combustion heater 38 is warmed up. Since the liquid fuel 28 is combusted by the combustion heater 38, it is not necessary to use a vaporizer when the combustion heater 38 is not warmed up. When the combustion heater 38 is warmed up, vaporization is not necessary. The liquid fuel 28 can be vaporized and burned by the thermal energy of the combustion heater 38 itself without using the device, and the combustion heater 38 can be operated without using the vaporization device. That is, the engine 2 can be warmed up by the combustion heater 38 having a simple structure.

  In particular, the ECU 56 burns the fuel vapor 30 and the blow-by gas in the combustion heater 38 when the combustion heater 38 is not warmed up. Therefore, when the combustion heater 38 is not warmed up, the ECU 56 The amount of vaporized fuel supplied can be increased, and the combustion heater 38 can be warmed up early. Therefore, the engine 2 can be warmed up earlier.

  Further, in order to be able to perform the operation by HCCI combustion in the HCCI combustion region, it is required to warm up the cold-started engine 2 as early as possible to increase the wall surface temperature of the cylinder 6 of the engine block 8. In the HCCI gasoline engine 2, the combustion heater 38 is attached to the engine block 8, so that the combustion heat generated by the combustion heater 38 can be efficiently transmitted to the cooling water flowing inside the engine block 8, Thereby, the wall surface temperature of the cylinder 6 of the engine block 8 can be raised early, and the combustion mode in the HCCI combustion region can be shifted to HCCI combustion early.

  Further, since the combustion gas generated in the combustion heater 38 is discharged to the intake passage 16 through the combustion gas discharge passage 52, the temperature of the intake air introduced into the cylinder 6 by the combustion gas generated in the combustion heater 38. As a result, the engine 2 can be warmed up more efficiently. In addition, since the combustion gas generated by the combustion heater 38 can be processed together with the exhaust of the engine 2 itself, the necessary emission performance can be ensured without providing an exhaust treatment device dedicated to the combustion heater 38. Thus, the engine 2 can be warmed up by the combustion heater 38 having a simple structure.

DESCRIPTION OF SYMBOLS 1 Engine system with a combustion heater 2 Engine 4 Fuel tank 8 Engine block 14 Crank chamber 16 Intake passage 20 Crank chamber communication passage 24 Fuel passage 28 Liquid fuel 30 Fuel vapor 32 Canister 34 Fuel vapor passage 36 Canister communication passage 38 Combustion heater 40 Fuel vapor supply passage 42 Blow-by gas supply passage 44 Liquid fuel supply passage 46, 48, 50 Control valve 52 Combustion gas discharge passage 56 ECU

Claims (4)

A combustion heater-equipped engine system having a combustion heater attached to the engine and warming the engine by combustion heat,
A fuel tank for storing fuel supplied to the engine;
A canister that adsorbs fuel vapor generated inside the fuel tank;
A canister communication passage for communicating the canister and the intake passage of the engine;
A crank chamber communication passage for communicating the crank chamber of the engine and the intake passage;
The canister communication passage and the combustion heater are connected, and a fuel vapor supply passage for supplying fuel vapor from the canister communication passage to the combustion heater, and / or the crank chamber communication passage and the combustion heater are provided. A blowby gas supply passage for connecting and supplying blowby gas from the crank chamber communication passage to the combustion heater;
A liquid fuel supply passage connecting the fuel tank and the combustion heater, and supplying liquid fuel from the fuel tank to the combustion heater;
Switching means for switching the connection between the liquid fuel supply passage, the fuel vapor supply passage and / or the blow-by gas supply passage to the combustion heater;
It is determined whether or not the combustion heater is warmed up. When the combustion heater is not warmed up, the fuel vapor supply passage and / or the blow-by gas supply passage is connected to the combustion heater by the switching means. The fuel vapor and / or the blow-by gas is combusted by the combustion heater, and when the combustion heater is warmed up, the liquid fuel supply passage is connected to the combustion heater by the switching means. And a heater control means for combusting the liquid fuel with the combustion heater. The fuel vapor supply passage and the blow-by gas supply passage;
The switching means switches the connection of the liquid fuel supply passage, the fuel vapor supply passage, and the blowby gas supply passage to the combustion heater,
When the combustion heater is not warmed up, the heater control means connects the fuel vapor supply passage and the blow-by gas supply passage to the combustion heater by the switching means so as to supply the fuel vapor and the blow-by gas. The engine system with a combustion heater according to claim 1, wherein combustion is performed by the combustion heater. The engine is subjected to compression self-ignition combustion, which is combustion by self-ignition of an air-fuel mixture in a predetermined first operation region, and by spark ignition in a second operation region having a higher load or higher rotation speed than the first operation region. A compression self-ignition gasoline engine configured to perform spark ignition combustion, which is forced combustion,
The engine system with a combustion heater according to claim 1 or 2, wherein the combustion heater is attached to an engine block of the engine, and the engine is warmed up by heating cooling water flowing inside the engine block.   The combustion gas discharge passage according to any one of claims 1 to 3, further comprising a combustion gas discharge passage that connects the combustion heater and the intake passage and discharges combustion gas generated by the combustion heater to the intake passage. Engine system with combustion heater.

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