A calibration and control method for a non-road China IV diesel engine with EGR and range extender.

Abstract

This invention discloses a calibration method for a non-road China IV diesel engine with EGR and a range extender, comprising the following steps: S1, determining the engine's charging operating speed; S2, idling speed calibration, which is performed using injection timing and rail pressure values, and then the rationality of the idling speed calibration is confirmed by combining NOx and HC emissions; S3, charging operating speed calibration, under charging conditions, calibrating the engine charging load rate to <85% and the EGR valve opening to ≤10%. This invention has advantages such as good economy and low exhaust smoke.

Description

Technical Field

[0001] This invention relates to the field of engine calibration technology, and in particular to a calibration and control method for a non-road China IV diesel engine with EGR and a range extender. Background Technology

[0002] Range-extended electric vehicles (REEVs), a type of new energy vehicle, combine an engine and a generator into a range extender, allowing the engine to operate mostly in its high-efficiency range. This new energy approach is increasingly being used in various niche applications. From the perspective of product adaptability and electrification policy trends, REEVs can fully leverage their advantages in short-to-medium distance pure electric driving and long-distance extended-range driving in specific scenarios, alleviating range anxiety associated with pure electric buses.

[0003] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0004] The main objective of this invention is to propose a calibration and control method for a non-road Euro IV diesel engine with EGR and range extender that is economical and produces low exhaust smoke.

[0005] Therefore, this invention proposes a calibration and control method for a non-road China IV diesel engine with EGR and a range extender.

[0006] Preferably, the present invention may also have the following technical features:

[0007] A calibration method for a non-road China IV diesel engine with EGR and range extender includes the following steps:

[0008] S1. Determine the engine's charging operating speed;

[0009] S2. Idle speed calibration: Idle speed is calibrated by using fuel injection timing and rail pressure values. Then, the rationality of the idle speed calibration is confirmed by combining NOx and HC emissions.

[0010] S3. Charging operating speed calibration: Under charging conditions, calibrate the engine charging load rate to <85% and the EGR valve opening to ≤10%.

[0011] Further, in step S1, the rail pressure value is calibrated to be between 250 and 300 bar, and the fuel injection timing value is calibrated to be between 0 and 4°CA.

[0012] Further, in step S3, the rail pressure value P and the fuel injection timing value Q corresponding to the generator speed of the range extender are determined.

[0013] Furthermore, during the charging operation, when the engine charging load rate is 75-85%, the injection timing and rail pressure at the 75-85% load rate are increased by a certain value relative to the rail pressure value P and the injection timing value Q.

[0014] Furthermore, the rail pressure at 75-85% load rate is increased by 20-40%, and the fuel injection timing at 75-85% load rate is increased by 40-100%.

[0015] Furthermore, when the engine load rate is below 75%, the injection timing and rail pressure are increased by a certain value relative to the rail pressure value P and the injection timing value Q.

[0016] Furthermore, the injection timing boost value at load rates below 75% is 40-60% lower than that at load rates of 75-85%, and the calibrated rail pressure boost value at load rates below 75% is 20-40%.

[0017] A diesel engine charging control method based on the above-mentioned calibration method for a non-road China IV diesel engine with EGR and range extender, characterized by comprising the following steps:

[0018] S101. The engine is started by driving the motor. When the engine speed reaches the first preset value, the engine is ignited and runs to the idle speed.

[0019] S102. After the engine has been idling for a first preset time, the engine will switch from idling speed to charging speed.

[0020] S103. Under charging operating speed conditions, control the engine charging load rate to be <85% and the EGR valve opening to be ≤10%;

[0021] S104. After charging is completed, the engine gradually reduces its load and decelerates from the charging operating speed to idle speed.

[0022] S105. After the engine has been running at idle speed for a second preset time, the engine stops at idle speed by turning off the throttle and the electronic water pump is controlled to cool for a third preset time.

[0023] Furthermore, in step S102, when the engine is cold-started, the engine enters the idle warm-up condition after idling for a first preset time; after the warm-up is completed, the engine is then uniformly loaded from idle speed to charging operating speed.

[0024] Furthermore, the second preset time is ≥10S, the third preset time is 5~10min; the loading time of the engine from idle speed to charging operating speed is ≥5S; the unloading time of the engine from charging operating speed to idle speed is ≥5S.

[0025] The beneficial effects of this invention compared to existing technologies include: The charging operating point, since the operating speed does not fall within the eight emission conditions, allows for a suitable reduction in EGR opening, not exceeding 10%. This effectively ensures good fuel economy and low exhaust smoke during diesel engine operation, and further extends the regeneration cycle of the aftertreatment system. The electronic water pump cooling system effectively lowers the engine temperature. Attached Figure Description

[0026] Figure 1 This is a control flowchart of the range extender calibration method of the present invention.

[0027] Figure 2 This is a schematic diagram of the operating conditions of the range extender in the diesel engine charging control method of the present invention.

[0028] Figure 3 This is a control flowchart of the diesel engine charging control method of the present invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope or application of the present invention.

[0030] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0031] like Figure 1 The calibration method shown is for a non-road China IV diesel engine with EGR and range extender, which includes the following steps:

[0032] S1. Determine the engine's charging operating speed. When the engine speed reaches the charging operating speed, the engine acts as a generator to continuously charge the power battery.

[0033] Currently, the power generation speed of range extenders is generally 1700-1800 r / min, while the intermediate speed of steady-state emission eight operating conditions is generally 1600 r / min. It can be seen that the charging operating speed of range extenders is different from the intermediate speed of steady-state emission eight operating conditions.

[0034] When the engine equipped with a range extender is running, pay close attention to its idle speed and charging speed.

[0035] S2. Idle speed calibration: Idle speed is calibrated by using fuel injection timing and rail pressure values. Then, the rationality of the idle speed calibration is confirmed by combining NOx and HC emissions.

[0036] Because there is no pressure difference (turbo pressure - boost pressure) at engine idle, exhaust gas cannot enter the intake manifold through the EGR valve and thus mix before flowing into the piston. Therefore, in this embodiment, idle speed can only be calibrated by fuel injection timing and rail pressure. The calibrated rail pressure value is between 250 and 300 bar, and the calibrated fuel injection timing value is between 0 and 4°CA.

[0037] S3. Charging operating speed calibration: Under charging conditions, calibrate the engine charging load rate to <85% and the EGR valve opening to ≤10%.

[0038] During charging, since the charging operating speed is not at the emission point of the steady-state eight operating conditions, a strategy of appropriately reducing the EGR valve opening is adopted, and the EGR valve opening does not exceed 10%. This can effectively ensure good fuel economy during engine operation, reduce exhaust smoke by 50%, and further extend the regeneration cycle of the aftertreatment system.

[0039] Specifically, during charging conditions, when the engine charging load rate is 75-85%, the injection timing and rail pressure at this load rate are increased by a certain value relative to the rail pressure value P and the injection timing value Q. For example, in some engine models, the calibrated rail pressure value P is 1000-1200 bar, and the injection timing value Q is 5-7°CA. When the charging condition is at 75-85% load rate, the injection timing is increased from 5-7°CA to 7-10°CA, and the rail pressure is increased from 1000-1200 bar to 1200-1400 bar. When the load rate is below 75%, the injection timing and rail pressure relative to the rail pressure value P and injection timing value Q can also be appropriately increased. Specifically, the injection timing increase below 75% load rate is 2-3°CA lower than the increase at 75-85% load rate, and the calibrated rail pressure value P is increased from 1000-1200 bar to 1200-1400 bar to meet the requirements of transient NRTC emissions. This calibration ensures that emissions meet requirements while improving economy and the after-treatment regeneration cycle.

[0040] In the above, the calibrated rail pressure value P and the injection timing value Q are the rail pressure and injection timing corresponding to the generator speed of the range extender at 1700~1800 r / min.

[0041] Figures 2-3 A diesel engine charging control method based on the calibration method for a non-road China IV diesel engine with EGR and range extender includes the following steps:

[0042] S101. The engine is started by driving the motor. When the engine speed reaches the first preset value, the engine is ignited and runs to the idle speed.

[0043] S102. After the engine has been running at idle speed for a first preset time, the engine is uniformly loaded from idle speed to charging operating speed, for example, the engine idle speed is ≥5 seconds; preferably, the loading time from idle speed to charging operating speed is ≥5 seconds.

[0044] In step S102, when the engine is cold-started, it idles for a first preset time before entering the idle warm-up mode. After the warm-up is complete, the engine gradually accelerates from idle to the charging operating speed. The coolant temperature is used to determine whether to enter the idle warm-up mode. In other words, during a cold start, the idling time is increased to warm up the engine.

[0045] S103. Under charging operating speed conditions, control the engine charging load rate to be <85% and the EGR valve opening to be ≤10%;

[0046] S104. After charging is completed, the engine gradually reduces its load and decelerates from the charging operating speed to idle speed. Preferably, the deceleration time of the engine gradually reducing its load and decelerating from the charging operating speed to idle speed is ≥5 seconds;

[0047] S105. After the engine has been running at idle speed for a second preset time, the engine stops at idle speed by turning off the throttle and the electronic water pump is controlled to cool for a third preset time.

[0048] In step S105, the second preset time is ≥10 seconds, and the third preset time is 5–10 minutes. After the engine stops, the electric water pump continues to operate for 5–10 minutes to continuously cool the engine.

[0049] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0050] Although exemplary embodiments of the invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the invention without departing from the central concepts of the invention described herein. Therefore, the invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the invention.

Claims

1. A non-road stage IV with EGR diesel engine with range extender calibration method, characterized in that: Includes the following steps: S1. Determine the engine's charging operating speed; S2. Idle speed calibration: Idle speed is calibrated by using injection timing and rail pressure values. Then, the rationality of the idle speed calibration is confirmed by combining NOx and HC emissions. The calibrated rail pressure value is between 250 and 300 bar, and the calibrated injection timing value is between 0 and 4°CA. S3. Calibration of charging operating speed: Under charging conditions, calibrate the engine charging load rate to <85% and the EGR valve opening to ≤10%; determine the rail pressure value P and injection timing value Q corresponding to the generator speed of the range extender; under charging conditions, when the engine charging load rate is 75~85%, the injection timing and rail pressure at the 75~85% load rate are increased by a certain value relative to the rail pressure value P and the injection timing value Q; the rail pressure at the 75~85% load rate is increased by 20~40%, and the injection timing at the 75~85% load rate is increased by 40~100%; When the engine load rate is below 75%, the injection timing and rail pressure are increased by a certain value relative to the rail pressure value P and the injection timing value Q. The increase in injection timing below 75% load rate is 40-60% lower than the increase in 75-85% load rate, and the calibrated rail pressure is increased by 20-40% below 75% load rate.

2. A method for charging control of a diesel engine performed according to the calibration method of the non-road state IV diesel engine with EGR with a range extender according to claim 1, characterized in that: Includes the following steps: S101. The engine is started by driving the motor. When the engine speed reaches the first preset value, the engine is ignited and runs to the idle speed. S102. After the engine has been idling for a first preset time, the engine will switch from idling speed to charging speed. S103. Under charging operating speed conditions, control the engine charging load rate to be <85% and the EGR valve opening to be ≤10%; S104. After charging is completed, the engine gradually reduces its load and decelerates from the charging operating speed to idle speed. S105. After the engine has been running at idle speed for a second preset time, the engine stops at idle speed by turning off the throttle and the electronic water pump is controlled to cool for a third preset time.

3. A method for charging control of a diesel engine according to the method for calibrating a non-road US IV diesel engine with EGR with a range extender according to claim 2, characterized in that: In step S102, when the engine is cold-started, the engine enters the idle warm-up condition after idling for a first preset time, and the engine is uniformly loaded from idle speed to charging working speed.

4. The diesel engine charging control method according to the calibration method of a non-road China IV diesel engine with EGR and range extender as described in claim 2, characterized in that: The second preset time is ≥10S, and the third preset time is 5~10min; the loading time of the engine from idle speed to charging operating speed is ≥5S; the unloading time of the engine from charging operating speed to idle speed is ≥5S.

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