A method for improving plateau cold engine creeping start smoothness

Abstract

This invention provides a method to improve the smoothness of starting a cold-engine vehicle at high altitudes. It includes two steps: Step 1: When the vehicle is cold at high altitudes, during the initial creep start phase, a portion of the battery power is consumed, increasing the engine load. Then, the air conditioning compressor is shut off, and the engine starts to overcome obstacles. Step 2: By consuming a portion of the battery power during the creep start phase, the engine load is significantly increased after startup. Therefore, during use, by using forward or reverse gear and releasing the brake, the vehicle can overcome obstacles and escape from potholes. Simultaneously, the air conditioning compressor can be accurately shut off, increasing the engine load and reducing fuel consumption. Once the creep speed stabilizes, the air conditioning compressor engages normally, resulting in smooth vehicle start-up. This avoids the engine speed dropping due to insufficient engine torque and the resulting vehicle vibration.

Description

Technical Field

[0001] This invention relates to the field of vehicle engine control, specifically to a method for improving the smoothness of cold engine creep start at high altitudes. Background Technology

[0002] The car engine is the device that provides power to a car; it is the heart of the car and determines its power, economy, stability, and environmental performance. Depending on the power source, car engines can be divided into diesel engines, gasoline engines, electric motors for electric vehicles, and hybrid engines. Common gasoline and diesel engines are both reciprocating piston internal combustion engines, which convert the chemical energy of fuel into the mechanical energy of piston movement and output power. Gasoline engines have high speed, small mass, low noise, easy starting, and low manufacturing cost. Diesel engines have a large compression ratio, high thermal efficiency, and better economic and emission performance than gasoline engines.

[0003] At high altitudes, the ambient pressure is lower than at sea level, resulting in a smaller intake air volume for engine combustion. Consequently, at the same engine speed, the combustion torque is lower. When the vehicle is crawling at an altitude of 4700m, with the engine cold (below 40℃) and the air conditioning compressor engaged, the engine speed drops to 700rpm due to excessive engine resistance, causing the entire vehicle to vibrate (see...). Figure 2 In the diagram, line 1 represents vehicle speed (sp), line 2 represents engine speed (n), line 3 represents transmission target speed (ntcu), line 4 represents throttle opening (acc), line 5 represents compressor disconnection indicator (B_ac), and line 6 represents brake indicator (B_brk).

[0004] When the vehicle is in a cold state (immersed for more than 8 hours, at which point the engine water temperature is basically equal to the ambient temperature), power it on while it is stationary, turn on the headlights, air conditioning blower (fan speed set to maximum), hazard lights and other electrical equipment, and continue for about 10 minutes. During this process, the battery charge will drop rapidly, and the engine will start and enter idle mode.

[0005] Because the battery is in a depleted state after discharging, the generator is under a heavy load. When the air conditioner is turned on (compressor engages), the gearbox shifts to forward or reverse, and then the brake is released, before the vehicle starts moving, the sum of the engine friction resistance (high resistance when the engine is cold), accessory torque (high generator load, air conditioner torque), and gearbox creep torque is very high, exceeding the engine combustion torque. This causes the engine speed to drop into the pit, resulting in the vehicle shaking. At the same time, after the vehicle drops into the pit, it cannot get out of the pit, preventing the vehicle from moving forward. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a method for improving the smoothness of cold-start acceleration in high-altitude environments. This method solves the problem that when the battery is discharged and the generator is under heavy load, the air conditioning is turned on (compressor engaged), the transmission shifts to forward or reverse, and the brakes are released, the sum of engine friction resistance (high cold-start resistance), accessory torque (high generator load, air conditioning torque), and transmission creep torque is extremely high before the vehicle starts, exceeding the engine combustion torque. This causes the engine speed to drop below the ditch, resulting in vehicle vibration. Furthermore, after falling into the ditch, the vehicle cannot move forward.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for improving the smoothness of creep start-up of a high-altitude chiller, comprising the following steps:

[0010] Step 1: When the vehicle is cold at high altitude, during the initial crawling start phase, the battery will be partially depleted, increasing the engine load. Then, the air conditioning compressor will be shut off, and the engine will be started to pass the obstacle.

[0011] Step 2: With the vehicle cold at high altitude and the creeping speed stabilized, adjust the engine speed n, the transmission target speed ntcu, the computer control module ECU, and the air conditioning compressor B_ac.

[0012] Preferably, step one, which consumes part of the battery power, includes turning on the headlights, turning the air conditioner fan speed to maximum, and turning on the hazard lights for 10 minutes.

[0013] Furthermore, in step one, the engine is started, forward or reverse gear is engaged, and the brake is released to pass the obstacle.

[0014] Furthermore, after the vehicle reaches a stable creeping state in step two, the engine speed n responds to the transmission target speed ntcu, the computer control module ECU disconnects, the air conditioning compressor B_ac = 1, the total accessory torque is reduced by the air conditioning torque, and the vehicle begins to move.

[0015] Furthermore, in the high-altitude refrigeration state, the main control parameters for cutting off the air conditioning compressor include:

[0016] Altitude AL1 is a value based on the engine speed during creep start-up.

[0017] Generator load GL1 is a value based on the engine speed during creep start-up.

[0018] Vehicle speed SP1 is a value based on the engine speed during creep start-up.

[0019] The brake release delay time T1 is selected based on the engine speed performance during creep start-up.

[0020] Accelerator pedal opening ACC1 is a value based on the smoothness of vehicle start-up when accelerating.

[0021] Engine coolant temperature T2 is a value based on the engine speed during creep.

[0022] Vehicle speed SP and compressor delay time T3 are both values ​​based on the vehicle's smoothness of start-up performance.

[0023] The engine speed n is the engine's own idle speed before the brake is released, and it will respond to the gearbox's target speed when creeping.

[0024] The target speed of the transmission is ntcu, and the transmission controller takes the value based on the creep performance.

[0025] Furthermore, the operating procedures after the vehicle has been immersed for more than 8 hours are as follows:

[0026] Step 1: Power on the vehicle while it is stationary, keep the transmission gear signal Tra in neutral, turn on the headlights, turn the air conditioner blower fan to maximum, and turn on the hazard lights for 10 minutes to consume the battery power and significantly increase the alternator load after starting.

[0027] Step 2: Start the engine and let it idle. Turn on the air conditioner to cool down. The compressor will engage. Shift the gearbox to drive or reverse. Release the brake pedal (B_brk) and do not press the accelerator pedal (acc=0).

[0028] Step 3: After the compressor disconnection delay time T1, the computer control module ECU disconnects the air conditioning compressor;

[0029] Step 4: When the vehicle speed sp exceeds SP2, and after a delay of time T3, the air conditioning compressor engages.

[0030] Furthermore, the basic conditions that must be met for the vehicle to be powered on while in a cold state are as follows:

[0031] The transmission gear Tra is not in neutral (N);

[0032] The altitude AL is greater than the threshold AL1;

[0033] The generator load gl is greater than the threshold GL1;

[0034] The vehicle speed sp is lower than the threshold SP1;

[0035] Release the brake B_brk(1→0) and delay for time T1;

[0036] The engine coolant temperature t is lower than the threshold T2.

[0037] (III) Beneficial Effects

[0038] This invention provides a method for improving the smoothness of creep start-up in high-altitude chillers. It has the following beneficial effects:

[0039] 1. In high-altitude vehicles with cold engines, this invention significantly increases the engine load after starting by consuming part of the battery's charge during creeping starts. Therefore, when using the forward or reverse gear and releasing the brake, the vehicle can pass over obstacles and get out of potholes. At the same time, the air conditioning compressor can be accurately shut off, increasing the engine load and reducing fuel consumption. Once the creeping speed stabilizes, the air conditioning compressor engages normally, resulting in smooth vehicle start-up. This avoids the engine speed dropping due to insufficient combustion torque and the resulting vehicle vibration.

[0040] 2. This invention accurately cuts off the air conditioning compressor when the engine coolant temperature is below 40°C, preventing the engine speed from dropping and maintaining normal vehicle creep. This reduces the engine load and stabilizes vehicle creep. Once the vehicle is stable, the air conditioning compressor re-engages normally, thus avoiding vehicle vibration. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the compressor control logic for the high-altitude chiller creep start-up of the present invention;

[0042] Figure 2 This is a schematic diagram illustrating the compressor operation of the present invention, including a high-altitude creep start and a drop in engine speed.

[0043] Figure 3 This is a schematic diagram illustrating the normal engine speed performance of the high-altitude chiller during creep start-up, after the compressor is shut off.

[0044] Figure 4 This is a schematic diagram of the method for improving the smoothness of creeping start-up of a high-altitude chiller according to the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1:

[0047] like Figure 1 , 3 As shown in Figure 4 ( Figure 3Line 1 represents vehicle speed (sp), line 2 represents engine auto-speed (n), line 3 represents transmission target speed (ntcu), line 4 represents throttle opening (acc), line 5 represents compressor disconnection indicator (B_ac), and line 6 represents brake indicator (B_brk). This invention provides a method for improving the smoothness of starting a cold engine in high-altitude conditions, comprising the following steps:

[0048] Step 1: When the vehicle is cold at high altitude, during the crawling start-up phase, some of the battery power will be consumed. You need to turn on the headlights, turn the air conditioning fan to the maximum, and turn on the hazard lights. Keep this for 10 minutes to increase the engine load. Then start the engine, engage forward or reverse gear, and release the brake to pass the obstacle.

[0049] Step 2: When the vehicle is cold at high altitude, after the creeping speed stabilizes, the engine speed n responds to the transmission target speed ntcu, the computer control module ECU disconnects, the air conditioning compressor B_ac = 1, the total accessory torque is reduced by the air conditioning torque, and the vehicle begins to move.

[0050] When a vehicle is cold at high altitudes, the engine load increases significantly by consuming some of the battery power during creep start-up. Therefore, when using this method, releasing the brake while in forward or reverse gear allows the vehicle to overcome obstacles and get out of potholes. At the same time, the air conditioning compressor can be accurately shut off, increasing the engine load. Once the creep speed stabilizes, the air conditioning compressor engages normally, resulting in a smooth start-up. This avoids the engine torque loss that could cause the engine speed to drop below the pothole and the vehicle to vibrate.

[0051] Example 2:

[0052] like Figure 4 As shown, this embodiment of the invention provides a method for improving the smoothness of creeping start-up of a high-altitude chiller, which is a further expansion of the content in specific embodiment one:

[0053] Among them, the main control parameters for shutting off the air conditioning compressor when the unit is in high-altitude refrigeration mode include:

[0054] Altitude AL1 is selected based on the engine speed performance during creep start-up;

[0055] The generator load GL1 is selected based on the engine speed performance during creep start. After the headlights and air conditioning blower have been discharging for a long time, the battery is severely depleted. After starting the engine, the generator load is relatively high.

[0056] Vehicle speed SP1 is selected based on the engine speed performance during creep start. Creep torque is the largest when the vehicle just starts, so the compressor needs to be cut off at low vehicle speed.

[0057] The brake release delay time T1 is selected based on the engine speed performance during creep start-up;

[0058] Accelerator pedal opening ACC1 is set to an appropriate value based on the vehicle's smoothness during acceleration.

[0059] The engine coolant temperature T2 should be selected based on the engine speed performance during creep.

[0060] When the vehicle speed is greater than SP2, the compressor will engage at a delayed time (T3), with appropriate values ​​selected based on the vehicle's smoothness during start-up.

[0061] The engine speed n is the engine's own idle speed before the brake is released (which is less than the transmission's target speed when crawling). When crawling, it will respond to the transmission's target speed.

[0062] The target speed of the transmission is ntcu, and the transmission controller selects an appropriate value based on the creeping performance.

[0063] By increasing the engine load and disconnecting the air conditioning compressor for a period of time, the engine power is increased, thus increasing the vehicle's running power and allowing the vehicle to get out of the ditch. After the vehicle starts and runs smoothly, the computer control module ECU controls the air conditioning compressor to engage, maintaining the vehicle's smooth operation.

[0064] Example 3:

[0065] like Figure 3 As shown, this embodiment of the invention provides a method for improving the smoothness of creeping start-up of a high-altitude chiller, which is a further expansion of the content in specific embodiment one:

[0066] The following are the procedures for handling vehicles that have been submerged for more than 8 hours:

[0067] Step 1: Power on the vehicle while it is stationary, keep the transmission gear signal Tra in neutral, turn on the headlights, turn the air conditioner blower fan to maximum, and turn on the hazard lights for 10 minutes to consume the battery power and significantly increase the alternator load after starting.

[0068] Step 2: Start the engine and let it idle. Turn on the air conditioner to cool down. The compressor will engage. Shift the gearbox to drive or reverse. Release the brake pedal (B_brk) and do not press the accelerator pedal (acc=0).

[0069] Step 3: After the compressor disconnection delay time T1, the computer control module ECU disconnects the air conditioning compressor;

[0070] Step 4: When the vehicle speed sp exceeds SP2, and after a delay of T3, the air conditioning compressor engages;

[0071] When the vehicle starts to creep, the battery is partially discharged to increase the engine load and reduce fuel consumption. After the air conditioning compressor is disconnected for time T3, the engine speed n is stable, so the vehicle speed sp is stable. The air conditioning compressor is then controlled to engage by the computer control module ECU.

[0072] Example 4:

[0073] like Figure 4 As shown, this embodiment of the invention provides a method for improving the smoothness of creeping start-up of a high-altitude chiller, which is a further expansion of the content in specific embodiment one:

[0074] Among them, when the vehicle is cold and stationary, power it on, turn on the headlights, turn the air conditioning to maximum fan speed, turn on the hazard lights, and keep it running for about 10 minutes to consume some of the battery's charge. Then start the engine, engage a drive or reverse gear, and release the brake. If the following basic conditions are met:

[0075] The transmission gear Tra is not in neutral (N);

[0076] The altitude al is greater than the threshold AL1;

[0077] The generator load gl is greater than the threshold GL1;

[0078] The vehicle speed sp is lower than the threshold SP1;

[0079] Release the brake B_brk(1→0) and delay for a period of time T1;

[0080] The engine coolant temperature t is lower than the threshold T2;

[0081] When the engine speed n responds to the transmission target speed ntcu (ntcu>n), the computer control module ECU disconnects the air conditioning compressor B_ac=1. At this time, the total accessory torque needs to be reduced by the air conditioning torque, which reduces the engine resistance, and the vehicle begins to move.

[0082] Example 5:

[0083] like Figure 4 As shown, this embodiment of the invention provides a method for improving the smoothness of creeping start-up of a high-altitude chiller, which is a further expansion of the content in specific embodiment one:

[0084] The computer control module (ECU) needs to meet any one of the following conditions to control the air conditioner compressor to engage:

[0085] If the vehicle speed sp is higher than the threshold SP2, there will be a delay of T3.

[0086] Accelerator pedal opening acc is greater than the threshold ACC1;

[0087] Once any one of the conditions is met, the air conditioner compressor B_ac = 0, and the air conditioner compressor engages.

[0088] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for improving the smoothness of creep start-up of a high-altitude chiller, characterized in that: Includes the following steps: Step 1: When the vehicle is cold at high altitude, during the initial crawling start phase, the battery will be partially depleted, increasing the engine load. Then, the air conditioning compressor will be shut off, and the engine will be started to pass the obstacle. Step 2: With the vehicle cold at high altitude and the creeping speed stabilized, adjust the engine speed n, transmission target speed ntcu, computer control module ECU, and air conditioning compressor B_ac. After the vehicle has been submerged for more than 8 hours, step one further includes: Step S1: Power on the vehicle while stationary, keep the gearbox gear signal Tra in neutral, turn on the headlights, set the air conditioner blower to maximum fan speed, and turn on the hazard lights for 10 minutes to consume battery power and significantly increase the alternator load after startup. Step S2: Start the engine and idle, turn on the air conditioner to cool, the compressor engages, shift the gear to forward or reverse, release the brake pedal B_brk, and do not press the accelerator pedal acc=0; Step S3: After the brake delay time T1 is released, the computer control module ECU disconnects the air conditioning compressor; Step two also includes: Step S4: When the vehicle speed sp exceeds SP2, and after a delay of T3, the air conditioning compressor is activated by the computer control module ECU. The basic conditions that the computer control module (ECU) needs to meet to disconnect the air conditioning compressor also include: The transmission gear Tra is not in neutral (N); The altitude AL is greater than the threshold AL1; The generator load gl is greater than the threshold GL1; The vehicle speed sp is lower than the threshold SP1; The engine coolant temperature t is lower than the threshold T2.

2. The method for improving the smoothness of creep start-up of a high-altitude chiller according to claim 1, characterized in that: Step S3 specifically includes: after the vehicle is in a stable creeping state, the engine speed n responds to the transmission target speed ntcu, the computer control module ECU disconnects the air conditioning compressor B_ac=1, the total accessory torque is reduced by the air conditioning torque, and the vehicle begins to move.

3. The method for improving the smoothness of creep start-up of a high-altitude chiller according to claim 1, characterized in that: When the air conditioning compressor is turned off in the cold state of a high-altitude vehicle, the main control parameters include: Altitude AL1 is a value based on the engine speed during creep start-up. Generator load GL1 is a value based on the engine speed during creep start-up. Vehicle speed SP1 is a value based on the engine speed during creep start-up. The brake release delay time T1 is selected based on the engine speed performance during creep start-up. Accelerator pedal opening ACC1 is a value based on the smoothness of vehicle start-up when accelerating. Engine coolant temperature T2 is a value based on the engine speed during creep. Vehicle speed SP2 and compressor delay time T3 are both values ​​based on the vehicle's smoothness during start-up. The engine speed n is the engine's own idle speed before the brake is released, and it will respond to the gearbox's target speed when creeping. The target speed of the transmission is ntcu, and the transmission controller takes the value based on the creep performance.

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