Heavy truck integrated extreme low temperature starting system

Abstract

The utility model relates to a kind of heavy truck integration extreme low temperature starting system of coordination, solve the current lack of coordinated control strategy for dual-voltage system, the problem of low energy conversion efficiency.System includes generator, lithium battery group, DCDC, whole vehicle controller VCU, 24V lead-acid battery group, starter and engine, wherein, generator, lithium battery group, DCDC, engine respectively through CAN bus and whole vehicle controller VCU communication, generator is electrically connected with lithium battery group and DCDC respectively, lithium battery group is connected with 24V lead-acid battery group by DCDC, 24V lead-acid battery group and starter are electrically connected, engine is mechanically connected with generator and starter respectively.Method includes low temperature starting stage, energy recovery stage and fault tolerance mechanism.The utility model ensures that engine reaches ignition speed under extremely low temperature environment;Realize energy efficient recovery;Build redundancy safety system;Improve system compatibility: adapt to existing heavy truck, without modifying engine compartment layout, reduce modification cost.

Description

Technical Field

[0001] This utility model relates to a low-temperature starting system, specifically to a heavy-duty truck collaborative integrated extreme low-temperature starting system. Background Technology

[0002] Currently, heavy-duty truck starting systems primarily rely on traditional starters powered by 24V lead-acid batteries. However, in low-temperature environments (such as below -40°C), on the one hand, the increased viscosity of engine oil leads to increased internal mechanical resistance and flywheel passive torque; on the other hand, the capacity of lead-acid batteries can decrease by 40%-50% at low temperatures. These combined factors result in insufficient starter torque, making it difficult for the engine to reach ignition speed. Existing solutions suffer from the following technical deficiencies:

[0003] 1. System function is fragmented: Traditional generators and starters operate independently. The generator is only used for charging and cannot provide auxiliary power during the starting phase. Moreover, the energy recovery efficiency is low.

[0004] 2. Insufficient low-temperature adaptability: Relying on a single starter motor, even with the addition of preheating devices (such as fuel heaters or glow plugs), there are still problems with starting delays and starting difficulties.

[0005] 3. Lack of system redundancy: Traditional generators and starters are separate functions, and there is no backup power source in case of failure.

[0006] Existing solutions lack coordinated control strategies for dual-voltage systems, resulting in low energy conversion efficiency. Therefore, there is an urgent need for a highly coordinated and redundant starting system that can overcome starting limitations in low-temperature environments through coordinated control of the generator and starter motor, while simultaneously improving energy utilization efficiency. Utility Model Content

[0007] This invention provides a heavy-duty truck collaborative integrated extreme low-temperature starting system, which solves the current problems of lacking collaborative control strategies for dual-voltage systems and low energy conversion efficiency.

[0008] This utility model is achieved through the following technical solution:

[0009] A heavy-duty truck collaborative integrated extreme low-temperature starting system includes a generator 101, a lithium battery pack 102, a DC-DC converter 103, a vehicle controller (VCU) 104, a 24V lead-acid battery pack 105, a starter motor 106, and an engine 107. The generator 101, lithium battery pack 102, DC-DC converter 103, and engine 107 communicate with the vehicle controller (VCU) 104 via a CAN bus. The generator 101 is electrically connected to both the lithium battery pack 102 and DC-DC converter 103. The lithium battery pack 102 is connected to the 24V lead-acid battery pack 105 via DC-DC converter 103. The 24V lead-acid battery pack 105 is electrically connected to the starter motor 106. The engine 107 is mechanically connected to both the generator 101 and the starter motor 106.

[0010] The generator 101 is installed at the front end of the engine 107 and is connected to the crankshaft pulley via a multi-ribbed belt. It supports positive / negative torque modes, with a control circuit voltage of 24V and a drive circuit voltage of >40V.

[0011] The lithium battery pack 102 is managed by a BMS, with an operating temperature range of -40℃ to 60℃ and a discharge efficiency of ≥85% at low temperatures.

[0012] The DCDC103 features a bidirectional isolation design and supports two conversion modes: >40V high voltage → 24V and 24V → >40V high voltage. The >40V high voltage → 24V charging mode takes priority, and the reverse mode is activated only when pre-charging is required.

[0013] The vehicle controller VCU104 receives KL15 / STAR gear signals, engine speed 107, and BMS status in real time, and can dynamically calculate the IBSG torque request value and perform torque gradient control.

[0014] The 24V lead-acid battery pack 105 supplies power to the vehicle and starter motor.

[0015] Using the above system, the extreme low temperature start-up method includes:

[0016] Low temperature start-up phase:

[0017] Step 1:

[0018] When KL15 is powered on, VCU104 triggers the DC-DC10324V→>40V high voltage mode pre-charging, aiming to raise the voltage of the lithium battery pack 102 to 85% of the rated voltage within 500ms. At the same time, the instrument displays "Pre-charging in progress, please start later".

[0019] Step 2:

[0020] If pre-charging is complete, the STAR mode is triggered. VCU104 requests positive torque and a suitable torque gradient from generator 101. Generator 101 outputs positive torque, which is amplified to crankshaft torque through the speed ratio to ensure that the engine reaches 600 rpm within 3 seconds.

[0021] If pre-charging is not completed, generator 101 will not engage, torque will be 0, starter 106 will operate, and the instrument panel will display "Starting assistance limited";

[0022] Energy recovery stage:

[0023] When the vehicle brakes, VCU104 controls the generator 101 to switch to negative torque mode to recover energy and store it in the lithium battery pack 102. At the same time, DCDC103 replenishes the 24V lead-acid battery pack 105 as needed.

[0024] Fault tolerance mechanism:

[0025] CAN failure communication interruption: VCU104 disables generator 101 torque mode by default, and starter 106 is fully responsible for starting;

[0026] Lithium battery pack 102 voltage abnormality: BMS disables power output, DCDC105 switches to 24V→>40V high voltage emergency power replenishment mode.

[0027] The beneficial effects of this utility model are:

[0028] 1. The generator outputs torque via belt drive, which is amplified by the flywheel speed ratio to provide some auxiliary torque to the engine, ensuring that the engine can quickly reach the ignition speed in extremely low temperature environments.

[0029] 2. Achieve efficient energy recovery: After recovering kinetic energy using the generator's negative torque mode, it is stored in the lithium battery and dynamically distributed to the 24V lead-acid battery via DC-DC converter to power the entire vehicle, thus improving fuel economy.

[0030] 3. Construct a redundant safety system: When the main coordinating unit fails, it automatically switches to the backup start-up mode to ensure the basic operating capability of the vehicle.

[0031] 4. Improve system compatibility: Adapts to existing heavy-duty truck platforms without requiring modifications to the engine compartment layout, reducing modification costs. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0033] This utility model is a heavy-duty truck collaborative integrated extreme low-temperature starting system.

[0034] 1 System Architecture and Core Components

[0035] Appendix Figure 1 The system's structure is shown, including the following key components:

[0036] Generator 101

[0037] It replaces the original vehicle's traditional alternator, is installed at the front of the engine, and is connected to the crankshaft pulley via a multi-ribbed belt with a speed ratio greater than 3.8. Peak torque is greater than 55 Nm (peak torque duration greater than 4 seconds), supports positive / negative torque modes, control circuit voltage is 24V, and drive circuit voltage is greater than 40V.

[0038] Lithium battery pack 102

[0039] Capacity ≥ 20Ah, managed by BMS (Battery Management System), and supports CAN communication.

[0040] Operating temperature range: -40℃ to 60℃; discharge efficiency at low temperatures: ≥85%.

[0041] DCDC103

[0042] The bidirectional isolation design supports two modes: high voltage (>40V) → 24V (>1.5kW, conversion power) and 24V → high voltage (>40V) (>500W, conversion power).

[0043] Priority strategy: High voltage (>40V) → 24V charging mode takes priority, and reverse mode is activated only when pre-charging is required.

[0044] Vehicle controller VCU104

[0045] It integrates multiple CAN communication interfaces to receive KL15 / STAR gear signals, engine speed (from engine ECU, part number 107), and BMS status in real time.

[0046] The torque request value of IBSG is dynamically calculated and torque gradient control is performed through VCU control.

[0047] 24V lead-acid battery pack 105

[0048] The heavy-duty truck uses a traditional 120Ah battery to supply power to the vehicle and starter motor.

[0049] Starter 106

[0050] The traditional 24V starter motor of a heavy-duty truck engine is controlled by the ignition switch in the Star position and provides starting torque to the engine.

[0051] Engine 107

[0052] Heavy-duty truck engine, starting torque <2100Nm, starting speed >600rpm.

[0053] 2. Working Principle and Control Logic

[0054] Low temperature start-up phase:

[0055] Step 1 (Powering on KL15):

[0056] VCU104 triggers 24V → high voltage (>40V) DC-DC103 pre-charge, aiming to raise the voltage of lithium battery pack 102 to 85% of the rated voltage within 500ms. At the same time, the instrument displays "Pre-charging in progress, please start later".

[0057] Step 2 (STAR ​​file triggered):

[0058] If pre-charging is complete, VCU104 requests positive torque and a suitable torque gradient from generator 101. Generator 101 outputs positive torque, which is amplified to crankshaft torque via a speed ratio to ensure that the engine reaches 600 rpm within 3 seconds.

[0059] If pre-charging is not completed, generator 101 will not engage, torque will be 0, only traditional starter 106 will work, and the instrument will display "Starting assistance limited".

[0060] Energy recovery stage:

[0061] When the vehicle brakes, VCU104 controls the generator 101 to switch to negative torque mode to recover energy and store it in the lithium battery pack 102. At the same time, DC-DC103 replenishes the 24V lead-acid battery pack 105 as needed (activated when SOC < 80%).

[0062] Fault tolerance mechanism:

[0063] Communication interruption (CAN failure): VCU104 disables the generator 101 torque mode by default, and the traditional starter motor 106 is fully responsible for starting.

[0064] Lithium battery pack 102 voltage abnormal (below or above the safe voltage range): BMS disables power output, DCDC105 switches to 24V→high voltage (>40V) emergency power replenishment mode.

[0065] 3 Key Parameters and Performance Indicators

[0066]

[0067] This utility model has the following features:

[0068] Deep integration of dual-voltage system: Through the collaborative design of high-voltage (>40V) generator and 24V lead-acid battery, physical isolation between high-voltage drive and low-voltage control is achieved to avoid electromagnetic interference.

[0069] Modular installation and adaptation: The generator directly replaces the original vehicle generator without changing the engine compartment layout, reducing modification costs by 30%.

[0070] Dynamic torque distribution strategy: Based on real-time speed and battery SOC feedback, the VCU dynamically adjusts the generator torque gradient to balance start-up speed and mechanical shock (e.g., gradient of 150 Nm / s during the intervention phase and <50 Nm / s during the withdrawal phase).

[0071] Pre-charge-startup decoupling mechanism: After the KL15 is powered on, pre-charge and traditional starter activation are performed in parallel, reducing the total startup time to 70% of the traditional solution.

[0072] This invention breaks through the technical bottleneck of starting heavy-duty trucks in extreme low temperatures, supporting reliable starting in environments as low as -40°C; the energy recovery system reduces fuel consumption by 10% and reduces CO2 emissions by approximately 1.2 tons per year (based on 100,000 km / year); the lead-acid battery replacement cycle is extended to 5 years, and maintenance costs are reduced by 25%; it is compatible with existing heavy-duty truck platforms, with modification costs of less than 5,000 yuan per vehicle and an investment payback period of less than 2 years; it provides a reusable integrated solution for generators and starters for the electrification of commercial vehicles, accelerating the industry's transformation towards low-carbon development.

Claims

1. A heavy-duty truck collaborative integrated extreme low-temperature starting system, characterized in that: The system includes a generator (101), a lithium battery pack (102), a DC-DC converter (103), a vehicle control unit (VCU) (104), a 24V lead-acid battery pack (105), a starter motor (106), and an engine (107). The generator (101), lithium battery pack (102), DC-DC converter (103), and engine (107) communicate with the vehicle control unit (VCU) (104) via a CAN bus. The generator (101) is electrically connected to the lithium battery pack (102) and DC-DC converter (103). The lithium battery pack (102) is connected to the 24V lead-acid battery pack (105) via DC-DC converter (103). The 24V lead-acid battery pack (105) is electrically connected to the starter motor (106). The engine (107) is mechanically connected to the generator (101) and starter motor (106).

2. The heavy-duty truck collaborative integrated extreme low-temperature starting system according to claim 1, characterized in that: The generator (101) is installed at the front end of the engine (107) and connected to the crankshaft pulley via a multi-ribbed belt. It supports positive / negative torque modes, with a control circuit voltage of 24V and a drive circuit voltage of >40V. The lithium battery pack (102) is managed by the BMS, with an operating temperature range of -40℃ to 60℃ and a discharge efficiency of ≥85% at low temperatures; The DCDC (103) bidirectional isolation design supports two conversion modes: >40V high voltage → 24V and 24V → >40V high voltage. The >40V high voltage → 24V charging mode takes priority, and the reverse mode is activated only when pre-charging is required. The vehicle control unit (VCU) (104) receives the KL15 / STAR gear signal, engine (107) speed and BMS status in real time, and can dynamically calculate the IBSG torque request value and perform torque gradient control. A 24V lead-acid battery pack (105) supplies power to the vehicle and starter motor.

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