Collaborative and integrated extreme low-temperature starting system and method for heavy truck
The coordinated integrated design of the generator and starter solves the problem of heavy trucks having difficulty starting at low temperatures, achieves rapid start-up and efficient energy utilization, reduces modification costs and reduces carbon emissions.
Patent Information
- Application Number
- CN202510849514.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-10-03
AI Technical Summary
Heavy trucks have difficulty starting in low-temperature environments. The existing starting system has fragmented functions, insufficient low-temperature adaptability and lacks redundancy, resulting in insufficient starter torque and low energy conversion efficiency.
It adopts a coordinated integrated design of the generator and starter, realizes bidirectional voltage conversion through a DCDC converter, combines lithium battery packs and lead-acid battery packs, and uses the vehicle controller to dynamically control torque gradient and energy recovery to build a redundant safety system.
Ensure quick engine start-up in extremely low temperatures, improve energy utilization efficiency, reduce modification costs, improve system compatibility and redundancy, and reduce fuel consumption and carbon emissions.
Smart Images
Figure CN120735707A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a low-temperature starting system, and in particular to a coordinated integrated extreme low-temperature starting system and method for heavy trucks. Background Art
[0002] Currently, heavy-duty truck starting systems primarily rely on traditional starters powered by 24V lead-acid batteries. However, in low-temperature environments (e.g., below -40°C), engine oil viscosity increases, increasing internal mechanical resistance and flywheel torque. Furthermore, the capacity of lead-acid batteries can decay by 40%-50% in low-temperature environments. These two factors lead to insufficient starter torque, making it difficult for the engine to reach ignition speed. Existing solutions suffer from the following technical drawbacks:
[0003] 1. System function separation: The traditional generator and starter operate independently. The generator is only used for charging and cannot provide auxiliary power during the starting phase. In addition, the energy recovery efficiency is low.
[0004] 2. Insufficient adaptability to low temperatures: Relying on a single starter, even if a preheating device (such as a fuel heater or glow plug) is installed, there are still problems of starting delay and starting difficulty.
[0005] 3. Lack of system redundancy: The traditional generator and starter functions are separated, and there is a lack of backup power source in the event of a failure.
[0006] Existing solutions lack a coordinated control strategy for dual-voltage systems, resulting in low energy conversion efficiency. Therefore, a highly coordinated and redundant starting system is urgently needed. By coordinating the generator and starter, it can overcome the starting limitations in low-temperature environments and improve energy efficiency. Summary of the Invention
[0007] The present invention solves the current problems of lack of collaborative control strategy for dual voltage systems and low energy conversion efficiency by providing a coordinated integrated extreme low temperature starting system and method for heavy trucks.
[0008] The present invention is achieved by the following technical solutions:
[0009] A coordinated and integrated extreme low-temperature starting system for a heavy-duty truck 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 106, and an engine 107. The generator 101, the lithium battery pack 102, the DC / DC converter 103, and the engine 107 communicate with the vehicle controller VCU 104 via a CAN bus. The generator 101 is electrically connected to the lithium battery pack 102 and the DC / DC converter 103, respectively. The lithium battery pack 102 is connected to the 24V lead-acid battery pack 105 via the DC / DC converter 103, the 24V lead-acid battery pack 105 is electrically connected to the starter 106, and the engine 107 is mechanically connected to the generator 101 and the starter 106.
[0010] The generator 101 is installed at the front end of the engine 107 and is connected to the crankshaft pulley through a poly-V belt. It supports positive / negative torque mode, the control circuit voltage is 24V, and the drive circuit voltage is greater than 40V.
[0011] The lithium battery pack 102 is managed by a BMS, has an operating temperature range of -40°C to 60°C, and a discharge efficiency of ≥85% at low temperatures.
[0012] The DCDC103 has 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 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.
[0014] The 24V lead-acid battery pack 105 supplies power to the entire vehicle and the starter.
[0015] A coordinated and integrated extreme low-temperature starting method for heavy trucks, utilizing the above-mentioned system, comprises:
[0016] Low temperature start-up phase:
[0017] Step 1:
[0018] When KL15 is powered on, VCU104 triggers DCDC10324V→>40V high-voltage mode pre-charging, aiming to increase the voltage of lithium battery pack 102 to 85% of the rated voltage within 500ms. At the same time, the instrument displays "Pre-charging, please start later";
[0019] Step 2:
[0020] If pre-charging is completed, the STAR gear is triggered, and the VCU 104 requests positive torque and a suitable torque gradient from the generator 101. The generator 101 outputs positive torque, which is amplified to the crankshaft torque through the speed ratio to ensure that the engine reaches 600 rpm within 3 seconds.
[0021] If pre-charging is not completed, the generator 101 does not intervene, the torque is 0, the starter 106 works, and the instrument prompts "starting assistance limited";
[0022] Energy recovery stage:
[0023] When the vehicle brakes, the VCU 104 controls the generator 101 to switch to negative torque mode, recovering energy and storing it in the lithium battery pack 102 . At the same time, the DCDC 103 replenishes power to the 24V lead-acid battery pack 105 as needed.
[0024] Fault tolerance mechanism:
[0025] CAN failure communication interruption: VCU 104 disables the full torque mode of generator 101 by default, and starter 106 takes full responsibility for starting;
[0026] The voltage of the lithium battery pack 102 is abnormal: the BMS disables power output, and the DCDC105 switches to the 24V→>40V high-voltage emergency power supply mode.
[0027] Beneficial effects of the present invention:
[0028] 1. The generator outputs torque through belt drive, which is amplified by the flywheel speed ratio to provide partial auxiliary torque for the engine, ensuring that the engine quickly reaches the ignition speed in an extremely low temperature environment.
[0029] 2. Achieve efficient energy recovery: Utilize the generator's negative torque mode to recover kinetic energy and store it in the lithium battery. This energy is then dynamically distributed to the 24V lead-acid battery through DC-DC to power the entire vehicle, improving fuel economy.
[0030] 3. Build a redundant safety system: When the main collaborative unit fails, it automatically switches to the backup startup mode to ensure the basic operating capability of the vehicle.
[0031] 4. Improve system compatibility: Adapt to existing heavy-duty truck platforms without modifying the engine compartment layout, reducing modification costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION
[0033] The present invention provides a coordinated and integrated extreme low-temperature starting system and method for heavy trucks.
[0034] 1System Architecture and Core Components
[0035] Attachment Figure 1 The structure of this system is shown, including the following key components:
[0036] Generator 101
[0037] This replaces the original vehicle's traditional alternator, installed at the front of the engine and connected to the crankshaft pulley via a poly-V belt. It boasts a speed ratio of >3.8. Peak torque is >55Nm (peak torque duration >4 seconds), and it supports both positive and negative torque modes. The control circuit voltage is 24V, and the drive circuit voltage is >40V.
[0038] Lithium battery pack 102
[0039] Capacity ≥ 20Ah, managed by BMS (Battery Management System), supports CAN communication.
[0040] The operating temperature range is -40℃~60℃, and the discharge efficiency at low temperature is ≥85%.
[0041] DCDC103
[0042] 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] Integrated multi-channel CAN communication interface, real-time reception of KL15 / STAR gear signal, engine speed (from engine ECU, part number 107) and BMS status.
[0046] Through VCU control, the IBSG torque request value is dynamically calculated and torque gradient control is performed.
[0047] 24V lead-acid battery pack 105
[0048] Heavy-duty truck traditional power supply battery, 120Ah, supplies power to the entire vehicle and starter.
[0049] Starter 106
[0050] The traditional 24V starter of the heavy-duty truck engine is controlled by the Star gear of the key door to provide starting torque to the engine.
[0051] Engine 107
[0052] Heavy truck engine, starting torque <2100Nm, starting speed >600 rpm.
[0053] 2 Working principle and control logic
[0054] Low temperature start-up phase:
[0055] Step 1 (Power on KL15):
[0056] VCU104 triggers 24V→high voltage (>40V) DCDC103 pre-charge, aiming to increase the voltage of lithium battery pack 102 to 85% of the rated voltage within 500ms. At the same time, the instrument displays "Pre-charging, please start later".
[0057] Step 2 (STAR trigger):
[0058] If pre-charging is completed, VCU 104 requests positive torque and appropriate torque gradient from generator 101 , and 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.
[0059] If the pre-charging is not completed, the generator 101 does not intervene, the torque is 0, and only the traditional starter 106 works, and the instrument prompts "starting assistance limited".
[0060] Energy recovery stage:
[0061] When the vehicle brakes, the VCU 104 controls the generator 101 to switch to negative torque mode, recovering energy and storing it in the lithium battery pack 102 . At the same time, the DCDC 103 replenishes power to the 24V lead-acid battery pack 105 as needed (activated when SOC is less than 80%).
[0062] Fault tolerance mechanism:
[0063] Communication interruption (CAN failure): VCU 104 disables the full torque mode of generator 101 by default, and the traditional starter 106 is fully responsible for starting.
[0064] The voltage of the lithium battery pack 102 is abnormal (lower than or higher than the safe voltage range): the BMS disables power output, and the DCDC 105 switches to the 24V→high voltage (>40V) emergency power supply mode.
[0065] 3 Key parameters and performance indicators
[0066]
[0067] The present invention has the following characteristics:
[0068] Deep integration of dual-voltage systems: Through the coordinated design of a high-voltage (>40V) generator and a 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 the modification cost by 30%.
[0070] Dynamic torque distribution strategy: Based on feedback from real-time speed and battery SOC, the VCU dynamically adjusts the generator torque gradient to balance starting speed and mechanical impact (e.g., a gradient of 150 Nm / s in the intervention phase and <50 Nm / s in the exit phase).
[0071] Pre-charge-start decoupling mechanism: After the KL15 is powered on, pre-charge and traditional starter activation are performed in parallel, reducing the total start time to 70% of the traditional solution.
[0072] This invention breaks through the technical bottleneck of extremely low-temperature starting of heavy-duty trucks and supports reliable starting in an environment of -40°C; the energy recovery system reduces fuel consumption by 10%, and reduces annual CO2 emissions by about 1.2 tons (calculated at 100,000 kilometers / 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 / vehicle and an investment payback period of less than 2 years; it provides a reusable generator and starter collaborative integrated solution for the electrification of commercial vehicles, accelerating the industry's transition to low-carbon development.
Claims
1. A coordinated and integrated extreme low-temperature starting system for heavy trucks, characterized by: The invention comprises a generator (101), a lithium battery pack (102), a DC / DC (103), a vehicle controller VCU (104), a 24V lead-acid battery pack (105), a starter (106) and an engine (107), wherein the generator (101), the lithium battery pack (102), the DC / DC (103) and the engine (107) respectively communicate with the vehicle controller VCU (104) via a CAN bus, the generator (101) is electrically connected to the lithium battery pack (102) and the DC / DC (103), the lithium battery pack (102) is connected to the 24V lead-acid battery pack (105) via the DC / DC (103), the 24V lead-acid battery pack (105) is electrically connected to the starter (106), and the engine (107) is mechanically connected to the generator (101) and the starter (106).
2. The heavy-duty truck coordinated integrated extreme low-temperature starting system according to claim 1 is characterized by: The generator (101) is installed at the front end of the engine (107) and is connected to the crankshaft pulley via a poly-V belt, supporting 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 a BMS, has an operating temperature range of -40°C to 60°C, and a discharge efficiency of ≥85% at low temperatures; 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 is prioritized, and the reverse mode is activated only when pre-charging is required. The vehicle controller VCU (104) receives the KL15 / STAR gear signal, the engine (107) speed and the BMS status in real time, and can dynamically calculate the IBSG torque request value and perform torque gradient control; The 24V lead-acid battery pack (105) provides power to the entire vehicle and the starter.
3. A coordinated and integrated extreme low-temperature starting method for heavy trucks, utilizing the low-temperature starting system of claim 2, comprising: Low temperature start-up phase: Step (1): KL15 is powered on, and VCU (104) triggers the 24V→>40V high-voltage mode pre-charging of DCDC103, with the goal of increasing 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, please start later"; Step (2): If the pre-charge is completed, the STAR gear is triggered, and the VCU (104) requests positive torque and a suitable torque gradient from the generator (101). The generator (101) outputs positive torque, which is amplified to the crankshaft torque through the speed ratio to ensure that the engine reaches 600 rpm within 3 seconds; If the pre-charging is not completed, the generator (101) does not intervene, the torque is 0, the starter (106) works, and the instrument prompts "starting assistance limited"; Energy recovery stage: When the vehicle brakes, the VCU (104) controls the generator (101) to switch to a negative torque mode, recovering energy and storing it in the lithium battery pack (102), while the DCDC (103) replenishes power to the 24V lead-acid battery pack (105) as needed. Fault tolerance mechanism: CAN failure communication interruption: VCU (104) disables the generator (101) full torque mode by default, and the starter (106) takes full responsibility for starting; The voltage of the lithium battery pack (102) is abnormal: the BMS disables the power output, and the DCDC (105) switches to the 24V→>40V high-voltage emergency power supply mode.