Engine intervention control method for different driving modes of a hybrid vehicle
By collecting noise signals and constructing a noise target curve in hybrid vehicles, and calibrating engine speed limits, the problem of imperceptible engine intervention in different driving modes was solved, achieving a balance between NVH and fuel economy, and improving overall vehicle performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGLING MOTORS
- Filing Date
- 2026-05-19
- Publication Date
- 2026-06-19
AI Technical Summary
Hybrid vehicles are prone to abrupt engine intervention in different driving modes, making it difficult to meet customers' diverse needs for NVH performance at the same time. Existing technologies are also unable to achieve precise control of seamless engine intervention.
By collecting in-vehicle noise signals in pure electric mode, noise target curves for different driving modes are constructed, engine speed limits are calibrated, and control is performed in conjunction with real-time operating parameters to ensure a balance between engine speed and NVH and fuel economy.
It achieves differentiated control based on customer NVH expectations, reduces the abruptness of engine intervention, and improves the overall vehicle performance balance and fuel economy.
Smart Images
Figure CN122232614A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automobile manufacturing, and more specifically to a method for sensorless engine intervention control in different driving modes of hybrid vehicles. Background Technology
[0002] Hybrid vehicles offer significantly lower fuel consumption and emissions compared to traditional internal combustion engine vehicles, while also boasting a longer driving range, making them the mainstream electrification method for drive systems. Unlike traditional internal combustion engine vehicles, hybrid systems switch between pure electric, hybrid, and direct drive modes. The engine intervention sound is abrupt during the switch from gasoline to electric, and the engine in hybrid vehicles starts and stops far more frequently than in traditional internal combustion engine vehicles. For example, the engine starts and shuts off during parking and charging, during acceleration, and during deceleration, which can easily create a sense of abruptness and draw attention from passengers.
[0003] Currently, hybrid vehicles commonly use three driving modes: Economy, Normal, and Sport. A single hybrid system cannot simultaneously meet the extreme demands of all performance dimensions (economy, driving dynamics, and NVH comfort, etc.). Customers have significantly different performance expectations for different driving modes in hybrid vehicles. Economy mode typically uses electric power as much as possible, with the engine only starting when necessary to maximize fuel economy and reduce fuel consumption. Customers in this mode have high NVH expectations, requiring the engine to intervene as gently and subtly as possible. It is suitable for use in congested urban traffic or situations requiring sustained stable speeds. Comfort mode typically features more linear acceleration and deceleration, with moderate power output and throttle response, resulting in a smooth and comfortable overall driving experience. This allows drivers to easily handle various daily driving needs. Customers in this mode have moderate NVH expectations. Sport mode typically prioritizes a superior driving experience, emphasizing acceleration and maximizing both electric and fuel power for significantly enhanced performance. However, this comes at the cost of increased energy consumption. It's suitable for situations requiring ample power, such as highway acceleration, overtaking, or mountain driving. In this mode, the engine remains running for an extended period to prioritize driving and battery power. Customer expectations for NVH (Noise, Vibration, and Harshness) are significantly lowered, allowing for a degree of mechanical feel. A key challenge and focus in the hybrid vehicle industry is how to proactively set differentiated NVH performance targets in the early stages of development based on varying customer expectations for NVH performance under different driving modes. This involves employing a differentiated engine intervention control strategy based on these targets to achieve seamless NVH performance improvement across different driving modes. Summary of the Invention
[0004] The purpose of this invention is to provide a method for controlling the engine intervention without abruptness in different driving modes of hybrid vehicles. The method aims to positively set differentiated in-vehicle noise targets based on customers' expectations for NVH performance in different driving modes, and formulate differentiated engine speed limit strategies based on these targets, so as to achieve seamless engine intervention in different modes and achieve a perfect balance of vehicle performance.
[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for sensorless engine intervention control in different driving modes of hybrid vehicles includes the following steps: Step 1: Acquisition of in-vehicle noise baseline in pure electric mode: In the pure electric drive mode of the vehicle, in-vehicle noise signals are collected at different vehicle speeds to obtain the in-vehicle sound pressure level baseline curve in pure electric mode. Step 2: Construction of In-Vehicle Noise Target Curves for Different Driving Modes: Based on customers' subjective evaluation data of acceptable engine intervention noise increments under different driving modes, determine the target value of the overall in-vehicle sound pressure level increment for each driving mode, as well as the target value of the difference between the engine characteristic order noise and the overall in-vehicle sound pressure level; combined with the pure electric mode in-vehicle sound pressure level baseline curve, construct the overall in-vehicle sound pressure level target curve and the engine characteristic order noise target curve for each driving mode; Step 3: Engine speed limit calibration for different driving modes: Under the vehicle speed conditions corresponding to each driving mode, gradually increase the engine speed, measure the actual overall sound pressure level inside the vehicle and the characteristic order noise of the engine, and compare it with the corresponding target curve constructed in Step 2 to determine the maximum allowable engine speed at each vehicle speed that meets the NVH target requirements, and form an engine speed limit table for different driving modes. Step 4: Real-time operating parameter acquisition: During actual vehicle operation, acquire the currently selected driving mode, throttle opening and vehicle speed signals, and determine the current target engine power demand based on the preset energy management strategy; Step 5: Engine actual operating speed decision: Based on the engine target power requirement, determine the optimal fuel consumption speed according to the engine's optimal fuel economy curve; compare the optimal fuel consumption speed with the engine speed limit corresponding to the current driving mode and vehicle speed determined in Step 3, and select the smaller value of the two as the engine's actual target operating speed for control.
[0006] Furthermore, the subjective evaluation data in step two is obtained in the following way: several evaluators are organized in a listening room to play the noise samples in the pure electric mode vehicle at the same loudness, and the overall sound pressure level of the noise samples and the sound pressure level of the engine characteristic order noise are gradually increased. The average value of the acceptable increment for each driving mode is calculated and used as the target value of the overall sound pressure level increment in the vehicle and the target value of the difference.
[0007] Furthermore, the characteristic order noise of the engine is the second-order noise of the engine.
[0008] Furthermore, step five also includes limiting the rate of change of the engine's actual target operating speed to prevent a sudden auditory sensation caused by excessively rapid increases in speed.
[0009] The present invention also provides a hybrid vehicle engine seamless intervention control system, comprising: a sound acquisition device for acquiring in-vehicle noise signals; and a vehicle control unit for executing the aforementioned control method to control the engine operating speed.
[0010] The beneficial effects of this invention are as follows: This invention transforms customers' subjective NVH expectations for different driving modes into quantifiable in-vehicle noise sound pressure level targets, providing clear and differentiated design inputs for engine intervention control, making NVH performance development more forward-looking. By progressively increasing engine speed at different vehicle speeds and comparing it with preset noise targets, engine speed limits for various driving modes can be quickly and accurately calibrated, significantly shortening the vehicle development and tuning cycle. In the actual engine operating speed decision, by adopting the smaller value between the "optimal fuel consumption speed" and the "NVH limit speed," fuel economy is maximized while ensuring imperceptible intervention, achieving a refined balance between power, economy, and NVH comfort in different driving modes. This method does not rely on specific hardware and can be widely applied to various hybrid vehicles, possessing significant practical value in guiding engineering development. Attached Figure Description
[0011] Figure 1 The overall flowchart of the control method provided in the embodiments of the present invention.
[0012] Figure 2 This is a schematic diagram of the target curves for the overall sound pressure level inside the vehicle under different driving modes.
[0013] Figure 3 This diagram illustrates the relationship between engine speed and in-vehicle noise at a certain vehicle speed, and the method for determining the limits.
[0014] Figure 4 This is a diagram showing the engine speed limits for different vehicle speeds under different driving modes. Detailed Implementation
[0015] 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. Example
[0016] like Figure 1 The overall flowchart shown in this embodiment illustrates a method for sensorless engine intervention control in different driving modes of a hybrid vehicle, which specifically includes the following steps: Step S1: In-vehicle noise baseline acquisition in pure electric mode Before the formal test, a microphone sensor was placed near the driver's ear in the vehicle's cab. The vehicle's power battery was fully charged, and the engine was forcibly disabled via the vehicle control unit (VCU) to put the vehicle into pure electric drive mode. In this mode, in-vehicle noise audio files were tested and collected when the vehicle was traveling at a constant speed from 0 to 120 km / h, denoted as audio file a. The in-vehicle sound pressure level at different speeds was extracted from the audio file a reference curve for the in-vehicle sound pressure level in pure electric mode, denoted as curve 1.
[0017] Step S2: Constructing target curves for in-vehicle noise in different driving modes: This step quantifies customers' acceptance of engine noise intervention under different driving modes (such as Eco, Comfort, and Sport) through subjective evaluation tests.
[0018] Overall sound pressure level increment target determination: Fifty ordinary customers were organized as evaluators. In a listening room, audio file 'a' was played at equal loudness, and its overall sound pressure level was gradually increased in steps of 0.5 dBA. The upper limit of the acceptable increase in overall noise before and after engine intervention for each evaluator in each driving mode was calculated and denoted as ΔA1~ΔA50 (Economy), ΔB1~ΔB50 (Comfort), and ΔC1~ΔC50 (Sport). The arithmetic mean of the data for each mode was taken as the target values for the overall sound pressure level increment ΔA, ΔB, and ΔC for each mode. For example, the calibration results for a certain model were ΔA=1 dBA, ΔB=1.5 dBA, and ΔC=2.5 dBA.
[0019] Engine order noise difference target determination: While playing audio file 'a' with increased sound pressure levels (ΔA / ΔB / ΔC), simultaneously play audio file 'b' of engine second-order noise. Initially, the sound pressure level of audio file 'b' is 20 dBA lower than that of audio file 'a'. The sound pressure level of audio file 'b' is gradually increased in 1 dBA increments. The minimum acceptable difference between engine second-order noise and the overall in-vehicle sound pressure level for each evaluator under each driving mode is recorded as ΔD1~ΔD50, ΔE1~ΔE50, and ΔF1~ΔF50, respectively. The arithmetic mean of these differences is taken as the target values ΔD, ΔE, and ΔF for the engine second-order noise difference in each mode. For example, the calibration results for a certain vehicle model are ΔD=13 dBA, ΔE=12 dBA, and ΔF=10 dBA.
[0020] Target curve generation: Based on the above target values and combined with curve 1, construct the target curves for each mode, such as... Figure 2 As shown.
[0021] The target curve for the in-vehicle sound pressure level in economy mode is: Curve 2 = Curve 1 + ΔA; The target curve for the in-vehicle sound pressure level in comfort mode is curve 3 = curve 1 + ΔB; The target curve for the in-vehicle sound pressure level in Sport mode is: Curve 4 = Curve 1 + ΔC; The target second-order noise curve for the engine in economic mode is: Curve 1 + ΔA - ΔD; The target curve for the second-order engine noise in comfort mode is: Curve 1 + ΔB - ΔE; The target curve for second-order engine noise in sport mode is 7 = curve 1 + ΔC - ΔF.
[0022] Step S3: Engine speed limit calibration for different driving modes This step uses Sport mode as an example to explain how to calibrate the engine speed limit at a certain vehicle speed.
[0023] The VCU controls the vehicle's wheel-side drive power to be equal to the driving resistance power at a speed of 10 km / h, thus enabling the vehicle to maintain a constant speed of 10 km / h.
[0024] Start the engine and gradually increase its speed from 1000 rpm in 100 rpm increments. Simultaneously, measure and record the overall sound pressure level inside the vehicle and the engine's second-order noise sound pressure level at different engine speeds, forming a graph as follows: Figure 3 The corresponding curves are shown.
[0025] The measured noise value is compared with the limit values of the target curves 4 and 7 of the motion mode determined in step S2 at the 10km / h operating point. For example... Figure 3 As shown, curve 4 has a limit of 49 dBA at 10 km / h, and curve 7 has a limit of 39 dBA. The in-vehicle sound pressure level reaches the 49 dBA limit at 1600 rpm, and the engine's second-order noise reaches the 39 dBA limit at 1700 rpm. To ensure that both indicators meet the requirements, the engine speed limit S10 under this condition is determined to be 1600 rpm.
[0026] The vehicle speed is gradually increased from 10 km / h to 120 km / h in 10 km / h intervals. At each speed point, the engine speed limit determined at the previous speed point is used as the starting speed. Steps 1-3 are repeated to obtain the engine speed limit table (S10~S120) for the entire speed range of 10 to 120 km / h in the sport mode.
[0027] Using the exact same process, an engine speed limit table for both Economy and Comfort modes across the entire vehicle speed range was calibrated. The final engine speed limit table is shown below. Figure 4 As shown.
[0028] Steps S4 and S5: Real-time operation control. During actual vehicle operation, the VCU executes the following control logic in real time: Acquire the driver's selected driving mode (Eco / Comfort / Sport), current accelerator pedal opening, and vehicle speed signal.
[0029] The system uses a built-in energy management strategy to look up the current wheel-side power demand and then calculates the target power generation value required by the engine.
[0030] Based on the engine's target power output, consult the engine's universal characteristic curve to determine the optimal fuel consumption speed at which the lowest fuel consumption rate is achieved under that power output.
[0031] Based on the current driving mode and vehicle speed, find the corresponding engine speed limit from the speed limit table calibrated in step S3.
[0032] The optimal fuel consumption speed is compared with the speed limit, and the smaller value between the two is selected as the actual target operating speed of the engine, and the engine is controlled to operate at that speed.
[0033] Meanwhile, to avoid the abrupt changes caused by excessively rapid speed changes under extreme operating conditions, the slope of the engine target speed change is limited, for example, the speed increase slope is controlled within 300 rpm / (10 km / h).
[0034] Using the above method, the engine's engagement speed is always constrained within a range that satisfies both NVH comfort goals and maximizes fuel economy, thus achieving seamless engine engagement in different driving modes.
[0035] The preferred embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.
Claims
1. A method for sensorless engine intervention control in different driving modes of a hybrid vehicle, characterized in that: Includes the following steps: Step 1: Acquisition of in-vehicle noise baseline in pure electric mode: In the pure electric drive mode of the vehicle, in-vehicle noise signals are collected at different vehicle speeds to obtain the in-vehicle sound pressure level baseline curve in pure electric mode. Step 2: Construction of in-vehicle noise target curves for different driving modes: Based on the subjective evaluation data of customers on the acceptable engine intervention noise increment under different driving modes, determine the target value of the overall in-vehicle sound pressure level increment for each driving mode, as well as the target value of the difference between the engine characteristic order noise and the overall in-vehicle sound pressure level. Based on the pure electric mode in-vehicle sound pressure level reference curve, construct the overall in-vehicle sound pressure level target curve and the engine characteristic order noise target curve for each driving mode; Step 3: Engine speed limit calibration for different driving modes: Under the vehicle speed conditions corresponding to each driving mode, gradually increase the engine speed, measure the actual overall sound pressure level inside the vehicle and the characteristic order noise of the engine, and compare it with the corresponding target curve constructed in Step 2 to determine the maximum allowable engine speed at each vehicle speed that meets the NVH target requirements, and form an engine speed limit table for different driving modes. Step 4: Real-time operating parameter acquisition: During actual vehicle operation, acquire the currently selected driving mode, throttle opening and vehicle speed signals, and determine the current target engine power demand based on the preset energy management strategy; Step 5: Engine actual operating speed decision: Based on the engine target power requirement, determine the optimal fuel consumption speed according to the engine's optimal fuel economy curve; compare the optimal fuel consumption speed with the engine speed limit corresponding to the current driving mode and vehicle speed determined in Step 3, and select the smaller value of the two as the engine's actual target operating speed for control.
2. The method for sensorless engine intervention control in different driving modes of a hybrid vehicle according to claim 1, characterized in that: The subjective evaluation data in step two is obtained in the following way: Several evaluators are organized in a listening room to play the noise samples in the pure electric mode vehicle at the same loudness, and the overall sound pressure level of the noise samples and the sound pressure level of the engine characteristic order noise are gradually increased. The average value of the acceptable increment for each driving mode is calculated and used as the target value of the overall sound pressure level increment in the vehicle and the target value of the difference.
3. The method for sensorless engine intervention control in different driving modes of a hybrid vehicle according to claim 1, characterized in that: The characteristic order noise of the engine is the second-order noise of the engine.
4. The method for sensorless engine intervention control in different driving modes of a hybrid vehicle according to claim 1, characterized in that: Step five also includes limiting the rate of change of the engine's actual target operating speed to prevent a sudden auditory sensation caused by excessively rapid increases in speed.
5. A sensorless engine intervention control system for hybrid vehicles, characterized in that: The control system includes a sound acquisition device for acquiring in-vehicle noise signals; and a vehicle control unit for executing the control method described in any one of claims 1-4 to control the engine's operating speed.