Optimization control method for target boost pressure

Abstract

The invention discloses an optimal control method for target boost pressure, which comprises the following steps of: entering boost closed-loop enabling under the condition that boost closed-loop enabling conditions are met, and obtaining a filtered EGR rate characteristic coefficient after first-order low-pass filtering according to filtering time and an EGR rate characteristic coefficient; according to the currently disclosed target supercharging pressure, the EGR rate characteristic coefficient and the filtering EGR rate characteristic coefficient, the target supercharging pressure which is not dynamically optimized is obtained through calculation; dynamically optimizing the target supercharging pressure which is not dynamically optimized according to the actual supercharging pressure read in real time to obtain the dynamically optimized target supercharging pressure; and controlling a supercharging actuator according to the dynamically optimized target supercharging pressure. According to the method provided by the invention, optimal control on the target supercharging pressure can be realized, and the supercharging closed-loop control stability and the EGR response precision are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and in particular to an optimization control method for a target boost pressure. Background Art

[0002] In order to respond to the engine intake boost and engine torque increase request, the boost system needs to be controlled to achieve more exhaust energy to achieve boost, and boost control determines the engine's power and economy, etc. Boost closed-loop control refers to actively controlling the action of the boost actuator to achieve the following of the actual boost pressure and the target boost pressure. When the boost is not closed-loop controlled, the boost actuator opening is not actively controlled. Therefore, it is necessary to study the optimization control of the target boost pressure. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for optimizing the control of the target boost pressure, which can achieve optimized control of the target boost pressure and further improve the boost closed-loop control stability and EGR response accuracy.

[0004] To achieve the above object, according to one aspect of the present invention, a method for optimizing and controlling a target boost pressure is provided, comprising:

[0005] Entering the boost closed-loop enabling condition when the boost closed-loop enabling condition is met, obtaining the filtered EGR rate characteristic coefficient after the first-order low-pass filtering according to the filtering time and the EGR rate characteristic coefficient; calculating the target boost pressure without dynamic optimization according to the currently disclosed target boost pressure, the EGR rate characteristic coefficient and the filtered EGR rate characteristic coefficient; this step optimizes the target boost pressure based on the EGR rate to ensure that after the EGR function is activated, due to the hysteresis of the actual EGR rate response, the target boost pressure overshoot caused by the dynamic change of the EGR rate occurs, and the target boost pressure is optimized;

[0006] dynamically optimizing the target boost pressure that has not been dynamically optimized according to the actual boost pressure read in real time to obtain the dynamically optimized target boost pressure;

[0007] The boost actuator is controlled according to the dynamically optimized target boost pressure.

[0008] In the above scheme, the specific method of obtaining the filtered EGR rate characteristic coefficient after the first-order low-pass filtering according to the filtering time and the EGR rate characteristic coefficient is:

[0009]

[0010] Wherein, T is the filtering time, which is obtained by calibration; Δt is the sampling period; is the EGR rate characteristic coefficient; is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the Nth sampling period, is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the N-1th sampling period, N = 1, 2, 3, ..., where is the characteristic coefficient of the filtered EGR rate when the engine is just started, and

[0011] In the above scheme, according to the currently disclosed target boost pressure, the EGR rate characteristic coefficient and the filtered EGR rate characteristic coefficient, the specific method for calculating the target boost pressure without dynamic optimization is:

[0012]

[0013] In the formula, p BoostReqUnDyn is the target boost pressure without dynamic optimization, p BoostReqRaw is the target boost pressure disclosed herein.

[0014] In the above scheme, the method for obtaining the filtering time T is:

[0015] T=f(dm CylAir )

[0016] Where T is the filtering time, dm CylAir is the mass flow of fresh air entering the cylinder. The filter time T is obtained by a calibration method, specifically: when different engine speeds and different fresh air intake densities entering the cylinder are fixed, by adjusting the target EGR rate, the target boost pressure finally obtained changes and the overshoot under the stable working condition does not exceed the preset value, and the corresponding fresh air mass flow dm entering the cylinder is read. CylAir The time is taken as the filtering time T.

[0017] In the above scheme, the target boost pressure that has not been dynamically optimized is dynamically optimized according to the actual boost pressure read in real time, and the method of obtaining the dynamically optimized target boost pressure is specifically shown in the following three cases:

[0018] The first case: If the actual boost pressure p read in real time during this sampling period BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference does not exceed the preset value p1, p1>0, then the dynamically optimized target boost pressure p BoostReqDyn In this sampling cycle, it is updated to the target boost pressure p without dynamic optimization. BoostReqUnDyn ;

[0019] Second situation: During this sampling period, the actual boost pressure p is read in real time. BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference exceeds the preset value p1; the actual boost pressure p read in real time BoostAct Compared with the target boost pressure p without dynamic optimization BoostReqUnDyn The absolute value of the difference exceeds the preset value p2, and p2 is greater than p1. If the actual boost pressure p BoostAct Less than the target boost pressure p without dynamic optimization BoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn -p2+C1 as the target boost pressure p after dynamic optimization BoostReqDyn , where C1 is the preset value; if the actual boost pressure p BoostAct Greater than the target boost pressure p without dynamic optimization BoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn +p2-C1 as the target boost pressure p after dynamic optimization BoostReqDyn ;

[0020] Case 3: In other cases, the target boost pressure p after dynamic optimization BoostReqDyn = is equal to the dynamically optimized target boost pressure in the previous sampling cycle plus C2, where C2 is equal to the deviation Δ×k2, where k2 is the coefficient of variation and can be continuously updated and saved after the vehicle is powered off; the deviation Δ is equal to the dynamically optimized target boost pressure p in the previous sampling cycle BoostReqDyn The actual boost pressure p read in real time BoostAct difference.

[0021] In the above scheme, the updating method of the variation coefficient k2 is:

[0022] When the change coefficient judgment condition is met, the counter CNT2 corresponding to the change coefficient k2 is increased by 1, and the default value of the counter CNT2 is 0;

[0023] If CNT2≤m2, then k2=k2(z), where m2 is a preset value and k2(z) is the coefficient of change learned in the previous sampling cycle; in other cases, k2=k2(z)-0.03, and the counter CNT2 is cleared; here, the boost pressure deviation is accelerated by limiting the boost pressure control too fast.

[0024] If during the continuous CNT3≥m3 driving cycles, the situation in which the engine speed is greater than the preset value and the electronic pressure relief valve of the supercharger assembly is not opened in the boost closed-loop enabling condition has not occurred at the same time, then k2=k2(z)+0.01, and CNT3 is immediately cleared; where m3 is the preset value.

[0025] In the above scheme, the variation coefficient k2 satisfies: 0.02≤k2≤0.8.

[0026] In the above scheme, the variation coefficient judgment condition is:

[0027] (1) The boost control is in the closed-loop enabled state;

[0028] (2) The difference between the target EGR rate and the actual EGR rate exceeds the preset value;

[0029] (3) The difference between the target boost pressure and the actual boost pressure exceeds a preset value;

[0030] (4) There were no faults in the supercharging system and EGR system.

[0031] In the above scheme, the boost closed loop enabling condition is:

[0032] (1) The target pressure at the compressor outlet of the supercharger assembly is greater than the minimum boost pressure;

[0033] (2) The engine speed is greater than the preset value;

[0034] (3) The electronic pressure relief valve of the supercharger assembly is not opened.

[0035] In the above scheme, the compressor outlet target pressure of the supercharger assembly is calculated based on the target boost pressure, the gas temperature at the compressor inlet on the intake side of the supercharger, and the gas pressure and temperature before the throttle.

[0036] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0037] The present invention provides an optimization control method for a target boost pressure. The method optimizes the boost closed-loop control in order to improve the pressure control stability when the boost enters a closed loop and improve the boost responsiveness and the EGR system responsiveness. Specifically, the target boost pressure is optimized and the learning parameters are continuously updated in the subsequent control process to further improve the boost closed-loop control stability and the EGR response accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0039] Figure 1 Schematic diagram of a low-pressure EGR system in an embodiment of the present invention.

[0040] Figure 2 Schematic diagram of the flow chart of the optimization control method of the target boost pressure in the embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] It should be understood that the size of the serial numbers of the steps in the embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0043] Example 1

[0044] The system structure with low-pressure EGR system and exhaust gas turbocharger system based on the present invention includes air filter, mixing valve, supercharger compressor, throttle, engine, supercharger turbine, catalyst, particulate matter trap, EGR cooler, EGR valve, EGR temperature sensor, EGR pressure difference sensor, flow meter and linear oxygen sensor, such as Figure 1 As shown. The supercharger compressor is used to compress fresh air for supercharging; the supercharger turbine controls the working efficiency of the turbine by controlling the opening of the supercharger's exhaust bypass valve, thereby achieving different supercharging capabilities; compared with the non-low-pressure EGR system, the low-pressure EGR system has the following additional components: EGR cooler, EGR temperature sensor, EGR valve, EGR pressure difference sensor, mixing valve, flow meter and oxygen sensor; the flow meter is installed between the air filter and the mixing valve to detect the fresh air flow entering the engine. The flow meter is an optional accessory and can be installed according to the vehicle model. It is optional. If it is not selected, the estimation method will be used to obtain the corresponding information; the mixing valve is used to adjust the pressure of the EGR valve outlet, increase the pressure difference at both ends of the EGR valve, and increase the EGR rate; the oxygen sensor, which is also an optional accessory, is installed between the compressor and the throttle, close to the throttle, and is used to detect the flow of mixed gas entering the cylinder; the EGR cooler is used to cool the exhaust gas, which is convenient for increasing the exhaust gas flow and reducing the exhaust gas temperature; the EGR valve acts as a throttling function to control the exhaust gas flow entering the cylinder; the EGR temperature sensor is used to detect the exhaust gas temperature entering the EGR valve; the EGR differential pressure sensor is used to detect the pressure at the EGR inlet and outlet.

[0045] According to one aspect of the present invention, an embodiment of the present application provides a method for optimizing and controlling a target boost pressure. Figure 2 ,include:

[0046] S1, when the boost closed-loop enabling conditions are met, enters the boost closed-loop enabling, obtains the filtered EGR rate characteristic coefficient after the first-order low-pass filtering according to the filtering time and the EGR rate characteristic coefficient; calculates the target boost pressure without dynamic optimization according to the currently disclosed target boost pressure, EGR rate characteristic coefficient and filtered EGR rate characteristic coefficient.

[0047] Specifically, in this embodiment, the boost closed loop enabling condition and boost closed loop enabling may be specifically referred to Chinese patent publication number CN110748409A, wherein the boost closed loop enabling condition is specifically:

[0048] (1) The target pressure at the compressor outlet of the supercharger assembly is greater than the minimum boost pressure;

[0049] (2) The engine speed is greater than a preset value; the preset value used in this embodiment is 1000 rpm;

[0050] (3) The electronic pressure relief valve of the supercharger assembly is not opened.

[0051] When the above conditions (1) to (3) are met simultaneously, the boost closed loop is enabled.

[0052] In this embodiment, the specific method for obtaining the filtered EGR rate characteristic coefficient after first-order low-pass filtering according to the filtering time and the EGR rate characteristic coefficient is:

[0053]

[0054] Wherein, T is the filtering time, which is obtained by calibration; Δt is the sampling period, which is 10ms in this embodiment; is the EGR rate characteristic coefficient; is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the Nth sampling period, is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the N-1th sampling period, N = 1, 2, 3, ..., where is the characteristic coefficient of the filtered EGR rate when the engine is just started, and

[0055] Specifically, the method for obtaining the filtering time T is:

[0056] T=f(dm CylAir )

[0057] Where T is the filtering time, dm CylAiris the mass flow of fresh air entering the cylinder. The filter time T is obtained by a calibration method, specifically: when different engine speeds and different fresh air intake densities entering the cylinder are fixed, by adjusting the target EGR rate, the target boost pressure finally obtained is changed. When the overshoot under the stable working condition does not exceed the preset value (in this embodiment, ±3 kPa), the corresponding fresh air mass flow dm entering the cylinder is read. CylAir The time is taken as the filtering time T.

[0058] In this embodiment, according to the currently disclosed target boost pressure, EGR rate characteristic coefficient and filtered EGR rate characteristic coefficient, the specific method for calculating the target boost pressure without dynamic optimization is:

[0059]

[0060] In the formula, p BoostReqUnDyn is the target boost pressure without dynamic optimization, p BoostReqRaw is the currently disclosed target boost pressure.

[0061] S2, dynamically optimizing the target boost pressure that has not been dynamically optimized according to the actual boost pressure read in real time, to obtain the dynamically optimized target boost pressure.

[0062] Specifically, in this embodiment, the target boost pressure that has not been dynamically optimized is dynamically optimized according to the actual boost pressure read in real time, and the method for obtaining the dynamically optimized target boost pressure is specifically shown in the following three cases:

[0063] The first case: If the actual boost pressure p read in real time during this sampling period BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference does not exceed the preset value p1. In this embodiment, p1 is 3 kPa. Then the dynamically optimized target boost pressure p BoostReqDyn In this sampling cycle, it is updated to the target boost pressure p without dynamic optimization. BoostReqUnDyn ;

[0064] Second situation: During this sampling period, the actual boost pressure p is read in real time. BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference exceeds the preset value p1; the actual boost pressure p read in real time BoostAct Compared with the target boost pressure p without dynamic optimization BoostReqUnDyn The absolute value of the difference exceeds the preset value p2. In this embodiment, p2 is 10 kPa. If the actual boost pressure p BoostAct Less than the target boost pressure p without dynamic optimizationBoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn -p2+C1 as the target boost pressure p after dynamic optimization BoostReqDyn , where C1 is a preset value. In this embodiment, C1 is 3 kPa; if the actual boost pressure p BoostAct Greater than the target boost pressure p without dynamic optimization BoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn +p2-C1 as the target boost pressure p after dynamic optimization BoostReqDyn ;

[0065] Case 3: In other cases, the target boost pressure p after dynamic optimization BoostReqDyn = is equal to the dynamically optimized target boost pressure in the previous sampling period plus C2, where C2 is equal to the deviation Δ×k2, where k2 is the coefficient of variation. In this embodiment, the default value of k2 is 0.35 and can be continuously updated and saved after the vehicle is powered off; the deviation Δ is equal to the dynamically optimized target boost pressure p in the previous sampling period BoostReqDyn The actual boost pressure p read in real time BoostAct difference.

[0066] Specifically, the updating method of the variation coefficient k2 is:

[0067] When the change coefficient judgment condition is met, the counter CNT2 corresponding to the change coefficient k2 is increased by 1, and the default value of the counter CNT2 is 0;

[0068] In this embodiment, the variation coefficient determination condition is:

[0069] (1) The boost control is in the closed-loop enabled state;

[0070] (2) The difference between the target EGR rate and the actual EGR rate exceeds a preset value, which in this embodiment is ±0.2;

[0071] (3) The difference between the target boost pressure and the actual boost pressure exceeds a preset value, which in this embodiment is ±5 kPa;

[0072] (4) There were no faults in the supercharging system and EGR system.

[0073] If CNT2≤m2, then k2=k2(z), where m2 is a preset value. In this embodiment, the preset value m2 is 500, and k2(z) is the coefficient of change learned in the previous sampling period; in other cases, k2=k2(z)-0.03, and the counter CNT2 is cleared;

[0074] If during the continuous CNT3≥m3 driving cycles, the situation in which the engine speed is greater than the preset value and the electronic pressure relief valve of the supercharger assembly is not opened in the boost closed-loop enabling condition has not occurred at the same time, then k2=k2(z)+0.01, and CNT3 is immediately cleared; wherein m3 is a preset value, and in this embodiment, the preset value m3 is 200.

[0075] In particular, the coefficient of variation k2 satisfies: 0.02≤k2≤0.8.

[0076] S3, controlling the boost actuator according to the dynamically optimized target boost pressure.

[0077] Specifically, in this embodiment, after the dynamically optimized target boost pressure is obtained, the action of the boost actuator is actively controlled to achieve the tracking of the actual boost pressure with the target boost pressure.

[0078] In summary, the present invention provides a method for optimizing control of a target boost pressure, which can achieve optimized control of the target boost pressure and further improve boost closed-loop control stability and EGR response accuracy.

[0079] It should be pointed out that, according to the needs of implementation, the various steps described in this application can be divided into more steps, or two or more steps or partial operations of the steps can be combined into a new step to achieve the purpose of the present invention.

[0080] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing and controlling a target boost pressure, characterized in that: include: When the boost closed-loop enabling condition is met, the boost closed-loop enabling is entered, and the filtered EGR rate characteristic coefficient after the first-order low-pass filtering is obtained according to the filtering time and the EGR rate characteristic coefficient; Calculating a target boost pressure that is not dynamically optimized based on the currently disclosed target boost pressure, the EGR rate characteristic coefficient, and the filtered EGR rate characteristic coefficient; dynamically optimizing the target boost pressure that has not been dynamically optimized according to the actual boost pressure read in real time to obtain the dynamically optimized target boost pressure; The boost actuator is controlled according to the dynamically optimized target boost pressure.

2. The method for optimizing and controlling target boost pressure according to claim 1, characterized in that: The specific method of obtaining the filtered EGR rate characteristic coefficient after first-order low-pass filtering according to the filtering time and the EGR rate characteristic coefficient is: Wherein, T is the filtering time, which is obtained by calibration; Δt is the sampling period; is the EGR rate characteristic coefficient; is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the Nth sampling period, is the characteristic coefficient of the filtered EGR rate after the first-order low-pass filter in the N-1th sampling period, N = 1, 2, 3, ..., where is the characteristic coefficient of the filtered EGR rate when the engine is just started, and 3. The method for optimizing and controlling target boost pressure according to claim 2, characterized in that: According to the currently disclosed target boost pressure, the EGR rate characteristic coefficient and the filtered EGR rate characteristic coefficient, a specific method for calculating the target boost pressure without dynamic optimization is: In the formula, p BoostReqUnDyn is the target boost pressure without dynamic optimization, p BoostReqRaw is the target boost pressure disclosed herein.

4. The method for optimizing and controlling target boost pressure according to claim 2, characterized in that: The method for obtaining the filtering time T is: T=f(dm CylAir ) Where T is the filtering time, dm CylAir is the mass flow of fresh air entering the cylinder. The filter time T is obtained by a calibration method, specifically: when different engine speeds and different fresh air intake densities entering the cylinder are fixed, by adjusting the target EGR rate, the target boost pressure finally obtained changes and the overshoot under the stable working condition does not exceed the preset value, and the corresponding fresh air mass flow dm entering the cylinder is read. CylAir The time is taken as the filtering time T.

5. The method for optimizing and controlling target boost pressure according to claim 3, characterized in that: The method of dynamically optimizing the target boost pressure that has not been dynamically optimized according to the actual boost pressure read in real time to obtain the dynamically optimized target boost pressure is specifically shown in the following three cases: The first case: If the actual boost pressure p read in real time during this sampling period BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference does not exceed the preset value p1, p1>0, then the dynamically optimized target boost pressure p BoostReqDyn In this sampling cycle, it is updated to the target boost pressure p without dynamic optimization. BoostReqUnDyn ; Second situation: During this sampling period, the actual boost pressure p is read in real time. BoostAct The target boost pressure p after dynamic optimization in the previous sampling cycle BoostReqDyn The absolute value of the difference exceeds the preset value p1; the actual boost pressure p read in real time BoostAct Compared with the target boost pressure p without dynamic optimization BoostReqUnDyn The absolute value of the difference exceeds the preset value p2, and p2 is greater than p1. If the actual boost pressure p BoostAct Less than the target boost pressure p without dynamic optimization BoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn -p2+C1 as the target boost pressure p after dynamic optimization BoostReqDyn , where C1 is the preset value; if the actual boost pressure p BoostAct Greater than the target boost pressure p without dynamic optimization BoostReqUnDyn , the target boost pressure p that is not dynamically optimized is BoostReqUnDyn +p2-C1 as the target boost pressure p after dynamic optimization BoostReqDyn ; Case 3: In other cases, the target boost pressure p after dynamic optimization BoostReqDyn = is equal to the dynamically optimized target boost pressure in the previous sampling cycle plus C2, where C2 is equal to the deviation Δ×k2, where k2 is the coefficient of variation and can be continuously updated and saved after the vehicle is powered off; the deviation Δ is equal to the dynamically optimized target boost pressure p in the previous sampling cycle BoostReqDyn The actual boost pressure p read in real time BoostAct difference.

6. The method for optimizing and controlling target boost pressure according to claim 5, characterized in that: The updating method of the variation coefficient k2 is: When the change coefficient judgment condition is met, the counter CNT2 corresponding to the change coefficient k2 is increased by 1, and the default value of the counter CNT2 is 0; If CNT2≤m2, then k2=k2(z), where m2 is a preset value and k2(z) is the coefficient of change learned in the previous sampling period; in other cases, k2=k2(z)-0.03, and the counter CNT2 is cleared; If the engine speed is greater than the preset value and the electronic pressure relief valve of the supercharger assembly is not opened in the boost closed loop enabling condition, k2=k2(z)+0.01, and CNT3 is immediately cleared; Among them, m3 is the preset value.

7. The method for optimizing and controlling target boost pressure according to claim 6, characterized in that: The variation coefficient k2 satisfies: 0.02≤k2≤0.

8.

8. The method for optimizing and controlling target boost pressure according to claim 6, characterized in that: The variation coefficient judgment condition is: (1) The boost control is in the closed-loop enabled state; (2) The difference between the target EGR rate and the actual EGR rate exceeds the preset value; (3) The difference between the target boost pressure and the actual boost pressure exceeds a preset value; (4) There were no faults in the supercharging system and EGR system.

9. The method for optimizing and controlling target boost pressure according to claim 1, characterized in that: The boost closed loop enabling condition is: (1) The target pressure at the compressor outlet of the supercharger assembly is greater than the minimum boost pressure; (2) The engine speed is greater than the preset value; (3) The electronic pressure relief valve of the supercharger assembly is not opened.

10. The method for optimizing and controlling target boost pressure according to claim 9, characterized in that: The compressor outlet target pressure of the supercharger assembly is calculated based on the target boost pressure, the gas temperature at the compressor inlet on the intake side of the supercharger, and the gas pressure and temperature before the throttle valve.

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