Method for analyzing the actual energy consumption of a motor vehicle over a journey

Abstract

Method (10) for analyzing the actual energy consumption of a motor vehicle, comprising: - a step (13) of calculating an instantaneous consumption penalty (Pen_cons_inst) per liter per second as a function of an ignition advance efficiency (Rend_Av), a richness efficiency (Rend_Rich) of said efficiencies (Rend_Av, Rend_Rich) and an instantaneous fuel consumption (Cons_Inst) of the engine in liters per second; - a step (14) of verifying the activated or non-activated state of the different strategies (S) acting on the ignition advance and / or on the richness embedded in the engine computer; and - a step (15) of calculating, on a journey (T), a consumption penalty (Pen_cons_S_T) linked to the active strategy (S) as a function of the instantaneous consumption penalty (Pen_cons_inst) calculated for each active strategy (S). Figure for abstract: Fig 1

Description

Title of the invention: Method for analyzing the actual energy consumption of a motor vehicle over a journey

[0001] The present invention relates to the field of internal combustion engines, and in particular spark-ignition engines.

[0002] More particularly, the invention relates to the analysis of the actual fuel consumption of the internal combustion engine of the motor vehicle.

[0003] Current standards require diagnostics to be carried out on internal combustion engines, and in particular fuel consumption diagnostics, known as “On-board fuel consumption monitoring” in Anglo-Saxon terms.

[0004] Current regulations require that information concerning the vehicle's actual fuel consumption be made available on a vehicle diagnostic socket, in particular the average consumption in litres per 100 km, the absolute consumption in litres, etc.

[0005] The objective of this regulation is to be able to compare the actual consumption of motor vehicles with that which is approved on a reference regulatory cycle known as "worldwide harmonized light vehicles test cycles" in Anglo-Saxon terms, acronym WLTC.

[0006] Actual fuel consumption is generally estimated by the vehicle's engine control system from the quantity injected by the fuel injection system. This actual consumption must be faithful to the measurement with a tolerance of plus or minus 5% over the regulatory cycle. This is verified during the approval of the vehicle on a test bench.

[0007] When the actual fuel consumption is very different from the measurement made on the regulatory cycle, it may be interesting for the car manufacturer to analyze such a difference and to be able to explain such a difference with a view to remedying it.

[0008] It is known to analyze the type of driving performed by the vehicle in terms of time distribution between City, Road and Motorway or expressway, known as "VRA". The VRA is calculated by the engine control. It is available on the diagnostic socket and can be retrieved by the manufacturer's computer servers, in particular by a telemetry system.

[0009] The approved WLTC reference cycle corresponds to a mixture of driving phases in town, on the road and on the motorway.

[0010] When the actual fuel consumption of the motor vehicle is very far from the approved reference consumption, and the VRA is very far from the approved WLTC reference cycle, the fuel consumption difference may can be explained by this difference in the type of driving carried out by the vehicle.

[0011] However, such an analysis is generally not sufficient to exhaustively explain the consumption differences between actual fuel consumption and approved consumption.

[0012] Document US 2015 / 0314789 - Al is also known, which describes a method for analyzing the causes of a vehicle's energy consumption in order to reduce it. The causes of energy consumption are linked in particular to the driver's behavior and to environmental factors.

[0013] However, this document does not aim to analyze excess fuel consumption due to particular operating modes of an internal combustion engine and which are not present in the approved reference cycle.

[0014] There is a need to analyze excess fuel consumption due to particular operating modes of an internal combustion engine and which are not present in the approved reference cycle.

[0015] The present invention aims to analyze the actual fuel consumption of a motor vehicle when said actual consumption is very far from the approved consumption and to deduce the causes of the excess fuel consumption.

[0016] The present invention relates to a method for analyzing the actual energy consumption of a motor vehicle over a journey, the method being intended to be implemented in part by an electronic control unit embedded in a computer of a spark-ignition internal combustion engine of a motor vehicle, characterized in that the method comprises: - a step of determining an ignition advance efficiency; - a step of determining a wealth yield; - a step of calculating a penalty in instantaneous consumption in liters per second, based on said efficiencies and an instantaneous fuel consumption of the engine in liters per second; - a step of verifying the activated or inactive state of the different strategies embedded in the engine computer and chosen from the group comprising at least strategies acting on the ignition advance and strategies acting on the richness; and - a step of calculating, on a journey, a penalty in consumption linked to the active strategy, both in absolute value in liters and in relative value in percentage compared to the total consumption according to the penalty in instantaneous consumption calculated at the step for each active strategy.

[0017] The method makes it possible to analyze actual fuel consumption and to identify fuel consumption penalties compared to optimal operation at using motor control variables.

[0018] Advantageously, the method comprises a step of recording in the memory of the engine computer the consumption penalties calculated in the calculation step for a plurality of journeys, and of calculating the average values ​​over this plurality of journeys, with i between 1 and 20, preferably equal to the number 20, a step of synthesizing the data recorded during the recording step in a comparative table and a step of comparing said data synthesized in the comparative table with reference values ​​of an approved cycle to determine the origin of the excess fuel consumption.

[0019] Thus, the origins of any possible excess fuel consumption can be determined based on the consumption penalties of the activated strategies.

[0020] Advantageously, the consumption penalty linked to the ignition advance is calculated according to the following equation:

[0021] [Math.2] Pen_cons _inst = (1 - Returns _ AV).Cons _Inst

[0022] Advantageously, the wealth-related consumption penalty is calculated according to the following equation:

[0023] [Math.3] Pen_cons _inst — (1- Makes _Rich).Cons _Inst

[0024] Advantageously, the consumption penalty Pen_cons_S_T linked to the active strategy (S) is calculated according to the following equations:

[0025] [Math.4] / \ rt_firt_JrajetT Pen_cons_S_T / ffre - Jf start tra!etT(Pen_cons_inst_S) {Activ_S).dl

[0026] [Math.5] Pen_cons_S_T(%)=

[0027] For example, the ignition advance efficiency Rend_Av is calculated according to the following equation:

[0028] [Math.l] Makes _ AV = 1 - k. (Av_opt-Av_appl)~ •> with : k, a coefficient from a mapping present in the motor control system; Av_opt, the optimal value of the ignition advance, or optimum advance; Av_appl, the actual value of the ignition advance, or advance actually applied.

[0029] For example, the ignition advance efficiency Rend_Av translates the difference of engine efficiency related to the difference between the applied advance Av_appl and the optimal advance Av_opt. It is therefore 1 at the optimal advance and is less than 1 for lower advances. The response as a function of the advance is of the parabolic type with a coefficient k mapped in the engine control system from tests. It depends on the engine speed and load.

[0030] For example, the richness efficiency Rend_Rich translates the difference in engine efficiency linked to the difference between the applied richness R and the optimal richness 1. It is therefore worth 1 at richness equal to 1 and is less than 1 for richnesses greater than 1, i.e. rich mixture. This law is calibrated in the engine control system from tests.

[0031] Preferably, the strategies acting on the ignition advance comprise at least: a strategy for heating an engine depollution catalyst, a strategy for reserving torque at idle, an anti-shock strategy and an anti-knock strategy.

[0032] The catalyst heating strategy, in particular a three-way catalyst of the engine, in the case of a spark-ignition engine, is activated after cold starting of the engine in order to quickly heat the catalyst so that it can treat the pollutant gas emissions (carbon monoxide CO, unburned hydrocarbons HC, nitrogen oxides NOx) as quickly as possible. To do this, the ignition advance is greatly reduced compared to the optimal values ​​to degrade the efficiency and obtain high exhaust gas temperatures. Once the catalyst is primed, i.e. at a temperature sufficient to treat the pollutants with at least a predetermined minimum efficiency, this strategy is deactivated. Depending on the type of engine, and the architecture of the exhaust line, this strategy can last between 20s and 120s. There is therefore a penalty in consumption for the entire time during which this catalyst heating strategy is activated.

[0033] The so-called idle torque reserve strategy is activated to be able to ensure precise regulation of the idle speed, typically at + / - 10 rpm, and which is robust when activating engine consumers such as an air conditioning compressor. To do this, the nominal advance is reduced compared to the optimal values ​​in order to quickly provide a torque surplus by temporarily increasing the advance when necessary, for example when activating the air conditioning, so as to avoid a sharp drop in speed. This reduction in advance makes it possible in the same way to avoid a sharp drop in speed in other circumstances, in particular during a take-off maneuver due to a rapid clutch engagement.This variation of the torque by modification of the advance is generally called the "fast" torque because it can be modulated cycle to cycle, that is to say from one engine combustion cycle to another, whereas the variation of the torque which is obtained by modifying the flow of air entering the engine is called so-called "slow" torque, because the response time is much higher, being conditioned by the movement of an intake flap of the engine. The flap. intake does not allow the torque to be modulated as quickly as necessary. There is therefore a fuel consumption penalty when this idle torque reserve strategy is activated.

[0034] The anti-jolt strategy makes it possible to limit the jolts and oscillations in engine speed that appear during transient maneuvers on the vehicle's accelerator pedal, typically when the foot is put down and when the foot is lifted. It can include a preventive part (avoiding the jolt) and a curative part (eliminating residual oscillations). To do this, the engine control will modulate the torque generated by the engine in relation to the driver's torque demand, which is reflected by the depression of the pedal (or alternatively the force applied to the pedal), by reducing the ignition advance more or less. Typically, when the foot is put down, if the torque requested by the driver were immediately provided by setting the ignition advance to the optimal advance, this would create a jolt linked to the rocking of the engine and the impact on its suspension buffers on the body.To avoid this, the ignition advance is temporarily reduced to gradually tilt the engine and avoid the shock. Once the engine is settled on its buffers, the optimal ignition advances are applied. There is therefore a fuel consumption penalty when this anti-shock strategy is activated.

[0035] The anti-knock strategy makes it possible to avoid and treat the abnormal combustion phenomenon known as knocking, which can be destructive for the piston. The means for reducing or even eliminating knocking is to reduce the ignition advance compared to the optimal values. It generally comprises a preventive part (the advance values ​​are reduced in advance in conditions where knocking is more present than at the nominal value, such as in a very hot environment) and a curative part (the advances applied are quickly reduced to eliminate the occurrence of knocking detected by a knock sensor mounted on the engine). There is therefore a penalty in consumption when this anti-knock strategy is active.

[0036] For example, the strategies acting on the richness include at least: a start-up strategy, a richness regulation strategy, a strategy for managing the quantity of oxygen present in an engine depollution catalyst and an intrusive richness diagnostic strategy.

[0037] The start-up strategy is activated during cold start phases, the mixture is enriched, i.e. the richness R is strictly greater than 1, in order to ensure optimal combustion, particularly in the case of low volatility fuel, which has more difficulty evaporating and therefore ensuring optimal combustion. There is therefore a penalty in consumption during these start-up phases.

[0038] The richness regulation strategy adjusts the injected quantity in real time so that the richness R of the air-fuel mixture is equal to a set value (in general stoichiometry therefore 1). But during very transient operating phases, the richness control is not perfect and it can therefore happen that the actual richness is temporarily higher than the setpoint, for example with a richness of 1.05 for an objective equal to 1. There is therefore a penalty in consumption when this is the case.

[0039] The strategy for managing the quantity of oxygen present in the catalyst, or oxygen storage in English terms, with the acronym "OS" can also be used. For example, reference will be made to publication FR-A1-3101673: this strategy aims to place the level of quantity of oxygen OS stored in the catalyst in an optimal window for both the treatment of NOx pollutants on the one hand, and CO on the other hand. Indeed, if the OS becomes higher than a given maximum threshold value, predetermined by tests, it treats NOx ineffectively. Conversely, if the OS becomes lower than a given minimum threshold value, predetermined by tests, it treats CO ineffectively. This strategy therefore consists of defining a setpoint value between said minimum threshold and said maximum threshold and regulating the OS to the setpoint value.If the OS is too high compared to the target, the system will enrich the air-fuel mixture, with a richness setpoint greater than 1, to consume oxygen in the catalyst and return to the optimal OS level for treating pollutants. These enrichment phases occur, for example, during acceleration following a long deceleration, for example when the vehicle is on a downward slope and the driver takes his foot off the accelerator pedal: during this last descent phase, the fuel injection is cut off. Clean air is sent to the exhaust, and the catalyst is saturated with oxygen, which is then unable to treat the NOx during re-acceleration. We will therefore enrich from the start of the re-acceleration phase to quickly lower the OS and return to the optimal value for treating pollutants (more specifically NOx in this case).So we end up with a penalty in consumption when these enrichments are activated.

[0040] The intrusive diagnostic strategy on richness aims to diagnose the catalyst aging state, OBD diagnostic strategies need to generate richness slots of a few seconds. Typically a rich slot at 1.07 instead of 1 which also leads to a consumption penalty. We will refer for example to the publication FR-A1-3057022 which describes such a method.

[0041] According to a second aspect, the invention relates to a motor vehicle comprising a spark-ignition internal combustion engine, an engine computer and an electronic control unit embedded in the engine computer and capable of partially implementing the method as described previously.

[0042] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0043] [Fig-1] represents the synopsis of a method for analyzing the actual energy consumption of a motor vehicle and determining the origins of any possible overconsumption;

[0044] [Fig.2A], [Fig.2B] illustrate curves representative of the laws of evolution respec tively of the advance yield and the wealth yield; and

[0045] [Fig.3] is a summary table of the actual values ​​of the parameters of several journeys, fuel consumption on each of said journeys and consumption penalties based on reference values ​​on an approved cycle.

[0046] As illustrated in [Fig.l], the method 10 for analyzing the actual energy consumption of a motor vehicle and determining the origins of any overconsumption is intended to be implemented in part by an electronic control unit (not shown) embedded in a computer of the spark-ignition internal combustion engine of a motor vehicle (not shown).

[0047] Method 10 allows actual fuel consumption to be analyzed and fuel consumption penalties to be identified relative to optimal operation using engine control variables.

[0048] The method 10 comprises a step 11 of determining the ignition advance efficiency Rend_Av according to the following equation:

[0049] [Math.l] J Rend_AV = ï - k.[Av _opt-Av _appiy

[0050] With:

[0051] k, a coefficient resulting from a mapping present in the engine control system;

[0052] Av_opt, the optimal value of the ignition advance, or optimal advance; and

[0053] Av_appl, the actual value of the ignition advance, or advance actually applied.

[0054] The method 10 further comprises a step 12 of determining the yield of wealth Rend_Rich according to [Fig.2B].

[0055] Indeed, in a spark-ignition engine, optimal operation is defined:

[0056] - with respect to the ignition advance: the optimal operation is at the so-called advance optimal Av_opt. Anything that leads to operating with a degraded advance, i.e. lower than the optimal advance, penalizes consumption.

[0057] - in relation to the richness of the air-fuel mixture: optimal operation is at richness equal to 1, or stoichiometric. Anything that leads to functioning in a mixture rich, i.e. wealth strictly greater than 1, penalizes consumption.

[0058] In the engine control software, two variables are mainly used:

[0059] - the ignition advance efficiency Rend_Av: it retranslates the efficiency gap engine related to the difference between the applied advance Av_appl and the optimal advance Av_opt. It is therefore 1 at the optimal advance and is less than 1 for lower advances. The response as a function of the advance is of the parabolic type with a coefficient k mapped in the engine control system from tests. It depends on the engine speed and load.

[0060] - the richness yield Rend_Rich: it retranslates the difference in engine efficiency linked to the difference between the applied richness R and the optimal richness 1. It is therefore worth 1 at richness equal to 1 and is less than 1 for richnesses greater than 1, i.e. rich mixture. This law is calibrated in the engine control system from tests.

[0061] From the yields Rend_Av, Rend_Rich, we calculate, in step 13, an instantaneous consumption penalty Pen_cons_inst per liter / s according to the following equations:

[0062] Consumption penalty linked to ignition advance:

[0063] [Math.2] Pen_cons_inst- (1- Returns _AV ).Cons_Inst

[0064] Consumption penalty linked to wealth:

[0065] [Math.3] Pen_cons_inst = (1 - Makes_Rich).Cons_Inst

[0066] With:

[0067] Cons_Inst, the instantaneous fuel consumption of the engine in liters per second.

[0068] The interest is to identify the contributions of the different strategies in the penalty total consumption which will be calculated on a journey T.

[0069] The method 10 further comprises a step 14 of verifying the activated or inactivated state of the different strategies S present in the engine control software.

[0070] For each of the strategies S, the method determines, via the motor control, when it is active via a boolean Activ_S which changes to 1 instead of 0 when the strategy is active.

[0071] The S strategies present in the engine control software are of a nature to act on the ignition advance or the richness and chosen from the group comprising at least the strategies acting on the ignition advance and the strategies acting on the richness.

[0072] Strategies playing on ignition advance include at least:

[0073] - a strategy for heating a depollution catalyst: this strategy is activated after cold starting of the engine in order to quickly heat the catalyst, in particular a three-way catalyst, in the case of a spark-ignition engine so that it can process pollutant gas emissions (HC, CO, NOx) as quickly as possible. To do this, the ignition advance is significantly reduced compared to the optimal values ​​to degrade efficiency and obtain high exhaust gas temperatures. Once the catalyst is primed, i.e. at a temperature sufficient to process the pollutants, this strategy is deactivated. Depending on the type of engine and the architecture of the exhaust line, this strategy can last between 20 seconds and 120 seconds. There is therefore a fuel consumption penalty for the entire time this catalyst heating strategy is activated.

[0074] - an idle torque reserve strategy: this strategy is activated to be able to ensure precise idle speed regulation, typically within + / - 10 rpm, and robust when activating engine consumers, for example an air conditioning compressor. To achieve this, the nominal advance is reduced compared to the optimal values ​​in order to quickly provide additional torque by temporarily increasing the advance when necessary, for example when activating the air conditioning. This strategy can also be implemented in other situations where there is a risk of encountering a sharp drop in speed, such as during a take-off maneuver due to a rapid clutch engagement.This variation of torque by modification of the advance is generally called the "fast" torque because it can be modulated cycle to cycle by modifying the ignition advance from one combustion cycle of the engine to the next, whereas the so-called "slow" torque has a much higher response time because it is conditioned by the mass of air admitted into the engine via the adjustment of the opening position of an intake flap. The intake flap does not allow the torque to be modulated as quickly as necessary due to the duration of its movements. There is therefore a penalty in consumption when this idle torque reserve strategy is activated.

[0075] - an anti-shock strategy: this strategy makes it possible to limit jolts and bones RPM fluctuations that appear during transient maneuvers on the accelerator pedal, typically when putting the foot down and lifting the foot off. It generally includes a preventive part (avoiding the jerk) and a curative part (eliminating residual oscillations). To do this, the engine control will modulate the torque generated by the engine in relation to the driver's request by reducing the ignition advance more or less. Typically when putting the foot down, if the torque requested by the driver were immediately provided by adopting the optimal advance, this would create a jerk linked to the rocking of the engine and the shock on its suspension buffers at the body. To avoid this, the ignition advance is temporarily reduced to gradually rock the engine and avoid the shock. Once the engine is settled on its buffers, the optimal ignition advances are applied. There is therefore a fuel consumption penalty when this anti-jerk strategy is activated.

[0076] - an anti-knock strategy: this strategy makes it possible to avoid and treat the phenomenon abnormal combustion known as knocking which can be destructive for the piston. The way to reduce or even eliminate knocking is to reduce the ignition advance compared to the optimal values. This strategy generally includes a preventive part (the advances are reduced as standard in conditions where knocking is more present than nominal, such as in a very hot environment) and a curative part (the advances applied are quickly reduced to eliminate the appearance of knocking detected by the knock sensor). There is therefore a penalty in consumption when this anti-knock strategy is active.

[0077] Strategies playing on wealth include at least:

[0078] - a start-up strategy: during cold start phases, the mixture is enriched, i.e. the richness R is greater than 1, in order to ensure optimal combustion, particularly in the case of "heavy" fuel, i.e. with low volatility, which has more difficulty evaporating and therefore ensuring optimal combustion. There is therefore a penalty in consumption during these start-up phases.

[0079] - a wealth regulation strategy: this strategy adjusts in real time the quantity injected so that the air-fuel mixture is at a given richness setpoint value (generally stoichiometry, therefore richness R equal to 1). But during very transient operating phases, richness control is not perfect and it can therefore happen that the actual richness is temporarily higher than the setpoint, for example with a richness of 1.05 for a target of 1. There is therefore a penalty in consumption when this is the case.

[0080] - a strategy for managing the amount of oxygen present in the catalyst, or oxygen storage in Anglo-Saxon terms, with the acronym "OS": this strategy aims to place the OS level in an optimal window for the treatment of NOx and CO pollutants, and more precisely to regulate the quantity of oxygen OS to a set value that is included in said range. If the OS is too high compared to the set value, the system will enrich the mixture, by imposing a richness setpoint greater than 1 determined according to the difference between the actual quantity of oxygen and the oxygen quantity setpoint, to consume oxygen in the catalyst and return to the optimal OS level for the treatment of pollutants.These enrichment phases occur, for example, during acceleration following a long deceleration: during the deceleration phase, which occurs, for example, when the vehicle is on a downward slope and the driver takes his foot off the accelerator pedal, the fuel injection is cut off and clean air is sent to the engine exhaust. If the deceleration is long enough, the catalyst ends up saturating with oxygen, which is then no longer able to process the NOx during re-acceleration. We will therefore enrich from the start of the re-acceleration phase to reduce . the OS quickly and return to the optimal value for treating pollutants (particularly NOx in this case). We therefore end up with a penalty in consumption when these enrichments are activated. We will refer for example to publication FR-A1-3101673 which describes such a process.

[0081] - an intrusive wealth diagnostic strategy: this strategy aims to To diagnose the catalyst aging state, OBD diagnostic strategies need to generate richness slots of a few seconds. Typically, a rich slot has a richness equal to 1.07 instead of 1, which also leads to a fuel consumption penalty. For example, we will refer to publication FR-Al-3057022 which describes such a process.

[0082] The method 10 further comprises a step 15 of calculating, on a path T, a consumption penalty linked to the active strategy S, both in absolute value in liters and in relative value in percentage with respect to the total consumption Cons_T in liters according to the following equations:

[0083] [Math.4] (\ rt _end_trajetT litre= Jr start[ Jra -etT{Pen_cons_inst_S) (Activ _S\dt

[0084] [Math.5] P in cons 5 n%=100.—~ — — — \ f Contribution {liter)

[0085] With:

[0086] Pen_cons_S_T, the consumption penalty in liters of strategy S on route T;

[0087] Pen_cons_S_T(%), the consumption penalty as a percentage of the total fuel consumption of strategy S on route T;

[0088] t_start_travelT, the start time of the journey T, in seconds;

[0089] t_fin_trajetT, the end time of the journey T, in seconds;

[0090] Pen_cons_inst_S, the instantaneous consumption penalty in liters per second of strategy S;

[0091] Activ_S, a boolean for activating strategy S, equal to 1 if the strategy is activated, equal to 0 if the strategy is not activated;

[0092] dt, the integration time step, in seconds; and

[0093] Cons_T (liter), the engine fuel consumption in liters on the journey T calculated according to the following equation:

[0094] [Math.6] / \ çt_end_trajetT Cons_T [litre} = )t_déhiajmjetTCons^

[0095] The method 10 further comprises a step 16 of recording in the memory of the engine computer the consumption penalties calculated in step 15 for a plurality of paths Ti, and calculation of the average values ​​on said plurality of paths Ti, in particular with i between 1 and 20.

[0096] During a step 17, the data recorded during step 16 are synthesized in a comparative table and, in step 18, said recorded data are compared with reference values ​​from a WLTC approved cycle to determine the origin of the excess fuel consumption.

[0097] Such a comparative table is illustrated in [Fig.3].

[0098] In this example, for which three journeys were considered, we see an average consumption (l / 100km) significantly higher than the approved consumption, namely 1.1 litres per 100km.

[0099] The first point which differs from the use of the vehicle is the high proportion of use in town, which is on average 93% compared to 20% on a WLTC approved cycle, on short journeys, on average 4.3km compared to 23.3km on a WLTC approved cycle.

[0100] We note to begin with that the consumption of this vehicle is penalized because the engine operates on low load zones with lower efficiency and more so with a cold / warm water temperature (<90°C) which also penalizes consumption. The calculated consumption penalties make it possible to complete this first macroscopic analysis.

[0101] Firstly, we find a much higher contribution from catalyst heating because the journeys being short, the activation time of the catalyst heating strategy relative to the total journey time is longer. This is necessary for the depollution of the vehicle and can therefore be justified.

[0102] The other item that emerges from these typical "city" journeys is the greater penalty of the torque reserve strategy at idle because there are many phases where the vehicle is stopped (traffic lights, traffic jams, etc.).

[0103] It then appears that the user has a fairly dynamic driving style because we see a high penalty from the Anti-jolt strategy, which involves a lot of acceleration and deceleration, gear changes with very sharp presses on the accelerator pedal. This very dynamic or transient driving also results in a high penalty on the OS management strategy which must very often reset the catalyst to the correct OS level given the multiple deceleration phases saturating the catalyst with oxygen. This can also be justified for pollution control needs.

[0104] Concerning the other penalties, the differences are not very significant.

[0105] Overall, the total penalty in consumption is on average increased by 5.5% in absolute terms compared to the WLTC approved reference cycle.

[0106] The analysis of these penalties therefore made it possible to clarify the origins of the overcon summation in relation to an initial macroscopic analysis and will allow the manufacturer to enrich its argument with the authorities.

[0107] Such a method for analyzing actual fuel consumption and determining the origins of any excess consumption is easy to incorporate on board the engine computer since it uses variables already present in the engine computer.

[0108] Thanks to the invention, it is easy to explain the origin of the differences in vehicle consumption in real life compared to that which is approved on the WLTC cycle.

Claims

Claims

1. Method (10) for analyzing an actual energy consumption of a motor vehicle on a journey (T), the method being intended to be implemented in part by an electronic control unit embedded in a computer of a spark-ignition internal combustion engine of a motor vehicle, characterized in that the method (10) comprises: - a step (11) of determining an ignition advance efficiency (Rend_Av); - a step (12) of determining a richness efficiency (Rend_Rich); - a step (13) of calculating an instantaneous consumption penalty (Pen_cons_inst), in liters per second, as a function of said efficiencies (Rend_Av, Rend_Rich) and an instantaneous fuel consumption (Cons_Inst) of the engine in liters per second;- a step (14) of verifying the activated or inactive state of the different strategies (S) embedded in the engine computer and chosen from the group comprising at least strategies acting on the ignition advance and strategies acting on the richness; and - a step (15) of calculating, on a journey (T), a consumption penalty (Pen_cons_S_T) linked to the active strategy (S), both in absolute value in liters and in relative value in percentage compared to the total consumption (Cons_T (liter)) as a function of the instantaneous consumption penalty (Pen_cons_inst) calculated in step (13) for each active strategy (S).;

2. Method according to claim 1, comprising a step (16) of recording in the memory of the engine computer the consumption penalties (Pen_cons_S_T) calculated in the calculation step (15) for a plurality of journeys (Ti), and of calculating the average values ​​over said plurality of journeys (Ti), in particular with i between 1 and 20, a step (17) of synthesizing the data recorded during the recording step (16) in a comparative table and a step (18) of comparing said data synthesized in the comparative table with reference values ​​of a WLTC approved cycle to determine the origin of the excess fuel consumption.

3. A method according to claim 1 or 2, wherein the fuel consumption penalty related to the ignition advance is calculated according to the equation next: [Math 2] Pen_cons _inst = ( \ - Rend_AV ).Cons_Inst-

4. A method according to any preceding claim, wherein the wealth-related consumption penalty is calculated according to the following equation: [Math 3] Pen_cons_mst = (Rend _Rich} Cons _lnst-

5. Method according to any one of the preceding claims, in which the consumption penalty (Pen_cons_S_T) linked to the active strategy (S) is calculated according to the following equations: [Math 4] Pen_cons_S_T I litre = jf start t etTPen_cons_inst_S Activ_S.dt [Math 5]pen_cons_S_T^

6. Method (10) according to, in which the ignition advance efficiency (Rend_Av) is calculated according to the following equation: [Math 1] Rend_AV = lk^Av_opt-Av_appl)2' with: k, a coefficient resulting from a map present in the engine control system; Av_opt, the optimal value of the ignition advance; and Av_appl, the actual value of the ignition advance.

7. Method according to any one of the preceding claims, in which the strategies (S) acting on the ignition advance comprise at least: a strategy for heating an engine depollution catalyst, a strategy for reserving torque at idle, an anti-shock strategy and an anti-knock strategy.

8. Method according to any one of the preceding claims, in which the strategies (S) acting on the richness comprise at least: a starting strategy, a richness regulation strategy, a strategy for managing the quantity of oxygen present in a pollution control catalyst of the engine and an intrusive diagnostic strategy on the richness.

9. Motor vehicle comprising a spark-ignition internal combustion engine, an engine computer and an electronic control unit embedded in the engine computer and capable of partially implementing the method (10) according to any one of the preceding claims.

Images