GB2579646A

GB2579646A - A system, controller and method for stopping an engine

Info

Publication number: GB2579646A
Application number: GB1820066.7A
Authority: GB
Inventors: Walsh Joseph; Jean Brice Roques Olivier
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2018-12-10
Filing date: 2018-12-10
Publication date: 2020-07-01
Anticipated expiration: 2038-12-10
Also published as: GB201820066D0; GB2579646B

Abstract

Systems, methods, vehicles and controllers are disclosed that control a pump 420 to change pressure in an intake manifold 130 of an internal combustion engine 140 of a vehicle; and command the pump to reduce pressure in the intake manifold in dependence upon a received request to stop the internal combustion engine of the vehicle. The pump can be the impellor of an electrically controlled supercharger or turbocharger and the speed of the compressor stage of the turbocharger or supercharger can be used to throttle air supplied to intake, reducing pressure in the air intake and thus stopping the engine.

Description

A SYSTEM, CONTROLLER AND METHOD FOR STOPPING AN ENGINE

TECHNICAL FIELD

The present disclosure relates to systems controllers and methods for stopping an engine. In particular, but not exclusively, it relates to systems, controllers and methods for stopping an engine in a vehicle fitted with a diesel engine and stop/start system.

Aspects of the invention relate to systems, a controller, methods and vehicles.

BACKGROUND

Diesel engines tend to cause significant vibration and noise when shutting down, known as "shutdown shake". This is due to the high compression ratios in diesel engines.

There has been a trend to prolong the period for shutting down the diesel engine after a request to stop the engine has been received so that the noise and vibration is reduced. The period is prolonged by maintaining fueling for longer during shutdown of the engine. The noise and vibration are reduced as a consequence of reducing the effective compression ratio in the cylinders of the engine during this period. By reducing the pressure in the intake manifold of the engine, the volume of air inducted into the cylinders with each successive engine stroke is reduced, thereby reducing the effective compression ratio. The pressure in the intake manifold is reduced by closing a valve at the inlet of the intake manifold such that the volume inducted into the cylinders with each engine stroke and expelled through the exhaust is not replenished This prolonged period negatively affects stop/start systems, where an engine may be required to restart to meet a torque demand very shortly after an automatic shut down, due to for example stopping at a traffic junction. Due to the prolonged period for shutting down the diesel engine, there may be a delay before the engine can be restarted.

It is an aim of the present invention to maintain a low level of noise and vibration when stopping a diesel engine whilst improving the effectiveness of a stop/start system.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide systems, controllers, methods and vehicles as claimed in the appended claims.

According to an aspect of the invention there is provided a system comprising: a controller and a pump; wherein the pump is configured to change pressure in an intake manifold of an internal combustion engine of a vehicle; and wherein the controller is configured to command the pump to reduce pressure in the intake manifold in dependence upon a received request to stop the internal combustion engine of the vehicle.

This provides the advantage that a diesel engine may be stopped quicker after a request to stop the engine has been received.

In some, but not necessarily all, examples, the pump comprises a forced induction device.

In some, but not necessarily all, examples, the forced induction device comprises an electric supercharger.

In some, but not necessarily all, examples, the forced induction device comprises an electric turbocharger.

In some, but not necessarily all, examples, in a first mode of operation the pump increases pressure in the intake manifold of the engine and in a second mode of operation, the pump reduces pressure in the intake manifold and the controller is configured to command the pump to operate in the second mode of operation in dependence upon the received request to stop the internal combustion engine.

In some, but not necessarily all, examples, the pump comprises an electric motor and an impeller; wherein the controller is configured to control a direction of spin of the impeller; wherein in the first mode of operation, the controller commands the impeller to spin in a first direction to compress air into the intake manifold; and wherein in the second mode of operation, the controller commands the impeller to spin in a second direction, opposite to the first direction, to reduce pressure in the intake manifold.

In some, but not necessarily all, examples, the pump comprises an electric motor and an impeller; wherein in the first mode of operation, the controller commands the impeller to spin in a first direction at a first speed that compresses air into the intake manifold; and wherein in the second mode of operation, the controller commands the impeller to spin in the first direction at a second speed that reduces pressure in the intake manifold.

This provides the advantage that the pump has dual functionality, reducing the requirement for additional components within the vehicle.

In some, but not necessarily all, examples, the system additionally comprises an intake manifold pressure sensor and the controller is configured to control a speed of the pump in dependence upon a value of pressure measured by the intake manifold pressure sensor.

According to an aspect of the invention there is provided a vehicle comprising the system of any preceding paragraph.

According to an aspect of the invention there is provided a method comprising: receiving a request to stop an internal combustion engine of a vehicle; commanding a pump to reduce pressure in an intake manifold of the internal combustion engine in dependence upon the request to stop the internal combustion engine.

In some, but not necessarily all, examples, the method additionally comprises measuring the speed of the internal combustion engine, measuring the intake manifold pressure and determining a target intake manifold pressure based on the speed of the internal combustion engine and the target manifold pressure prior to commanding the pump to reduce the intake manifold pressure.

In some, but not necessarily all, examples, the method further comprises commanding the pump to stop reducing the intake manifold pressure when the target intake manifold pressure has been reached.

According to an aspect of the invention there is provided a controller, configured to command a pump to reduce pressure in an intake manifold of an internal combustion of an engine of a vehicle in dependence upon a received request to stop the internal combustion engine.

According to an aspect of the invention there is provided a vehicle comprising the controller of any preceding paragraph.

According to an aspect of the invention there is provided a system comprising: means for changing pressure in an intake manifold of an internal combustion engine of a vehicle; and means for commanding the means for changing pressure in the intake manifold to reduce pressure in the intake manifold in dependence upon a received request to stop the internal combustion engine of the vehicle.

According to a further aspect of the invention there is provided a system as described above, wherein: said means to change pressure in an intake manifold of an internal combustion engine comprises an electronic processor having one or more electrical inputs for changing pressure in the intake manifold; and an electronic memory device electrically coupled to the electronic processor and having computer program instructions stored therein; and said means for commanding changing pressure in the intake manifold to reduce pressure in the intake manifold in dependence upon a received request comprises the processor being configured to access the memory device and execute the instructions stored therein such that it is operable to command changing the pressure in the intake manifold to reduce pressure in the intake manifold in dependence upon a received request.

In some, but not necessarily all, examples, the means for changing pressure in an intake manifold of an internal combustion engine of a vehicle comprises a pump and the means for commanding the means for changing pressure in the intake manifold to reduce pressure in the intake manifold in dependence upon a received request to stop the internal combustion engine of the vehicle comprises a controller.

According to an aspect of the invention there is provided a controller configured to perform the method disclosed herein.

According to a further aspect of the invention there is provided a system comprising means for causing the method as described herein to be performed.

According to a further aspect of the invention there is provided a system operable to control a pump of a vehicle, the system comprising at least one electronic processor, and at least one electronic memory device having computer program instructions stored therein, wherein the at least one electronic memory device and the computer program instructions are configured to, with the at least one electronic processor, cause the system to perform: receiving a request to stop an internal combustion engine of a vehicle; commanding the pump to reduce pressure in an intake manifold of the internal combustion engine in dependence upon the request to stop the internal combustion engine.

According to a further aspect of the invention there is provided a non-transitory tangible physical entity embodying a computer program comprising computer program instructions that, when executed by at least one electronic processor, enable a system at least to perform: receiving a request to stop an internal combustion engine of a vehicle; commanding a pump to reduce pressure in an intake manifold of the internal combustion engine in dependence upon the request to stop the internal combustion engine.

According to a further aspect of the invention there is provided a computer program that, when run on at least one electronic processor, causes a system to perform the method disclosed herein.

The term 'means to' as used herein is intended to have the same meaning as 'means for' to the extent that in the data-processing/computer program field, apparatus features of the means-plus-function type ("means for...") are interpreted as means adapted to carry out the relevant steps/functions, rather than merely means suitable for carrying them out.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a system for decreasing pressure of an intake manifold of an engine; Figures 2A and 2B illustrate graphs of intake manifold pressure against time and engine speed against time whilst an intake manifold pressure is decreased; Figure 3 illustrates an example flow chart of operation of a system for decreasing pressure of an intake manifold of an engine; Figure 4 illustrates a system for decreasing pressure of an intake manifold of an engine; Figure 5 illustrates a system for decreasing pressure of an intake manifold of an engine; Figure 6 illustrates a system for decreasing pressure of an intake manifold of an engine; Figure 7 illustrates a vehicle comprising a system for decreasing pressure of an intake manifold of an engine; Figure 8 illustrates a method for decreasing pressure of an intake manifold of an engine; Figure 9 illustrates a method for decreasing pressure of an intake manifold of an engine; Figure 10 illustrates a controller that controls decreasing pressure of an intake manifold of an engine.

DETAILED DESCRIPTION

The figures illustrate systems, methods, controllers and a vehicle.

Figure 1 illustrates a system 100 comprising a controller 110 and a pump 120. The pump 120 changes pressure in an intake manifold 130 of an internal combustion engine 140 of a vehicle. The controller 110 is configured to command 117 the pump 120 to reduce pressure in the intake manifold 130 in dependence upon a received request 115 to stop the internal combustion engine 140 of the vehicle.

Figure 1 illustrates cylinders 145 in the engine 140. The four cylinders 145 in figure 1 are illustrated for example purposes only.

Figures 2A and 2B illustrate graphs showing intake manifold pressure and engine speed over time whilst an engine is in the process of stopping.

Figure 2A illustrates intake manifold pressure (hPa) against time (s).

Trace 201 of figure 2A illustrates the pressure of an intake manifold 130 of a vehicle comprising the system 100. At time t = 4 a request to stop the engine 140 is received. As described above a pump 120 connected to the intake manifold 130 reduces the pressure in the intake manifold 130. Trace 201 shows that the pressure in the intake manifold 130 decreases over time after the request to stop the engine 140 is received.

Trace 202 of figure 2A illustrates the pressure of an intake manifold of a vehicle after a request to stop the engine has been received at time t = 4 if pressure in the intake manifold 130 were not reduced using the pump 120. Traces 201 and 202 show that the system 100 decreases the pressure of the intake manifold 130 faster. The timescale on Figure 2A is for illustrative purposes only.

Figure 2B illustrates engine speed (rpm) against time (s). Trace 203 of figure 2B illustrates the engine speed over time of a vehicle comprising the system 100 and corresponds with the trace 201 of figure 2A. As described above for figure 2A, at time t = 4 a request to stop the engine is received. Trace 203 illustrates the corresponding decrease in engine speed as the intake manifold pressure decreases over time as shown in trace 201 of figure 2A.

Trace 204 of figure 2B illustrates the engine speed over time of a vehicle after a request to stop the engine has been received at time t = 4 if pressure in the intake manifold 130 were not reduced using the pump 120. It can be seen from traces 203 and 204 that it takes less time for the engine speed of the vehicle to reduce to a stop at zero rpm when the pump 120 is used to reduce pressure in the intake manifold 130.

The engine speed drops quicker when the pressure of the intake manifold 130 is decreased by the pump 120 because the diesel engine draws in air from the intake manifold 130 on the induction stroke of each cylinder 145 that is of lower pressure quicker than a vehicle without the system 100. Diesel engines continue to rotate after a command to stop the engine has been received because of the high compression and expansion forces caused by continuing to draw in the air on the induction stroke of the cylinders. Reducing the pressure of the inducted air quicker reduces the compression and expansion forces quicker, causing the pistons in the cylinders 145 to slow down. The timescale on Figure 2B is for illustrative purposes only.

Therefore the advantage of system 100 is that the time taken to stop an internal combustion engine 140 of a vehicle can be reduced, whilst maintaining a desired reduction in the noise and vibration caused by stopping the internal combustion engine 140. This is advantageous, for example, in a stop/start system, where the engine has been commanded to stop during the progress of a journey, i.e. at a junction where the vehicle has come to a stop. If the driver demands torque by the engine very shortly after the engine has been commanded to stop by the stop/start system, then if the engine takes longer to stop there is a delay before the engine can be restarted to carry out the demand by the driver. The delay may be noticeable by the driver, and therefore the present invention has the advantage that the engine can stop and restart quicker due to a driver demand.

The pump 120 in some, but not necessarily all, examples is a forced induction device. For example, the forced induction device comprises a turbocharger or a supercharger. In one or more examples, the forced induction device is an electric supercharger or an electric turbocharger. Alternatively, the pump 120 can be any pump for reducing the pressure in the intake manifold 130.

The forced induction device is typically used for increasing pressure in an intake manifold of an engine. This can, for example, increase the performance of the engine by increasing the density of the air that is induced into the engine resulting in greater power production by the engine.

In the present invention, the forced induction device may, for example, also be used to reduce the pressure of the intake manifold 130 to reduce the time it takes to stop the engine 140.

For example, the forced induction device comprises a compressor housing with an axial inlet, a radial outlet and a compressor impeller. When the forced induction device is used for increasing pressure in an intake manifold 130 of an engine 140, the compressor impeller is spun in a first direction so as to cause air from the axial inlet to be forced out of the radial outlet. The radial outlet is connected to the intake manifold 130 of the engine 140.

In a first example to reduce pressure in the intake manifold 130 of the engine 140, the compressor impeller may be spun in a second direction, opposite to the first direction so as to cause air to flow from the radial outlet to the axial inlet. This causes air to flow from the intake manifold 130 to the axial inlet of the compressor, causing a reduction in pressure in the intake manifold 130. In this example, the "radial outlet" becomes the inlet for the air exiting the intake manifold 130 and the "axial inlet" becomes the outlet for the air exiting the intake manifold 130.

In this example, when the compressor impeller is spinning in the second direction, the behavior of air flowing from the "radial outlet" to the "axial inlet" is similar to the behavior of a turbine of a turbocharger. A turbine of a turbocharger has a turbine housing with a radial inlet, an axial outlet and a turbine impeller. The structure of a turbine is similar to the structure of a compressor but typically operates in the reverse direction to a compressor. In a turbine for a turbocharger, the motion of the exhaust gas from the engine into the radial inlet causes the turbine impeller to spin and the exhaust gas exits through the axial outlet. It follows logically that if, hypothetically, the turbine impeller was made to spin, in the same direction that the exhaust gas causes it to spin, the turbine impeller would cause air to flow from the radial inlet to the axial outlet. Therefore in this example, the behavior of air flowing from the "radial outlet" to the "axial inlet" in the compressor when it is operated to spin in the second direction is similar to the behavior of a turbine.

In a second example to reduce pressure in the intake manifold 130 of an engine 140, the compressor impeller may be spun in the first direction, the same direction that the compressor impeller spins to increase the pressure in the intake manifold 130. To cause the pressure to decrease, rather than increase, when the compressor impeller is spun in the first direction, it is spun at a speed that causes a flow of air from the radial outlet to the axial inlet, causing a reduction in pressure in the intake manifold 130 of the engine 140. This type of air flow may be called a reverse flow. This effect is explained by the concept of surge lines for compressors.

To operate satisfactorily for increasing pressure in an intake manifold 130, the compressor impeller is designed to spin at a speed so that the compressor works above a surge line for the compressor. On a graph of pressure ratio vs. air flow for a compressor, the surge line identifies a boundary on the graph which represents the minimum achievable pressure ratio (the ratio of output pressure to input pressure) for a given compressor impeller speed. If the compressor operates near to the surge line it will be subjected to temporary reversals of air flow. If the objective is to increase pressure at the radial outlet of a compressor to increase pressure in the intake manifold 130, operating near the surge line is not beneficial. Operating the compressor at speeds below the nominal surge speed, the compressor cannot achieve significant pressure gain and is subjected to prolonged reversals of flow. Therefore operating the compressor at a speed below the nominal surge speed will cause a reduction in the intake manifold pressure. Therefore according to this example, when the engine is being shut down, the compressor impeller may be spun at a speed in the first direction that causes the pressure in the intake manifold 130 to reduce.

Figure 3 illustrates an example flow chart of different modes of operation of a forced induction device. In the example of figure 3 an electric turbocharger is used, but it is to be understood that any forced induction device can be used.

At step A in figure 3, an acceleration is demanded, and at this time the electric turbocharger is off. At step B, in response to the acceleration demand, the electric turbocharger is switched on, and operates in a first mode of operation 310, where the pressure in the intake manifold 130 is increased by the electric turbocharger. At step C, the vehicle is demanded to decelerate and at this moment in time the electric turbocharger is switched off or has already been switched off before the deceleration demand. It is to be understood that the electric turbocharger does not have to be switched off in response to the deceleration, but may be switched off at another time before deceleration has been demanded. At step D, a command to stop the engine 140 is received, and the controller 110 commands 117 the electric turbocharger to operate in a second mode of operation 320, which reduces the pressure in the intake manifold 130.

Figure 4 illustrates an example of the system 100.

In the example illustrated in figure 4, the pump 120 comprises a forced induction device 420.

In this example the forced induction device 420 comprises an electric supercharger 430. The electric supercharger 430 comprises an impeller 431, an electric motor 432 and power electronics 433.

The power electronics 433 respond to receiving a command 117 to reduce pressure in the intake manifold 130 by operating the electric supercharger 430 in the second mode of operation 320. The power electronics 433 respond to receiving a request 118 to increase pressure in the intake manifold 130 by operating the electric supercharger 430 in the first mode of operation 310.

In the example of figure 4, the request 118 and the request 117 is from the controller 110. It is to be understood that the request 118 can be from another controller of the vehicle, not illustrated in figure 4.

In figure 4, the electric supercharger 430 supplements a non-electric turbocharger 440, which comprises an intake impeller 441 and an exhaust impeller 442, which is rotated by exhaust gases from the exhaust manifold 135. For example the electric supercharger 430 may supplement the turbocharger 440 by operating in the first mode of operation 310 during a lag period of the turbocharger 440.

Figure 4 also illustrates a sensor arrangement 450, which comprises at least one sensor. The sensor arrangement 450 is operatively connected to the controller 110. One sensor in the arrangement 450 may be an intake manifold pressure sensor, which measures the pressure of the intake manifold 130 to determine whether the electric supercharger 430 is required to further reduce the pressure in the intake manifold 130. Another sensor of the arrangement 450 may be a crankshaft position sensor, which detects a position of the crankshaft and determines whether the engine has stopped rotating. The crankshaft position sensor or another sensor of the arrangement 450 may measure the engine speed.

Figure 4 illustrates valves 460 and 470. Valve 460 is an intake valve and valve 470 is a bypass 30 valve.

To shut the engine down without using the electric supercharger 430 to reduce the pressure of the intake manifold 130, one or more of valves 460 and 470 are closed to seal the intake manifold. This allows the pressure of the intake manifold to reduce through the action of the engine drawing in the air on the induction stroke of the cylinders and expelling the air out of the engine on the exhaust stroke, thereby reducing the pressure in the intake manifold 130 over time. In this example system or other systems, to shut the engine 140 down without using the electric supercharger 430 or another forced induction device, an intake throttle valve may be closed and the inertia of the one or more impellers of the induction device will prevent them from rotating to allow air to escape out of the intake manifold 130.

In the example of Figure 4, to shut the engine down using the electric supercharger 430 to reduce the pressure of the intake manifold 130, the valve 460 is opened by controller 110 when the engine 140 has been commanded to stop and the electric supercharger 430 reduces the pressure of the intake manifold 130 by operating in the second mode of operation 320.

The bypass valve 470 is simultaneously closed, to ensure that all air is taken through the electric supercharger 430 to reduce the pressure of the intake manifold 130.

In one or more examples, the system 100 may switch between (i) reducing the pressure of the intake manifold 130 using a pump 120 (e.g. by operating the electric supercharger 430 in the second mode of operation 320 when a command 115 to stop the engine 140 has been received, and (H) closing the intake valve 460 to lock the volume of the intake manifold 130 when a command 115 to stop the engine has been received.

Figure 4 illustrates a fuel controller 480 which is commanded by the controller 110 to either reduce the fueling to the cylinders 145 after a demand to stop the engine 140 has been received. The reduction may be gradual over each rotation of the engine or the reduction may be an immediate stop to the fueling to the cylinders 145. For example the fuel controller 480 may reduce the amount of fuel into each cylinder over several rotations of the engine instead of immediately cutting all fuel to the cylinders to reduce noise and vibration whilst the engine shuts down to allow the air in the intake manifold 130 to go through the engine 140 progressively by slowing down the engine speed decay rate.

The quantity of fuel injected into each cylinder to help reduce is related to the pressure in the intake manifold. As the system 100 reduces the manifold pressure quickly, the volume of fuel required to be injected to each cylinder 145 per engine rotation is reduced. This has a twofold benefit of reducing the volume of fuel used during the engine stop phase and also allowing the engine to stop more quickly.

During operation of the system 100, the turbocharger 440 and the electric supercharger 430 may be used to increase pressure in the intake manifold 130. This is done, for example, to increase performance of the vehicle. Whilst the turbocharger 440 and the electric supercharger 430 are increasing the pressure in the intake manifold 130, the electric supercharger 430 is operating in the first mode of operation 310 and the impeller 431 spins in a first direction at a speed that causes an increase in pressure in the intake manifold 130.

When the engine 140 has been commanded to stop, by the received request 115, the controller may receive an intake manifold pressure from the sensor arrangement 450 and/or may receive a signal indicating the speed of the engine 140. The controller 110 may determine a target manifold pressure based on the measured intake manifold pressure and/or measured speed of the engine 140. The controller 110 commands the electric supercharger 430 to operate in the second mode of operation 320. In one example, when the controller 110 commands the electric supercharger 430 to operate in the second mode of operation 320, the controller 110 commands the impeller 431 of the electric supercharger to spin in a second direction, opposite to the direction of the first direction to reduce the pressure in the intake manifold 130. In a second example, when the controller 110 commands the electric supercharger 430 to operate in the second mode of operation 320, the controller 110 commands the impeller 431 of the electric supercharger to spin in the first direction, at a speed that causes a reduction of the pressure in the intake manifold 130.

In one or more examples the controller 110 commands the electric supercharger 430 to reduce the intake manifold pressure until the controller 110 determines that the pressure has reached a target manifold pressure and/or when it has determined that the engine 140 has stopped.

During the process of stopping the engine 140 and reducing the pressure by the electric supercharger 430, the controller 110 may command the fuel controller 480 to either stop fueling the cylinders 145 completely or to gradually reduce the fueling to each cylinder 145 over each rotation of the engine 140, to reduce noise and vibration caused by the engine 140 3o shutting down. During stopping of the engine 140, the valve 460 is opened and the valve 470 is closed by the controller 110. In one or more examples, during the process of stopping the engine 140 the impellers 441 and 442 of the turbocharger 440 are not rotating or are rotating at a substantially low speed that does not increase the pressure in the intake manifold 130.

Figure 5 illustrates another example of the system 100. In Figure 5 the position of the turbocharger 440 is placed after the electric supercharger 430 with respect to the air intake 510. In this particular example an exhaust gas recirculation valve 520 is shown, which is used to recirculate exhaust gases from the exhaust manifold 135. When the controller 110 commands the electric supercharger 430 to reduce pressure in the intake manifold 130 to stop the engine 140, the valve 520 is closed by the controller 110. It is to be understood that the exhaust gas recirculation valve 520 is optional in the system 100 illustrated in Figure 5. The system 100 of figure 5 works in substantially the same way as described in the previous figures, where during the second mode of operation 320 the intake throttle valve 460 is opened, the exhaust gas recirculation valve 520, if it is present, is closed, and the fuel controller 480, is commanded to either stop fueling the cylinders 145, or is commanded to gradually reduce the fueling of each cylinder 145 over each rotation of the engine 140.

Figure 6 shows another example of the system 100. In the example of Figure 6, the forced induction device 420 is an electric turbocharger 610. The electric turbocharger 610 operates by using the exhaust gas from the exhaust manifold 135 to spin the exhaust impeller 611 which in turn rotates the intake impeller 612. The intake impeller 612 is also supplemented with an electric motor 620 with power electronics 625. In one or more examples, a clutch 630 is used to connect and disconnect the electric motor 620 to the intake impeller 612. It is to be understood that the clutch 630 is optional. During operation of the system 100, during a first mode of operation 310, the controller 110 or another controller commands the motor 620 to spin the intake impeller 612 in a first direction to increase the pressure in the intake manifold 130 of the engine 140. In the second mode of operation 320, the controller 110 commands the motor 620 to spin the intake impeller 612 to reduce the pressure in the intake manifold 130 of the engine 140. In a first example, when the controller 110 commands the motor 620 to spin the intake impeller 612 to reduce the pressure in the intake manifold 130, the controller 110 commands the motor 620 to spin the intake impeller 612 in a second direction opposite to the first direction to reduce the pressure in the intake manifold 130 of the engine 140. In a second example, when the controller 110 commands the motor 620 to spin the intake impeller 612 to reduce the pressure in the intake manifold 130, the controller 110 commands the motor 620 to spin the intake impeller 612 in the first direction, at a speed that causes a reduction of the pressure in the intake manifold 130. The system 100 of figure 6 works in substantially the same way as described in the previous figures, where during the second mode of operation 320 the intake throttle valve 460 is opened, the exhaust gas recirculation valve 520, if it is present, is closed, and the fuel controller 480, is commanded to either stop fueling the cylinders 145, or is commanded to gradually reduce the fueling of each cylinder 145 over each rotation of the engine 140.

Figure 7 illustrates a vehicle 700 comprising the system 100. In one or more examples the vehicle 700 comprises only one of the controller 110 or the pump 120, the other to be fitted later. In other examples, the vehicle 700 comprises both the pump 120 and the controller 110. The controller 110 is configured to command the pump 120 to reduce pressure in an intake manifold 130 of an internal combustion engine 140 of the vehicle 700 in dependence upon a received request 115 to stop the internal combustion engine 140.

Figure 8 shows an example method 800 for commanding a pump 120 to reduce pressure in an intake manifold 130 of an internal combustion engine 140. In step 810, a request 115 is received to stop an internal combustion engine 140 of a vehicle 700. The request 115 may be from a driver depressing a brake pedal while the vehicle 700 is stopped or is at a substantially slow speed, or the driver has pressed a button to switch off the engine 140. In other examples, the request 115 to stop the internal combustion engine 140 is received from a stop/start system. In step 820 a pump 120 is commanded to reduce pressure in an intake manifold 130 of the internal combustion engine 140 in dependence upon the request signal 115 to stop the internal combustion engine 140.

Figure 9 illustrates an example method 900 for commanding a pump 120 to reduce pressure in an intake manifold 130 of an internal combustion engine 140. In step 910 a request 115 is received to stop an internal combustion engine 140 of a vehicle 700. As described above, a request 115 may be from a driver or from a stop/start system. In step 920, the speed of the internal combustion engine 140 is measured and in step 930 the intake manifold pressure of the internal combustion engine 140 is measured. Following this, in step 940, a target intake manifold pressure is determined. The target intake manifold pressure is the pressure value which is determined to be the pressure at which the engine 140 will have stopped/will stop imminently, due to the reduced pressure in the intake manifold 130. The target intake manifold pressure is based on the measured speed of the engine 140 and the measured intake manifold pressure in steps 920 and 930. In step 950 the pump 120 is commanded to reduce intake manifold pressure to reach the target intake manifold pressure. In step 960 the pump is commanded to stop reducing the intake manifold pressure when the target manifold pressure is reached. In an alternative example, the pump may be commanded to stop reducing the pressure when it is determined by a sensor from arrangement 450 that the engine has stopped, or if the target manifold pressure has been reached and the engine is detected to have not stopped by the sensor, the pump is commanded to continue reducing the pressure until the engine is detected to have been stopped.

Figure 10 illustrates a controller 110. Implementation of a controller 110 may be as controller circuitry. The controller 110 may be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware).

As illustrated in figure 10 the controller 110 may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 111 in a general-purpose or special-purpose processor 112 that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor 112.

The processor 112 is configured to read from and write to the memory 113. The processor 112 may also comprise an output interface via which data and/or commands are output by the processor 112 and an input interface via which data and/or commands are input to the processor 112.

The memory 113 stores a computer program 111 comprising computer program instructions (computer program code) that controls the operation of the system 100 when loaded into the processor 112. The computer program instructions, of the computer program 111, provide the logic and routines that enables the system to perform the methods illustrated in figures 8 and 9. The processor 112 by reading the memory 113 is able to load and execute the computer program 111.

In one or more examples, a signal indicative of the engine speed and a signal indicating the position of the crankshaft from sensor arrangement 450 are received by the controller 110 and the actuation of the pump 120 to reduce the pressure in the intake manifold 130 is timed in dependence upon these signals. The positon of the crankshaft corresponds to a positon of the cylinder valves of the engine 140 at any given time. The purpose of this is to time the reduction in pressure by the pump 120 to match the cycle of the pistons in cylinders 145 in an antiphase relationship.

For example, if the pump comprises the forced induction device 420, for example the electric supercharger 430, instead of operating the impeller 431 of the forced induction device 420 at a continuous speed to reduce the pressure of the intake manifold 130, the speed is modulated to be in antiphase with the engine speed, to match pulsations of the manifold pressure.

Pulsations in the manifold pressure and engine speed occur because of the valves of the cylinders 145 opening and closing, which causes the air flow in the intake manifold 130 to not be smooth. To run the forced induction device 420 to be in antiphase with engine speed, the speed of the impeller 431 is reduced whilst the engine 140 draws air in to the cylinders 145 by opening intake valves of the cylinders 145. When the engine is not drawing the air into the cylinders 145, the speed of the impeller 431 is increased. The aim of running the forced induction device 420 in antiphase with the engine speed is to achieve a smooth decrease in pressure within the intake manifold 130. The advantage provided by this is that it reduces the amount of energy used by the forced induction device 420, and it reduces the noise due to pulsation in manifold pressure.

For purposes of this disclosure, it is to be understood that the controller(s) described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle and/or a system thereof may comprise a single control unit or electronic controller or alternatively different functions of the controller(s) may be embodied in, or hosted in, different control units or controllers. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) to implement the control techniques described herein (including the described method(s)). The set of instructions may be embedded in one or more electronic processors, or alternatively, the set of instructions could be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present disclosure is not intended to be limited to any particular arrangement. In any event, the set of instructions described above may be embedded in a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM ad EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions.

The blocks illustrated in the figures 8 an 9 may represent steps in a method and/or sections of a computer program code. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS1 A system comprising: a controller and a pump; wherein the pump is configured to change pressure in an intake manifold of an internal combustion engine of a vehicle; and wherein the controller is configured to command the pump to reduce pressure in the intake manifold in dependence upon a received request to stop the internal combustion engine of the vehicle.
2. A system as claimed in claim 1, wherein the pump comprises a forced induction device.
3. A system as claimed in claim 2, wherein the forced induction device comprises an electric supercharger.
4. A system as claimed in claim 2, wherein the forced induction device comprises an electric turbocharger.
5. A system as claimed in any preceding claim, wherein in a first mode of operation, the pump increases pressure in the intake manifold of the engine; wherein in a second mode of operation, the pump reduces pressure in the intake manifold; and wherein the controller is configured to command the pump to operate in the second mode of operation in dependence upon the received request to stop the internal combustion 25 engine.
6. A system as claimed in claim 5, wherein the pump comprises an electric motor and an impeller; wherein the controller is configured to control a direction of spin of the impeller; wherein in the first mode of operation, the controller commands the impeller to spin in a first direction to compress air into the intake manifold; and wherein in the second mode of operation, the controller commands the impeller to spin in a second direction, opposite to the first direction, to reduce pressure in the intake manifold.
7. A system as claimed in claim 5, wherein the pump comprises an electric motor and an impeller; wherein in the first mode of operation, the controller commands the impeller to spin in a first direction at a first speed that compresses air into the intake manifold; and wherein in the second mode of operation, the controller commands the impeller to spin in the first direction at a second speed that reduces pressure in the intake manifold.
8. A system as claimed in any preceding claim, additionally comprising an intake manifold pressure sensor; and wherein the controller is configured to control a speed of the pump in dependence upon a value of pressure measured by the intake manifold pressure sensor.
9. A vehicle comprising the system of any preceding claim.
10. A method comprising: receiving a request to stop an internal combustion engine of a vehicle; commanding a pump to reduce pressure in an intake manifold of the internal combustion engine in dependence upon the request to stop the internal combustion engine.
11. A method as claimed in claim 10 additionally comprising measuring the speed of the internal combustion engine, measuring the intake manifold pressure and determining a target intake manifold pressure based on the speed of the internal combustion engine and the target manifold pressure prior to commanding the pump to reduce the intake manifold pressure.
12. A method as claimed in claim 11, further comprising commanding the pump to stop reducing the intake manifold pressure when the target intake manifold pressure has been reached.
13. A controller, configured to command a pump to reduce pressure in an intake manifold of an internal combustion of an engine of a vehicle in dependence upon a received request to stop the internal combustion engine.
14. A vehicle comprising the controller of claim 13.