Military Review

Mobility at stake: the victory of the "hybrids" is still in doubt

Mobility at stake: the victory of the "hybrids" is still in doubt

BMP "Puma" of the German army needs a power unit, which could offer more power, located in a limited volume. The MTU 10V 890 meets this requirement, providing exceptional power density.

Excellent mobility in the most difficult conditions is the primary characteristic of all military vehicles. However, to achieve this for armored vehicles is much more difficult, but it is extremely important that they successfully carry out their tasks.

Mobility is very important for armored vehicles, but at the same time it competes with other important characteristics, such as, for example, ensuring the survivability of the vehicle and crew. And here this requirement can easily conflict with the requirement to preserve mobility. However, it is clear that the soldiers, whose safety depends on such machines, need increased off-road maneuverability, fast acceleration and higher speed, and all this without a negative impact on survivability. Such needs make it necessary to develop new power units and undercarriage systems in order to find optimal solutions that can meet these often contradictory requirements. However, in order to comply with them, a combination and balance of a number of design parameters is necessary. These include the characteristics of the suspension system, on which the quality of movement directly depends, the bearing surface of the tracks or wheels, which determines the ground pressure, the vehicle's ground clearance and engine output power. It is believed that the latter characteristic is the most important and most difficult to achieve. This is due to the fact that even in the issue of generating and distributing engine power, the designer needs to make compromises, sometimes even stepping on the throat of his own song. The increase in power in an armored vehicle is limited by factors such as the volume of the engine compartment, the need to maintain a power reserve, limitations on mass, and the need to meet the electricity needs of the onboard systems, such as communication equipment, navigation systems, sensors, and active and passive protection systems.

It is imperative that effective protection against current evolving threats is necessary, especially those that place the greatest demands on the power unit and the undercarriage of the machine. Protection almost inevitably means armor, and armor adds mass. There is a contradiction, which leads to uncomfortable compromises: as the level of threats increases, the level of protection also needs to be increased. Increasing the level of protection, as a rule, translates into a need for additional armor, and additional booking can increase the weight of the car. Saving or improving the performance of the armored vehicle inevitably entails an increase in engine power and efficiency of the transmission and actuators connected to it. However, the weight of the car is also determined by its size: the larger the car and the surface area that must be armored, the heavier it becomes. Thus, the new power unit (engine with transmission and drives) should not only be more powerful, but it should at least fit into the allotted volume or, preferably, have a smaller total volume. This criterion, above all, is absolute for power units designed to modernize existing armored vehicles, but also highly desirable for new platforms.

Armored cars, for example, this MBT Leopard 2A, have special requirements for the developers of engines and transmissions. They need more power to fit in as little as possible.

The generally accepted value of the level of mobility provided by an armored vehicle is the so-called power density or ratio of power (most often in horsepower) to vehicle mass. This ratio, although it does not take into account all the possible factors that determine mobility, is a suitable, albeit a rough criterion, and is useful both as a design parameter and as a tool for comparing different machines. As a rule, the greater the power density, for example, in hp per ton, the better the overall driving performance that the machine will show. Despite the fact that when evaluating a machine, its maximum speed is often taken into account, for a combat vehicle, the acceleration or acceleration of the engine (the ability to quickly and smoothly change from stable operation at minimum power to maximum power mode) may actually be much more important characteristic. Often overlooked in the vehicle’s characteristics is the ability to accelerate quickly and move quickly to a safe place in response to attacking actions is invaluable. It directly affects the survivability of the machine and its crew. Thus, the available power contributes not only to increased mobility, but also survivability, especially when used in combination with self-defense measures, including sensors for determining shot and laser irradiation, as well as passive and active countermeasures.

In the power unit for an armored vehicle, it is extremely important to achieve the required output power in the smallest amount. The key factor contributing to the increase in the mass of the machine is the surface area to be booked.

Power in small

Despite individual cases of the use of gas turbine engines, such as in the main combat family tanks (MBT) M1 Abrams manufactured by General Dynamics, the most popular engine for armored vehicles continues to be a diesel engine, or rather a multi-fuel diesel. One of the leaders in the production of power units is the German company MTU. Its integrated approach consists in the fact that the single “power unit” includes not only the engine, transmission and power drives, but also the subsystems for supplying and filtering air, cooling, generating electricity and others. Each of the components of the power unit is carefully designed and assembled in order to obtain the most compact and efficient solution. MTU recognizes that for the developer and integrator of military vehicles, the ratio of power to volume is a critical factor. Giovanni Spadaro, head of the state-owned enterprises department at MTU, explained that for them “the integration of all components into a single system is very important, we are constantly developing our philosophy of symbiotic development of all parts of the solution being developed. For us, this means that literally everything, architecture, concept, software and all parameters, is aimed at improving the characteristics of the final complete power unit. ” The impact of this approach on the final platform is huge, given the close cooperation with such major leading manufacturers of military vehicles as, for example, Krause-Mafei Wegmann (KMW), Nexter, BAE Systems and General Dynamics. The representative of General Dynamics Land Systems explained: “With regard to the power unit, more power - better, less size - better, cheaper - generally excellent, but with the mandatory increase in safety, reliability, noiselessness and serviceability."

MTU has demonstrated that the adaptation and modification for military purposes of commercial power units is suitable for light and medium armored vehicles, for example, the ARTEC Boxer four-axle combat armored vehicle, in which the MTU 8V199 TE20 diesel engine is installed. However, for heavier armored vehicles and tanks, their engines are needed, such as, for example, the 880 and 890 series engines, designed specifically for installation in heavy military platforms. The capabilities of modern power units are demonstrated in the Puma tracked infantry fighting vehicles. Spadaro said that “the MTU power unit for the Puma car includes a gearbox, a starter / generator and cooling and air cleaning systems. The MTU 10V 890 diesel engine is known for its very high power density and compact dimensions. Compared to other military engines of the same power class, mass and volume were reduced by about 60 percent. " The director of the special engines department at MTU commented that "This unit is more compact than any other previous power unit." The advantages of MTU engines are especially obvious when installing power units in previous-generation machines. Its engines from the EuroPowerPack model range are used by the French company GIAT (now Nexter) to replace the engines of Leclerc-EAU tanks for the United Arab Emirates. The engines of this family are also installed on the Challenger-2E MBT, while a significant amount was saved while simultaneously increasing the power reserve due to reduced fuel consumption.

Caterpillar, known for its heavy construction equipment, has become the main supplier of engines for tactical and armored vehicles. Its proposals for the military are based on ready-made commercial systems operating in many countries around the world. From here and considerable advantages - the decrease in cost connected with volumes of production, and availability of technical support. Nevertheless, the developments of the company are also known for military use, for example, the С9.3 engine with an increased power density of the HP 600. However, the real innovation is that the C9.3 is able to change its nominal power. In order to meet the strict European requirements for exhaust Euro-III, it switches to reduced mode to 525 HP. power. At Caterpillar, they note that “The advantage is that the user can choose the mode of operation. It is possible to achieve maximum performance during active operation in the field, but during training or when working in areas with civilians, you can switch to exhaust control. ” In fact, this “switch” is rooted in technology that Caterpillar has developed for commercial systems.

The company is invariably chosen for programs of replacement and modernization of existing fleets of armored vehicles. For example, its CV8 engine is currently mounted on the British Army's Warrior tracked infantry fighting vehicles. This work is carried out under a contract with Lockheed Martin to upgrade the machine to the WCSP standard (Warrior Capability Sustainment Program - the Warrior BMP capacity extension program), which will extend the operation of machines to 2040 of the year. Caterpillar is also changing the engine of armored vehicles of the American Army Stryker family with an HP 350 power. on the engine С9 power 450 hp The new engine "fits" in the volume, which occupied the previous engine. This replacement is carried out as part of General Dynamics’s proposal to introduce ESR-1 technical changes, which include an 910 ampere generator, suspension upgrades and other improvements.

Caterpillar "war-driven" engines are based on its special-engineered engines for heavy commercial vehicles. This provides benefits in terms of cost, logistics and availability. The С9 engine, part of the Stryker armored vehicle modernization program, is also widely used in construction vehicles.

Electric drives

Traditionally, power from the engine is transmitted to the wheels or tracks mechanically. Electric drives replace this physical connection with electric motors placed in driving wheels or sprockets. The energy for the operation of these electric motors can be taken from batteries, an internal combustion engine, or from both sources at once. In the “hybrid” approach, either a diesel or a gas turbine engine is used, which, being freed from mechanical connections, can now be installed anywhere in the chassis, which gives designers greater freedom in designing. It is also possible to install two engines, as implemented by the company BAE Systems in its mobile test installation HED (Hybrid Electric Drive). The representative of BAE Systems Deepak Bazaz noticed that two HED engines are connected to generators and batteries, which allows working in different modes: one engine runs in idle mode, saving fuel, two engines running when more power is needed, or a machine in silent mode It works only from batteries. The concept of HED is implemented on the tracked AMPV (Armored Multipurpose Vehicle) platform, but it is planned to be made scalable and used on any type of vehicle in mass, both wheeled and tracked. The experimental HED powerplant was modified by BAE Systems for the Northrop Grumman hybrid concept as part of its proposal for the ground combat vehicle of the American Army GCV (Ground Combat Vehicle).

The work of the NATO Technology Research Organization says: “The characteristics of hybrid electric vehicles regarding speed, acceleration, ability to climb and noiselessness exceed those of mechanically driven vehicles ... while fuel savings can range from 20 to 30 percent ". Electric motors also provide almost instant acceleration, good acceleration and better tractive effort. The latter is directly dependent on the improved torque, which is inherent in electric motors. For combat vehicles, this means several advantages: less reaction time when moving to the shelter, more difficult to get and better cross-country maneuverability. HED has two six-cylinder engines, a specially designed transmission from QinetiQ and lithium-ion batteries on 600 volts.

Another attractive aspect of an electric drive is its ability to generate more efficient and high levels of electrical energy. The power plant of the Northrop Grumman / BAE Systems GCV platform will be able to provide 1100 kilowatts, although it is significantly smaller and lighter than traditional power units. However, since energy storage is an important part of a hybrid electric drive, the mismatch of modern batteries becomes a serious problem. Therefore, currently several types of advanced batteries with higher energy density are considered for hybrid vehicles, including lithium-ion, nickel-metal hydride, nickel-sodium-chloride and lithium-polymer. However, all of them are still at the stage of technology development and have certain disadvantages that must be solved before they are considered suitable for use in military applications. Another area of ​​work that needs to be developed so that hybrid drives can be massively mounted on armored vehicles is the removal of the design limitations of modern traction motors. Although successfully integrated into HED demonstration experimental samples, these systems have limitations in size, mass, and cooling. Until these problems are solved, all electrical circuits, despite their advantages, will remain an illusion for armored vehicles.

However, many research organizations retain an interest in the concept of electric drive. For example, in accordance with the contracts of the DARPA Advanced Defense Research Department, QinetiQ will test its concept of hub electric motors (geared motors), setting them up for testing on experimental running models. Numerous gear reducers, differentials and actuators will replace powerful compact electric motors in the wheels of the car. It is possible that this concept can also be implemented on existing wheeled armored vehicles. In fact, in June 2017, the company BAE Systems signed an agreement with QinetiQ to introduce new electric drive technology in combat vehicles. A representative of the company BAE Systems said that this would allow "to offer customers a proven low-cost technology that will enhance the capabilities of current and future combat vehicles."

BAE Systems, in collaboration with QinetiQ, developed and manufactured a demonstration sample of a hybrid HED solution for armored vehicles based on AMPV chassis

Future power challenges

Over the past decade, the needs of military vehicles for electric power have increased several times. Marc Signorelli, head of combat vehicles at BAE Systems, remarked that “in the future, armored vehicles will find it increasingly difficult to meet electricity needs.” Attempts are being made to solve this escalating problem. For example, for machines of the M2 Bradley family, a generator for 300 amperes CE Niehof is considered, and for the new AMPV platform, two generators for 150 are amps. MTU Spadaro stated that “the key factors that influenced and influenced the development of higher power generation solutions are the ever-growing mass of MBT and wheeled vehicles (mainly as a consequence of the requirements for increasing protection levels) and at the same time the need for more electricity for airborne systems of any type, be it electronics, protection complexes and crew comfort, for example, an advanced air conditioning system. ” The company MTU believes that “they are solved by deeper integration of electrical components into the power unit. A good example here is again the above mentioned MTU power unit of the Puma armored vehicle, which includes a starter / generator with a rated power of 170 kW, supplying current to two cooling fans, as well as the refrigerant compressor of the air conditioning system. "

The power of armored vehicles directly affects the combat capabilities and survivability. The main criteria for survival on the battlefield are as follows: “take all measures not to be noticed, if seen, not to be hit, if they are still caught, not to be killed”. The first is promoted by the ability to move to where your opponent does not expect you. The second requires quick acceleration and good maneuverability to find cover and is complicated by the ability of the enemy shooter to effectively capture the target to defeat. And the third is determined by the ability to take appropriate passive protection and use passive and active countermeasures. However, each of these criteria may adversely affect the others. For example, additional armor increases mass and, as a result, mobility.

Progress in the field of power plants for armored vehicles, new engines, transmissions and power drives, innovative methods of integration and layout allow the developers of military equipment to satisfy the most ambitious wishes of customers. Many of the improvements that we see on military platforms are directly taken from commercial projects: engines and on-board computers, digital electronic control, automatic control of system status, electric drives and energy storage, and, finally, practical implementations of hybrid solutions. However, the challenges of this fragile equilibrium are forcing the industry to develop more and more innovative solutions.

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21 comment
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  1. kashcheevo egg
    kashcheevo egg April 9 2018 09: 50
    Well, the direction of movement is predetermined. Moving forward
  2. san4es
    san4es April 9 2018 09: 59
    hi Leopard 2A, have special requirements for the developers of engines and transmissions. They need a lot of power that fits into the smallest possible volume
    Pzh2000: 18.3 Liter - V8 - 1000HP
    Leopard 2: 47.6 Liter - V12 - 1500HP
    1. Conserp
      Conserp April 9 2018 17: 24
      This is a rare squalor with absolutely shameful figures of overall and specific power.

      Pathetic 1500 hp for an engine of this mass and size - nothing.
      1. san4es
        san4es April 9 2018 18: 15
        Quote: Conserp
        This is a rare squalor with absolutely shameful figures of overall and specific power ...

        belay ... sure?
        Pathetic 1500 hp for an engine of such mass and size - nothing

        ... But Germans do not rummage in diesels laughing
        The most important features of a modern diesel engine are high boost, intermediate cooling of the boost engine, regulation of the flow part of the turbocharger, etc.
        And today, the best diesel engines for tanks MT 883 Ka-500 (1100 kW), MT 883 Ka-501 (1325 kW), mass-produced by MTU, installed in the EUROPAC power unit (Euro Power Pack), have long surpassed the power characteristics in terms of specific characteristics block with the gas turbine engine of the M1 Abrams tank.Installing the Euro Power Pack in the M1 Abrams tank can shorten the tank by about 1000 mm.
        The flagship in the world tank diesel is the German company MTU. Her achievements are demonstrated by the publications:
        - “In the mid-1990s. General Dynamics Land Systems installed on its own initiative to participate in the tender for MBT for the Turkish army Euro Power Pack in the American tank M1A2 Abrams instead of the gas turbine AGT-1500, while the hull was shortened by 950 mm and the known high consumption was halved fuel ...
        ... Highly boosted version of the MT 883, developing a capacity of 2740 hp (2016 kW) was adopted for the Expeditionary Combat Vehicle (EFV), which is being developed for the US Marine Corps (USMC).
        In addition, the MT 883 was adopted for the latest version of Mark 4 (Mk 4. - Approx. Aut.) Israeli tank "Merkava", for which diesel is produced in the United States by General Dynamics (Detroit Diesel under license. - Approx. Aut.) as the GD 883. It is believed that the MT 883 will be selected for the new South Korean tank XK-2 "
        1. Conserp
          Conserp April 9 2018 22: 06
          Quote: san4es
          ... sure?

          When you finish school, they will tell you about arithmetic operations, about specific parameters, and so on - then you will understand what is at stake.

          Quote: san4es
          ... But Germans do not rummage in diesels

          You’re not fumbling in the engines here, only you personally.

          today the best diesel engines for tanks MT 883 Ka-500

          What is the relation of advertising mediocre MT 883 has to utter misery MB 873which was my comment about?

          Are you even confused about the numbers?
          1. Conserp
            Conserp April 10 2018 00: 38
            In order not to be unfounded.

            Mass and specific power:
            MB 873: 1500 hp 2200 kg = 0.68 hp / kg
            B-84: 840 hp 1020 kg = 0.82 hp / kg

            MB 873: 1801 x 1975 x 1030 mm = 3663.7 dm3
            B-84: 1480 x 896 x 902 mm = 1196.1 dm3

            Overall power:
            MB 873: 0.41 hp / dm3
            B-84: 0.70 hp / dm3

            In this way, the old Soviet V-84 is better than the vaunted German by 20% in specific power and by 70% in overall power
            1. san4es
              san4es April 10 2018 09: 59
              Quote: Conserp
              ... Mass and specific power:
              MB 873: 1500 hp 2200 kg = 0.68 hp / kg
              B-84: 840 hp 1020 kg = 0.82 hp / kg ....

              So it is necessary to write, instead of farting yesterday:
              Conserp (Conserp) Yesterday, 17:24 ↑
              This is a rare squalor with absolutely shameful numbers.
              In order not to be unfounded.

              When you finish school, they will tell you there ...

              ... Apparently, they didn’t tell you that you need to bring the facts before you pull them “all over the ocean”.
              1. Conserp
                Conserp April 10 2018 19: 01
                I wrote simply and clearly:
                "A miserable 1500 hp for an engine of this mass and size - nothing."

                You already didn’t have enough intelligence to understand this personally. But you didn’t even try to understand. Thinking with your head is harder than pulling obscene ads.

                If you don’t understand anything and don’t know anything, take a normal interest, they will explain to you.
            2. Conserp
              Conserp April 10 2018 10: 39
              But that's not all. Here are the dimensions we measure:

              And this is how honest Germans measure their dimensions (using MT 883 as an example):
  3. san4es
    san4es April 9 2018 10: 07
    It acts as a power plant - MTU MB 873 diesel engine with a capacity of 1100 kW. This is a four-stroke, 12-cylinder turbocharged, liquid-cooled engine with a capacity of 47,6 liters. The design provides for a multi-fuel installation with a flow rate of 300 liters per 100 km of highway and 500 liters when driving over rough terrain. Engine replacement can be done in the field in 15 minutes.
  4. iouris
    iouris April 9 2018 10: 33
    Even I did not understand your metric: "generator for 900 Amps", "battery for 600 Volts." I was taught in high school that power is measured in (kilo) watts, and capacity in ampere hours. Therefore, I can’t trust the author’s conclusions and cast doubt on them for now.
  5. voyaka uh
    voyaka uh April 9 2018 10: 57
    The advantage of electric motors is tempting: a multi-ton fighting vehicle will be able to tear
    like a ferrari.
    Now in the US they are launching the production of trucks (seven-trailers) on electricity.
    Directly from a traffic light, a loaded wagon "props" passenger cars, not a single meter behind.
    1. abc_alex
      abc_alex April 10 2018 01: 12
      And what's the point?
  6. Forever so
    Forever so April 9 2018 14: 42
    Everything is beautiful on paper, but what will happen to the electric motor if a small bullet with a caliber of 12.7 or a little more gets into the wheel ?? Electric motors are very afraid of sharp shocks, do not forget that between the armature rotor and stator there are tenths of a mm gap. Again, upon impact, permanent magnets are demagnetized or remagnetized. Although for the next drank dibs, this topic is bottomless.
    1. voyaka uh
      voyaka uh April 9 2018 18: 12
      We must think about the benefits.
      Imagine that each of the 6 rollers has an electromotor.
      12 pieces All bullets do not penetrate. And the car pulls on several.
      Again, wheel caps are booked.
      But the tank vomits from scratch at full speed, like racing. Noticed ATGM - a jerk back, miss.
      And no moving mechanics inside. The fighting compartment is increasing. More shells
      1. iouris
        iouris April 9 2018 20: 06
        The main thing is that such technologies are first developed by the Pentagon at the expense of the state budget, and only then they are introduced into production in the civilian sector.
        1. voyaka uh
          voyaka uh April 9 2018 22: 47
          Usually the opposite. Civil technology is ahead of the military, because it gives direct and quick profits.
      2. abc_alex
        abc_alex April 10 2018 01: 09
        ???? Are you seriously?
        Do you imagine what currents will be in the windings with such a “jerk-slip”? Maybe you forgot, but you already had the experience of creating a tank with electric transmission. Even during the Second World War. Remember how it ended? Yes, and the tank does not have time to jerk so as to get out of the aiming sector of the ATGM operator.
        1. voyaka uh
          voyaka uh April 10 2018 10: 34
          If the load is distributed to all 12 electric motors
          (and now the computer easily monitors this), then a small one.
          Watch the video how a loaded wagon weighing like a tank vomits.
          Motors do not burn.
          Experiments before the Second World War or the time of the industrial revolution are hardly relevant.

          "to exit the aiming sector of the ATGM operator." ////

          Will come out if you do not sleep. Even now, Russian tanks in Syria, with their primitive reverse, sometimes manage to, if not to yawn. And Merkava with her 5 speeds back in time.
          Moreover, the tank will have time on electric traction.
          1. abc_alex
            abc_alex April 15 2018 21: 48
            Israeli Merkava manages to get out of the ATGM when the ATGM operators are crooked. Once again I tell you, the Israeli experience is "hardly relevant", since in your case we are talking about a war with a technologically backward enemy, who practically has no normal military organization (the experience of Syria shows this absolutely categorically). Even the most advanced forward movement of the T-90 tank, not to mention the primitive forward movement of the Israeli Merkava, will not be able to leave the ATGM controlled by a normal operator. :)

            But seriously, for an attempt to evade the ATGM it is important not so much to "take off" as to detect the launch as early as possible. If the crew has 20-30 seconds and the tank has a system similar to the "Shtor", it will be able to evade the ATGM if not on a diesel engine, then on a gas turbine for sure.

            Are you going to carry out your 12 motors in skating rinks with 2-3 times the power reserve? It is at the start that the current in the motor windings can rush up in two or three relative to the nominal.

            And what kind of truck that "tears up loaded like a tank" are you talking about? Not about what Musk is showing? So this is just ridiculous. And who told you that a heavy truck weighs like a tank? As far as I know, the truck with the "Eurotruck" weighs extremely 40-44 tons. Compared to Merkava, it’s a passenger car, your well-done mass starts at 65-70 tons, and threatens to grow even more.

            In principle, in my opinion, hybrid power plants are promising. But certainly not as a means of "evading ATGMs."
    2. iouris
      iouris April 9 2018 20: 09
      The size of the gap is the result of engineering according to the principle: you win in strength - you lose in the distance ..
    3. The comment was deleted.
  7. Dedall
    Dedall April 9 2018 22: 32
    3/4 of the article floats in water. Some general words and wishes. The most informative photos seemed to me. They would also have mass-dimensional analysis, power analysis curves and layouts.