A visit to the Jaguar Land Rover engine manufacturing facility in the UK reveals what it takes to create a modern engine...
Everyone stops and stares at the expanded Jaguar Land Rover (JLR) Ingenium engine on display in the foyer of the engine manufacturing facility (known as the EMC) in Wolverhampton. We all know an engine consists of many parts, but to see it represented in this way shows how complex the technology is that we sometimes take for granted when we turn the ignition key. Internal-combustion engines (ICE) are not exactly the flavour of the month these days, with electric powertrains being punted as the alternative propulsion technology of the future. Perhaps the latter will be what powers all new cars by the middle of the century, but, until then, ICE will continue to play a prominent role. JLR’s recent £1-billion investment in EMC speaks louder than words. Read on to follow the process of creating an ICE.
1. Computer simulation
The basic ICE design is more than a 100 years old, yet engineers continue to find ways to improve the formula. They’re able to evaluate different engine designs by using powerful simulation software such as Ricardo’s WAVE package. This allows them to build a virtual engine (right) and specify key criteria like the number of cylinders, capacity, bore, stroke, compression ratio, turbocharging and so on. The software has building blocks – like the turbocharger, for example – that are compiled to complete the engine and each block can be optimised.
SIMULATION software: 1,4 L GTDi turbo @ 6 000 r/min
Building a virtual engine is a lengthy process that needs to include all the sensors and actuators, but it allows the engineers to predict performance and fuel economy long before a prototype engine is manufactured. With thousands of calculations taking place – especially in something like modelling gas dynamics in the combustion process – this software requires a high-specification computer processor to run the simulations. Once engineers know the predictive performance of a certain design, they can then alter some of the building blocks (ignition timing, manifold lengths, boost pressure, intercooler size, etc.) to see if they can improve the design. For the Ingenium engine family, a 500 cm3 capacity for each cylinder is an optimum value. It’s also one favoured by many other manufacturers, too, including Volvo and its Drive-E engine range. Once the model is signed off, it is time for prototype testing.
2. Validation testing
Prototype engines are produced in small numbers to validate the simulation concept before tooling is created for mass production. These engines represent “production intent”, meaning that they mirror the final unit. This is the last chance to make small changes, as it becomes increasingly expensive to introduce alterations once volume production takes place. Prototype engines will also spend numerous hours on an engine dynamometer before they are signed off and the nod is given for mass production.
The JLR engine plant is divided into three sections: machining; petrol assembly line; and diesel assembly line. The machining section is responsible for receiving the raw castings of the block, head and crank, and machining it to the precise components needed. Walking into the machining hall, you see few workers on the shop floor.
The machining lines are highly automated and robotised, with humans only supervising. The area is also spotlessly clean; far removed from a traditional engine plant. The following are main processes that impact the components.
The basic Ingenium aluminium block is identical for petrol and diesel engines. One of the first processes (of 23) is to laser-etch the engine number onto the block to give it an identity. A leak test on the bores is a crucial step to see if there is any porosity in the cylinder walls. The reason for this is, when the steel liners get press-fitted, the steel should touch the entire wall of the block casting. Otherwise, “hot spots” can form that are detrimental to longevity. In order to fit the steel liners, the blocks need to be heated to 200°C in an oven for half an hour to allow them to expand before the liners are pressed in. The block is then cooled to ensure tight-fitting liners. The block proceeds to a multitude of tools that machine the mating and bearing areas to a fine tolerance. All the work is monitored by precision measuring equipment and blocks with even slight defects discarded.
The heads follow a similar process, with machining taking place on the mating surfaces to fit valve seats and guides. It is interesting see how the machining lines are set up in a way that there is multiple redundancy (also applies to the block and crank); if one machine has a problem, the line can continue with identical machines in parallel (the production rate is somewhat reduced, though). Component buffers are strategically placed to store a set number of units and provide a delay time for the machines to be fixed before production volumes are impacted.
The crank is a critical component, with a tolerance band of 1-2 microns on the journals. From a rough casting state, the crank is first crudely balanced to mark the location holes on either end of the shaft. The journals are then hardened by heating them for about 10 seconds with a special fluid at 1 000 °C, before they are rapidly quenched with cold water. After all the machining has taken place and the balance-shaft gear fitted, it is time for the fine balancing exercise of the now shiny component.
In contrast to the automated machining facility, the assembly line is very much a hands-on process. The block is fitted to an engine carrier and forms the basis of the assembly during the ongoing process. Each carrier has a radio frequency (RFID) tag that stores the precise engine specification. This allows the assembly-line workers at each station to fit the correct parts to the engine. Most of the parts fitted come from suppliers and the engines take shape in the 17 zones on the assembly line. The wiring harness is one of the last items to be fitted to the engine and oil is added before it is ready for testing.
Will it run? This is the big question because there is no point in shipping an engine that does not start. In order to guarantee success, the following tests are conducted...
Every single engine is cold tested, and the term “cold” refers to the fact that the engine does not actually run. Diagnostic testing is used to assess all the sensors and actuators (each cycled where appropriate). Compression testing is carried out, as well as visual inspections. When an engine passes, JLR is confident it is ready to be installed into a vehicle.
This test determines simply whether the engine starts. There is no load on the powertrain, like during dynamo-meter testing. According to JLR, this was done on all engines when the plant was new, but as its confidence grew in the cold testing’s ability to catch all the problems, now only a few engines are hot-run tested each day. Some engines are still fully tested in the adjacent dyno facility, though, to validate certain performance criteria.
The end result is that engines are shipped to vehicle-assembly plants in Castle Bromwich, Halewood and Solihull, where they are fitted to Jaguar and Land Rover’s entire vehicle ranges, from the XE to the new Range Rover Velar. Spare a thought for the clever people building engines next time you fire up the powertrain of your vehicle and set off on a road-trip adventure or commute to work.
Author: Nicol Louw