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Additional details on Honda’s new 1.6L diesel

Honda’s 1.6L i-DTEC engine. Click to enlarge.

The new 1.6-liter i-DTEC diesel engine to be applied first in the Civic is the first engine from Honda’s Earth Dreams Technology series to be launched in Europe. This new engine offers 88 kW (120 PS, 118 hp) of power and 300 N·m (221 lb-ft) of torque at 2000 rpm with CO2 emissions of 94 g/km (equivalent to 65 mpg US, 3.6 l/100 km). (Earlier post.)

Reduced weight. Honda’s new 1.6-liter i-DTEC features an aluminium cylinder head joined to an open deck aluminium block. It is the lightest diesel engine in its class, weighing 47 kg (104 lbs) less than Honda’s 2.2-liter i-DTEC engine. All the individual components were redesigned to minimize their weight and size; advanced production techniques have helped reduce weight even further.

Cylinder and piston. Click to enlarge.

The thickness of the cylinder walls has been reduced to 8mm, compared with 9mm for the 2.2-liter i-DTEC—an achievement for a diesel engine. In addition, lighter pistons and connection rods have been utilized in the 1.6-liter i-DTEC.

Reduced mechanical friction. The key target for Honda’s development engineers was to reduce the mechanical friction of the 1.6-liter i-DTEC engine to the level equivalent of a gasoline engine. All the rotating parts were optimized to reduce their friction, notes Tetsuya Miyake, project leader for the engine. For example, a shorter and thinner piston skirt was used. At 1500 rpm, the 1.6-litre i-DTEC has around 40% less mechanical friction than the 2.2-liter i-DTEC.

Turbocharger. The 4th generation Garrett turbocharger used on the 1.6-liter i-DTEC engine features an efficient variable-nozzle design and its rotational speed is precisely controlled by the car’s electronics, minimizing turbo lag and providing a combination of low- to mid-range pull and high-speed performance. The turbo has a maximum boost pressure of 1.5bar.

Fuel injection system and air flow. Honda’s 1.6 i-DTEC uses a Bosch solenoid injection system which is capable of operating at 1800 bar. With a high fuel pressure, fuel is injected at a faster rate and the fuel spray is atomized more finely. This improves the fuel mixing with the air resulting in a cleaner and more efficient combustion helping to achieve the low emissions and fuel consumption.

High swirl head port inlet. Click to enlarge.

Honda’s engineers have also worked to improve the volumetric efficiency of the cylinders, employing a high intake flow and a high swirl head port precisely controlling the combustion process to reduce hot spots that create unwanted emissions. The engine air flow is managed by using an EGR (exhaust gas recirculation) system that operates at high and low pressure to reduce NOx emissions.

The new 1.6-liter i-DTEC engine was specifically designed for the European market, to meet growing customer demand for low emission diesel engines. The new engine will be built at Honda’s European manufacturing facility in Swindon, UK.

Demonstrating the importance of this new diesel engine to Honda’s sales plans in Europe, a new purpose built diesel engine production line has been installed at Honda of the UK Manufacturing (HUM). This new line is capable of producing up to 500 diesel engines in one day. The new line will produce both the new 1.6-liter i-DTEC and the existing 2.2-liter i-DTEC engines.

The 1.6-liter i-DTEC diesel engine will also be applied to the new CR-V (also built at HUM) later in 2013.



Should sell well in Europe where it (in the Civic) will give the Golf a run for its money.
2.2 litres is too large for mainstream diesel cars these days: 1.5-1.6 litres is more usual.

Nice to see more > 64mpg(US) cars being produced, even if the number is a bit aspirational.


The proof of the success of this new diesel will be durability and reliability. Previous attempts at lightweight diesels have not met expectations in this regard. Marginal strength from weight reduction has not previously shown able to contain diesel operating pressures. To my knowledge there are few full aluminum diesels for that very same reason.

Thomas Pedersen

These are my favorite kind of articles here on GCC - details about new efficient engines.

I know near-zero about chemistry, so most of the electrode/electrolyte/etc. articles might as well be written in Russian for all I care ;-)

Not that I don't like batteries. I hope they get cheaper and lighter fast, because hybrid cars need more powerful batteries to justify the added complexity and really take a load off the ICE. That way ICE power can drop below 100 hp without sacrificing 'driveability' and performance.

Meanwhile, engines such as this one will save a lot of fuel per kilometer driven. Please put it in a car without the horrible rear of the current Civic hatchback. The CR-V has no interest for me either for my personal taste.

I second mahonj's statement that 2.2 litres is too large for mainstream B-C class cars in Europe. And the Civic should be able to reach around 200 km/t with this gem of a diesel.


Too bad aluminum was not available before??? Otherwise,
the world could have had light weight diesel ICE many years ago.

Small, light weight diesel (660 cc to 750 cc) would be ideal for light weight PHEVs?

Less weight = less batteries = less initial cost = more mpg = less pollution etc.


The only problem with diesel engines has to do with emissions and in particular NOx. I am pleased for the holistic approach in terms of reducing weight and internal friction.

An engine that can be placed in a variety of platforms will eventually produce profits for the company and also help the end consumer to reduce its cost sheet during the useful life of the vehicle.


Let´s compare with some state-of-the art diesel engines. The topics I comment follow the same order as in the article. I will just separate my assessments in a couple of contributions, to make each one of them shorter.

State-of-the-art power for a 1.6-liter diesel engine is currently 130 PS. However, power density for 2-liter engines is much higher. Single-turbo engines achieve 184 PS (135 kW), implying that 147 PS would be possible if similar technology (see for example, the comment on fuel injection in a later comment) would be applied also on 1.6-liter engines. Why engine manufacturers do not utilize this opportunity for downsizing (they could replace a low-power 2-liter engine) seems somewhat puzzling to me. It might be a cost issue, i.e. if all your competitors save whatever they can on this size of engines, somehow, you must also follow a similar strategy. Alternatively, it is just a matter of time before this will happen. It did not happen with the Honda engine.


Reduced weight
It is possible to make a lightweight diesel engine without using aluminum. For example compacted graphite iron (CGI) can be cast in thin sections and save weight in comparison to grey cast iron, i.e. come very close to an al-engine. CGI also enables higher cylinder pressures and thus, higher power density and/or downsizing. However, some manufacturers consider CGI too expensive for a 4-cylinder engine. So far, CGI is mostly used for V6 and V8 engines and on heavy-duty engines, of course. Returning to aluminum, it has also been considered expensive for this class of engines. However, Honda is not the first one to use aluminum in diesel engines. BMW, for example, solely use aluminum since a couple of years in all their diesel engines. While BMW is a “premium” car manufacturer, we can also note that PSA (Peugeot/Citroën) have used aluminum for more than a decade in their engine families (1.4-2.2 liters) that have emerged from the co-operation with Ford (and other manufacturers). This is a 1.6-liter diesel engine with, to my knowledge, the highest production numbers in the world. It is also very light but since Honda did not provide any absolute numbers, we cannot compare. The PSA engine is also supposed to be cost-effective, so apparently, PSA has solved the cost issue. One often cited issue with aluminum engines is the low limit for maximum cylinder pressure and thus, performance and power density. This would apply to the PSA engine that has an output of 115 PS in the most powerful version. However, as noted above, the PSA basic design is now pretty old, so the progress by Honda (120 PS) seems negligible. Furthermore, other aluminum engines, such as the BMW, have much higher power density than the Honda engine. The cylinder pressure limit for the BMW engines has been 180/185 bar but was recently raised to 200 bar for the tri-turbo 3-liter 6-cylinder engine. Honda does not state the cylinder pressure but I doubt that it is much higher than 165 bar. Regarding durability with aluminum… well, I think it has been proven by so many other manufacturers that these pressure levels can quite easily be handled with aluminum. If they would aim for >200 bar, I would have some doubts. However, this does not imply that Honda might not have made some mistakes…


Reduced mechanical friction
First, it is a pity that Honda does not refer to if the reduction referred to is in absolute or relative numbers. This engine is 30% smaller than the 2.2-liter engine, so if the reduction would be in absolute numbers, it is not impressive at all. The measures mentioned (piston) is nothing new. If the reduction in friction refers to “friction mean effective pressure” (if someone need an explanation for this terminology, I can add that later), we can note that two engines with similar design but different size would have the same numerical value. If the reduction is 40% on this base, it is substantial. However, the comparison is made with a relatively old engine, so it might not be that impressive as at first glance. As common for most Japanese manufacturers, they do not give any absolute numbers, so we cannot really compare with any other engine.

Nothing new here.


Fuel injection
Bosch solenoid-actuated fuel injection with an injection pressure of 1800 bar is definitely mainstream, not state-of-the art. While top of the line FI with piezo actuators and 2200 bar would probably be too expensive for this engine, one could at least envision that 2000 bar could have been an ambition for those who want to be in the front line in the development. Engineers of course wish much more, i.e. in the range of 3000+ bar but we will have to wait many years before we see this in a passenger car engine. As a comment to HarveyD, this is the area where you should look if you want to track the progress for the last 15 years (CR started at 1350 bar, 15 years ago) and in the long-term future. Of course, it is not only about the pressure but I will skip all other parameters for a later contribution.

Air flow
It seems as Honda use both high and low-pressure EGR (high-pressure EGR is what all manufacturers used in the past). Well, this is the first area where we can say that there is a state-of-the-art level. Honda was not first, since the VW Group and BMW have used this technology for engines certified for USA during a couple of years. We also have examples from “non-premium” manufacturers, e.g. the new 1.6-liter Renault engine. With low-pressure EGE, Euro 6 can be met without any kind of NOx aftertreatment. This is definitely more cost-effective than a NOx catalyst. Again, Honda does not mention anything about the emission level. Surprising! If they would not meet Euro 6, they do not reach the state-of-the-art level regarding this parameter either.

Honda has made a nice little 1.6-liter engine that appears lightweight and compact. However, it reaches state-of-the-art level only in a few areas. In comparison with larger engines, it is lagging behind even more, albeit that such a comparison might be somewhat unfair. Similar conclusions could be drawn for the Honda 2.2-liter engine. However, it should be noted that this engine is much older than the new 1.6-liter engine.


Honda has a long history of using aluminium for engine blocks and the necessary know how and machinery but none for compacted graphite iron and the different machinery. I presume aluminium was chosen on cost as was the solenoid v. the more efficient piezo actuators for the fuel injection.

Autocar has additional info. on the engine re. the crankshaft that is not included on GCC write up which is unusual in that is normally 100%.

"Honda says the engine is the lightest in class and has internal friction levels comparable with the best petrol engine. It gets 1800 bar injection (on the lower side by the latest standards), uses a small single turbo and gets a catalyst and DPF filter.

It is built around a new aluminium block which uses an open deck block (where the cylinder is surrounded by a continuous water jacket) and it also gets a radically smaller and lighter crankshaft. Compared to the 15.9kg crankshaft in the 2.2-litre Honda diesel, the unit in the new engine weighs 10.1kg - a 36 per cent reduction. The pistons have shorter skirts and are said to be 10 per cent lighter than other best-in-class pistons, both of which should make the engine quick and smoother revving.

Having separate crankshaft bearing caps in the lower block (they are integrated in the 2.2-litre engine) has also massively reduced radiated noise, according to the engineers. They also claim that, at 1500rpm, the engine has 40 per cent lower internal friction than a typical rival diesel engine. Impressively, it does without a balancer shaft. The Civic diesel also gets a new, 7kg lighter, six-speed manual gearbox which sits in a stiffer casing. This, and the 47kg saved over the heavier 2.2-litre engine, takes a noticeable 54kg out of the car’s nose.


It is obvious that Honda is in for aluminum, regardless of if it is a diesel or a gasoline engine.

The additional information from Honda does not really contribute very much to an assessment of the progress. I would like to compare the weight with the PSA engine, where I have data. This engine is very light and I doubt that the Honda engine could be much more than just a few kg lighter. The comparison with the 2.2-liter engine is also irrelevant, unless the difference in size is taken into account. If we anticipate that the 1.6-liter engine weighs in the range of 120-130 kg, the 47 kg heavier engine would weigh ~40% more. However, this engine is also ~40% larger, so where is the progress? I am not so surprised to find that the crankshaft of the smaller engine is 36% lighter and the same could be said about many other data. With a very gentle approach, we could anticipate that Honda tries to explain the advantage of downsizing by implying that the smaller engine can provide similar power as the larger engine. However, even that is not fully true either, since the larger engine is more powerful. The remaining small advantage is that the new engine has somewhat higher power density (and cylinder pressure) than the older and larger engine but a comparison with, let´s say, a 2-liter engine might have been more appropriate. On the other hand, if you design a new engine, why would you not aim for higher power density?

I am not at all impressed with an engine that does not have a balance shaft. Most 4-cylinder engines below 2 liter capacity do not have a balance shaft. The cost is high, increased friction and the simple fact that the engine is smaller reduces vibration and customer acceptance for smaller engines might allow for a somewhat higher vibration level. Gasoline engines of this size usually do not have balance shafts either; for the same reasons.


We could have a look at the 2.2-liter engine as well (see link below). The latest version gives 150 PS (torque = 350 Nm). Recall, that I mentioned earlier that a state-of-the-art single-turbo 2-liter engine gives 184 PS. With the same power density, the 2.2 Honda engine should produce 202 PS. State-of-the-art for twin-turbo engines is 218 PS. At 150 PS, Honda plays in a very different league than the examples mentioned. The 1.6-liter engine might be a big leap for Honda but it is a very small step for mankind. If you wish, you could also look at my comments to the article about the 2.2-liter engine.


D Wrote:
"The proof of the success of this new diesel will be durability and reliability. Previous attempts at lightweight diesels have not met expectations in this regard. Marginal strength from weight reduction has not previously shown able to contain diesel operating pressures. To my knowledge there are few full aluminum diesels for that very same reason"

Yes, there are few aluminium turbodiesel in Europe, but one of them is maybe the most popular, the 1.6 (90-115 hp) jointly developed by PSA (Peugeot-Citroën) and Ford. It's used also by Mazda, Volvo and Mini. There is also, since 2002, the 1.4 (75-90 hp) by Toyota, used by Yaris, Auris (kind of European Corolla) and Mini (before the PSA-Ford). Then there is the 2.2 by Honda and another 2.2 by Toyota, plus a V6 by Peugeot and ALL range of Bmw made turbodiesel (from 2.0 to 4.2), some of them will be adopted by Toyota in the near future.
Besides that, in the Le mans Series Peugeot and Audi have clearly showed that an aluminium 600 hp turbodiesel could run 24 hours/5000 km in racing conditions (and win the race).
Widespread diffusion of aluminium diesels is probably limited by unit cost. And by the need for very good R&D, since, you're right, it's not that easy to get the standard target of at least 250,000 km (155,000 miles) trouble-free, target strictly required by automakers before launching a new engine in Europe. At least Toyota, Honda and Bmw-Mini don't give up on reliability.


Thanks for amending the list of al-block diesel, of which I already mentioned PSA and BMW. However, you also mentioned a V6 by Peugeot. This engine was actually developed by Ford within the framework of the PSA-Ford co-operation; not by PSA. In addition, this engine block is made of CGI, not aluminum. In contrast, the Renault-Nissan V6 diesel engine has a block of conventional cast iron. I could add the 5-cylinder Volvo engine and Mercedes V6 and (discontinued) V8 engines to the list. The current 4-cylinder Mercedes engines have cast iron blocks but a previous 1.7-liter engine for the A Class had an al-block. Also the now discontinued VW 3-cylinder 1.2-liter engine for Lupo and Audi A2 had al-block. There are probably a couple of other engines that I cannot recall for the moment. In summary, there is quite extensive and long experience from using aluminum in blocks for diesel engines.

According to my information, the 2.2-liter cast iron block Mercedes engine, at 200 bar, recently was alone on the top regarding the highest maximum cylinder pressure. However, now the new al-block BMW tri-turbo 6-cylinder engine has reached the same level. Perhaps some of the CGI 6-cylinder engines reach – or could reach – the same level but I have not seen any information that proves this. From heavy-duty engine experience we know that a CGI engine block can reach way over 200 bar; if it is necessary. However, we have two additional limiting factors, i.e. the pistons and the cylinder heads. Steel pistons could reach pressures far beyond 200 bar, perhaps ~250 bar. Al-heads with a “double-decker” design (one additional “roof”), such as in the Mercedes 2.2-liter engine, can reach 200 bar. Perhaps somewhat higher levels could be achieved with further development. When the first engine with steel pistons reaches the market, we will probably see pressure levels well above 200 bar. It remains to be seen if al-blocks and heads can be developed further to reach these levels or if the manufactures will change to CGI. We also know that inserts of CGI or ductile cast iron could extent the capability of al-blocks but this is more complex and it would increase the weight somewhat. Racing engines of course reach higher pressure levels but they have limited life expectations. Needless to mention, steel pistons are already used in racing engines.

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