Tamagoya — Japan
Three Toyota HiAce 3.0 delivery vans of the same model and nearly the same age improved by +13.4%, +19.1%, +20.5% — a median of +19.1%. The figure worth pausing on is not the result but the starting point: the three vans are recorded with baselines of 9.11, 4.40, 5.50 km/L. Three near-identical vehicles that consume at rates a factor of two apart are telling you something about the duty cycle, or about the baseline.
Same model, same engine, near-identical age — and one van recorded as using twice as much fuel per kilometre as another. The result is only as good as that starting figure.
| Operator | Tamagoya (株式会社玉子屋), Japan |
|---|---|
| Vehicles | 3 Toyota HiAce 3.0 L petrol vans, model years 2012 and 2013 |
| Method | Not recorded in the dataset |
| Measured quantity | Fuel efficiency, km per litre |
| Baselines | 9.11, 4.40, 5.50 km/L — for three vehicles of the same model |
| Result | Median +19.1%, range +13.4% to +20.5% |
| Control group | None |
Every measurement, not just the best one
| Vehicle | Before | After | Change |
|---|---|---|---|
| Toyota HiAce/3000CC/2013 | 9.11 | 10.33 | +13.4% |
| Toyota HiAce/3000CC/2102 | 4.40 | 5.24 | +19.1% |
| Toyota HiAce/3000CC/2012 | 5.50 | 6.63 | +20.5% |
| Median across all 3 measurements | +19.1% |
Method before result
No test method is recorded for this group. The entries contain a before figure, an after figure and the vehicle model, and nothing further.
The three vans are recorded at 9.11, 4.40, 5.50 km/L before treatment. For three vehicles of the same model and engine, a spread that wide has to come from somewhere — most plausibly from genuinely different duty (a van on short urban delivery rounds against one doing longer runs), or from baselines established in different ways or over different periods.
The percentages themselves are internally consistent — +13.4%, +19.1%, +20.5% — but each is measured against its own uncertain starting point, so the consistency does not add as much confidence as it first appears to.
Every percentage on this page was recalculated by us from the recorded before-and-after figures rather than taken from the summary column of the source; all of them reproduce the recorded value. That is a check on transcription, not on the measurement itself — it confirms the arithmetic is right, not that the reading was.
The limits of this trial
We publish these next to the result rather than in a footnote. If a limitation would change how you read the number, you should read it at the same time as the number.
Known limitations
- No test method is recorded, so this group cannot be weighted against the year-on-year or control-group datasets on this site.
- The baseline spread across three identical vehicles (4.40 to 9.11 km/L) is unexplained. If the baselines were established inconsistently, the percentages inherit that inconsistency.
- One record carries a model year of "2102", which we read as a typing error for 2012. It is a small thing, and it is the kind of small thing that indicates how carefully the row was transcribed.
- Three vehicles, one operator, no control group, no recorded period.
- This is a dataset entry, not a trial report. What we hold is the before-and-after fuel-efficiency figure per vehicle as recorded in the master test dataset — not the operator’s raw fuel logs, not the odometer readings behind them, and not a written test protocol.
- There is no control group. No comparable untreated vehicle was tracked over the same period, so seasonal, route and traffic effects cannot be separated from the treatment.
- The measurement dates and the length of each measurement period are not recorded in these entries. We therefore cannot say how far each vehicle ran between the two readings, or which months the comparison covers.
- The figures were recorded by the operator or by the local distributor, not by an independent party, and we cannot re-derive them from primary records.
Reading this evidence in context
Delivery vans on short urban rounds are a duty cycle where combustion efficiency plausibly matters — frequent starts, low speeds, long idling. This group is consistent with that, and does not demonstrate it.
We would summarise it as: three vans improved by +13.4% to +20.5% against baselines we cannot verify, with no method recorded. That is worth showing and not worth quoting.
If you run a van fleet, this is the shape of trial we would not repeat. A pilot with a defined baseline period and untreated control vehicles costs no more to run and produces a result you can defend.
Questions operators ask about this trial
Why do three identical vans have such different baselines?
Does the "2102" model year matter?
What is Tamagoya’s business?
Provenance
- Source
- Eco-Spray / NanoEFX master test dataset, compiled 22 March 2020 — operator-named section
- Recalculation
- All percentages recomputed from the recorded before-and-after figures
- Raw records
- Held by the operator or the local distributor — not in our possession
- Operator entry
- 株式会社玉子屋 — Tamagoya Co., Ltd.
- Method as recorded
- None — the method field is empty for all three entries
- Data note
- One entry records a model year of "2102", read as 2012
- Name release
- Operator naming approved by ECO EFX Solutions, 15 August 2026
- Last checked
- 15 August 2026
The only baseline that matters is yours
Every trial on this site was run on someone else’s vehicles, duty cycle and baseline. A NanoEFX pilot measures yours — and we will help you design it with a control group so the result stands up.